feat: Add max negative caps and enforce ledger bounds

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">

platforms/eCurrency-api/src/controllers/CurrencyController.ts

@@ -15,7 +15,7 @@ export class CurrencyController {
  return res.status(401).json({ error: "Authentication required" });
  }
 
- const { name, description, groupId, allowNegative } = req.body;
+ const { name, description, groupId, allowNegative, maxNegativeBalance } = req.body;
 
  if (!name || !groupId) {
  return res.status(400).json({ error: "Name and groupId are required" });
@@ -26,6 +26,7 @@ export class CurrencyController {
  groupId,
  req.user.id,
  allowNegative || false,
+ maxNegativeBalance ?? null,
  description
  );
 
@@ -36,6 +37,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -58,6 +60,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -84,6 +87,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -105,6 +109,7 @@ export class CurrencyController {
  ename: currency.ename,
  groupId: currency.groupId,
  allowNegative: currency.allowNegative,
+ maxNegativeBalance: currency.maxNegativeBalance,
  createdBy: currency.createdBy,
  createdAt: currency.createdAt,
  updatedAt: currency.updatedAt,
@@ -144,5 +149,47 @@ export class CurrencyController {
  res.status(500).json({ error: "Internal server error" });
  }
  };
+
+ updateMaxNegativeBalance = async (req: Request, res: Response) => {
+ try {
+ if (!req.user) {
+ return res.status(401).json({ error: "Authentication required" });
+ }
+
+ const { id } = req.params;
+ const { value } = req.body;
+
+ // Allow null to clear; otherwise must be a number
+ const parsedValue = value === null || value === undefined ? null : Number(value);
+ if (parsedValue !== null && Number.isNaN(parsedValue)) {
+ return res.status(400).json({ error: "Invalid value for maxNegativeBalance" });
+ }
+
+ const updated = await this.currencyService.updateMaxNegativeBalance(
+ id,
+ parsedValue,
+ req.user.id
+ );
+
+ res.status(200).json({
+ id: updated.id,
+ name: updated.name,
+ description: updated.description,
+ ename: updated.ename,
+ groupId: updated.groupId,
+ allowNegative: updated.allowNegative,
+ maxNegativeBalance: updated.maxNegativeBalance,
+ createdBy: updated.createdBy,
+ createdAt: updated.createdAt,
+ updatedAt: updated.updatedAt,
+ });
+ } catch (error: any) {
+ console.error("Error updating max negative balance:", error);
+ if (error.message.includes("Only group admins") || error.message.includes("not found") || error.message.includes("Cannot set max negative") || error.message.includes("Max negative")) {
+ return res.status(400).json({ error: error.message });
+ }
+ res.status(500).json({ error: "Internal server error" });
+ }
+ };
 }
 

platforms/eCurrency-api/src/database/entities/Currency.ts

@@ -36,6 +36,9 @@ export class Currency {
  @Column({ default: false })
  allowNegative!: boolean;
 
+ @Column("decimal", { precision: 18, scale: 2, nullable: true })
+ maxNegativeBalance!: number | null;
+
  @Column()
  createdBy!: string;
 

platforms/eCurrency-api/src/database/migrations/1765784749012-migration.ts

@@ -0,0 +1,14 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Migration1765784749012 implements MigrationInterface {
+ name = 'Migration1765784749012'
+
+ public async up(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" ADD "maxNegativeBalance" numeric(18,2)`);
+ }
+
+ public async down(queryRunner: QueryRunner): Promise<void> {
+ await queryRunner.query(`ALTER TABLE "currencies" DROP COLUMN "maxNegativeBalance"`);
+ }
+
+}

platforms/eCurrency-api/src/index.ts

@@ -112,6 +112,7 @@ app.get("/api/currencies", currencyController.getAllCurrencies);
 app.get("/api/currencies/:id", currencyController.getCurrencyById);
 app.get("/api/currencies/group/:groupId", currencyController.getCurrenciesByGroup);
 app.post("/api/currencies/:id/mint", authGuard, currencyController.mintCurrency);
+app.patch("/api/currencies/:id/max-negative", authGuard, currencyController.updateMaxNegativeBalance);
 
 // Ledger routes
 app.get("/api/ledger/balance", authGuard, ledgerController.getBalance);

platforms/eCurrency-api/src/services/CurrencyService.ts

@@ -22,6 +22,7 @@ export class CurrencyService {
  groupId: string,
  createdBy: string,
  allowNegative: boolean = false,
+ maxNegativeBalance: number | null = null,
  description?: string
  ): Promise<Currency> {
  // Verify user is group admin
@@ -40,6 +41,7 @@ export class CurrencyService {
  groupId,
  createdBy,
  allowNegative,
+ maxNegativeBalance,
  });
 
  const savedCurrency = await this.currencyRepository.save(currency);
@@ -82,6 +84,38 @@ export class CurrencyService {
  });
  }
 
+ async updateMaxNegativeBalance(
+ currencyId: string,
+ value: number | null,
+ requestedBy: string
+ ): Promise<Currency> {
+ const currency = await this.getCurrencyById(currencyId);
+ if (!currency) {
+ throw new Error("Currency not found");
+ }
+
+ const isAdmin = await this.groupService.isGroupAdmin(currency.groupId, requestedBy);
+ if (!isAdmin) {
+ throw new Error("Only group admins can update max negative balance");
+ }
+
+ if (!currency.allowNegative) {
+ throw new Error("Cannot set max negative balance when negative balances are not allowed");
+ }
+
+ if (value !== null) {
+ if (Number.isNaN(value)) {
+ throw new Error("Invalid max negative balance value");
+ }
+ if (value > 0) {
+ throw new Error("Max negative balance must be zero or negative");
+ }
+ }
+
+ currency.maxNegativeBalance = value;
+ return await this.currencyRepository.save(currency);
+ }
+
  async mintCurrency(
  currencyId: string,
  amount: number,

platforms/eCurrency-api/src/services/LedgerService.ts

@@ -40,10 +40,13 @@ export class LedgerService {
  senderAccountId?: string,
  senderAccountType?: AccountType,
  receiverAccountId?: string,
- receiverAccountType?: AccountType
+ receiverAccountType?: AccountType,
+ existingBalance?: number
  ): Promise<Ledger> {
  // Get current balance
- const currentBalance = await this.getAccountBalance(currencyId, accountId, accountType);
+ const currentBalance = existingBalance !== undefined
+ ? existingBalance
+ : await this.getAccountBalance(currencyId, accountId, accountType);
 
  // Calculate new balance
  const newBalance = type === LedgerType.CREDIT 
@@ -90,11 +93,17 @@ export class LedgerService {
  throw new Error("Currency not found");
  }
 
- // Only check balance if negative balances are not allowed
- if (!currency.allowNegative) {
- const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
- if (currentBalance < amount) {
- throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ const currentBalance = await this.getAccountBalance(currencyId, fromAccountId, fromAccountType);
+
+ // Validate debit bounds
+ if (!currency.allowNegative && currentBalance < amount) {
+ throw new Error("Insufficient balance. This currency does not allow negative balances.");
+ }
+
+ if (currency.allowNegative && currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ const newBalance = currentBalance - amount;
+ if (newBalance < Number(currency.maxNegativeBalance)) {
+ throw new Error(`Insufficient balance. This currency allows negative balances down to ${currency.maxNegativeBalance}.`);
  }
  }
 
@@ -110,7 +119,8 @@ export class LedgerService {
  fromAccountId, // sender
  fromAccountType, // sender type
  toAccountId, // receiver
- toAccountType // receiver type
+ toAccountType, // receiver type
+ currentBalance
  );
 
  // Create credit entry (to receiver's account)

platforms/eCurrency/client/src/pages/currency-detail.tsx

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLocation, useRoute } from "wouter";
 import { apiClient } from "../lib/apiClient";
 import { useAuth } from "../hooks/useAuth";
@@ -15,12 +15,17 @@ export default function CurrencyDetail() {
  const [, params] = useRoute("/currency/:currencyId");
  const [, setLocation] = useLocation();
  const { user } = useAuth();
+ const queryClient = useQueryClient();
  const [transferOpen, setTransferOpen] = useState(false);
  const [mintOpen, setMintOpen] = useState(false);
  const [selectedTransactionId, setSelectedTransactionId] = useState<string | null>(null);
  const [transactionOffset, setTransactionOffset] = useState(0);
  const [allTransactions, setAllTransactions] = useState<any[]>([]);
  const PAGE_SIZE = 10;
+ const MAX_NEGATIVE_SLIDER = 1_000_000;
+ const [maxNegativeInput, setMaxNegativeInput] = useState<string>("");
+ const [maxNegativeSaving, setMaxNegativeSaving] = useState(false);
+ const [maxNegativeError, setMaxNegativeError] = useState<string | null>(null);
 
  // Load account context from localStorage
  const [accountContext, setAccountContext] = useState<{ type: "user" | "group"; id: string } | null>(() => {
@@ -48,6 +53,16 @@ export default function CurrencyDetail() {
  enabled: !!currencyId,
  });
 
+ useEffect(() => {
+ if (currency) {
+ if (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined) {
+ setMaxNegativeInput(Math.abs(Number(currency.maxNegativeBalance)).toString());
+ } else {
+ setMaxNegativeInput("");
+ }
+ }
+ }, [currency]);
+
  const { data: accountDetails } = useQuery({
  queryKey: ["accountDetails", currencyId, accountContext],
  queryFn: async () => {
@@ -177,6 +192,40 @@ export default function CurrencyDetail() {
 
  const isAdminOfCurrency = currency && groups?.some((g: any) => g.id === currency.groupId && g.isAdmin);
 
+ const saveMaxNegative = async () => {
+ if (!currencyId) return;
+ setMaxNegativeError(null);
+ setMaxNegativeSaving(true);
+ try {
+ const trimmed = maxNegativeInput.trim();
+ const isClearing = trimmed === "";
+ let payloadValue: number | null = null;
+
+ if (!isClearing) {
+ const magnitude = parseFloat(trimmed);
+ if (Number.isNaN(magnitude) || magnitude < 0) {
+ setMaxNegativeError("Enter a valid non-negative number.");
+ setMaxNegativeSaving(false);
+ return;
+ }
+ // Store as negative (or zero)
+ payloadValue = magnitude === 0 ? 0 : -Math.abs(magnitude);
+ }
+
+ await apiClient.patch(`/api/currencies/${currencyId}/max-negative`, {
+ value: payloadValue,
+ });
+
+ await queryClient.invalidateQueries({ queryKey: ["currency", currencyId] });
+ await queryClient.invalidateQueries({ queryKey: ["accountDetails", currencyId, accountContext] });
+ } catch (error: any) {
+ const message = error?.response?.data?.error || error?.message || "Failed to update max negative balance";
+ setMaxNegativeError(message);
+ } finally {
+ setMaxNegativeSaving(false);
+ }
+ };
+
  if (!currencyId) {
  return <div>Currency not found</div>;
  }
@@ -240,6 +289,16 @@ export default function CurrencyDetail() {
  {currency.allowNegative ? "Yes" : "No"}
  </p>
  </div>
+ <div>
+ <h3 className="text-sm font-medium text-muted-foreground mb-1">Max Negative Balance</h3>
+ <p className="text-lg font-medium">
+ {currency.allowNegative
+ ? (currency.maxNegativeBalance !== null && currency.maxNegativeBalance !== undefined
+ ? Number(currency.maxNegativeBalance).toLocaleString()
+ : "No cap")
+ : "Not applicable"}
+ </p>
+ </div>
  <div>
  <h3 className="text-sm font-medium text-muted-foreground mb-1">Total Currency Supply</h3>
  <p className="text-lg font-semibold">
@@ -257,6 +316,66 @@ export default function CurrencyDetail() {
  </div>
  )}
 
+ {/* Max Negative Control - only for admins when negatives are allowed */}
+ {currency && currency.allowNegative && isAdminOfCurrency && accountContext?.type === "group" && accountContext.id === currency.groupId && (
+ <div className="bg-white border rounded-lg p-6 mb-6">
+ <h3 className="text-lg font-semibold mb-2">Set max negative balance</h3>
+ <p className="text-sm text-muted-foreground mb-4">
+ Limit how far any account can go negative for this currency. Leave blank for no cap.
+ </p>
+ <div className="space-y-4">
+ <input
+ type="range"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput === "" ? 0 : Math.min(MAX_NEGATIVE_SLIDER, Math.max(0, Number(maxNegativeInput) || 0))}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ className="w-full"
+ />
+ <div className="flex flex-col gap-3 md:flex-row md:items-center">
+ <div className="flex-1">
+ <label className="block text-sm font-medium mb-1">Max negative (absolute value)</label>
+ <input
+ type="number"
+ min={0}
+ max={MAX_NEGATIVE_SLIDER}
+ step={0.01}
+ value={maxNegativeInput}
+ onChange={(e) => setMaxNegativeInput(e.target.value)}
+ placeholder="Leave blank for no cap"
+ className="w-full px-4 py-2 border rounded-lg"
+ />
+ <div className="text-xs text-muted-foreground mt-1">
+ Saved as negative value: {maxNegativeInput === "" ? "No cap" : `-${Math.abs(Number(maxNegativeInput) || 0).toLocaleString()}`}
+ </div>
+ </div>
+ <div className="flex gap-2">
+ <button
+ onClick={saveMaxNegative}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 bg-primary text-primary-foreground rounded-lg hover:opacity-90 disabled:opacity-50"
+ >
+ {maxNegativeSaving ? "Saving..." : "Save"}
+ </button>
+ <button
+ onClick={() => setMaxNegativeInput("")}
+ disabled={maxNegativeSaving}
+ className="px-4 py-2 border rounded-lg hover:bg-gray-50 disabled:opacity-50"
+ >
+ Clear cap
+ </button>
+ </div>
+ </div>
+ {maxNegativeError && (
+ <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-2 rounded-lg">
+ {maxNegativeError}
+ </div>
+ )}
+ </div>
+ </div>
+ )}
+
  {/* Transactions */}
  <div className="mb-6">
  <div className="flex justify-between items-center mb-4">