1 files changed, 105 insertions, 0 deletions
diff --git a/packages/demobank-ui/src/hooks/circuit.ts b/packages/demobank-ui/src/hooks/circuit.ts
index 137a7aee2..f90469e24 100644
--- a/packages/demobank-ui/src/hooks/circuit.ts
+++ b/packages/demobank-ui/src/hooks/circuit.ts
@@ -32,6 +32,7 @@ import {
 
 // FIX default import https://github.com/microsoft/TypeScript/issues/49189
 import _useSWR, { SWRHook } from "swr";
+import { AmountJson, Amounts } from "@gnu-taler/taler-util";
 const useSWR = _useSWR as unknown as SWRHook;
 
 export function useAdminAccountAPI(): AdminAccountAPI {
@@ -218,6 +219,23 @@ async function getBusinessStatus(
 ): Promise<boolean> {
   try {
     const url = getInitialBackendBaseURL();
+    const result = await request<SandboxBackend.Circuit.CircuitAccountData>(
+      url,
+      `circuit-api/accounts/${basicAuth.username}`,
+      { basicAuth },
+    );
+    return result.ok;
+  } catch (error) {
+    return false;
+  }
+}
+
+async function getEstimationByCredit(
+  request: ReturnType<typeof useApiContext>["request"],
+  basicAuth: { username: string; password: string },
+): Promise<boolean> {
+  try {
+    const url = getInitialBackendBaseURL();
     const result = await request<
       HttpResponseOk<SandboxBackend.Circuit.CircuitAccountData>
     >(url, `circuit-api/accounts/${basicAuth.username}`, { basicAuth });
@@ -227,6 +245,93 @@ async function getBusinessStatus(
   }
 }
 
+export type TransferCalculation = {
+  debit: AmountJson;
+  credit: AmountJson;
+  beforeFee: AmountJson;
+};
+type EstimatorFunction = (
+  amount: AmountJson,
+  sellFee: AmountJson,
+  sellRate: number,
+) => Promise<TransferCalculation>;
+
+type CashoutEstimators = {
+  estimateByCredit: EstimatorFunction;
+  estimateByDebit: EstimatorFunction;
+};
+
+export function useEstimator(): CashoutEstimators {
+  const { state } = useBackendContext();
+  const { request } = useApiContext();
+  const basicAuth =
+    state.status === "loggedOut"
+      ? undefined
+      : { username: state.username, password: state.password };
+  return {
+    estimateByCredit: async (amount, fee, rate) => {
+      const zeroBalance = Amounts.zeroOfCurrency(fee.currency);
+      const zeroFiat = Amounts.zeroOfCurrency(fee.currency);
+      const zeroCalc = {
+        debit: zeroBalance,
+        credit: zeroFiat,
+        beforeFee: zeroBalance,
+      };
+      const url = getInitialBackendBaseURL();
+      const result = await request<SandboxBackend.Circuit.CashoutEstimate>(
+        url,
+        `circuit-api/cashouts/estimates`,
+        {
+          basicAuth,
+          params: {
+            amount_credit: Amounts.stringify(amount),
+          },
+        },
+      );
+      // const credit = Amounts.parseOrThrow(result.data.data.amount_credit);
+      const credit = amount;
+      const _credit = { ...credit, currency: fee.currency };
+      const beforeFee = Amounts.sub(_credit, fee).amount;
+
+      const debit = Amounts.parseOrThrow(result.data.amount_debit);
+      return {
+        debit,
+        beforeFee,
+        credit,
+      };
+    },
+    estimateByDebit: async (amount, fee, rate) => {
+      const zeroBalance = Amounts.zeroOfCurrency(fee.currency);
+      const zeroFiat = Amounts.zeroOfCurrency(fee.currency);
+      const zeroCalc = {
+        debit: zeroBalance,
+        credit: zeroFiat,
+        beforeFee: zeroBalance,
+      };
+      const url = getInitialBackendBaseURL();
+      const result = await request<SandboxBackend.Circuit.CashoutEstimate>(
+        url,
+        `circuit-api/cashouts/estimates`,
+        {
+          basicAuth,
+          params: {
+            amount_debit: Amounts.stringify(amount),
+          },
+        },
+      );
+      const credit = Amounts.parseOrThrow(result.data.amount_credit);
+      const _credit = { ...credit, currency: fee.currency };
+      const debit = amount;
+      const beforeFee = Amounts.sub(_credit, fee).amount;
+      return {
+        debit,
+        beforeFee,
+        credit,
+      };
+    },
+  };
+}
+
 export function useBusinessAccountFlag(): boolean | undefined {
   const [isBusiness, setIsBusiness] = useState<boolean | undefined>();
   const { state } = useBackendContext();