wallet-core: return currency specification from exchange

6 files changed, 203 insertions, 45 deletions

diff --git a/packages/taler-util/src/taler-types.ts b/packages/taler-util/src/taler-types.ts
index 66f98ea9a..ac42ca278 100644
--- a/packages/taler-util/src/taler-types.ts
+++ b/packages/taler-util/src/taler-types.ts
@@ -723,6 +723,8 @@ export class ExchangeKeysJson {
 
   currency: string;
 
+  currency_specification?: CurrencySpecification;
+
   /**
    * The exchange's master public key.
    */
@@ -1504,6 +1506,7 @@ export const codecForExchangeKeysJson = (): Codec<ExchangeKeysJson> =>
   buildCodecForObject<ExchangeKeysJson>()
     .property("base_url", codecForString())
     .property("currency", codecForString())
+    .property("currency_specification", codecOptional(codecForCurrencySpecificiation()))
     .property("master_public_key", codecForString())
     .property("auditors", codecForList(codecForAuditor()))
     .property("list_issue_date", codecForTimestamp)
diff --git a/packages/taler-util/src/taleruri.ts b/packages/taler-util/src/taleruri.ts
index b22dc3c59..d3186d2f5 100644
--- a/packages/taler-util/src/taleruri.ts
+++ b/packages/taler-util/src/taleruri.ts
@@ -29,6 +29,7 @@ import { opFixedSuccess, opKnownTalerFailure } from "./operation.js";
 import { TalerErrorCode } from "./taler-error-codes.js";
 import { AmountString } from "./taler-types.js";
 import { URL, URLSearchParams } from "./url.js";
+
 /**
  * A parsed taler URI.
  */
diff --git a/packages/taler-util/src/wallet-types.ts b/packages/taler-util/src/wallet-types.ts
index 2c92d9295..42c0148e7 100644
--- a/packages/taler-util/src/wallet-types.ts
+++ b/packages/taler-util/src/wallet-types.ts
@@ -558,11 +558,13 @@ export enum ScopeType {
 }
 
 export type ScopeInfoGlobal = { type: ScopeType.Global; currency: string };
+
 export type ScopeInfoExchange = {
   type: ScopeType.Exchange;
   currency: string;
   url: string;
 };
+
 export type ScopeInfoAuditor = {
   type: ScopeType.Auditor;
   currency: string;
@@ -571,6 +573,22 @@ export type ScopeInfoAuditor = {
 
 export type ScopeInfo = ScopeInfoGlobal | ScopeInfoExchange | ScopeInfoAuditor;
 
+/**
+ * Encode scope info as a string.
+ *
+ * Format must be stable as it's used in the database.
+ */
+export function stringifyScopeInfo(si: ScopeInfo): string {
+  switch (si.type) {
+    case ScopeType.Global:
+      return `taler-si:global/${si.currency}}`;
+    case ScopeType.Auditor:
+      return `taler-si:auditor/${si.currency}/${encodeURIComponent(si.url)}`;
+    case ScopeType.Exchange:
+      return `taler-si:exchange/${si.currency}/${encodeURIComponent(si.url)}`;
+  }
+}
+
 export interface BalancesResponse {
   balances: WalletBalance[];
 }
diff --git a/packages/taler-wallet-core/src/db.ts b/packages/taler-wallet-core/src/db.ts
index d28566910..336ffab67 100644
--- a/packages/taler-wallet-core/src/db.ts
+++ b/packages/taler-wallet-core/src/db.ts
@@ -40,6 +40,7 @@ import {
   CoinPublicKeyString,
   CoinRefreshRequest,
   CoinStatus,
+  CurrencySpecification,
   DenomLossEventType,
   DenomSelectionState,
   DenominationInfo,
@@ -51,6 +52,7 @@ import {
   HashCodeString,
   Logger,
   RefreshReason,
+  ScopeInfo,
   TalerErrorDetail,
   TalerPreciseTimestamp,
   TalerProtocolDuration,
@@ -61,6 +63,7 @@ import {
   WireInfo,
   WithdrawalExchangeAccountDetails,
   codecForAny,
+  stringifyScopeInfo,
 } from "@gnu-taler/taler-util";
 import { DbRetryInfo, TaskIdentifiers } from "./common.js";
 import {
@@ -2370,6 +2373,23 @@ export interface DenomLossEventRecord {
   exchangeBaseUrl: string;
 }
 
+export interface CurrencyInfoRecord {
+  /**
+   * Stringified scope info.
+   */
+  scopeInfoStr: string;
+
+  /**
+   * Currency specification.
+   */
+  currencySpec: CurrencySpecification;
+
+  /**
+   * How did the currency info get set?
+   */
+  source: "exchange" | "user" | "preset";
+}
+
 /**
  * Schema definition for the IndexedDB
  * wallet database.
@@ -2404,6 +2424,11 @@ export const WalletStoresV1 = {
       }),
     },
   }),
+  currencyInfo: describeStoreV2({
+    recordCodec: passthroughCodec<CurrencyInfoRecord>(),
+    storeName: "currencyInfo",
+    keyPath: "scopeInfoStr",
+  }),
   globalCurrencyAuditors: describeStoreV2({
     recordCodec: passthroughCodec<GlobalCurrencyAuditorRecord>(),
     storeName: "globalCurrencyAuditors",
@@ -3362,3 +3387,75 @@ export async function deleteTalerDatabase(
     req.onsuccess = () => resolve();
   });
 }
+
+/**
+ * High-level helpers to access the database.
+ * Eventually all access to the database should
+ * go through helpers in this namespace.
+ */
+export namespace WalletDbHelpers {
+  export interface GetCurrencyInfoDbResult {
+    /**
+     * Currency specification.
+     */
+    currencySpec: CurrencySpecification;
+
+    /**
+     * How did the currency info get set?
+     */
+    source: "exchange" | "user" | "preset";
+  }
+
+  export interface StoreCurrencyInfoDbRequest {
+    scopeInfo: ScopeInfo;
+    currencySpec: CurrencySpecification;
+    source: "exchange" | "user" | "preset";
+  }
+
+  export async function getCurrencyInfo(
+    tx: WalletDbReadOnlyTransaction<["currencyInfo"]>,
+    scopeInfo: ScopeInfo,
+  ): Promise<GetCurrencyInfoDbResult | undefined> {
+    const s = stringifyScopeInfo(scopeInfo);
+    const res = await tx.currencyInfo.get(s);
+    if (!res) {
+      return undefined;
+    }
+    return {
+      currencySpec: res.currencySpec,
+      source: res.source,
+    };
+  }
+
+  /**
+   * Store currency info for a scope.
+   *
+   * Overrides existing currency infos.
+   */
+  export async function upsertCurrencyInfo(
+    tx: WalletDbReadWriteTransaction<["currencyInfo"]>,
+    req: StoreCurrencyInfoDbRequest,
+  ): Promise<void> {
+    await tx.currencyInfo.put({
+      scopeInfoStr: stringifyScopeInfo(req.scopeInfo),
+      currencySpec: req.currencySpec,
+      source: req.source,
+    });
+  }
+
+  export async function insertCurrencyInfoUnlessExists(
+    tx: WalletDbReadWriteTransaction<["currencyInfo"]>,
+    req: StoreCurrencyInfoDbRequest,
+  ): Promise<void> {
+    const scopeInfoStr = stringifyScopeInfo(req.scopeInfo);
+    const oldRec = await tx.currencyInfo.get(scopeInfoStr);
+    if (oldRec) {
+      return;
+    }
+    await tx.currencyInfo.put({
+      scopeInfoStr: stringifyScopeInfo(req.scopeInfo),
+      currencySpec: req.currencySpec,
+      source: req.source,
+    });
+  }
+}
diff --git a/packages/taler-wallet-core/src/exchanges.ts b/packages/taler-wallet-core/src/exchanges.ts
index 8fa439715..ab3f95214 100644
--- a/packages/taler-wallet-core/src/exchanges.ts
+++ b/packages/taler-wallet-core/src/exchanges.ts
@@ -31,6 +31,7 @@ import {
   CancellationToken,
   CoinRefreshRequest,
   CoinStatus,
+  CurrencySpecification,
   DeleteExchangeRequest,
   DenomKeyType,
   DenomLossEventType,
@@ -124,6 +125,7 @@ import {
   ExchangeEntryDbRecordStatus,
   ExchangeEntryDbUpdateStatus,
   ExchangeEntryRecord,
+  WalletDbHelpers,
   WalletDbReadOnlyTransaction,
   WalletDbReadWriteTransaction,
   WalletStoresV1,
@@ -710,6 +712,7 @@ export interface ExchangeKeysDownloadResult {
   globalFees: GlobalFees[];
   accounts: ExchangeWireAccount[];
   wireFees: { [methodName: string]: WireFeesJson[] };
+  currencySpecification?: CurrencySpecification;
 }
 
 /**
@@ -872,6 +875,7 @@ async function downloadExchangeKeysInfo(
     globalFees: exchangeKeysJsonUnchecked.global_fees,
     accounts: exchangeKeysJsonUnchecked.accounts,
     wireFees: exchangeKeysJsonUnchecked.wire_fees,
+    currencySpecification: exchangeKeysJsonUnchecked.currency_specification,
   };
 }
 
@@ -1470,6 +1474,7 @@ export async function updateExchangeFromUrlHandler(
         "recoupGroups",
         "coinAvailability",
         "denomLossEvents",
+        "currencyInfo",
       ],
     },
     async (tx) => {
@@ -1575,6 +1580,19 @@ export async function updateExchangeFromUrlHandler(
       r.updateStatus = ExchangeEntryDbUpdateStatus.Ready;
       r.cachebreakNextUpdate = false;
       await tx.exchanges.put(r);
+
+      if (keysInfo.currencySpecification) {
+        await WalletDbHelpers.insertCurrencyInfoUnlessExists(tx, {
+          currencySpec: keysInfo.currencySpecification,
+          scopeInfo: {
+            type: ScopeType.Exchange,
+            currency: newDetails.currency,
+            url: exchangeBaseUrl,
+          },
+          source: "exchange",
+        });
+      }
+
       const drRowId = await tx.exchangeDetails.put(newDetails);
       checkDbInvariant(
         typeof drRowId.key === "number",
diff --git a/packages/taler-wallet-core/src/wallet.ts b/packages/taler-wallet-core/src/wallet.ts
index 4e5fdab71..b6167be12 100644
--- a/packages/taler-wallet-core/src/wallet.ts
+++ b/packages/taler-wallet-core/src/wallet.ts
@@ -38,6 +38,7 @@ import {
   DenominationInfo,
   Duration,
   ExchangesShortListResponse,
+  GetCurrencySpecificationRequest,
   GetCurrencySpecificationResponse,
   InitResponse,
   KnownBankAccounts,
@@ -191,6 +192,7 @@ import {
   CoinSourceType,
   ConfigRecordKey,
   DenominationRecord,
+  WalletDbHelpers,
   WalletDbReadOnlyTransaction,
   WalletStoresV1,
   clearDatabase,
@@ -758,7 +760,7 @@ async function dispatchRequestInternal(
         await fillDefaults(wex);
       }
       const resp: InitResponse = {
-        versionInfo: getVersion(wex),
+        versionInfo: handleGetVersion(wex),
       };
 
       if (req.config?.lazyTaskLoop) {
@@ -777,7 +779,7 @@ async function dispatchRequestInternal(
         exchangeBaseUrl: "https://exchange.test.taler.net/",
       });
       return {
-        versionInfo: getVersion(wex),
+        versionInfo: handleGetVersion(wex),
       };
     }
     case WalletApiOperation.WithdrawTestBalance: {
@@ -1197,48 +1199,8 @@ async function dispatchRequestInternal(
       return {};
     }
     case WalletApiOperation.GetCurrencySpecification: {
-      // Ignore result, just validate in this mock implementation
       const req = codecForGetCurrencyInfoRequest().decode(payload);
-      // Hard-coded mock for KUDOS and TESTKUDOS
-      if (req.scope.currency === "KUDOS") {
-        const kudosResp: GetCurrencySpecificationResponse = {
-          currencySpecification: {
-            name: "Kudos (Taler Demonstrator)",
-            num_fractional_input_digits: 2,
-            num_fractional_normal_digits: 2,
-            num_fractional_trailing_zero_digits: 2,
-            alt_unit_names: {
-              "0": "ク",
-            },
-          },
-        };
-        return kudosResp;
-      } else if (req.scope.currency === "TESTKUDOS") {
-        const testkudosResp: GetCurrencySpecificationResponse = {
-          currencySpecification: {
-            name: "Test (Taler Unstable Demonstrator)",
-            num_fractional_input_digits: 0,
-            num_fractional_normal_digits: 0,
-            num_fractional_trailing_zero_digits: 0,
-            alt_unit_names: {
-              "0": "テ",
-            },
-          },
-        };
-        return testkudosResp;
-      }
-      const defaultResp: GetCurrencySpecificationResponse = {
-        currencySpecification: {
-          name: req.scope.currency,
-          num_fractional_input_digits: 2,
-          num_fractional_normal_digits: 2,
-          num_fractional_trailing_zero_digits: 2,
-          alt_unit_names: {
-            "0": req.scope.currency,
-          },
-        },
-      };
-      return defaultResp;
+      return handleGetCurrencySpecification(wex, req);
     }
     case WalletApiOperation.ImportBackupRecovery: {
       const req = codecForAny().decode(payload);
@@ -1554,7 +1516,7 @@ async function dispatchRequestInternal(
       return {};
     }
     case WalletApiOperation.GetVersion: {
-      return getVersion(wex);
+      return handleGetVersion(wex);
     }
     case WalletApiOperation.TestingWaitTransactionsFinal:
       return await waitUntilAllTransactionsFinal(wex);
@@ -1626,7 +1588,66 @@ async function dispatchRequestInternal(
   );
 }
 
-export function getVersion(wex: WalletExecutionContext): WalletCoreVersion {
+export async function handleGetCurrencySpecification(
+  wex: WalletExecutionContext,
+  req: GetCurrencySpecificationRequest,
+): Promise<GetCurrencySpecificationResponse> {
+  const spec = await wex.db.runReadOnlyTx(
+    {
+      storeNames: ["currencyInfo"],
+    },
+    async (tx) => {
+      return WalletDbHelpers.getCurrencyInfo(tx, req.scope);
+    },
+  );
+  if (spec) {
+    return {
+      currencySpecification: spec.currencySpec,
+    };
+  }
+  // Hard-coded mock for KUDOS and TESTKUDOS
+  if (req.scope.currency === "KUDOS") {
+    const kudosResp: GetCurrencySpecificationResponse = {
+      currencySpecification: {
+        name: "Kudos (Taler Demonstrator)",
+        num_fractional_input_digits: 2,
+        num_fractional_normal_digits: 2,
+        num_fractional_trailing_zero_digits: 2,
+        alt_unit_names: {
+          "0": "ク",
+        },
+      },
+    };
+    return kudosResp;
+  } else if (req.scope.currency === "TESTKUDOS") {
+    const testkudosResp: GetCurrencySpecificationResponse = {
+      currencySpecification: {
+        name: "Test (Taler Unstable Demonstrator)",
+        num_fractional_input_digits: 0,
+        num_fractional_normal_digits: 0,
+        num_fractional_trailing_zero_digits: 0,
+        alt_unit_names: {
+          "0": "テ",
+        },
+      },
+    };
+    return testkudosResp;
+  }
+  const defaultResp: GetCurrencySpecificationResponse = {
+    currencySpecification: {
+      name: req.scope.currency,
+      num_fractional_input_digits: 2,
+      num_fractional_normal_digits: 2,
+      num_fractional_trailing_zero_digits: 2,
+      alt_unit_names: {
+        "0": req.scope.currency,
+      },
+    },
+  };
+  return defaultResp;
+}
+
+function handleGetVersion(wex: WalletExecutionContext): WalletCoreVersion {
   const result: WalletCoreVersion = {
     implementationSemver: walletCoreBuildInfo.implementationSemver,
     implementationGitHash: walletCoreBuildInfo.implementationGitHash,