Use explicit currency for locked prices

prisma/migrations/5_remove_country_currency_policy/migration.sql

@@ -0,0 +1,2 @@
+-- DropTable
+DROP TABLE "exchange_pricing_currency_policies";

prisma/schema.prisma

@@ -99,12 +99,3 @@ model CurrencyRate {
   @@index([quoteCurrency])
   @@map("exchange_currency_rates")
 }
-
-model PricingCurrencyPolicy {
-  countryCode  String   @id @map("country_code") @db.VarChar(2)
-  currencyCode String   @map("currency_code") @db.VarChar(3)
-  updatedAt    DateTime @updatedAt @map("updated_at")
-
-  @@index([currencyCode])
-  @@map("exchange_pricing_currency_policies")
-}

src/m2m-schema.ts

@@ -10,6 +10,7 @@ import { prisma } from './db.js'
 type LockCurrencyPriceInput = {
   sourceAmount: number
   sourceCurrency: string
+  clientCurrency: string
   pricingCountryCode: string
   rateDate?: string | null
 }
@@ -18,6 +19,7 @@ export const m2mTypeDefs = `#graphql
   input LockCurrencyPriceInput {
     sourceAmount: Float!
     sourceCurrency: String!
+    clientCurrency: String!
     pricingCountryCode: String!
     rateDate: String
   }
@@ -37,13 +39,8 @@ export const m2mTypeDefs = `#graphql
     pricingCountryCode: String!
   }
 
-  type PricingCurrencyPolicy {
-    countryCode: String!
-    currencyCode: String!
-  }
-
   type Query {
-    pricingCurrencyForCountry(countryCode: String!): PricingCurrencyPolicy
+    health: String!
   }
 
   type Mutation {
@@ -70,18 +67,6 @@ function historicalDate(value: string): Date {
   return result
 }
 
-async function pricingCurrencyForCountryValue(rawCountryCode: unknown) {
-  const normalizedCountryCode = countryCode(rawCountryCode)
-  const policy = await prisma.pricingCurrencyPolicy.findUnique({
-    where: { countryCode: normalizedCountryCode },
-  })
-  if (policy === null) return null
-  return {
-    countryCode: policy.countryCode,
-    currencyCode: policy.currencyCode,
-  }
-}
-
 async function lockCurrencyPrice(
   _: unknown,
   args: { input: LockCurrencyPriceInput },
@@ -92,13 +77,8 @@ async function lockCurrencyPrice(
     throw new GraphQLError('sourceAmount must be a non-negative finite number')
   }
   const sourceCurrency = currencyCode(args.input.sourceCurrency)
-  const policy = await pricingCurrencyForCountryValue(args.input.pricingCountryCode)
-  if (policy === null) {
-    throw new GraphQLError(
-      `Pricing currency policy is missing for country ${countryCode(args.input.pricingCountryCode)}`,
-    )
-  }
-  const clientCurrency = currencyCode(policy.currencyCode)
+  const clientCurrency = currencyCode(args.input.clientCurrency)
+  const pricingCountryCode = countryCode(args.input.pricingCountryCode)
   if (sourceCurrency === clientCurrency) {
     const effectiveDate = args.input.rateDate
       ? historicalDate(args.input.rateDate)
@@ -115,7 +95,7 @@ async function lockCurrencyPrice(
       rateLockedAt: lockedAt.toISOString(),
       provider: 'identity',
       attributionUrl: null,
-      pricingCountryCode: policy.countryCode,
+      pricingCountryCode,
     }
   }
   const snapshot = args.input.rateDate
@@ -134,16 +114,13 @@ async function lockCurrencyPrice(
     rateLockedAt: lockedAt.toISOString(),
     provider: snapshot.provider,
     attributionUrl: snapshot.attributionUrl,
-    pricingCountryCode: policy.countryCode,
+    pricingCountryCode,
   }
 }
 
 export const m2mResolvers = {
   Query: {
-    pricingCurrencyForCountry: (
-      _: unknown,
-      args: { countryCode: string },
-    ) => pricingCurrencyForCountryValue(args.countryCode),
+    health: () => 'ok',
   },
   Mutation: {
     lockCurrencyPrice,