Initial Commit

openspec/changes/enterprise-currency-providers/proposal.md

@@ -0,0 +1,128 @@
+# OpenSpec Change: enterprise-currency-providers
+
+- **Change ID**: enterprise-currency-providers
+- **Package**: `@suaveplan/currency-providers`
+- **Category**: finance
+- **Target path**: `finance/currency/currency-providers`
+- **Status**: PROPOSED
+- **Date**: 2026-04-24
+- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/currency-providers.md`
+
+---
+
+## Summary
+
+Deliver `@suaveplan/currency-providers` on the genesis branch from scratch at enterprise quality. The package implements concrete `CurrencyProvider` implementations (from `@suaveplan/currency`) for eight real exchange-rate APIs: three fiat providers (ECB XML feed, Open Exchange Rates, Fixer) and five crypto providers (CoinGecko, CoinMarketCap, Binance, Kraken, CryptoCompare), plus a `VirtualCurrencyProvider`. All HTTP calls go through a shared `fetch` wrapper with timeout, retry via `@suaveplan/retry`, rate-limit header parsing, and in-flight request coalescing. Typed error hierarchy (`AuthError`, `RateLimitError`, `NetworkError`, `ParseError`). Optional `RateLimitedProvider` decorator.
+
+---
+
+## Current-state audit (genesis)
+
+Does not exist on genesis — fresh build.
+
+---
+
+## Available workspace deps on genesis
+
+| Package | Role |
+|---|---|
+| `@suaveplan/error` (`workspace:^`) | Typed `CURRENCY_PROVIDER.*` error codes |
+| `@suaveplan/types` (`workspace:^`) | `LoggerLike` |
+| `@suaveplan/currency` (`workspace:^`) | `CurrencyProvider` interface |
+| `@suaveplan/retry` (`workspace:^`) | HTTP retry + backoff |
+| `@suaveplan/logger` (`workspace:^`) | Structured logs |
+| `zod` (`catalog:forms`) | Response parsing schemas |
+| `@opentelemetry/api` (`catalog:observability`) | Spans + counters + histograms |
+| `tslib` (`catalog:build`) | Runtime helpers |
+
+---
+
+## Public API surface
+
+```ts
+// Fiat providers
+class EcbProvider implements CurrencyProvider { ... }
+class FixerProvider implements CurrencyProvider { constructor(config: ApiKeyConfig) }
+class OpenExchangeRatesProvider implements CurrencyProvider { constructor(config: ApiKeyConfig) }
+
+// Crypto providers
+class BinanceProvider implements CurrencyProvider { ... }
+class CoinGeckoProvider implements CurrencyProvider { ... }
+class CoinMarketCapProvider implements CurrencyProvider { constructor(config: ApiKeyConfig) }
+class CryptoCompareProvider implements CurrencyProvider { ... }
+class KrakenProvider implements CurrencyProvider { ... }
+
+// Virtual
+class VirtualCurrencyProvider implements CurrencyProvider { ... }
+
+// Wrapper
+class RateLimitedProvider implements CurrencyProvider {
+  constructor(provider: CurrencyProvider, options: RateLimitOptions)
+}
+
+// Errors
+class ProviderError extends SuaveplanError { ... }
+class AuthError extends ProviderError { ... }
+class RateLimitError extends ProviderError { retryAfterMs?: number }
+class NetworkError extends ProviderError { ... }
+class ParseError extends ProviderError { ... }
+
+// HTTP utilities
+function createFetchWrapper(options: FetchWrapperOptions): FetchWrapper
+function coalesce<T>(key: string, fn: () => Promise<T>): Promise<T>
+```
+
+---
+
+## File layout
+
+```text
+finance/currency/currency-providers/
+  package.json
+  tsconfig.json
+  vitest.config.ts
+  src/
+    index.ts
+    error-codes.ts
+    types/
+      provider.types.ts
+      provider.types.md
+    http/
+      fetch-wrapper/
+        fetch-wrapper.ts
+        fetch-wrapper.md
+        fetch-wrapper.test.ts
+        index.ts
+      coalesce/
+        coalesce.ts
+        coalesce.md
+        coalesce.test.ts
+        index.ts
+    fiat/
+      ecb-provider/
+        ecb-provider.ts / .md / .test.ts / index.ts
+      fixer-provider/
+        fixer-provider.ts / .md / .test.ts / index.ts
+      open-exchange-rates-provider/
+        open-exchange-rates-provider.ts / .md / .test.ts / index.ts
+    crypto/
+      binance-provider/ ...
+      coingecko-provider/ ...
+      coinmarketcap-provider/ ...
+      cryptocompare-provider/ ...
+      kraken-provider/ ...
+    virtual/
+      virtual-currency-provider/ ...
+    wrappers/
+      rate-limited-provider/ ...
+  tests/
+    integration.test.ts
+```
+
+---
+
+## Impact
+
+Requires `@suaveplan/currency` to be published first (implements its `CurrencyProvider` interface). Downstream: `@suaveplan/currency` consumers via the fallback chain.
+
+**Prerequisites on Verdaccio**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/currency`, `@suaveplan/retry`, `@suaveplan/logger`.