Add PriceFetcher API to fetch prices of multiple currencies

Sources/SatsPrice/Network/CoinGeckoPriceFetcher.swift

@@ -23,6 +23,11 @@ class CoinGeckoPriceFetcher : PriceFetcher {
         "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=\(currency.identifier.lowercased())&precision=18"
     }
 
+    func urlString(toCurrencies currencies: [Locale.Currency]) -> String {
+        let currenciesString = currencies.map { $0.identifier.lowercased() }.joined(separator: ",")
+        return "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=\(currenciesString)&precision=18"
+    }
+
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal? {
         do {
             guard let urlComponents = URLComponents(string: urlString(toCurrency: currency)), let url = urlComponents.url else {
@@ -45,4 +50,43 @@ class CoinGeckoPriceFetcher : PriceFetcher {
             return nil
         }
     }
+
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency : Decimal] {
+        do {
+            guard !currencies.isEmpty else {
+                return [:]
+            }
+
+            if currencies.count == 1, let currency = currencies.first {
+                guard let price = try await convertBTC(toCurrency: currency) else {
+                    return [:]
+                }
+
+                return [currency: price]
+            }
+
+            guard let urlComponents = URLComponents(string: urlString(toCurrencies: currencies)), let url = urlComponents.url else {
+                return [:]
+            }
+
+            let (data, _) = try await URLSession.shared.data(from: url, delegate: nil)
+
+            let priceResponse = try JSONDecoder().decode(CoinGeckoPriceResponse.self, from: data)
+
+            var results: [Locale.Currency : Decimal] = [:]
+            for currency in currencies {
+                if let price = priceResponse.bitcoin[currency.identifier] {
+#if !SKIP
+                    results[currency] = price
+#else
+                    results[currency] = Decimal(price)
+#endif
+                }
+            }
+
+            return results
+        } catch {
+            return [:]
+        }
+    }
 }

Sources/SatsPrice/Network/CoinbasePriceFetcher.swift

@@ -20,11 +20,22 @@ private struct CoinbasePrice: Codable {
     let currency: String
 }
 
+private struct CoinbaseExchangeRatesResponse: Codable {
+    let data: CoinbaseExchangeRatesResponseData
+}
+
+private struct CoinbaseExchangeRatesResponseData: Codable {
+    let currency: String
+    let rates: [String: String]
+}
+
 class CoinbasePriceFetcher : PriceFetcher {
     func urlString(toCurrency currency: Locale.Currency) -> String {
         "https://api.coinbase.com/v2/prices/BTC-\(currency.identifier)/spot"
     }
 
+    private static let urlStringForAllCurrencies: String = "https://api.coinbase.com/v2/exchange-rates?currency=BTC"
+
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal? {
         do {
             guard let urlComponents = URLComponents(string: urlString(toCurrency: currency)), let url = urlComponents.url else {
@@ -49,4 +60,48 @@ class CoinbasePriceFetcher : PriceFetcher {
             return nil
         }
     }
+
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency : Decimal] {
+        do {
+            guard !currencies.isEmpty else {
+                return [:]
+            }
+
+            if currencies.count == 1, let currency = currencies.first {
+                guard let price = try await convertBTC(toCurrency: currency) else {
+                    return [:]
+                }
+
+                return [currency: price]
+            }
+
+            guard let urlComponents = URLComponents(string: CoinbasePriceFetcher.urlStringForAllCurrencies), let url = urlComponents.url else {
+                return [:]
+            }
+
+            let (data, _) = try await URLSession.shared.data(from: url, delegate: nil)
+
+            let coinbaseExchangeRatesResponse = try JSONDecoder().decode(CoinbaseExchangeRatesResponse.self, from: data)
+            let rates = coinbaseExchangeRatesResponse.data.rates
+
+            guard coinbaseExchangeRatesResponse.data.currency == "BTC" else {
+                return [:]
+            }
+
+            var results: [Locale.Currency : Decimal] = [:]
+            for currency in currencies {
+                if let price = rates[currency.identifier] {
+#if !SKIP
+                    results[currency] = Decimal(string: price)
+#else
+                    results[currency] = Decimal(price)
+#endif
+                }
+            }
+
+            return results
+        } catch {
+            return [:]
+        }
+    }
 }

Sources/SatsPrice/Network/FakePriceFetcher.swift

@@ -14,6 +14,19 @@ import Foundation
 /// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
 class FakePriceFetcher: PriceFetcher {
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal? {
+        randomPrice()
+    }
+
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency : Decimal] {
+        guard !currencies.isEmpty else {
+            return [:]
+        }
+
+        let prices = currencies.map { _ in randomPrice() }
+        return Dictionary(uniqueKeysWithValues: zip(currencies, prices))
+    }
+
+    private func randomPrice() -> Decimal {
         Decimal(Double.random(in: 10000...100000))
     }
 }

Sources/SatsPrice/Network/ManualPriceFetcher.swift

@@ -12,9 +12,19 @@ import Foundation
 
 /// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
 class ManualPriceFetcher: PriceFetcher {
-    var price: Decimal = Decimal(1)
+    var prices: [Locale.Currency: Decimal] = [:]
 
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal? {
-        return price
+        prices[currency]
+    }
+
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency : Decimal] {
+        guard !currencies.isEmpty else {
+            return [:]
+        }
+
+        let filteredCurrencies = currencies.filter { prices.keys.contains($0) }
+        let priceValues = filteredCurrencies.map { prices[$0, default: Decimal(0)] }
+        return Dictionary(uniqueKeysWithValues: zip(filteredCurrencies, priceValues))
     }
 }

Sources/SatsPrice/Network/PriceFetcher.swift

@@ -12,4 +12,5 @@ import Foundation
 
 protocol PriceFetcher {
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal?
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency: Decimal]
 }

Sources/SatsPrice/Network/PriceFetcherDelegator.swift

@@ -42,4 +42,8 @@ class PriceFetcherDelegator: PriceFetcher {
     func convertBTC(toCurrency currency: Locale.Currency) async throws -> Decimal? {
         return try await delegate.convertBTC(toCurrency: currency)
     }
+
+    func convertBTC(toCurrencies currencies: [Locale.Currency]) async throws -> [Locale.Currency : Decimal] {
+        return try await delegate.convertBTC(toCurrencies: currencies)
+    }
 }