Convert SatsPrice to a Skip multiplatform app

Sources/SatsPrice/Network/CoinbasePriceFetcher.swift

@@ -0,0 +1,52 @@
+// This is free software: you can redistribute and/or modify it
+// under the terms of the GNU General Public License 3.0
+// as published by the Free Software Foundation https://fsf.org
+//
+//  CoinbasePriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/19/24.
+//
+
+import Foundation
+
+private struct CoinbasePriceResponse: Codable {
+    let data: CoinbasePrice
+}
+
+private struct CoinbasePrice: Codable {
+    let amount: String
+    let base: String
+    let currency: String
+}
+
+class CoinbasePriceFetcher : PriceFetcher {
+    private static let urlString = "https://api.coinbase.com/v2/prices/BTC-USD/spot"
+    private static let btc = "BTC"
+    private static let usd = "USD"
+
+    func btcToUsd() async throws -> Decimal? {
+        do {
+            guard let urlComponents = URLComponents(string: CoinbasePriceFetcher.urlString), let url = urlComponents.url else {
+                return nil
+            }
+
+            let (data, _) = try await URLSession.shared.data(from: url, delegate: nil)
+
+            let coinbasePriceResponse = try JSONDecoder().decode(CoinbasePriceResponse.self, from: data)
+            let coinbasePrice = coinbasePriceResponse.data
+
+            guard coinbasePrice.base == CoinbasePriceFetcher.btc && coinbasePrice.currency == CoinbasePriceFetcher.usd else {
+                return nil
+            }
+
+            #if !SKIP
+            return Decimal(string: coinbasePrice.amount)
+            #else
+            return Decimal(coinbasePrice.amount)
+            #endif
+        } catch {
+            return nil
+        }
+    }
+}