Convert SatsPrice to a Skip multiplatform app

Sources/SatsPrice/Network/CoinGeckoPriceFetcher.swift

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+// 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
+//
+//  CoinGeckoPriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/19/24.
+//
+
+import Foundation
+
+private struct CoinGeckoPriceResponse: Codable {
+    let bitcoin: CoinGeckoPrice
+}
+
+private struct CoinGeckoPrice: Codable {
+#if !SKIP
+    let usd: Decimal
+#else
+    let usd: String
+#endif
+}
+
+class CoinGeckoPriceFetcher : PriceFetcher {
+    private static let urlString = "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd&precision=18"
+
+    func btcToUsd() async throws -> Decimal? {
+        do {
+            guard let urlComponents = URLComponents(string: CoinGeckoPriceFetcher.urlString), let url = urlComponents.url else {
+                return nil
+            }
+
+            let (data, _) = try await URLSession.shared.data(from: url, delegate: nil)
+
+            let priceResponse = try JSONDecoder().decode(CoinGeckoPriceResponse.self, from: data)
+            let price = priceResponse.bitcoin
+
+#if !SKIP
+            return price.usd
+#else
+            return Decimal(price.usd)
+#endif
+        } catch {
+            return nil
+        }
+    }
+}

Sources/SatsPrice/Network/CoinbasePriceFetcher.swift

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+// 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
+        }
+    }
+}

Sources/SatsPrice/Network/FakePriceFetcher.swift

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+// 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
+//
+//  FakePriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/21/24.
+//
+
+#if DEBUG
+import Foundation
+
+/// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
+class FakePriceFetcher: PriceFetcher {
+    func btcToUsd() async throws -> Decimal? {
+        Decimal(Double.random(in: 10000...100000))
+    }
+}
+#endif

Sources/SatsPrice/Network/ManualPriceFetcher.swift

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+// 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
+//
+//  ManualPriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 8/29/24.
+//
+
+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)
+
+    func btcToUsd() async throws -> Decimal? {
+        return price
+    }
+}

Sources/SatsPrice/Network/PriceFetcher.swift

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+// 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
+//
+//  PriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/19/24.
+//
+
+import Foundation
+
+protocol PriceFetcher {
+    func btcToUsd() async throws -> Decimal?
+}

Sources/SatsPrice/Network/PriceFetcherDelegator.swift

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+// 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
+//
+//  PriceFetcherDelegator.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/20/24.
+//
+
+import Foundation
+
+class PriceFetcherDelegator: PriceFetcher {
+    private let coinbasePriceFetcher = CoinbasePriceFetcher()
+    private let coinGeckoPriceFetcher = CoinGeckoPriceFetcher()
+    private let manualPriceFetcher = ManualPriceFetcher()
+#if DEBUG
+    private let fakePriceFetcher = FakePriceFetcher()
+#endif
+
+    var priceSource: PriceSource
+
+    init(_ priceSource: PriceSource) {
+        self.priceSource = priceSource
+    }
+
+    private var delegate: PriceFetcher {
+        switch priceSource {
+        case .coinbase:
+            coinbasePriceFetcher
+        case .coingecko:
+            coinGeckoPriceFetcher
+        case .manual:
+            manualPriceFetcher
+#if DEBUG
+        case .fake:
+            fakePriceFetcher
+#endif
+        }
+    }
+
+    func btcToUsd() async throws -> Decimal? {
+        return try await delegate.btcToUsd()
+    }
+}

Sources/SatsPrice/Network/PriceSource.swift

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+// 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
+//
+//  PriceSource.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/20/24.
+//
+
+import Foundation
+
+enum PriceSource: CaseIterable, CustomStringConvertible {
+    
+    static var allCases: [PriceSource] {
+#if DEBUG
+        [.coinbase, .coingecko, .manual, .fake]
+#else
+        [.coinbase, .coingecko, .manual]
+#endif
+    }
+
+    case coinbase
+    case coingecko
+    case manual
+
+#if DEBUG
+    case fake
+#endif
+
+    var description: String {
+        switch self {
+        case .coinbase:
+            "Coinbase"
+        case .coingecko:
+            "CoinGecko"
+        case .manual:
+            "Manual"
+#if DEBUG
+        case .fake:
+            "Fake"
+#endif
+        }
+    }
+}