Add fake price fetcher for debug mode

SatsPrice/ContentView.swift

@@ -12,15 +12,19 @@ import Combine
 struct ContentView: View {
     @ObservedObject private var satsViewModel = SatsViewModel()
 
-    @State private var priceSource: PriceSource = .coinbase
+    @State private var priceSource: PriceSource
 
-    private let dateFormatter = DateFormatter()
+    private let dateFormatter: DateFormatter
 
-    private let priceFetcherDelegator = PriceFetcherDelegator()
+    private let priceFetcherDelegator: PriceFetcherDelegator
 
-    init() {
+    init(_ priceSource: PriceSource) {
+        dateFormatter = DateFormatter()
         dateFormatter.dateStyle = .short
         dateFormatter.timeStyle = .short
+
+        self.priceSource = priceSource
+        priceFetcherDelegator = PriceFetcherDelegator(priceSource)
     }
 
     @MainActor
@@ -107,5 +111,5 @@ struct ContentView: View {
 }
 
 #Preview {
-    ContentView()
+    ContentView(.fake)
 }

SatsPrice/Network/FakePriceFetcher.swift

@@ -0,0 +1,18 @@
+//
+//  FakePriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/21/24.
+//
+
+#if DEBUG
+import Foundation
+import BigDecimal
+
+/// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
+class FakePriceFetcher: PriceFetcher {
+    func btcToUsd() async throws -> BigDecimal? {
+        BigDecimal(Double.random(in: 10000...100000))
+    }
+}
+#endif

SatsPrice/Network/PriceFetcherDelegator.swift

@@ -11,8 +11,15 @@ import BigDecimal
 class PriceFetcherDelegator: PriceFetcher {
     private let coinbasePriceFetcher = CoinbasePriceFetcher()
     private let coinGeckoPriceFetcher = CoinGeckoPriceFetcher()
+#if DEBUG
+    private let fakePriceFetcher = FakePriceFetcher()
+#endif
 
-    var priceSource: PriceSource = .coinbase
+    var priceSource: PriceSource
+
+    init(_ priceSource: PriceSource) {
+        self.priceSource = priceSource
+    }
 
     private var delegate: PriceFetcher {
         switch priceSource {
@@ -20,6 +27,10 @@ class PriceFetcherDelegator: PriceFetcher {
             coinbasePriceFetcher
         case .coingecko:
             coinGeckoPriceFetcher
+#if DEBUG
+        case .fake:
+            fakePriceFetcher
+#endif
         }
     }
 

SatsPrice/Network/PriceSource.swift

@@ -8,15 +8,32 @@
 import Foundation
 
 enum PriceSource: CaseIterable, CustomStringConvertible {
+    
+    static var allCases: [PriceSource] {
+#if DEBUG
+        [.coinbase, .coingecko, .fake]
+#else
+        [.coinbase, .coingecko]
+#endif
+    }
+
     case coinbase
     case coingecko
 
+#if DEBUG
+    case fake
+#endif
+
     var description: String {
         switch self {
         case .coinbase:
             "Coinbase"
         case .coingecko:
             "CoinGecko"
+#if DEBUG
+        case .fake:
+            "Fake"
+#endif
         }
     }
 }

SatsPrice/SatsPriceApp.swift

@@ -11,7 +11,7 @@ import SwiftUI
 struct SatsPriceApp: App {
     var body: some Scene {
         WindowGroup {
-            ContentView()
+            ContentView(.coinbase)
         }
     }
 }