Add support for manual price entry

SatsPrice/ContentView.swift

@@ -50,22 +50,21 @@ struct ContentView: View {
                         Text($0.description)
                     }
                 }
-                .onChange(of: priceSource) { newPriceSource in
-                    priceFetcherDelegator.priceSource = newPriceSource
-                    Task {
-                        await updatePrice()
-                    }
-                }
 
                 HStack {
                     TextField("", text: $satsViewModel.btcToUsdString)
-                        .disabled(true)
-                    Button(action: {
-                        Task {
-                            await updatePrice()
+                        .disabled(priceSource != .manual)
+#if os(iOS)
+                        .keyboardType(.decimalPad)
+#endif
+                    if priceSource != .manual {
+                        Button(action: {
+                            Task {
+                                await updatePrice()
+                            }
+                        }) {
+                            Image(systemName: "arrow.clockwise")
                         }
-                    }) {
-                        Image(systemName: "arrow.clockwise")
                     }
                 }
             } header: {
@@ -104,6 +103,12 @@ struct ContentView: View {
         .task {
             await updatePrice()
         }
+        .onChange(of: priceSource) { newPriceSource in
+            priceFetcherDelegator.priceSource = newPriceSource
+            Task {
+                await updatePrice()
+            }
+        }
 #if os(macOS)
         .formStyle(.grouped)
 #endif

SatsPrice/Network/ManualPriceFetcher.swift

@@ -0,0 +1,18 @@
+//
+//  ManualPriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 8/29/24.
+//
+
+import Foundation
+import BigDecimal
+
+/// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
+class ManualPriceFetcher: PriceFetcher {
+    var price: BigDecimal = 1
+
+    func btcToUsd() async throws -> BigDecimal? {
+        return price
+    }
+}

SatsPrice/Network/PriceFetcherDelegator.swift

@@ -11,6 +11,7 @@ import BigDecimal
 class PriceFetcherDelegator: PriceFetcher {
     private let coinbasePriceFetcher = CoinbasePriceFetcher()
     private let coinGeckoPriceFetcher = CoinGeckoPriceFetcher()
+    private let manualPriceFetcher = ManualPriceFetcher()
 #if DEBUG
     private let fakePriceFetcher = FakePriceFetcher()
 #endif
@@ -27,6 +28,8 @@ class PriceFetcherDelegator: PriceFetcher {
             coinbasePriceFetcher
         case .coingecko:
             coinGeckoPriceFetcher
+        case .manual:
+            manualPriceFetcher
 #if DEBUG
         case .fake:
             fakePriceFetcher

SatsPrice/Network/PriceSource.swift

@@ -11,14 +11,15 @@ enum PriceSource: CaseIterable, CustomStringConvertible {
     
     static var allCases: [PriceSource] {
 #if DEBUG
-        [.coinbase, .coingecko, .fake]
+        [.coinbase, .coingecko, .manual, .fake]
 #else
-        [.coinbase, .coingecko]
+        [.coinbase, .coingecko, .manual]
 #endif
     }
 
     case coinbase
     case coingecko
+    case manual
 
 #if DEBUG
     case fake
@@ -30,6 +31,8 @@ enum PriceSource: CaseIterable, CustomStringConvertible {
             "Coinbase"
         case .coingecko:
             "CoinGecko"
+        case .manual:
+            "Manual"
 #if DEBUG
         case .fake:
             "Fake"