Add settings for prompt to code provider

Author: intitni

Copilot for Xcode/SettingsView.swift

@@ -22,6 +22,8 @@ struct SettingsView: View {
         var disableSuggestionFeatureGlobally: Bool
         @AppStorage(\.suggestionFeatureEnabledProjectList)
         var suggestionFeatureEnabledProjectList: [String]
+        @AppStorage(\.promptToCodeFeatureProvider)
+        var promptToCodeFeatureProvider: PromptToCodeFeatureProvider
         init() {}
     }
 
@@ -134,6 +136,19 @@ struct SettingsView: View {
                     Text("Use accessibility API to accept suggestion in widget")
                 }
                 .toggleStyle(.switch)
+                
+                Picker(selection: $settings.promptToCodeFeatureProvider) {
+                    ForEach(PromptToCodeFeatureProvider.allCases, id: \.rawValue) {
+                        switch $0 {
+                        case .openAI:
+                            Text("OpenAI").tag($0)
+                        case .githubCopilot:
+                            Text("GitHub Copilot (Less Accurate)").tag($0)
+                        }
+                    }
+                } label: {
+                    Text("Prompt to code with")
+                }
             }
         }.buttonStyle(.copilot)
     }

Core/Sources/Preferences/Keys.swift

@@ -151,6 +151,15 @@ public struct UserDefaultPreferenceKeys {
     public var suggestionFeatureEnabledProjectList: SuggestionFeatureEnabledProjectList {
         .init()
     }
+    
+    public struct PromptToCodeFeatureProviderKey: UserDefaultPreferenceKey {
+        public let defaultValue: PromptToCodeFeatureProvider = .openAI
+        public let key = "PromptToCodeFeatureProvider"
+    }
+    
+    public var promptToCodeFeatureProvider: PromptToCodeFeatureProviderKey {
+        .init()
+    }
 
     public var disableLazyVStack: FeatureFlags.DisableLazyVStack { .init() }
     public var preCacheOnFileOpen: FeatureFlags.PreCacheOnFileOpen { .init() }

Core/Sources/Preferences/PromptToCodeFeatureProvider.swift

@@ -0,0 +1,6 @@
+import Foundation
+
+public enum PromptToCodeFeatureProvider: Int, CaseIterable {
+    case openAI
+    case githubCopilot
+}

Core/Sources/PromptToCodeService/PromptToCodeService.swift

@@ -6,7 +6,16 @@ import OpenAIService
 public final class PromptToCodeService: ObservableObject {
     var designatedPromptToCodeAPI: PromptToCodeAPI?
     var promptToCodeAPI: PromptToCodeAPI {
-        designatedPromptToCodeAPI ?? OpenAIPromptToCodeAPI()
+        if let designatedPromptToCodeAPI {
+            return designatedPromptToCodeAPI
+        }
+        
+        switch UserDefaults.shared.value(for: \.promptToCodeFeatureProvider) {
+        case .openAI:
+            return OpenAIPromptToCodeAPI()
+        case .githubCopilot:
+            return CopilotPromptToCodeAPI()
+        }
     }
 
     var runningAPI: PromptToCodeAPI?