enhance: API Key is now optional

- Update README.md by adding tips for using OpenAI in this project

README.md

@@ -87,6 +87,19 @@ For **Linux** users:
 * Make sure [git-credential-manager](https://github.com/git-ecosystem/git-credential-manager/releases) is installed on your linux.
 * Maybe you need to set environment variable `AVALONIA_SCREEN_SCALE_FACTORS`. See https://github.com/AvaloniaUI/Avalonia/wiki/Configuring-X11-per-monitor-DPI.
 
+## OpenAI
+
+This software supports using OpenAI or other AI service that has an OpenAI comaptible HTTP API to generate commit message. You need configurate the service in `Preference` window.
+
+For `OpenAI`:
+
+* `Server` must be `https://api.openai.com/v1/chat/completions`
+
+For other AI service:
+
+* The `Server` should fill in a URL equivalent to OpenAI's `https://api.openai.com/v1/chat/completions`
+* The `API Key` is optional that depends on the service
+
 ## External Tools
 
 This app supports open repository in external tools listed in the table below.

src/Models/OpenAI.cs

@@ -95,7 +95,7 @@ namespace SourceGit.Models
 
         public static bool IsValid
         {
-            get => !string.IsNullOrEmpty(Server) && !string.IsNullOrEmpty(ApiKey) && !string.IsNullOrEmpty(Model);
+            get => !string.IsNullOrEmpty(Server) && !string.IsNullOrEmpty(Model);
         }
 
         public static OpenAIChatResponse Chat(string prompt, string question, CancellationToken cancellation)
@@ -105,6 +105,7 @@ namespace SourceGit.Models
             chat.AddMessage("user", question);
 
             var client = new HttpClient() { Timeout = TimeSpan.FromSeconds(60) };
+            if (!string.IsNullOrEmpty(ApiKey))
                 client.DefaultRequestHeaders.Add("Authorization", $"Bearer {ApiKey}");
 
             var req = new StringContent(JsonSerializer.Serialize(chat, JsonCodeGen.Default.OpenAIChatRequest));

src/Views/Preference.axaml

@@ -364,22 +364,22 @@
                      Text="{Binding OpenAIServer, Mode=TwoWay}"/>
 
             <TextBlock Grid.Row="1" Grid.Column="0"
-                       Text="{DynamicResource Text.Preference.AI.ApiKey}"
+                       Text="{DynamicResource Text.Preference.AI.Model}"
                        HorizontalAlignment="Right"
                        Margin="0,0,16,0"/>
             <TextBox Grid.Row="1" Grid.Column="1"
                      Height="28"
                      CornerRadius="3"
-                     Text="{Binding OpenAIApiKey, Mode=TwoWay}"/>
+                     Text="{Binding OpenAIModel, Mode=TwoWay}"/>
 
             <TextBlock Grid.Row="2" Grid.Column="0"
-                       Text="{DynamicResource Text.Preference.AI.Model}"
+                       Text="{DynamicResource Text.Preference.AI.ApiKey}"
                        HorizontalAlignment="Right"
                        Margin="0,0,16,0"/>
             <TextBox Grid.Row="2" Grid.Column="1"
                      Height="28"
                      CornerRadius="3"
-                     Text="{Binding OpenAIModel, Mode=TwoWay}"/>
+                     Text="{Binding OpenAIApiKey, Mode=TwoWay}"/>
           </Grid>
         </TabItem>