feat: add support for including example commit messages in context

- Introduced a `--examples` flag in the CLI to include recent commit
  messages as context for commit message generation.
- Updated `cmd/commitmsg/main.go`:
  - Added `flagExamples` to handle the new `--examples` flag.
  - Integrated logic to fetch the last 3 commit messages using the
    `internal/git` package.
  - Passed the fetched examples to the LLM client for enhanced context.
- Enhanced `internal/git` package:
  - Added `GetCommitMessages` function to retrieve recent commit messages
    from the repository.
- Updated `internal/llm` package:
  - Modified `GenerateCommitMessage` to accept an additional `examples`
    parameter.
  - Added logic to include examples in the prompt configuration if provided.
  - Introduced `createExamplesString` helper function to format examples for
    the prompt.
- Updated `commitmsg.prompt.yml` to include placeholders for example commit
  messages.
- Improved user feedback with additional console messages for better clarity.

Author: hazadus

cmd/commitmsg/main.go

@@ -14,6 +14,7 @@ const extensionName = "standup"
 
 var (
 	flagLanguage string
+	flagExamples bool
 )
 var rootCmd = &cobra.Command{
 	Use:   extensionName,
@@ -24,6 +25,7 @@ var rootCmd = &cobra.Command{
 
 func init() {
 	rootCmd.Flags().StringVarP(&flagLanguage, "language", "l", "english", "Language to generate commit message in")
+	rootCmd.Flags().BoolVarP(&flagExamples, "examples", "e", false, "Add examples of commit messages to context")
 }
 
 func main() {
@@ -38,23 +40,33 @@ func runCommitMsg(_ *cobra.Command, _ []string) error {
 	if err != nil {
 		return fmt.Errorf("failed to get staged changes: %w", err)
 	}
-
+	
 	if stagedChanges == "" {
 		fmt.Println("No staged changes in the repository.")
 		return nil
 	}
 
+	latestCommitMessages := ""
+	if flagExamples{
+		latestCommitMessages, err = git.GetCommitMessages(3)
+		if err != nil {
+			return fmt.Errorf("failed to get latest commit messages: %w", err)
+		}
+		fmt.Println("  Adding examples of previous commit messages to context")
+	}
+
 	llmClient, err := llm.NewClient()
 	if err != nil {
 		return fmt.Errorf("failed to create LLM client: %w", err)
 	}
 
-	commitMsg, err := llmClient.GenerateCommitMessage(stagedChanges, flagLanguage)
+	fmt.Println("  Language for commit message:", flagLanguage)
+	commitMsg, err := llmClient.GenerateCommitMessage(stagedChanges, flagLanguage, latestCommitMessages)
 	if err != nil {
 		return fmt.Errorf("failed to generate commit message: %w", err)
 	}
 
-	fmt.Println("Generated commit message:")
+	fmt.Println("💬 Generated commit message:")
 	fmt.Println(commitMsg)
 	return nil
 }

internal/git/git.go

@@ -23,6 +23,23 @@ func GetStagedChanges() (string, error) {
 	return string(output), nil
 }
 
+// GetCommitMessages retrieves the last <count> commit messages from the git repository
+func GetCommitMessages(count int) (string, error) {
+	// Check if we are in a git repository
+	if !isGitRepository() {
+		return "", fmt.Errorf("current directory is not a git repository")
+	}
+
+	// Execute the command git log -n <count>
+	cmd := exec.Command("git", "log", "-n", fmt.Sprintf("%d", count))
+	output, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("error executing git log: %v", err)
+	}
+
+	return string(output), nil
+}
+
 // isGitRepository checks if the current directory is a git repository
 func isGitRepository() bool {
 	cmd := exec.Command("git", "rev-parse", "--is-inside-work-tree")

internal/llm/client.go

@@ -88,7 +88,11 @@ func NewClient() (*Client, error) {
 }
 
 // GenerateCommitMessage generates a commit message based on the provided changes summary
-func (c *Client) GenerateCommitMessage(changesSummary string, language string) (string, error) {
+func (c *Client) GenerateCommitMessage(
+	changesSummary string,
+	language string,
+	examples string,
+) (string, error) {
 	fmt.Print("  Loading prompt configuration... ")
 	promptConfig, err := loadPromptConfig()
 	if err != nil {
@@ -111,6 +115,14 @@ func (c *Client) GenerateCommitMessage(changesSummary string, language string) (
 		content = strings.ReplaceAll(content, "{{changes}}", changesSummary)
 		content = strings.ReplaceAll(content, "{{language}}", selectedLanguage)
 
+		if examples != "" && strings.Contains(content, "{{examples}}") {
+			// If examples are provided, replace the {{examples}} placeholder
+			content = strings.ReplaceAll(content, "{{examples}}", createExamplesString(examples))
+		} else {
+			// If no examples are provided, remove the {{examples}} placeholder
+			content = strings.ReplaceAll(content, "{{examples}}", "")
+		}
+
 		messages[i] = Message{
 			Role:    msg.Role,
 			Content: content,
@@ -188,3 +200,11 @@ func (c *Client) callGitHubModels(request Request) (*Response, error) {
 
 	return &response, nil
 }
+
+func createExamplesString(examples string) string {
+	if examples == "" {
+		return ""
+	}
+	
+	return fmt.Sprintf("Here are some examples of good commit messages used previously in project:\n%s", examples)
+}

internal/llm/commitmsg.prompt.yml

@@ -26,6 +26,8 @@ messages:
       - Be concise but informative
 
       - Use bullet points for clarity
+
+      {{examples}}
   - role: user
     content: |
       Based on the following changes, generate a conventional commit message: