feat: add AI-powered release notes generation

- Add --ai-release-notes flag to generate prose release notes using Claude CLI
- Add --update-releases flag to update existing releases with AI notes
- Implement GetDiffBetweenTags to extract code changes between versions
- Integrate Claude CLI for intelligent release note generation
- Support fallback to multiple Claude models (sonnet-3.5, sonnet-4, default)
- Always print release notes to stdout for visibility
- Fix token loading messages to only show when falling back from config

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

2 files changed, 217 insertions, 26 deletions

diff --git a/internal/cli/flags.go b/internal/cli/flags.go
index 72ffa1a..fb367cb 100644
--- a/internal/cli/flags.go
+++ b/internal/cli/flags.go
@@ -33,6 +33,8 @@ type Flags struct {
 	CheckReleases      bool
 	NoCheckReleases    bool
 	AutoCreateReleases bool
+	AIReleaseNotes     bool
+	UpdateReleases     bool
 	
 	// Internal fields for batch run state management (not set by flags)
 	BatchRunStateManager *state.Manager
@@ -68,6 +70,8 @@ func ParseFlags() *Flags {
 	flag.BoolVar(&f.CheckReleases, "check-releases", false, "manually check for version tags without releases and create them (with confirmation)")
 	flag.BoolVar(&f.NoCheckReleases, "no-check-releases", false, "disable automatic release checking after sync operations")
 	flag.BoolVar(&f.AutoCreateReleases, "auto-create-releases", false, "automatically create releases without confirmation prompts")
+	flag.BoolVar(&f.AIReleaseNotes, "ai-release-notes", false, "generate release notes using Claude AI based on git diff")
+	flag.BoolVar(&f.UpdateReleases, "update-releases", false, "update existing releases with new AI-generated notes")
 	
 	flag.Parse()
 	
diff --git a/internal/cli/release.go b/internal/cli/release.go
index a83283d..e861533 100644
--- a/internal/cli/release.go
+++ b/internal/cli/release.go
@@ -4,14 +4,36 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"codeberg.org/snonux/gitsyncer/internal/config"
 	"codeberg.org/snonux/gitsyncer/internal/release"
 )
 
+// isVersionTag checks if a tag name is a version tag
+// Supports formats: vX.Y.Z, vX.Y, vX, X.Y.Z, X.Y, X
+func isVersionTag(tag string) bool {
+	// Pattern matches version tags with optional 'v' prefix
+	pattern := `^v?\d+(\.\d+)?(\.\d+)?$`
+	matched, _ := regexp.MatchString(pattern, tag)
+	return matched
+}
+
 // HandleCheckReleases checks for version tags without releases and creates them with confirmation
 func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
+	// Check all configured repositories
+	return HandleCheckReleasesForRepos(cfg, flags, cfg.Repositories)
+}
+
+// HandleCheckReleasesForRepo checks releases for a specific repository
+func HandleCheckReleasesForRepo(cfg *config.Config, flags *Flags, repoName string) int {
+	// Check only the specified repository
+	return HandleCheckReleasesForRepos(cfg, flags, []string{repoName})
+}
+
+// HandleCheckReleasesForRepos checks for version tags without releases and creates them with confirmation
+func HandleCheckReleasesForRepos(cfg *config.Config, flags *Flags, repositories []string) int {
 	releaseManager := release.NewManager(flags.WorkDir)
 	
 	// Set tokens from config with fallback to environment variables and files
@@ -24,24 +46,23 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 		if token == "" {
 			fmt.Println("No GitHub token in config, checking environment variable...")
 			token = os.Getenv("GITHUB_TOKEN")
-		}
-		if token == "" {
-			fmt.Println("No GITHUB_TOKEN env var, checking ~/.gitsyncer_github_token file...")
-			home, err := os.UserHomeDir()
-			if err == nil {
-				tokenFile := filepath.Join(home, ".gitsyncer_github_token")
-				data, err := os.ReadFile(tokenFile)
+			if token == "" {
+				fmt.Println("No GITHUB_TOKEN env var, checking ~/.gitsyncer_github_token file...")
+				home, err := os.UserHomeDir()
 				if err == nil {
-					token = strings.TrimSpace(string(data))
+					tokenFile := filepath.Join(home, ".gitsyncer_github_token")
+					data, err := os.ReadFile(tokenFile)
+					if err == nil {
+						token = strings.TrimSpace(string(data))
+					}
 				}
 			}
 		}
 		
 		if token != "" {
-			fmt.Printf("Setting GitHub token (length: %d)\n", len(token))
 			releaseManager.SetGitHubToken(token)
 		} else {
-			fmt.Println("No GitHub token found")
+			fmt.Println("WARNING: No GitHub token found - cannot create GitHub releases")
 		}
 	} else {
 		fmt.Println("No GitHub organization found in config")
@@ -56,31 +77,30 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 		if token == "" {
 			fmt.Println("No Codeberg token in config, checking environment variable...")
 			token = os.Getenv("CODEBERG_TOKEN")
-		}
-		if token == "" {
-			fmt.Println("No CODEBERG_TOKEN env var, checking ~/.gitsyncer_codeberg_token file...")
-			home, err := os.UserHomeDir()
-			if err == nil {
-				tokenFile := filepath.Join(home, ".gitsyncer_codeberg_token")
-				data, err := os.ReadFile(tokenFile)
+			if token == "" {
+				fmt.Println("No CODEBERG_TOKEN env var, checking ~/.gitsyncer_codeberg_token file...")
+				home, err := os.UserHomeDir()
 				if err == nil {
-					token = strings.TrimSpace(string(data))
+					tokenFile := filepath.Join(home, ".gitsyncer_codeberg_token")
+					data, err := os.ReadFile(tokenFile)
+					if err == nil {
+						token = strings.TrimSpace(string(data))
+					}
 				}
 			}
 		}
 		
 		if token != "" {
-			fmt.Printf("Setting Codeberg token (length: %d)\n", len(token))
 			releaseManager.SetCodebergToken(token)
 		} else {
-			fmt.Println("No Codeberg token found")
+			fmt.Println("WARNING: No Codeberg token found - cannot create Codeberg releases")
 		}
 	} else {
 		fmt.Println("No Codeberg organization found in config")
 	}
 	
-	// Process all configured repositories
-	for _, repoName := range cfg.Repositories {
+	// Process the specified repositories
+	for _, repoName := range repositories {
 		fmt.Printf("\nChecking releases for repository: %s\n", repoName)
 		
 		// Check if the repository is cloned locally
@@ -137,8 +157,35 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 		// Create missing releases with confirmation
 		if len(missingGitHub) > 0 && githubOrg != nil {
 			for _, tag := range missingGitHub {
+				// Get commits for this tag
+				commits, err := releaseManager.GetCommitsSinceTag(repoPath, "", tag)
+				if err != nil {
+					commits = []string{}
+				}
+				
 				// Generate release notes
-				releaseNotes := releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+				var releaseNotes string
+				if flags.AIReleaseNotes {
+					fmt.Printf("  Generating AI release notes for %s...\n", tag)
+					aiNotes, err := releaseManager.GenerateAIReleaseNotes(repoPath, repoName, tag, localTags, commits)
+					if err != nil {
+						fmt.Printf("  Warning: Failed to generate AI release notes: %v\n", err)
+						fmt.Printf("  Falling back to standard release notes\n")
+						releaseNotes = releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+					} else {
+						releaseNotes = aiNotes
+						fmt.Printf("  AI release notes generated successfully\n")
+					}
+				} else {
+					releaseNotes = releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+				}
+				
+				// Print release notes to stdout
+				fmt.Printf("\n%s\n", strings.Repeat("=", 70))
+				fmt.Printf("Release Notes for %s/%s tag %s:\n", githubOrg.Name, repoName, tag)
+				fmt.Printf("%s\n", strings.Repeat("-", 70))
+				fmt.Println(releaseNotes)
+				fmt.Printf("%s\n\n", strings.Repeat("=", 70))
 				
 				msg := fmt.Sprintf("Create GitHub release for %s/%s tag %s?", githubOrg.Name, repoName, tag)
 				
@@ -148,7 +195,7 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 					fmt.Printf("  Auto-creating GitHub release for %s/%s tag %s\n", githubOrg.Name, repoName, tag)
 					createRelease = true
 				} else {
-					createRelease = release.PromptConfirmationWithNotes(msg, releaseNotes)
+					createRelease = release.PromptConfirmation(msg)
 				}
 				
 				if createRelease {
@@ -163,8 +210,35 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 		
 		if len(missingCodeberg) > 0 && codebergOrg != nil {
 			for _, tag := range missingCodeberg {
+				// Get commits for this tag
+				commits, err := releaseManager.GetCommitsSinceTag(repoPath, "", tag)
+				if err != nil {
+					commits = []string{}
+				}
+				
 				// Generate release notes
-				releaseNotes := releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+				var releaseNotes string
+				if flags.AIReleaseNotes {
+					fmt.Printf("  Generating AI release notes for %s...\n", tag)
+					aiNotes, err := releaseManager.GenerateAIReleaseNotes(repoPath, repoName, tag, localTags, commits)
+					if err != nil {
+						fmt.Printf("  Warning: Failed to generate AI release notes: %v\n", err)
+						fmt.Printf("  Falling back to standard release notes\n")
+						releaseNotes = releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+					} else {
+						releaseNotes = aiNotes
+						fmt.Printf("  AI release notes generated successfully\n")
+					}
+				} else {
+					releaseNotes = releaseManager.GenerateReleaseNotes(repoPath, tag, localTags)
+				}
+				
+				// Print release notes to stdout
+				fmt.Printf("\n%s\n", strings.Repeat("=", 70))
+				fmt.Printf("Release Notes for %s/%s tag %s:\n", codebergOrg.Name, repoName, tag)
+				fmt.Printf("%s\n", strings.Repeat("-", 70))
+				fmt.Println(releaseNotes)
+				fmt.Printf("%s\n\n", strings.Repeat("=", 70))
 				
 				msg := fmt.Sprintf("Create Codeberg release for %s/%s tag %s?", codebergOrg.Name, repoName, tag)
 				
@@ -174,7 +248,7 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 					fmt.Printf("  Auto-creating Codeberg release for %s/%s tag %s\n", codebergOrg.Name, repoName, tag)
 					createRelease = true
 				} else {
-					createRelease = release.PromptConfirmationWithNotes(msg, releaseNotes)
+					createRelease = release.PromptConfirmation(msg)
 				}
 				
 				if createRelease {
@@ -186,6 +260,119 @@ func HandleCheckReleases(cfg *config.Config, flags *Flags) int {
 				}
 			}
 		}
+		
+		// Update existing releases if requested
+		if flags.UpdateReleases {
+			// Update GitHub releases
+			if githubOrg != nil && githubOrg.Name != "" {
+				githubReleases, err := releaseManager.GetGitHubReleases(githubOrg.Name, repoName)
+				if err == nil && len(githubReleases) > 0 {
+					fmt.Printf("\n  Updating existing GitHub releases...\n")
+					for _, tag := range githubReleases {
+						// Check if this is a version tag
+						if !isVersionTag(tag) {
+							continue
+						}
+						
+						// Get commits for this tag
+						commits, err := releaseManager.GetCommitsSinceTag(repoPath, "", tag)
+						if err != nil {
+							commits = []string{}
+						}
+						
+						// Generate AI release notes
+						if flags.AIReleaseNotes {
+							fmt.Printf("  Generating AI release notes for existing release %s...\n", tag)
+							aiNotes, err := releaseManager.GenerateAIReleaseNotes(repoPath, repoName, tag, localTags, commits)
+							if err != nil {
+								fmt.Printf("  Warning: Failed to generate AI release notes: %v\n", err)
+								continue
+							}
+							
+							// Print release notes to stdout
+							fmt.Printf("\n%s\n", strings.Repeat("=", 70))
+							fmt.Printf("Updated Release Notes for %s/%s tag %s:\n", githubOrg.Name, repoName, tag)
+							fmt.Printf("%s\n", strings.Repeat("-", 70))
+							fmt.Println(aiNotes)
+							fmt.Printf("%s\n\n", strings.Repeat("=", 70))
+							
+							msg := fmt.Sprintf("Update GitHub release for %s/%s tag %s?", githubOrg.Name, repoName, tag)
+							
+							updateRelease := false
+							if flags.AutoCreateReleases {
+								fmt.Printf("  Auto-updating GitHub release for %s/%s tag %s\n", githubOrg.Name, repoName, tag)
+								updateRelease = true
+							} else {
+								updateRelease = release.PromptConfirmation(msg)
+							}
+							
+							if updateRelease {
+								if err := releaseManager.UpdateGitHubRelease(githubOrg.Name, repoName, tag, aiNotes); err != nil {
+									fmt.Printf("  Error updating GitHub release: %v\n", err)
+								} else {
+									fmt.Printf("  Updated GitHub release for tag %s\n", tag)
+								}
+							}
+						}
+					}
+				}
+			}
+			
+			// Update Codeberg releases
+			if codebergOrg != nil && codebergOrg.Name != "" {
+				codebergReleases, err := releaseManager.GetCodebergReleases(codebergOrg.Name, repoName)
+				if err == nil && len(codebergReleases) > 0 {
+					fmt.Printf("\n  Updating existing Codeberg releases...\n")
+					for _, tag := range codebergReleases {
+						// Check if this is a version tag
+						if !isVersionTag(tag) {
+							continue
+						}
+						
+						// Get commits for this tag
+						commits, err := releaseManager.GetCommitsSinceTag(repoPath, "", tag)
+						if err != nil {
+							commits = []string{}
+						}
+						
+						// Generate AI release notes
+						if flags.AIReleaseNotes {
+							fmt.Printf("  Generating AI release notes for existing release %s...\n", tag)
+							aiNotes, err := releaseManager.GenerateAIReleaseNotes(repoPath, repoName, tag, localTags, commits)
+							if err != nil {
+								fmt.Printf("  Warning: Failed to generate AI release notes: %v\n", err)
+								continue
+							}
+							
+							// Print release notes to stdout
+							fmt.Printf("\n%s\n", strings.Repeat("=", 70))
+							fmt.Printf("Updated Release Notes for %s/%s tag %s:\n", codebergOrg.Name, repoName, tag)
+							fmt.Printf("%s\n", strings.Repeat("-", 70))
+							fmt.Println(aiNotes)
+							fmt.Printf("%s\n\n", strings.Repeat("=", 70))
+							
+							msg := fmt.Sprintf("Update Codeberg release for %s/%s tag %s?", codebergOrg.Name, repoName, tag)
+							
+							updateRelease := false
+							if flags.AutoCreateReleases {
+								fmt.Printf("  Auto-updating Codeberg release for %s/%s tag %s\n", codebergOrg.Name, repoName, tag)
+								updateRelease = true
+							} else {
+								updateRelease = release.PromptConfirmation(msg)
+							}
+							
+							if updateRelease {
+								if err := releaseManager.UpdateCodebergRelease(codebergOrg.Name, repoName, tag, aiNotes); err != nil {
+									fmt.Printf("  Error updating Codeberg release: %v\n", err)
+								} else {
+									fmt.Printf("  Updated Codeberg release for tag %s\n", tag)
+								}
+							}
+						}
+					}
+				}
+			}
+		}
 	}
 	
 	// Also check public repositories if they're synced