1 files changed, 213 insertions, 0 deletions
diff --git a/cmd/git-balai/main.go b/cmd/git-balai/main.go
new file mode 100644
index 0000000..4de5cdb
--- /dev/null
+++ b/cmd/git-balai/main.go
@@ -0,0 +1,213 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+)
+
+var preferredRemotes = []string{"origin", "github", "work"}
+
+type GitRepository struct {
+	WorkingDirectory string
+	RemoteName       string
+	RemoteURL        string
+	PrimaryBranch    string
+}
+
+func NewGitRepository(workingDir string) (*GitRepository, error) {
+	repo := &GitRepository{
+		WorkingDirectory: workingDir,
+	}
+
+	if err := repo.isGitRepository(); err != nil {
+		return nil, err
+	}
+
+	if err := repo.workdirIsClean(); err != nil {
+		return nil, err
+	}
+
+	if err := repo.guessRemote(); err != nil {
+		return nil, err
+	}
+
+	if err := repo.guessPrimaryBranch(); err != nil {
+		return nil, err
+	}
+
+	return repo, nil
+}
+
+func (r *GitRepository) runGitCommand(args ...string) ([]byte, error) {
+	cmd := exec.Command("git", append([]string{"-C", r.WorkingDirectory}, args...)...)
+	return cmd.Output()
+}
+
+func (r *GitRepository) guessPrimaryBranch() error {
+	output, err := r.runGitCommand("ls-remote", "--symref", r.RemoteName, "HEAD")
+	if err != nil {
+		return fmt.Errorf("failed to run git ls-remote: %w", err)
+	}
+
+	re := regexp.MustCompile(`ref: refs/heads/(\S+)\s+HEAD`)
+	matches := re.FindStringSubmatch(string(output))
+
+	if len(matches) < 2 {
+		return fmt.Errorf("could not determine primary branch")
+	}
+
+	r.PrimaryBranch = matches[1]
+	return nil
+}
+
+func (r *GitRepository) guessRemote() error {
+	output, err := r.runGitCommand("config", "--get-regexp", `remote\.[a-z0-9]+\.url`)
+	if err != nil {
+		return fmt.Errorf("failed to run git config: %w", err)
+	}
+
+	remotes := make(map[string]string)
+	scanner := bufio.NewScanner(strings.NewReader(string(output)))
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.Fields(line)
+		if len(parts) < 2 {
+			continue
+		}
+
+		configParts := strings.Split(parts[0], ".")
+		if len(configParts) < 2 {
+			continue
+		}
+
+		remoteName := configParts[1]
+		remoteURL := parts[1]
+		remotes[remoteName] = remoteURL
+	}
+
+	for _, preferred := range preferredRemotes {
+		if url, exists := remotes[preferred]; exists {
+			r.RemoteName = preferred
+			r.RemoteURL = url
+			return nil
+		}
+	}
+
+	return fmt.Errorf("no preferred remote configured")
+}
+
+func (r *GitRepository) isGitRepository() error {
+	_, err := r.runGitCommand("rev-parse", "--show-toplevel")
+	if err != nil {
+		return fmt.Errorf("%s is not a git repository", r.WorkingDirectory)
+	}
+	return nil
+}
+
+func (r *GitRepository) workdirIsClean() error {
+	_, err := r.runGitCommand("diff", "--quiet", "--exit-code")
+	if err != nil {
+		return fmt.Errorf("%s has unstaged changes, commit or stash them first", r.WorkingDirectory)
+	}
+	return nil
+}
+
+// getMergedBranches returns a list of local branches that have been merged into the primary branch
+func (r *GitRepository) getMergedBranches() ([]string, error) {
+	output, err := r.runGitCommand("branch", "--merged", r.PrimaryBranch)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get merged branches: %w", err)
+	}
+
+	var branches []string
+	scanner := bufio.NewScanner(strings.NewReader(string(output)))
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		// Skip current branch indicator and the primary branch itself
+		if strings.HasPrefix(line, "*") {
+			line = strings.TrimSpace(line[1:])
+		}
+
+		// Don't delete the primary branch
+		if line != r.PrimaryBranch && line != "" {
+			branches = append(branches, line)
+		}
+	}
+
+	return branches, scanner.Err()
+}
+
+// deleteBranch deletes a local branch
+func (r *GitRepository) deleteBranch(branch string) error {
+	_, err := r.runGitCommand("branch", "-d", branch)
+	if err != nil {
+		// Try force delete if normal delete fails
+		_, forceErr := r.runGitCommand("branch", "-D", branch)
+		if forceErr != nil {
+			return fmt.Errorf("failed to delete branch %s: %w", branch, err)
+		}
+		log.Printf("Force deleted branch: %s", branch)
+		return nil
+	}
+	log.Printf("Deleted branch: %s", branch)
+	return nil
+}
+
+// cleanupMergedBranches deletes all local branches that have been merged into the primary branch
+func (r *GitRepository) cleanupMergedBranches(dryRun bool) error {
+	mergedBranches, err := r.getMergedBranches()
+	if err != nil {
+		return err
+	}
+
+	if len(mergedBranches) == 0 {
+		log.Println("No merged branches to clean up")
+		return nil
+	}
+
+	log.Printf("Found %d merged branches:", len(mergedBranches))
+	for _, branch := range mergedBranches {
+		if dryRun {
+			log.Printf("Would delete: %s", branch)
+		} else {
+			if err := r.deleteBranch(branch); err != nil {
+				log.Printf("Error deleting branch %s: %v", branch, err)
+			}
+		}
+	}
+
+	return nil
+}
+
+func main() {
+	wd, err := os.Getwd()
+	if err != nil {
+		log.Fatalf("Failed to get working directory: %v", err)
+	}
+
+	repo, err := NewGitRepository(wd)
+	if err != nil {
+		log.Fatalf("Error: %v", err)
+	}
+
+	log.Printf("Working in: %s", repo.WorkingDirectory)
+	log.Printf("Main branch is: %s", repo.PrimaryBranch)
+	log.Printf("Remote is named %s and is at %s", repo.RemoteName, repo.RemoteURL)
+
+	dryRun := len(os.Args) > 1 && os.Args[1] == "--dry-run"
+
+	if dryRun {
+		log.Println("Running in dry-run mode")
+	}
+
+	if err := repo.cleanupMergedBranches(dryRun); err != nil {
+		log.Fatalf("Failed to cleanup merged branches: %v", err)
+	}
+}