feat(showcase): support per-repo stats branchesv0.16.0

4 files changed, 296 insertions, 11 deletions

diff --git a/internal/showcase/metadata.go b/internal/showcase/metadata.go
index 798b8fe..038dc08 100644
--- a/internal/showcase/metadata.go
+++ b/internal/showcase/metadata.go
@@ -131,9 +131,9 @@ func calculateRepoScore(linesOfCode int, avgCommitAge float64, tagCount int, has
 	return score
 }
 
-// getCommitCount returns the total number of commits
+// getCommitCount returns the total number of commits reachable from the current HEAD.
 func getCommitCount(repoPath string) (int, error) {
-	cmd := exec.Command("git", "-C", repoPath, "rev-list", "--all", "--count")
+	cmd := exec.Command("git", "-C", repoPath, "rev-list", "--count", "HEAD")
 	output, err := cmd.Output()
 	if err != nil {
 		return 0, err
@@ -179,7 +179,7 @@ func countLinesOfCode(repoPath string) (int, error) {
 
 // getFirstCommitDate returns the date of the first commit
 func getFirstCommitDate(repoPath string) (string, error) {
-	cmd := exec.Command("git", "-C", repoPath, "log", "--reverse", "--pretty=format:%ai", "--date=short")
+	cmd := exec.Command("git", "-C", repoPath, "log", "--reverse", "--pretty=format:%ai", "--date=short", "HEAD")
 	output, err := cmd.Output()
 	if err != nil {
 		return "", err
@@ -199,7 +199,7 @@ func getFirstCommitDate(repoPath string) (string, error) {
 
 // getLastCommitDate returns the date of the last commit
 func getLastCommitDate(repoPath string) (string, error) {
-	cmd := exec.Command("git", "-C", repoPath, "log", "-1", "--pretty=format:%ai", "--date=short")
+	cmd := exec.Command("git", "-C", repoPath, "log", "-1", "--pretty=format:%ai", "--date=short", "HEAD")
 	output, err := cmd.Output()
 	if err != nil {
 		return "", err
@@ -273,7 +273,7 @@ func detectLicense(repoPath string) string {
 // getAverageCommitAge calculates the average age of the last N commits in days
 func getAverageCommitAge(repoPath string, commitCount int) (float64, error) {
 	// Get the last N commit dates
-	cmd := exec.Command("git", "-C", repoPath, "log", fmt.Sprintf("-%d", commitCount), "--pretty=format:%at")
+	cmd := exec.Command("git", "-C", repoPath, "log", fmt.Sprintf("-%d", commitCount), "--pretty=format:%at", "HEAD")
 	output, err := cmd.Output()
 	if err != nil {
 		return 0, err
@@ -311,14 +311,15 @@ func getAverageCommitAge(repoPath string, commitCount int) (float64, error) {
 	return totalAge / float64(validCommits), nil
 }
 
-// getLatestTag returns the latest version-like tag, its date, whether the repo has releases, and total tag count.
+// getLatestTag returns the latest version-like tag merged into HEAD, its date,
+// whether the repo has releases, and total merged tag count.
 func getLatestTag(repoPath string) (string, string, bool, int, error) {
 	// First try to get tags sorted by version
-	cmd := exec.Command("git", "-C", repoPath, "tag", "-l", "--sort=-version:refname")
+	cmd := exec.Command("git", "-C", repoPath, "tag", "-l", "--merged", "HEAD", "--sort=-version:refname")
 	output, err := cmd.Output()
 	if err != nil {
 		// Fallback to describe
-		cmd = exec.Command("git", "-C", repoPath, "describe", "--tags", "--abbrev=0")
+		cmd = exec.Command("git", "-C", repoPath, "describe", "--tags", "--abbrev=0", "HEAD")
 		output, err = cmd.Output()
 		if err != nil {
 			// No tags at all
diff --git a/internal/showcase/metadata_test.go b/internal/showcase/metadata_test.go
index e8777ce..abc4664 100644
--- a/internal/showcase/metadata_test.go
+++ b/internal/showcase/metadata_test.go
@@ -79,6 +79,69 @@ func TestGetLatestTag_ReturnsTotalTagCount(t *testing.T) {
 	}
 }
 
+func TestExtractRepoMetadata_UsesCurrentBranchState(t *testing.T) {
+	t.Parallel()
+
+	repoPath := t.TempDir()
+	runGit(t, repoPath, "init", "--initial-branch=main")
+	runGit(t, repoPath, "config", "user.name", "Test User")
+	runGit(t, repoPath, "config", "user.email", "test@example.com")
+
+	writeAndCommit := func(name, content, message string) {
+		path := filepath.Join(repoPath, name)
+		if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+			t.Fatalf("write file %s: %v", name, err)
+		}
+		runGit(t, repoPath, "add", name)
+		runGit(t, repoPath, "commit", "-m", message)
+	}
+
+	writeAndCommit("main.go", "package main\n\nfunc main() {\n}\n", "main branch")
+	runGit(t, repoPath, "tag", "v1.0.0")
+
+	runGit(t, repoPath, "checkout", "-b", "content-gemtext")
+	writeAndCommit("content.go", "package main\n\nfunc render() string {\n\treturn \"gemtext\"\n}\n", "content branch")
+	runGit(t, repoPath, "tag", "v2.0.0")
+
+	runGit(t, repoPath, "checkout", "main")
+
+	mainMetadata, err := extractRepoMetadata(repoPath)
+	if err != nil {
+		t.Fatalf("extractRepoMetadata(main) error = %v", err)
+	}
+	if mainMetadata.CommitCount != 1 {
+		t.Fatalf("main branch CommitCount = %d, want %d", mainMetadata.CommitCount, 1)
+	}
+	if mainMetadata.LinesOfCode != 4 {
+		t.Fatalf("main branch LinesOfCode = %d, want %d", mainMetadata.LinesOfCode, 4)
+	}
+	if mainMetadata.LatestTag != "v1.0.0" {
+		t.Fatalf("main branch LatestTag = %q, want %q", mainMetadata.LatestTag, "v1.0.0")
+	}
+	if mainMetadata.TagCount != 1 {
+		t.Fatalf("main branch TagCount = %d, want %d", mainMetadata.TagCount, 1)
+	}
+
+	runGit(t, repoPath, "checkout", "content-gemtext")
+
+	contentMetadata, err := extractRepoMetadata(repoPath)
+	if err != nil {
+		t.Fatalf("extractRepoMetadata(content-gemtext) error = %v", err)
+	}
+	if contentMetadata.CommitCount != 2 {
+		t.Fatalf("content-gemtext CommitCount = %d, want %d", contentMetadata.CommitCount, 2)
+	}
+	if contentMetadata.LinesOfCode != 9 {
+		t.Fatalf("content-gemtext LinesOfCode = %d, want %d", contentMetadata.LinesOfCode, 9)
+	}
+	if contentMetadata.LatestTag != "v2.0.0" {
+		t.Fatalf("content-gemtext LatestTag = %q, want %q", contentMetadata.LatestTag, "v2.0.0")
+	}
+	if contentMetadata.TagCount != 2 {
+		t.Fatalf("content-gemtext TagCount = %d, want %d", contentMetadata.TagCount, 2)
+	}
+}
+
 func runGit(t *testing.T, repoPath string, args ...string) string {
 	t.Helper()
 
diff --git a/internal/showcase/showcase.go b/internal/showcase/showcase.go
index 25f28f9..9cf43a6 100644
--- a/internal/showcase/showcase.go
+++ b/internal/showcase/showcase.go
@@ -174,7 +174,11 @@ func (g *Generator) GenerateShowcase(repoFilter []string, forceRegenerate bool)
 // runCommandWithTimeout runs a command with a short timeout and returns trimmed stdout.
 // Stderr is included in the error message for easier debugging when GITSYNCER_DEBUG=1.
 func runCommandWithTimeout(name string, args ...string) (string, error) {
-	ctx, cancel := context.WithTimeout(context.Background(), 8*time.Second)
+	return runCommandWithCustomTimeout(8*time.Second, name, args...)
+}
+
+func runCommandWithCustomTimeout(timeout time.Duration, name string, args ...string) (string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
 	cmd := exec.CommandContext(ctx, name, args...)
 	out, err := cmd.CombinedOutput()
@@ -680,6 +684,88 @@ func (g *Generator) buildProjectLinks(repoName string) (string, string) {
 	return codebergURL, githubURL
 }
 
+func (g *Generator) prepareStatsRepoPath(repoName, repoPath string) (string, func() error, error) {
+	if g.config == nil {
+		return repoPath, func() error { return nil }, nil
+	}
+
+	branch := strings.TrimSpace(g.config.ShowcaseStatsBranches[repoName])
+	if branch == "" {
+		return repoPath, func() error { return nil }, nil
+	}
+
+	resolvedRef, err := resolveShowcaseStatsRef(repoPath, branch)
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to resolve showcase stats branch for %s: %w", repoName, err)
+	}
+
+	tempPrefix := strings.ReplaceAll(repoName, string(os.PathSeparator), "-")
+	tempRoot, err := os.MkdirTemp("", "gitsyncer-showcase-"+tempPrefix+"-")
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to create temporary worktree root for %s: %w", repoName, err)
+	}
+
+	worktreePath := filepath.Join(tempRoot, "repo")
+	if _, err := runCommandWithCustomTimeout(45*time.Second, "git", "-C", repoPath, "worktree", "add", "--detach", worktreePath, resolvedRef); err != nil {
+		_ = os.RemoveAll(tempRoot)
+		return "", nil, fmt.Errorf("failed to create showcase stats worktree for %s on branch %q: %w", repoName, branch, err)
+	}
+
+	cleanup := func() error {
+		defer os.RemoveAll(tempRoot)
+
+		if _, err := runCommandWithCustomTimeout(45*time.Second, "git", "-C", repoPath, "worktree", "remove", "--force", worktreePath); err != nil {
+			return fmt.Errorf("failed to remove temporary worktree for %s: %w", repoName, err)
+		}
+
+		return nil
+	}
+
+	if resolvedRef == branch {
+		fmt.Printf("Using showcase stats branch %q for %s\n", branch, repoName)
+	} else {
+		fmt.Printf("Using showcase stats branch %q for %s (resolved to %s)\n", branch, repoName, resolvedRef)
+	}
+
+	return worktreePath, cleanup, nil
+}
+
+func resolveShowcaseStatsRef(repoPath, branch string) (string, error) {
+	localRef := "refs/heads/" + branch
+	if _, err := runCommandWithTimeout("git", "-C", repoPath, "show-ref", "--verify", "--quiet", localRef); err == nil {
+		return branch, nil
+	}
+
+	output, err := runCommandWithTimeout("git", "-C", repoPath, "for-each-ref", "--format=%(refname)", "refs/remotes")
+	if err != nil {
+		return "", fmt.Errorf("failed to inspect remote refs for branch %q: %w", branch, err)
+	}
+
+	var candidates []string
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		ref := strings.TrimSpace(line)
+		if ref == "" || strings.HasSuffix(ref, "/HEAD") {
+			continue
+		}
+		if strings.HasSuffix(ref, "/"+branch) {
+			candidates = append(candidates, ref)
+		}
+	}
+
+	if len(candidates) == 0 {
+		return "", fmt.Errorf("branch %q not found locally or on any remote", branch)
+	}
+
+	sort.Strings(candidates)
+	for _, ref := range candidates {
+		if strings.HasPrefix(ref, "refs/remotes/origin/") {
+			return ref, nil
+		}
+	}
+
+	return candidates[0], nil
+}
+
 // generateProjectSummary generates a summary for a single project
 func (g *Generator) generateProjectSummary(repoName string, forceRegenerate bool) (*ProjectSummary, error) {
 	repoPath := filepath.Join(g.workDir, repoName)
@@ -708,9 +794,19 @@ func (g *Generator) generateProjectSummary(repoName string, forceRegenerate bool
 
 	readmeContent, readmeFile, readmeFound := findReadmeContent(repoPath)
 
+	statsRepoPath, cleanupStatsRepoPath, err := g.prepareStatsRepoPath(repoName, repoPath)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err := cleanupStatsRepoPath(); err != nil {
+			fmt.Printf("Warning: %v\n", err)
+		}
+	}()
+
 	// Always extract metadata (not cached)
 	fmt.Printf("Extracting repository metadata...\n")
-	metadata, err := extractRepoMetadata(repoPath)
+	metadata, err := extractRepoMetadata(statsRepoPath)
 	if err != nil {
 		fmt.Printf("Warning: Failed to extract some metadata: %v\n", err)
 		// Continue anyway with partial metadata
@@ -755,7 +851,7 @@ func (g *Generator) generateProjectSummary(repoName string, forceRegenerate bool
 	// Extract code snippet for all projects
 	var codeSnippet, codeLanguage string
 	if metadata != nil && len(metadata.Languages) > 0 {
-		snippet, lang, err := extractCodeSnippet(repoPath, metadata.Languages)
+		snippet, lang, err := extractCodeSnippet(statsRepoPath, metadata.Languages)
 		if err != nil {
 			fmt.Printf("Warning: Failed to extract code snippet: %v\n", err)
 		} else {
diff --git a/internal/showcase/showcase_test.go b/internal/showcase/showcase_test.go
index 8bcad88..fa18799 100644
--- a/internal/showcase/showcase_test.go
+++ b/internal/showcase/showcase_test.go
@@ -2,6 +2,7 @@ package showcase
 
 import (
 	"os"
+	"os/exec"
 	"path/filepath"
 	"reflect"
 	"strings"
@@ -229,3 +230,127 @@ func TestExtractUsefulSummary_SkipsFencedCodeBlocks(t *testing.T) {
 		t.Fatalf("extractUsefulSummary() = %q, want %q", got, want)
 	}
 }
+
+func TestPrepareStatsRepoPath_UsesConfiguredBranchWithoutChangingMainCheckout(t *testing.T) {
+	t.Parallel()
+
+	repoPath := t.TempDir()
+	runGit(t, repoPath, "init", "--initial-branch=main")
+	runGit(t, repoPath, "config", "user.name", "Test User")
+	runGit(t, repoPath, "config", "user.email", "test@example.com")
+
+	mainFile := filepath.Join(repoPath, "README.md")
+	if err := os.WriteFile(mainFile, []byte("main branch"), 0644); err != nil {
+		t.Fatalf("write README.md: %v", err)
+	}
+	runGit(t, repoPath, "add", "README.md")
+	runGit(t, repoPath, "commit", "-m", "main")
+
+	runGit(t, repoPath, "checkout", "-b", "content-gemtext")
+	branchOnlyFile := filepath.Join(repoPath, "branch-only.txt")
+	if err := os.WriteFile(branchOnlyFile, []byte("content branch"), 0644); err != nil {
+		t.Fatalf("write branch-only.txt: %v", err)
+	}
+	runGit(t, repoPath, "add", "branch-only.txt")
+	runGit(t, repoPath, "commit", "-m", "content branch")
+	runGit(t, repoPath, "checkout", "main")
+
+	g := &Generator{
+		config: &config.Config{
+			ShowcaseStatsBranches: map[string]string{
+				"foo.zone": "content-gemtext",
+			},
+		},
+	}
+
+	statsRepoPath, cleanup, err := g.prepareStatsRepoPath("foo.zone", repoPath)
+	if err != nil {
+		t.Fatalf("prepareStatsRepoPath() error = %v", err)
+	}
+	defer func() {
+		if err := cleanup(); err != nil {
+			t.Fatalf("cleanup() error = %v", err)
+		}
+	}()
+
+	if statsRepoPath == repoPath {
+		t.Fatal("expected a detached worktree path for configured stats branch")
+	}
+	if _, err := os.Stat(filepath.Join(statsRepoPath, "branch-only.txt")); err != nil {
+		t.Fatalf("expected branch-only file in detached worktree: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(repoPath, "branch-only.txt")); !os.IsNotExist(err) {
+		t.Fatalf("expected branch-only file to stay absent from main checkout, stat err = %v", err)
+	}
+
+	currentBranch := strings.TrimSpace(runGit(t, repoPath, "branch", "--show-current"))
+	if currentBranch != "main" {
+		t.Fatalf("current branch = %q, want %q", currentBranch, "main")
+	}
+}
+
+func TestPrepareStatsRepoPath_UsesRemoteTrackingBranchWhenLocalBranchMissing(t *testing.T) {
+	t.Parallel()
+
+	rootDir := t.TempDir()
+	seedRepoPath := filepath.Join(rootDir, "seed")
+	runGit(t, rootDir, "init", "--initial-branch=main", seedRepoPath)
+	runGit(t, seedRepoPath, "config", "user.name", "Test User")
+	runGit(t, seedRepoPath, "config", "user.email", "test@example.com")
+
+	if err := os.WriteFile(filepath.Join(seedRepoPath, "README.md"), []byte("main branch"), 0644); err != nil {
+		t.Fatalf("write README.md: %v", err)
+	}
+	runGit(t, seedRepoPath, "add", "README.md")
+	runGit(t, seedRepoPath, "commit", "-m", "main")
+
+	runGit(t, seedRepoPath, "checkout", "-b", "content-gemtext")
+	if err := os.WriteFile(filepath.Join(seedRepoPath, "branch-only.txt"), []byte("content branch"), 0644); err != nil {
+		t.Fatalf("write branch-only.txt: %v", err)
+	}
+	runGit(t, seedRepoPath, "add", "branch-only.txt")
+	runGit(t, seedRepoPath, "commit", "-m", "content branch")
+	runGit(t, seedRepoPath, "checkout", "main")
+
+	remoteRepoPath := filepath.Join(rootDir, "remote.git")
+	cloneCmd := exec.Command("git", "clone", "--bare", seedRepoPath, remoteRepoPath)
+	if output, err := cloneCmd.CombinedOutput(); err != nil {
+		t.Fatalf("git clone --bare failed: %v\n%s", err, string(output))
+	}
+
+	cloneRepoPath := filepath.Join(rootDir, "clone")
+	workingCloneCmd := exec.Command("git", "clone", remoteRepoPath, cloneRepoPath)
+	if output, err := workingCloneCmd.CombinedOutput(); err != nil {
+		t.Fatalf("git clone failed: %v\n%s", err, string(output))
+	}
+
+	g := &Generator{
+		config: &config.Config{
+			ShowcaseStatsBranches: map[string]string{
+				"foo.zone": "content-gemtext",
+			},
+		},
+	}
+
+	statsRepoPath, cleanup, err := g.prepareStatsRepoPath("foo.zone", cloneRepoPath)
+	if err != nil {
+		t.Fatalf("prepareStatsRepoPath() error = %v", err)
+	}
+	defer func() {
+		if err := cleanup(); err != nil {
+			t.Fatalf("cleanup() error = %v", err)
+		}
+	}()
+
+	if _, err := os.Stat(filepath.Join(statsRepoPath, "branch-only.txt")); err != nil {
+		t.Fatalf("expected branch-only file in detached worktree from remote branch: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(cloneRepoPath, "branch-only.txt")); !os.IsNotExist(err) {
+		t.Fatalf("expected branch-only file to stay absent from main checkout, stat err = %v", err)
+	}
+
+	currentBranch := strings.TrimSpace(runGit(t, cloneRepoPath, "branch", "--show-current"))
+	if currentBranch != "main" {
+		t.Fatalf("current branch = %q, want %q", currentBranch, "main")
+	}
+}