chore: add gitutils package to inspect local git repo

internal/gitutil/state.go

@@ -0,0 +1,91 @@
+package gitutil
+
+import (
+	"fmt"
+	"os/exec"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// GitState contains raw information about the Git repository state.
+type GitState struct {
+	// IsDirty indicates whether there are uncommitted changes.
+	IsDirty bool
+	// IsRepo indicates whether the directory is a Git repository.
+	IsRepo bool
+	// SHA is the full SHA-1 (40 characters) of the current commit.
+	SHA string
+	// Time is the current commit datetime.
+	Time time.Time
+}
+
+// InspectGitState inspects the Git repo state from the specified directory.
+// If the directory is not a Git repository, returns GitState with IsRepo=false.
+func InspectGitState(dir string) (GitState, error) {
+	state := GitState{
+		IsRepo: isGitRepo(dir),
+	}
+
+	if !state.IsRepo {
+		return state, nil
+	}
+
+	// Get the current commit SHA.
+	sha, err := gitCommand(dir, "rev-parse", "HEAD")
+	if err != nil {
+		return state, fmt.Errorf("get current commit SHA: %w", err)
+	}
+	state.SHA = strings.TrimSpace(sha)
+
+	// Get the current commit timestamp.
+	timestamp, err := gitCommand(dir, "log", "-1", "--format=%ct")
+	if err != nil {
+		return state, fmt.Errorf("get current commit timestamp: %w", err)
+	}
+	seconds, err := strconv.ParseInt(strings.TrimSpace(timestamp), 10, 64)
+	if err != nil {
+		return state, fmt.Errorf("parse current commit timestamp: %w", err)
+	}
+	state.Time = time.Unix(seconds, 0)
+
+	// Check for uncommitted changes.
+	status, err := gitCommand(dir, "status", "--porcelain")
+	if err != nil {
+		return state, fmt.Errorf("check git status: %w", err)
+	}
+	state.IsDirty = strings.TrimSpace(status) != ""
+
+	return state, nil
+}
+
+// isGitRepo checks if the directory is a Git repository.
+func isGitRepo(dir string) bool {
+	_, err := gitCommand(dir, "rev-parse", "--git-dir")
+	return err == nil
+}
+
+// gitCommand runs a git command in the specified directory.
+func gitCommand(dir string, args ...string) (string, error) {
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	output, err := cmd.Output()
+	if err != nil {
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			return "", fmt.Errorf("git command failed: %s", exitErr.Stderr)
+		}
+		return "", err
+	}
+
+	return string(output), nil
+}
+
+// ShortSHA returns a truncated SHA with the specified length.
+// If length is negative, zero, or greater than the SHA length, it returns the full SHA.
+// Returns empty string if SHA is empty.
+func (s *GitState) ShortSHA(length int) string {
+	if length <= 0 || length > len(s.SHA) {
+		length = len(s.SHA)
+	}
+	return s.SHA[:length]
+}

internal/gitutil/state_test.go

@@ -0,0 +1,152 @@
+package gitutil
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInspectGitState_NotARepo(t *testing.T) {
+	// Create a temporary directory that's not a git repo.
+	tmpDir := t.TempDir()
+
+	state, err := InspectGitState(tmpDir)
+	require.NoError(t, err)
+
+	// If tmpDir happens to be in a git repo (e.g., parent directory), skip this test.
+	// This is common when running tests from within the project itself.
+	if state.IsRepo {
+		t.Skip("tmpDir is within a git repository, skipping test")
+	}
+
+	assert.False(t, state.IsRepo)
+	assert.Empty(t, state.SHA)
+	assert.Empty(t, state.ShortSHA(7))
+	assert.True(t, state.Time.IsZero()) // Should have zero time if not a repo.
+	assert.False(t, state.IsDirty)
+}
+
+func TestInspectGitState_CleanRepo(t *testing.T) {
+	// Create a temporary git repo.
+	tmpDir := t.TempDir()
+	initGitRepo(t, tmpDir)
+
+	createAndCommitFile(t, tmpDir, "test.txt", "test content")
+
+	state, err := InspectGitState(tmpDir)
+	require.NoError(t, err)
+
+	assert.True(t, state.IsRepo)
+	assert.Len(t, state.SHA, 40)
+	assert.Equal(t, state.ShortSHA(7), state.SHA[:7])
+	assert.False(t, state.Time.IsZero())
+	assert.False(t, state.IsDirty)
+}
+
+func TestInspectGitState_DirtyRepo(t *testing.T) {
+	// Create a temporary git repo.
+	tmpDir := t.TempDir()
+	initGitRepo(t, tmpDir)
+
+	createAndCommitFile(t, tmpDir, "test.txt", "test content")
+
+	// Modify the file to make the repo dirty.
+	err := os.WriteFile(filepath.Join(tmpDir, "test.txt"), []byte("modified content"), 0o644)
+	require.NoError(t, err)
+
+	state, err := InspectGitState(tmpDir)
+	require.NoError(t, err)
+
+	assert.True(t, state.IsRepo)
+	assert.True(t, state.IsDirty)
+}
+
+func TestInspectGitState_UntrackedFiles(t *testing.T) {
+	// Create a temporary git repo.
+	tmpDir := t.TempDir()
+	initGitRepo(t, tmpDir)
+
+	createAndCommitFile(t, tmpDir, "test.txt", "test content")
+
+	// Add an untracked file.
+	err := os.WriteFile(filepath.Join(tmpDir, "untracked.txt"), []byte("untracked"), 0o644)
+	require.NoError(t, err)
+
+	state, err := InspectGitState(tmpDir)
+	require.NoError(t, err)
+
+	assert.True(t, state.IsRepo)
+	assert.True(t, state.IsDirty) // Untracked files make the repo dirty.
+}
+
+func TestGitState_ShortSHA(t *testing.T) {
+	state := &GitState{
+		SHA: "1234567890abcdef1234567890abcdef12345678",
+	}
+
+	tests := []struct {
+		name     string
+		length   int
+		expected string
+	}{
+		{"short 7", 7, "1234567"},
+		{"short 10", 10, "1234567890"},
+		{"full SHA", 40, "1234567890abcdef1234567890abcdef12345678"},
+		{"longer than SHA", 50, "1234567890abcdef1234567890abcdef12345678"},
+		{"negative", -42, "1234567890abcdef1234567890abcdef12345678"},
+		{"zero", 0, "1234567890abcdef1234567890abcdef12345678"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := state.ShortSHA(tt.length)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestGitState_ShortSHA_Empty(t *testing.T) {
+	state := &GitState{
+		SHA: "",
+	}
+
+	result := state.ShortSHA(7)
+	assert.Empty(t, result)
+}
+
+// Helper functions.
+
+func initGitRepo(t *testing.T, dir string) {
+	t.Helper()
+
+	// Initialize git repo.
+	runGitCommand(t, dir, "init")
+	runGitCommand(t, dir, "config", "user.email", "test@example.com")
+	runGitCommand(t, dir, "config", "user.name", "Test User")
+}
+
+func createAndCommitFile(t *testing.T, dir, filename, content string) {
+	t.Helper()
+
+	// Create file.
+	path := filepath.Join(dir, filename)
+	err := os.WriteFile(path, []byte(content), 0o644)
+	require.NoError(t, err)
+
+	// Commit file.
+	runGitCommand(t, dir, "add", filename)
+	runGitCommand(t, dir, "commit", "-m", "Add "+filename)
+}
+
+func runGitCommand(t *testing.T, dir string, args ...string) {
+	t.Helper()
+
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err, "git command failed: %s", output)
+}