chore(go): scaffold module and add failing link tests

internal/homesick/core/core.go

@@ -0,0 +1,185 @@
+package core
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+type App struct {
+	HomeDir  string
+	ReposDir string
+	Stdout   io.Writer
+	Stderr   io.Writer
+	Verbose  bool
+}
+
+func New(stdout io.Writer, stderr io.Writer) (*App, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return nil, fmt.Errorf("resolve home directory: %w", err)
+	}
+
+	return &App{
+		HomeDir:  home,
+		ReposDir: filepath.Join(home, ".homesick", "repos"),
+		Stdout:   stdout,
+		Stderr:   stderr,
+	}, nil
+}
+
+func (a *App) Version(version string) error {
+	_, err := fmt.Fprintln(a.Stdout, version)
+	return err
+}
+
+func (a *App) ShowPath(castle string) error {
+	_, err := fmt.Fprintln(a.Stdout, filepath.Join(a.ReposDir, castle))
+	return err
+}
+
+func (a *App) Clone(uri string, destination string) error {
+	if uri == "" {
+		return errors.New("clone requires URI")
+	}
+
+	if destination == "" {
+		destination = deriveDestination(uri)
+	}
+	if destination == "" {
+		return fmt.Errorf("unable to derive destination from uri %q", uri)
+	}
+
+	if err := os.MkdirAll(a.ReposDir, 0o755); err != nil {
+		return fmt.Errorf("create repos directory: %w", err)
+	}
+
+	destinationPath := filepath.Join(a.ReposDir, destination)
+
+	if fi, err := os.Stat(uri); err == nil && fi.IsDir() {
+		if err := os.Symlink(uri, destinationPath); err != nil {
+			return fmt.Errorf("symlink local castle: %w", err)
+		}
+		return nil
+	}
+
+	if err := runGit(a.ReposDir, "clone", "-q", "--config", "push.default=upstream", "--recursive", uri, destination); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (a *App) List() error {
+	if err := os.MkdirAll(a.ReposDir, 0o755); err != nil {
+		return err
+	}
+
+	var castles []string
+	err := filepath.WalkDir(a.ReposDir, func(path string, d fs.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		if !d.IsDir() || d.Name() != ".git" {
+			return nil
+		}
+
+		castleRoot := filepath.Dir(path)
+		rel, err := filepath.Rel(a.ReposDir, castleRoot)
+		if err != nil {
+			return err
+		}
+		castles = append(castles, rel)
+		return filepath.SkipDir
+	})
+	if err != nil {
+		return err
+	}
+
+	sort.Strings(castles)
+	for _, castle := range castles {
+		castleRoot := filepath.Join(a.ReposDir, castle)
+		remote, remoteErr := gitOutput(castleRoot, "config", "remote.origin.url")
+		if remoteErr != nil {
+			remote = ""
+		}
+		_, writeErr := fmt.Fprintf(a.Stdout, "%s %s\n", castle, strings.TrimSpace(remote))
+		if writeErr != nil {
+			return writeErr
+		}
+	}
+
+	return nil
+}
+
+func (a *App) Status(castle string) error {
+	return runGit(filepath.Join(a.ReposDir, castle), "status")
+}
+
+func (a *App) Diff(castle string) error {
+	return runGit(filepath.Join(a.ReposDir, castle), "diff")
+}
+
+func (a *App) Link(string) error {
+	return errors.New("link is not implemented in Go yet")
+}
+
+func (a *App) Unlink(string) error {
+	return errors.New("unlink is not implemented in Go yet")
+}
+
+func (a *App) Track(string, string) error {
+	return errors.New("track is not implemented in Go yet")
+}
+
+func runGit(dir string, args ...string) error {
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("git %s failed: %w", strings.Join(args, " "), err)
+	}
+	return nil
+}
+
+func gitOutput(dir string, args ...string) (string, error) {
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	out, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+	return string(out), nil
+}
+
+func deriveDestination(uri string) string {
+	candidate := strings.TrimSpace(uri)
+	candidate = strings.TrimPrefix(candidate, "https://github.com/")
+	candidate = strings.TrimPrefix(candidate, "http://github.com/")
+	candidate = strings.TrimPrefix(candidate, "git://github.com/")
+
+	if strings.HasPrefix(candidate, "file://") {
+		candidate = strings.TrimPrefix(candidate, "file://")
+	}
+
+	candidate = strings.TrimSuffix(candidate, ".git")
+	candidate = strings.TrimSuffix(candidate, "/")
+	if candidate == "" {
+		return ""
+	}
+
+	parts := strings.Split(candidate, "/")
+	last := parts[len(parts)-1]
+	if strings.Contains(last, ":") {
+		a := strings.Split(last, ":")
+		last = a[len(a)-1]
+	}
+	return last
+}