Initial Hop alpha

internal/hop/skill.go

@@ -0,0 +1,102 @@
+package hop
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	hopskill "github.com/hop-vcs/hop/skills/hop"
+)
+
+type SkillInstallResult struct {
+	Path  string   `json:"path"`
+	Files []string `json:"files"`
+}
+
+func DefaultSkillBase() (string, error) {
+	home := os.Getenv("CODEX_HOME")
+	if home == "" {
+		userHome, err := os.UserHomeDir()
+		if err != nil {
+			return "", fmt.Errorf("find home directory: %w", err)
+		}
+		home = filepath.Join(userHome, ".codex")
+	}
+	return filepath.Join(home, "skills"), nil
+}
+
+func EmbeddedSkillText() (string, error) {
+	contents, err := hopskill.Files.ReadFile("SKILL.md")
+	if err != nil {
+		return "", fmt.Errorf("read embedded Hop skill: %w", err)
+	}
+	return string(contents), nil
+}
+
+// InstallSkill writes the embedded skill below a skills directory. Existing
+// bundles require force; known files are overwritten without deleting unknown
+// user files from the destination.
+func InstallSkill(base string, force bool) (SkillInstallResult, error) {
+	if strings.TrimSpace(base) == "" {
+		var err error
+		base, err = DefaultSkillBase()
+		if err != nil {
+			return SkillInstallResult{}, err
+		}
+	}
+	absBase, err := filepath.Abs(base)
+	if err != nil {
+		return SkillInstallResult{}, fmt.Errorf("resolve skills directory: %w", err)
+	}
+	target := filepath.Join(absBase, "hop")
+	if info, err := os.Lstat(target); err == nil {
+		if info.Mode()&os.ModeSymlink != 0 {
+			return SkillInstallResult{}, fmt.Errorf("refusing to install through symlink %s", target)
+		}
+		if !info.IsDir() {
+			return SkillInstallResult{}, fmt.Errorf("skill target exists and is not a directory: %s", target)
+		}
+		if !force {
+			return SkillInstallResult{}, fmt.Errorf("Hop skill already exists at %s; pass --force to update it", target)
+		}
+	} else if !os.IsNotExist(err) {
+		return SkillInstallResult{}, fmt.Errorf("inspect skill target: %w", err)
+	}
+	if err := os.MkdirAll(target, 0o755); err != nil {
+		return SkillInstallResult{}, fmt.Errorf("create skill target: %w", err)
+	}
+
+	result := SkillInstallResult{Path: target}
+	err = fs.WalkDir(hopskill.Files, ".", func(path string, entry fs.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		if path == "." {
+			return nil
+		}
+		destination := filepath.Join(target, filepath.FromSlash(path))
+		if entry.IsDir() {
+			return os.MkdirAll(destination, 0o755)
+		}
+		if info, statErr := os.Lstat(destination); statErr == nil && info.Mode()&os.ModeSymlink != 0 {
+			return fmt.Errorf("refusing to overwrite symlink %s", destination)
+		} else if statErr != nil && !os.IsNotExist(statErr) {
+			return statErr
+		}
+		contents, readErr := hopskill.Files.ReadFile(path)
+		if readErr != nil {
+			return readErr
+		}
+		if writeErr := os.WriteFile(destination, contents, 0o644); writeErr != nil {
+			return writeErr
+		}
+		result.Files = append(result.Files, path)
+		return nil
+	})
+	if err != nil {
+		return SkillInstallResult{}, fmt.Errorf("install Hop skill: %w", err)
+	}
+	return result, nil
+}