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pigo/internal/pkgmgr/distribute_skill.go

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+// This file distributes a classified pi skill into pigo's skills directory so
+// runtime.LoadSkillsDir picks it up (#159).
+//
+// pigo loads skills from the skills dir (SkillsDir): ~/.agents/skills, or
+// PIGO_SKILLS_DIR when set. LoadSkillsDir recognizes the nested layout
+// "<skillsDir>/<name>/SKILL.md" (a directory per skill whose SKILL.md holds the
+// YAML frontmatter). An npm skill package is exactly such a bundle — a SKILL.md
+// plus its supporting files — so distribution is a straight copy of the package
+// tree into "<skillsDir>/<name>/".
+//
+// As with extensions, every file laid down is returned so the lockfile can
+// remove precisely what was installed on uninstall.
+package pkgmgr
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// DistributeSkill copies the skill package at pkgDir into the skills directory
+// under a "<name>/" subdirectory, where runtime.LoadSkillsDir discovers it via
+// its SKILL.md. It returns the absolute paths of every file (and the skill dir)
+// it created, for the lockfile. An unresolvable skills dir, or a package with no
+// SKILL.md, is an error.
+func DistributeSkill(pkgDir, name string) ([]string, error) {
+	skillsDir := SkillsDir()
+	if skillsDir == "" {
+		return nil, fmt.Errorf("pkgmgr: cannot resolve skills dir (home unavailable)")
+	}
+	if !fileExists(filepath.Join(pkgDir, "SKILL.md")) {
+		return nil, fmt.Errorf("pkgmgr: skill %q has no SKILL.md", name)
+	}
+
+	dest := filepath.Join(skillsDir, name)
+	// A stale skill from a prior install must not linger alongside the new one.
+	if err := os.RemoveAll(dest); err != nil {
+		return nil, fmt.Errorf("pkgmgr: clear old skill %q: %w", dest, err)
+	}
+	if err := os.MkdirAll(skillsDir, 0o755); err != nil {
+		return nil, fmt.Errorf("pkgmgr: create skills dir: %w", err)
+	}
+	files, err := copyTree(pkgDir, dest)
+	if err != nil {
+		return nil, err
+	}
+	return append(files, dest), nil
+}