// This file distributes a classified pi prompt/command package into pigo's
// prompts directory so runtime.LoadUserCommandsDir picks it up (#160, #342).
//
// pigo loads declarative slash commands from $PIGO_HOME/prompts/*.md (and the
// legacy $PIGO_HOME/commands/*.md) non-recursively: each markdown file defines
// a "/name" command, named after the file, whose body is the prompt template.
// A pi prompt package ships one or more such templates, conventionally under a
// "prompts/" subdirectory (the pi convention); the legacy "commands/" subdir is
// a fallback, and some packages place the .md files at the package root.
//
// Distribution copies those .md files (flattened, since the loader is
// non-recursive) into $PIGO_HOME/prompts/. Every file laid down is returned so
// the lockfile can remove precisely what was installed.
package pkgmgr

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

// DistributePrompt copies the prompt package's command templates at pkgDir into
// the commands directory. It looks first in "<pkgDir>/commands" for *.md files
// and falls back to *.md at the package root. It returns the absolute paths of
// every file it created, for the lockfile. An unresolvable commands dir, or a
// package with no command templates, is an error.
func DistributePrompt(pkgDir, name string) ([]string, error) {
	promptsDir := PromptsDir()
	if promptsDir == "" {
		return nil, fmt.Errorf("pkgmgr: cannot resolve prompts dir (PIGO_HOME/home unavailable)")
	}

	// Prefer the pi-aligned prompts/ subdir, then the legacy commands/ subdir,
	// then root-level *.md as a last resort.
	srcDir := ""
	for _, sub := range []string{"prompts", "commands"} {
		if dirExists(filepath.Join(pkgDir, sub)) {
			srcDir = filepath.Join(pkgDir, sub)
			break
		}
	}
	if srcDir == "" {
		srcDir = pkgDir // fall back to root-level *.md
	}
	entries, err := os.ReadDir(srcDir)
	if err != nil {
		return nil, fmt.Errorf("pkgmgr: read prompt source dir: %w", err)
	}

	var mds []string
	for _, e := range entries {
		if e.IsDir() || !strings.EqualFold(filepath.Ext(e.Name()), ".md") {
			continue
		}
		// A root-level README.md is not a command template; skip it when we've
		// fallen back to the package root.
		if srcDir == pkgDir && strings.EqualFold(e.Name(), "README.md") {
			continue
		}
		mds = append(mds, e.Name())
	}
	if len(mds) == 0 {
		return nil, fmt.Errorf("pkgmgr: prompt %q has no prompt templates (*.md)", name)
	}

	if err := os.MkdirAll(promptsDir, 0o755); err != nil {
		return nil, fmt.Errorf("pkgmgr: create prompts dir: %w", err)
	}

	created := make([]string, 0, len(mds))
	for _, md := range mds {
		src := filepath.Join(srcDir, md)
		dst := filepath.Join(promptsDir, md)
		info, statErr := os.Stat(src)
		if statErr != nil {
			return created, fmt.Errorf("pkgmgr: stat command %q: %w", src, statErr)
		}
		if err := copyFile(src, dst, info.Mode()); err != nil {
			return created, fmt.Errorf("pkgmgr: copy command %q: %w", md, err)
		}
		created = append(created, dst)
	}
	return created, nil
}