package discovery

import (
	"io/fs"
	"os"
	"path/filepath"
	"sort"
	"strings"
)

// FsTree adapts a filesystem root to the Tree interface (used for scanning
// the work repository's own items).
type FsTree struct {
	Root string
}

func (f *FsTree) Walk(fn func(rel string, isDir bool) error) error {
	var paths []string
	err := filepath.WalkDir(f.Root, func(p string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if p == f.Root {
			return nil
		}
		paths = append(paths, p)
		return nil
	})
	if err != nil {
		return err
	}
	sort.Strings(paths)
	for _, p := range paths {
		rel, err := filepath.Rel(f.Root, p)
		if err != nil {
			return err
		}
		info, err := os.Stat(p)
		if err != nil {
			return err
		}
		if err := fn(filepath.ToSlash(rel), info.IsDir()); err != nil {
			return err
		}
	}
	return nil
}

func (f *FsTree) ReadFile(rel string) ([]byte, error) {
	clean := filepath.FromSlash(rel)
	if strings.Contains(clean, "..") {
		return nil, os.ErrNotExist
	}
	return os.ReadFile(filepath.Join(f.Root, clean))
}