package main

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

	"r00t2.io/sysutils/paths"
)

// Open opens file fnm.
func (r *realFsMember) Open(fnm string) (fh fs.File, err error) {

	if fh, err = r.Root.Open(fnm); err != nil {
		return
	}

	return
}

// ReadDir returns directory entries at fpath joined with the realFsMember's root.
func (r *realFsMember) ReadDir(fpath string) (entries []fs.DirEntry, err error) {

	var rel string
	var fsp string = fpath

	if !filepath.IsAbs(fsp) {
		fsp = filepath.Join(
			r.Root.Name(),
			filepath.FromSlash(fsp),
		)
	}
	if err = paths.RealPath(&fsp); err != nil {
		return
	}
	if rel, err = filepath.Rel(r.Root.Name(), fsp); err != nil {
		// Not relative to this root, so skip.
		err = nil
		return
	}
	if strings.HasPrefix(rel, "..") {
		// Absolute but not relative to this root, so skip.
		return
	}

	if entries, err = os.ReadDir(fsp); err != nil {
		return
	}

	return
}