package plugin

import (
	"io/fs"
	"os"
	"strings"
)

var (
	_ fs.FS         = (*multiDirFS)(nil)
	_ fs.ReadDirFS  = (*multiDirFS)(nil)
	_ fs.ReadFileFS = (*multiDirFS)(nil)
	_ fs.StatFS     = (*multiDirFS)(nil)
)

func newMultiDirFS(paths ...string) multiDirFS {
	mdfs := make(multiDirFS, len(paths))
	for i := range paths {
		mdfs[paths[i]] = os.DirFS(paths[i])
	}

	return mdfs
}

type multiDirFS map[string]fs.FS

func (m multiDirFS) Open(name string) (fs.File, error) {
	for base, pathFS := range m {
		if strings.HasPrefix(name, base) {
			return pathFS.Open(name)
		}
	}

	return nil, fs.ErrNotExist
}

func (m multiDirFS) Stat(name string) (fs.FileInfo, error) {
	for base, pathFS := range m {
		if strings.HasPrefix(name, base) {
			return fs.Stat(pathFS, name)
		}
	}

	return nil, fs.ErrNotExist
}

func (m multiDirFS) ReadDir(name string) ([]fs.DirEntry, error) {
	for base, pathFS := range m {
		if strings.HasPrefix(name, base) {
			return fs.ReadDir(pathFS, name)
		}
	}

	return nil, fs.ErrNotExist
}

func (m multiDirFS) ReadFile(name string) ([]byte, error) {
	for base, pathFS := range m {
		if strings.HasPrefix(name, base) {
			return fs.ReadFile(pathFS, name)
		}
	}

	return nil, fs.ErrNotExist
}