// Utility functions useful for file-related tests

// Copyright (C) 2021  Simon Ruderich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package filetest

import (
	"io/fs"
	"os"
	"os/user"
	"path/filepath"
	"strconv"
	"syscall"
)

type File struct {
	Path string
	Mode fs.FileMode
	Data []byte
}

func WalkDir(basePath string) ([]File, error) {
	var res []File
	err := filepath.WalkDir(basePath, func(path string,
		d fs.DirEntry, err error) error {

		if err != nil {
			return err
		}
		info, err := d.Info()
		if err != nil {
			return err
		}
		rel, err := filepath.Rel(basePath, path)
		if err != nil {
			return err
		}

		f := File{
			Path: rel,
			Mode: info.Mode(),
		}
		if f.Mode.Type() == 0 {
			x, err := os.ReadFile(path)
			if err != nil {
				return err
			}
			f.Data = x
		} else if f.Mode.Type() == fs.ModeSymlink {
			x, err := os.Readlink(path)
			if err != nil {
				return err
			}
			f.Data = []byte(x)
			f.Mode |= 0777 // see sync/files.go
		}
		res = append(res, f)
		return nil
	})
	if err != nil {
		return nil, err
	}
	return res, nil
}

func CurrentUserAndGroup() (string, int, string, int) {
	u, err := user.Current()
	if err != nil {
		panic(err)
	}
	g, err := user.LookupGroupId(u.Gid)
	if err != nil {
		panic(err)
	}
	uid, err := strconv.Atoi(u.Uid)
	if err != nil {
		panic(err)
	}
	gid, err := strconv.Atoi(g.Gid)
	if err != nil {
		panic(err)
	}
	return u.Username, uid, g.Name, gid
}

func CreateFile(path string, data string, mode fs.FileMode) {
	err := os.WriteFile(path, []byte(data), 0644)
	if err != nil {
		panic(err)
	}
	err = os.Chmod(path, mode)
	if err != nil {
		panic(err)
	}
}

func CreateSymlink(path string, data string) {
	err := os.Symlink(data, path)
	if err != nil {
		panic(err)
	}
}

func CreateDirectory(path string, mode fs.FileMode) {
	err := os.Mkdir(path, 0700)
	if err != nil {
		panic(err)
	}
	err = os.Chmod(path, mode)
	if err != nil {
		panic(err)
	}
}

func CreateDirectoryExists(path string, mode fs.FileMode) {
	err := os.Mkdir(path, 0700)
	if err != nil && !os.IsExist(err) {
		panic(err)
	}
	err = os.Chmod(path, mode)
	if err != nil {
		panic(err)
	}
}

func CreateFifo(path string, mode fs.FileMode) {
	err := syscall.Mkfifo(path, 0600)
	if err != nil {
		panic(err)
	}
	err = os.Chmod(path, mode)
	if err != nil {
		panic(err)
	}
}