package main

import (
	"archive/tar"
	"encoding/hex"
	"fmt"
	"io"
	"math/rand"
	"os"
	"path/filepath"
	"strings"
)

func archiveDir(srcDir, dstPath string) error {
	var err error
	srcDir = filepath.Clean(srcDir)
	dstPath = filepath.Clean(dstPath)

	err = os.MkdirAll(filepath.Dir(dstPath), 0755)
	if err != nil {
		return err
	}
	tarFile, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0640)
	if err != nil {
		return err
	}
	defer tarFile.Close()

	tarWriter := tar.NewWriter(tarFile)
	defer tarWriter.Close()

	walker := func(filePath string, fileInfo os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !fileInfo.Mode().IsRegular() {
			return nil
		}
		header, err := tar.FileInfoHeader(fileInfo, fileInfo.Name())
		if err != nil {
			return err
		}
		header.Name = strings.TrimPrefix(filePath, filepath.Clean(srcDir))
		header.Name = strings.TrimPrefix(header.Name, string(filepath.Separator))

		err = tarWriter.WriteHeader(header)
		if err != nil {
			return err
		}
		file, err := os.Open(filePath)
		if err != nil {
			return err
		}
		defer file.Close()
		_, err = io.Copy(tarWriter, file)
		if err != nil {
			return err
		}
		return nil
	}
	err = filepath.Walk(srcDir, walker)
	if err != nil {
		return err
	}
	return err
}

func unarchive(filePath, dstDir string) error {
	var err error
	err = os.MkdirAll(dstDir, 0755)
	if err != nil {
		return err
	}
	file, err := os.OpenFile(filePath, os.O_RDONLY, 0)
	if err != nil {
		return err
	}
	defer file.Close()

	tarReader := tar.NewReader(file)
	//defer tarReader.Close()
	for {
		header, err := tarReader.Next()
		switch {
		case err == io.EOF:
			return nil
		case err != nil:
			return err
		case header == nil:
			continue
		}
		target := filepath.Join(dstDir, header.Name)
		target = filepath.Clean(target)
		//fileInfo := header.FileInfo()
		switch header.Typeflag {
		case tar.TypeDir:
			_, err := os.Stat(target)
			if err != nil {
				err := os.MkdirAll(target, 0755)
				if err != nil {
					return err
				}

			}
		case tar.TypeReg:
			err := os.MkdirAll(filepath.Dir(target), 0755)
			if err != nil {
				return err
			}
			file, err := os.OpenFile(target, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(header.Mode))
			if err != nil {
				return err
			}
			_, err = io.Copy(file, tarReader)
			if err != nil {
				return err
			}
			file.Close()
		}
	}
	return err
}

func makeTmpFileName(prefix string) string {
	randBytes := make([]byte, 6)
	rand.Read(randBytes)
	suffix := hex.EncodeToString(randBytes)
	return fmt.Sprintf("%s.tmp.%s", prefix, suffix)
}