package steam

import (
	"archive/tar"
	"io"
	"os"
	"strings"
	"path/filepath"
)

func (l *Library) ExtractUpdate(r io.Reader) error {
	if err := os.Chdir(l.Folder); err != nil {
		return err
	}

	// withinArchive := map[string]struct{}{}
	// onDisk, err := fileListing(

	treader := tar.NewReader(r)

	for {
		hdr, err := treader.Next()
		if err == io.EOF {
			// We've reached the end! Whoee
			break
		}
		if err != nil {
			return err
		}

		// Fix windows slashes...
		fileName := strings.Replace(hdr.Name, "\\", "/", -1)

		info := hdr.FileInfo()
		if info.IsDir() {
			// I don't like hard-coded permissions but it
			// it helps with overall platform compatibility
			if err = os.MkdirAll(fileName, 0775); err != nil {
				return err
			}
			continue
		}

		if err = os.MkdirAll(filepath.Dir(fileName), 0775); err != nil {
			return err
		}

		fi, err := os.Stat(fileName)
		if !os.IsNotExist(err) {
			// If the file in the archive is not newer, skip
			if !info.ModTime().After(fi.ModTime()) {
				continue
			}
		}

		// Create a file handle to work with
		f, err := os.OpenFile(fileName, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0664)
		if err != nil {
			return err
		}
		if _, err := io.Copy(f, treader); err != nil {
			return err
		}
		f.Close()

	}

	return nil
}