package zip

import (
	"archive/zip"
	"fmt"
	"io"
	"io/fs"
	"os"
	"strings"

	"git.sa-roci.de/oss/go_zipper"
)

const ArchiveExt = ".zip"

// NewZipper makes a new Zipper.
func NewZipper(zipFilename string) zipper.Zipper {
	if !strings.HasSuffix(strings.ToLower(zipFilename), ArchiveExt) {
		zipFilename += ArchiveExt
	}
	z := zZipper{
		Zipper: zipper.NewBaseZipper(zipFilename),
	}
	z.SetCompressor(z)
	return z
}

type zZipper struct {
	zipper.Zipper
}

func (z zZipper) OpenWriter(zipFile *os.File) error {
	z.SetWriter(zip.NewWriter(zipFile))
	return nil
}

func (z zZipper) MultiFileSupported() bool {
	return true
}

func (z zZipper) Compress(fileToZip *os.File, pathInArchive string) (err error) {
	// Get the file information
	var info fs.FileInfo
	if info, err = fileToZip.Stat(); err != nil {
		return err
	}

	var header *zip.FileHeader
	if header, err = zip.FileInfoHeader(info); err != nil {
		return err
	}

	filename := info.Name()

	// Using FileInfoHeader() above only uses the basename of the file. If we want
	// to preserve the folder structure we can overwrite this with the full path.
	if len(pathInArchive) > 0 || strings.Contains(filename, "/") || strings.Contains(filename, "\\") {
		header.Name = zipper.PrependPath(filename, pathInArchive)
	}

	// Change to deflate to gain better compression
	// see http://golang.org/pkg/archive/zip/#pkg-constants
	header.Method = zip.Deflate

	if zipWriter, ok := z.GetWriter().(*zip.Writer); ok {
		var writer io.Writer
		if writer, err = zipWriter.CreateHeader(header); err != nil {
			return err
		}

		_, err = io.Copy(writer, fileToZip)
	} else {
		err = fmt.Errorf("unable to access compressor")
	}

	return
}