package main

import (
	"image"
	"image/jpeg"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"time"
)

func init() {
	existing_backends = append(existing_backends, "local")
}

type LocalFileBackend struct {
	BaseDir string
}

func (l *LocalFileBackend) getPath(box, name string) string {
	return path.Join(l.BaseDir, box, name+".jpg")
}

func (l *LocalFileBackend) DeletePicture(box, name string) error {
	return os.Remove(l.getPath(box, name))
}

func (l *LocalFileBackend) ServeFile() http.Handler {
	return http.FileServer(http.Dir(l.BaseDir))
}

func (l *LocalFileBackend) createPictureInfo(local_path, name string, file os.FileInfo) *Picture {
	return &Picture{
		local_path,                           // Path
		name,                                 // Basename
		name[:len(name)-len(path.Ext(name))], // Sanitized filename
		file.ModTime(),                       // UploadTime
	}
}

func (l *LocalFileBackend) GetPicture(box, name string, w io.Writer) error {
	local_path := l.getPath(box, name)

	fd, err := os.Open(local_path)
	if err != nil {
		return err
	}
	defer fd.Close()

	_, err = io.Copy(w, fd)

	return err
}

func (l *LocalFileBackend) GetPictureInfo(box, name string) (*Picture, error) {
	local_path := l.getPath(box, name)

	file, err := os.Stat(local_path)
	if err != nil {
		return nil, err
	}

	return l.createPictureInfo(path.Join(box, name+".jpg"), name, file), nil
}

func (l *LocalFileBackend) ListPictures(box string) ([]*Picture, error) {
	files, err := ioutil.ReadDir(path.Join(l.BaseDir, box))
	if err != nil {
		return nil, err
	}

	pictures := make([]*Picture, 0)
	for _, file := range files {
		if !file.IsDir() {
			pictures = append(pictures, l.createPictureInfo(path.Join(box, file.Name()), file.Name(), file))
		}
	}

	return pictures, nil
}

func (l *LocalFileBackend) MovePicture(box_from, box_to, name string) error {
	newpath := l.getPath(box_to, name)

	err := os.Rename(
		l.getPath(box_from, name),
		newpath,
	)
	if err != nil {
		return err
	}

	return os.Chtimes(newpath, time.Now(), time.Now())
}

func (l *LocalFileBackend) PutPicture(box, name string, img *image.Image) error {
	fd, err := os.OpenFile(l.getPath(box, name), os.O_RDWR|os.O_CREATE, 0644)
	if err != nil {
		return err
	}
	defer fd.Close()

	return jpeg.Encode(fd, *img, nil)
}