package storage

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"path/filepath"

	"mstore/app/logger"
	"mstore/pkg/auxuuid"
)

type Storage struct {
	basepath string
	logg     *logger.Logger
}

func NewStorage(basepath string) *Storage {
	res := &Storage{
		basepath: basepath,
	}
	res.logg = logger.NewLogger("storage")
	return res
}

const (
	filesubdir = "files"
	tmpsubdir  = "tmps"
)

func (store *Storage) makeCollecionpath(collection string) string {
	return filepath.Join(store.basepath, filesubdir, collection)
}

func (store *Storage) makeFilepath(collection, filename string) string {
	return filepath.Join(store.basepath, filesubdir, collection, filename)
}

func (store *Storage) makeTmppath(tmpname string) string {
	return filepath.Join(store.basepath, tmpsubdir, tmpname)
}

func (store *Storage) makeTmpsubdir() string {
	return filepath.Join(store.basepath, tmpsubdir)
}

func (store *Storage) makeFilesubdir(collection, filename string) string {
	return filepath.Join(store.basepath, filesubdir)
}

func (store *Storage) GetFileReader(collection, filename string) (io.ReadCloser, error) {
	var err error
	var res io.ReadCloser

	filename = store.makeFilepath(collection, filename)
	file, err := os.OpenFile(filename, os.O_RDONLY, 0)
	if err != nil {
		return res, err
	}
	res = file
	return res, err
}

func (store *Storage) HardlinkFile(tmpname, collection, filename string) error {
	var err error
	dirname := store.makeCollecionpath(collection)
	err = os.MkdirAll(dirname, 0750)
	if err != nil {
		return err
	}

	filename = store.makeFilepath(collection, filename)
	os.Remove(filename) // TODO

	tmpname = store.makeTmppath(tmpname)
	err = os.Link(tmpname, filename)
	if err != nil {
		return err
	}
	err = os.Remove(tmpname)
	if err != nil {
		return err
	}
	return err
}

func (store *Storage) WriteTempFile(source io.Reader) (string, int64, string, error) {
	var err error
	var size int64
	var digest string

	tmpname := auxuuid.NewUUID()
	tmpname = fmt.Sprintf("file-%s.tmp", tmpname)
	tmppath := store.makeTmppath(tmpname)

	tmpdirpath := store.makeTmpsubdir()
	err = os.MkdirAll(tmpdirpath, 0750)
	if err != nil {
		return tmpname, size, digest, err
	}

	file, err := os.OpenFile(tmppath, os.O_WRONLY|os.O_CREATE, 0640)
	if err != nil {
		return tmpname, size, digest, err
	}
	defer file.Close()

	hasher := sha256.New()
	writer := io.MultiWriter(file, hasher)

	size, err = io.Copy(writer, source)
	if err != nil {
		return tmpname, size, digest, err
	}
	digest = hex.EncodeToString(hasher.Sum(nil))
	digest = fmt.Sprintf("sha256:%s", digest)

	return tmpname, size, digest, err
}

func (store *Storage) DeleteFile(collection, filename string) error {
	var err error
	filename = store.makeFilepath(collection, filename)
	err = os.Remove(filename)
	if err != nil {
		return err
	}

	// TODO: more safe removing
	dirname := store.makeCollecionpath(collection)

	err = os.RemoveAll(dirname)
	if err != nil {
		return err
	}
	return err
}

const (
	upsubdir   = "uploads"
	blobsubdir = "blobs"
)

func (store *Storage) makeUppath(upname string) string {
	return filepath.Join(store.basepath, upsubdir, upname) + ".bin"
}

func (store *Storage) makeUpsubdir() string {
	return filepath.Join(store.basepath, upsubdir)
}

func (store *Storage) makeBlobpath(upname string) string {
	return filepath.Join(store.basepath, blobsubdir, upname) + ".bin"
}

func (store *Storage) makeBlobsubdir() string {
	return filepath.Join(store.basepath, blobsubdir)
}

func (store *Storage) WriteUpload(digest string, source io.Reader) (int64, error) {
	var err error
	var recsize int64

	uploadDir := store.makeUpsubdir()
	err = os.MkdirAll(uploadDir, 0750)
	if err != nil {
		return recsize, err
	}

	uploadPath := store.makeUppath(digest)
	uploadFile, err := os.OpenFile(uploadPath, os.O_WRONLY|os.O_CREATE, 0644)
	if err != nil {
		return recsize, err
	}
	defer uploadFile.Close()

	hasher := sha256.New() // TODO: upload cheking
	streamWriter := io.MultiWriter(uploadFile, hasher)
	recsize, err = io.Copy(streamWriter, source)
	if err != nil {
		return recsize, err
	}
	return recsize, err
}

func (store *Storage) LinkUpload(reference, digest string) error {
	var err error
	uploadPath := store.makeUppath(reference)
	blobPath := store.makeBlobpath(digest)

	blobdir := store.makeBlobsubdir()
	err = os.MkdirAll(blobdir, 0750)
	if err != nil {
		return err
	}

	err = os.Link(uploadPath, blobPath)
	if err != nil {
		return err
	}
	err = os.Remove(uploadPath)
	if err != nil {
		return err
	}
	return err
}

func (store *Storage) RemoveUpload(digest string) error {
	var err error
	uploadPath := store.makeUppath(digest)
	err = os.Remove(uploadPath)
	if err != nil {
		return err
	}
	return err
}