package local

import (
	"bytes"
	"io"
	"io/fs"
	"os"
	"path/filepath"
	"strings"

	"codeberg.org/u1f320/filer/store"
	"emperror.dev/errors"
	"github.com/google/uuid"
	"github.com/rs/zerolog/log"
)

const (
	StoreKey         = "local"
	ErrNotDirectory  = errors.Sentinel("not a directory")
	ErrAlreadyExists = errors.Sentinel("file already exists")

	defaultPath = "uploads"
)

type localStore struct {
	path string
}

var _ store.Store = (*localStore)(nil)

// New creates a new local store.
// It creates the directory if it doesn't exist,
func New(path string) (store.Store, error) {
	if path == "" {
		path = defaultPath
	}

	if !strings.HasPrefix(path, "/") {
		wd, err := os.Getwd()
		if err != nil {
			return nil, errors.Wrap(err, "getting working directory")
		}

		path = filepath.Join(wd, path)
	}

	log.Info().Str("path", path).Msg("Using local storage")

	fi, err := os.Stat(path)
	if err != nil {
		if !errors.Is(err, fs.ErrNotExist) {
			return nil, errors.Wrap(err, "calling Stat on path")
		}

		err = os.MkdirAll(path, 0o744)
		if err != nil {
			return nil, errors.Wrap(err, "creating uploads directory")
		}
	} else if !fi.IsDir() {
		return nil, ErrNotDirectory
	}

	return &localStore{
		path: path,
	}, nil
}

func (l *localStore) WriteFile(id uuid.UUID, data io.Reader, contentType string) (err error) {
	path := filepath.Join(l.path, id.String())

	_, err = os.Stat(path)
	if err == nil {
		return ErrAlreadyExists
	}

	file, err := os.Create(path)
	if err != nil {
		return errors.Wrap(err, "creating file")
	}
	defer func() {
		err = errors.Append(err, file.Close())
	}()

	_, err = io.Copy(file, data)
	if err != nil {
		return errors.Wrap(err, "writing data to file")
	}

	return nil
}

func (l *localStore) GetFile(id uuid.UUID) (r io.Reader, err error) {
	path := filepath.Join(l.path, id.String())

	file, err := os.Open(path)
	if err != nil {
		if errors.Is(err, fs.ErrNotExist) {
			return nil, store.ErrNotExist
		}
	}
	defer func() {
		err = errors.Append(err, file.Close())
	}()

	b := new(bytes.Buffer)
	_, err = io.Copy(b, file)
	if err != nil {
		return nil, errors.Wrap(err, "copying file to buffer")
	}

	return b, nil
}

func (l *localStore) DeleteFile(id uuid.UUID) error {
	path := filepath.Join(l.path, id.String())

	err := os.Remove(path)
	if err != nil {
		if !errors.Is(err, fs.ErrNotExist) {
			return nil // a file already not existing is not an error
		}

		return errors.Wrap(err, "removing file")
	}
	return nil
}