// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.

package filestore

import (
	"context"
	"os"

	"github.com/zeebo/errs"
	monkit "gopkg.in/spacemonkeygo/monkit.v2"

	"storj.io/storj/storage"
)

var (
	// Error is the default filestore error class
	Error = errs.Class("filestore error")

	mon = monkit.Package()

	_ storage.Blobs = (*Store)(nil)
)

// Store implements a blob store
type Store struct {
	dir *Dir
}

// New creates a new disk blob store in the specified directory
func New(dir *Dir) *Store {
	return &Store{dir}
}

// NewAt creates a new disk blob store in the specified directory
func NewAt(path string) (*Store, error) {
	dir, err := NewDir(path)
	if err != nil {
		return nil, Error.Wrap(err)
	}
	return &Store{dir}, nil
}

// Close closes the store.
func (store *Store) Close() error { return nil }

// Open loads blob with the specified hash
func (store *Store) Open(ctx context.Context, ref storage.BlobRef) (_ storage.BlobReader, err error) {
	defer mon.Task()(&ctx)(&err)
	file, err := store.dir.Open(ctx, ref)
	if err != nil {
		if os.IsNotExist(err) {
			return nil, err
		}
		return nil, Error.Wrap(err)
	}
	return newBlobReader(file), nil
}

// Delete deletes blobs with the specified ref
func (store *Store) Delete(ctx context.Context, ref storage.BlobRef) (err error) {
	defer mon.Task()(&ctx)(&err)
	err = store.dir.Delete(ctx, ref)
	return Error.Wrap(err)
}

// GarbageCollect tries to delete any files that haven't yet been deleted
func (store *Store) GarbageCollect(ctx context.Context) (err error) {
	defer mon.Task()(&ctx)(&err)
	err = store.dir.GarbageCollect(ctx)
	return Error.Wrap(err)
}

// Create creates a new blob that can be written
// optionally takes a size argument for performance improvements, -1 is unknown size
func (store *Store) Create(ctx context.Context, ref storage.BlobRef, size int64) (_ storage.BlobWriter, err error) {
	defer mon.Task()(&ctx)(&err)
	file, err := store.dir.CreateTemporaryFile(ctx, size)
	if err != nil {
		return nil, Error.Wrap(err)
	}
	return newBlobWriter(ref, store, file), nil
}

// FreeSpace returns how much space left in underlying directory
func (store *Store) FreeSpace() (int64, error) {
	info, err := store.dir.Info()
	if err != nil {
		return 0, err
	}
	return info.AvailableSpace, nil
}