package blobs

import (
	"context"
	"errors"
	"io"
	"nf-repo/internal/interfaces"
	"nf-repo/internal/model"
	"nf-repo/internal/opt"
	"os"
	"path"
	"sync"
)

type localHandler struct {
	base string
	sync.Mutex
}

func (l *localHandler) path(hash model.Hash) string {
	//return path.Join(l.base, hash.Hex)
	dir := path.Join(l.base, hash.Hex[:2], hash.Hex[2:4])
	_ = os.MkdirAll(dir, 0755)
	return path.Join(dir, hash.Hex)
}

func (l *localHandler) Get(ctx context.Context, repo string, hash model.Hash) (io.ReadCloser, error) {
	var (
		err error
		f   *os.File
	)

	l.Lock()
	defer l.Unlock()

	if f, err = os.Open(l.path(hash)); err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return nil, opt.ErrNotFound
		}

		return nil, err
	}

	return f, nil
}

func (l *localHandler) Stat(ctx context.Context, repo string, hash model.Hash) (int64, error) {
	var (
		err  error
		info os.FileInfo
	)

	l.Lock()
	defer l.Unlock()

	if info, err = os.Stat(l.path(hash)); err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return 0, opt.ErrNotFound
		}

		return 0, err
	}

	return info.Size(), nil
}

func (l *localHandler) Put(ctx context.Context, repo string, hash model.Hash, rc io.ReadCloser) error {
	var (
		err error
		f   *os.File
	)

	l.Lock()
	defer l.Unlock()

	if f, err = os.OpenFile(l.path(hash), os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0644); err != nil {
		return err
	}

	if _, err = io.Copy(f, rc); err != nil {
		return err
	}

	return nil
}

func (l *localHandler) Delete(ctx context.Context, repo string, hash model.Hash) error {
	var (
		err      error
		info     os.FileInfo
		filename = l.path(hash)
	)

	l.Lock()
	defer l.Unlock()

	if info, err = os.Stat(filename); err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return opt.ErrNotFound
		}

		return err
	}

	_ = info

	return os.Remove(filename)
}

func NewLocalBlobHandler(baseDir string) interfaces.BlobHandler {
	_ = os.MkdirAll(baseDir, 0755)
	return &localHandler{base: baseDir}
}