package biz

import (
	"bufio"
	"context"
	"crypto/md5"
	"encoding/hex"
	"errors"
	"io"
	"net/http"
	"path/filepath"
	"strings"
	"time"

	"github.com/google/uuid"
)

type MediaRepo interface {
	MediaMetadataRepo
	UploadRepo
}

type MediaUsecase struct {
	MediaRepo
	files FileStorage
}

func NewMediaUsecase(repo MediaRepo, files FileStorage) *MediaUsecase {
	return &MediaUsecase{MediaRepo: repo, files: files}
}

var allowedMediaExtensions = map[string]bool{
	".jpg": true, ".jpeg": true, ".png": true, ".gif": true, ".webp": true, ".bmp": true, ".ico": true, ".avif": true,
	".mp3": true, ".wav": true, ".ogg": true, ".m4a": true, ".flac": true, ".aac": true,
	".mp4": true, ".webm": true, ".mov": true, ".avi": true, ".mkv": true,
	".txt": true, ".md": true, ".csv": true, ".json": true, ".log": true, ".pdf": true,
	".doc": true, ".docx": true, ".xls": true, ".xlsx": true, ".ppt": true, ".pptx": true,
	".zip": true, ".rar": true, ".7z": true, ".tar": true, ".gz": true, ".tgz": true, ".bin": true,
}

func validateMediaName(name string) error {
	if name == "" || strings.TrimSpace(name) != name || strings.ContainsAny(name, `/\`) {
		return errors.New("file extension is not allowed")
	}
	if !allowedMediaExtensions[strings.ToLower(filepath.Ext(name))] {
		return errors.New("file extension is not allowed")
	}
	return nil
}
func (uc *MediaUsecase) Upload(ctx context.Context, userID uint, name, mime string, categoryID int, reader io.Reader, save bool) (*MediaFile, error) {
	if err := validateMediaName(name); err != nil {
		return nil, err
	}
	ext := strings.ToLower(filepath.Ext(name))
	buffered := bufio.NewReader(reader)
	if header, _ := buffered.Peek(512); len(header) > 0 {
		mime = http.DetectContentType(header)
	}
	key := time.Now().Format("20060102") + "/" + uuid.NewString() + ext
	hash := md5.New()
	stored, err := uc.files.Put(ctx, key, io.TeeReader(buffered, hash))
	if err != nil {
		return nil, err
	}
	media := &MediaFile{Name: name, CategoryID: categoryID, URL: stored.URL, Tag: strings.TrimPrefix(ext, "."), Key: key, Size: stored.Size, Mime: mime, MD5: hex.EncodeToString(hash.Sum(nil)), UserID: userID}
	if save {
		if err = uc.CreateMedia(ctx, media); err != nil {
			_ = uc.files.Delete(ctx, key)
			return nil, err
		}
	}
	return media, nil
}
func (uc *MediaUsecase) Delete(ctx context.Context, id uint) error {
	media, err := uc.FindMedia(ctx, id)
	if err != nil {
		return err
	}
	count, err := uc.MediaKeyReferences(ctx, media.Key)
	if err != nil {
		return err
	}
	if count <= 1 {
		if err = uc.files.Delete(ctx, media.Key); err != nil {
			return err
		}
	}
	return uc.DeleteMedia(ctx, id)
}
func (uc *MediaUsecase) ListStorage(ctx context.Context, prefix, cursor string, limit int) ([]*StoredFile, string, bool, error) {
	return uc.files.List(ctx, prefix, cursor, limit)
}