package storage

import (
	"context"
	"fmt"
	"io"
	"mime/multipart"
	"os"
	"path/filepath"

	"photography-backend/internal/config"

	"go.uber.org/zap"
)

// UploadedFile 上传后的文件信息
type UploadedFile struct {
	Filename    string `json:"filename"`
	OriginalURL string `json:"original_url"`
	ThumbnailURL string `json:"thumbnail_url,omitempty"`
	Size        int64  `json:"size"`
	MimeType    string `json:"mime_type"`
}

// StorageService 存储服务接口
type StorageService interface {
	UploadPhoto(ctx context.Context, file multipart.File, filename string) (*UploadedFile, error)
	DeletePhoto(filename string) error
	GetPhotoURL(filename string) string
	GenerateThumbnail(ctx context.Context, filename string) error
}

// LocalStorageService 本地存储服务实现
type LocalStorageService struct {
	config    *config.Config
	logger    *zap.Logger
	uploadDir string
	baseURL   string
}

// NewLocalStorageService 创建本地存储服务
func NewLocalStorageService(config *config.Config, logger *zap.Logger) *LocalStorageService {
	uploadDir := config.Storage.Local.BasePath
	if uploadDir == "" {
		uploadDir = "./uploads"
	}
	
	baseURL := config.Storage.Local.BaseURL
	if baseURL == "" {
		baseURL = fmt.Sprintf("http://localhost:%d/uploads", config.App.Port)
	}
	
	// 确保上传目录存在
	if err := os.MkdirAll(uploadDir, 0755); err != nil {
		logger.Error("Failed to create upload directory", zap.Error(err))
	}
	
	// 创建子目录
	dirs := []string{"photos", "thumbnails", "temp"}
	for _, dir := range dirs {
		dirPath := filepath.Join(uploadDir, dir)
		if err := os.MkdirAll(dirPath, 0755); err != nil {
			logger.Error("Failed to create subdirectory", zap.String("dir", dir), zap.Error(err))
		}
	}
	
	return &LocalStorageService{
		config:    config,
		logger:    logger,
		uploadDir: uploadDir,
		baseURL:   baseURL,
	}
}

// UploadPhoto 上传照片
func (s *LocalStorageService) UploadPhoto(ctx context.Context, file multipart.File, filename string) (*UploadedFile, error) {
	// 保存原图
	photoPath := filepath.Join(s.uploadDir, "photos", filename)
	
	out, err := os.Create(photoPath)
	if err != nil {
		s.logger.Error("Failed to create file", zap.String("path", photoPath), zap.Error(err))
		return nil, err
	}
	defer out.Close()
	
	// 重置文件指针
	file.Seek(0, 0)
	
	// 复制文件内容
	size, err := io.Copy(out, file)
	if err != nil {
		s.logger.Error("Failed to copy file", zap.Error(err))
		return nil, err
	}
	
	// 获取文件信息
	_, err = out.Stat()
	if err != nil {
		s.logger.Error("Failed to get file info", zap.Error(err))
		return nil, err
	}
	
	uploadedFile := &UploadedFile{
		Filename:    filename,
		OriginalURL: s.GetPhotoURL(filename),
		Size:        size,
		MimeType:    s.getMimeType(filename),
	}
	
	s.logger.Info("Photo uploaded successfully", 
		zap.String("filename", filename),
		zap.Int64("size", size))
	
	return uploadedFile, nil
}

// DeletePhoto 删除照片
func (s *LocalStorageService) DeletePhoto(filename string) error {
	// 删除原图
	photoPath := filepath.Join(s.uploadDir, "photos", filename)
	if err := os.Remove(photoPath); err != nil && !os.IsNotExist(err) {
		s.logger.Error("Failed to delete photo", zap.String("path", photoPath), zap.Error(err))
		return err
	}
	
	// 删除缩略图
	thumbnailPath := filepath.Join(s.uploadDir, "thumbnails", filename)
	if err := os.Remove(thumbnailPath); err != nil && !os.IsNotExist(err) {
		s.logger.Warn("Failed to delete thumbnail", zap.String("path", thumbnailPath), zap.Error(err))
	}
	
	s.logger.Info("Photo deleted successfully", zap.String("filename", filename))
	return nil
}

// GetPhotoURL 获取照片 URL
func (s *LocalStorageService) GetPhotoURL(filename string) string {
	return fmt.Sprintf("%s/photos/%s", s.baseURL, filename)
}

// GetThumbnailURL 获取缩略图 URL
func (s *LocalStorageService) GetThumbnailURL(filename string) string {
	return fmt.Sprintf("%s/thumbnails/%s", s.baseURL, filename)
}

// GenerateThumbnail 生成缩略图
func (s *LocalStorageService) GenerateThumbnail(ctx context.Context, filename string) error {
	// TODO: 实现缩略图生成逻辑
	// 这里需要使用图像处理库，如 imaging 或 bild
	s.logger.Info("Generating thumbnail", zap.String("filename", filename))
	
	// 示例实现 - 实际项目中应该使用图像处理库
	photoPath := filepath.Join(s.uploadDir, "photos", filename)
	thumbnailPath := filepath.Join(s.uploadDir, "thumbnails", filename)
	
	// 检查原图是否存在
	if _, err := os.Stat(photoPath); os.IsNotExist(err) {
		return fmt.Errorf("original photo not found: %s", filename)
	}
	
	// 这里应该实现实际的缩略图生成逻辑
	// 暂时复制原图作为缩略图
	sourceFile, err := os.Open(photoPath)
	if err != nil {
		return err
	}
	defer sourceFile.Close()
	
	destFile, err := os.Create(thumbnailPath)
	if err != nil {
		return err
	}
	defer destFile.Close()
	
	_, err = io.Copy(destFile, sourceFile)
	if err != nil {
		return err
	}
	
	s.logger.Info("Thumbnail generated successfully", zap.String("filename", filename))
	return nil
}

// getMimeType 根据文件扩展名获取 MIME 类型
func (s *LocalStorageService) getMimeType(filename string) string {
	ext := filepath.Ext(filename)
	switch ext {
	case ".jpg", ".jpeg":
		return "image/jpeg"
	case ".png":
		return "image/png"
	case ".gif":
		return "image/gif"
	case ".webp":
		return "image/webp"
	case ".bmp":
		return "image/bmp"
	default:
		return "application/octet-stream"
	}
}

// NewStorageService 根据配置创建存储服务
func NewStorageService(config *config.Config, logger *zap.Logger) StorageService {
	switch config.Storage.Type {
	case "s3":
		// TODO: 实现 S3 存储服务
		logger.Warn("S3 storage not implemented yet, using local storage")
		return NewLocalStorageService(config, logger)
	case "minio":
		// TODO: 实现 MinIO 存储服务
		logger.Warn("MinIO storage not implemented yet, using local storage")
		return NewLocalStorageService(config, logger)
	default:
		return NewLocalStorageService(config, logger)
	}
}