package service

import (
	"crypto/md5"
	"encoding/base64"
	"fmt"
	"io"
	"mime/multipart"
	"os"
	"path/filepath"
	"strings"
	"time"

	"bugulma/backend/pkg/config"
)

type ImageService struct {
	config     *config.Config
	staticPath string
}

type UploadedImage struct {
	URL  string `json:"url"`
	Path string `json:"path"`
}

func NewImageService(cfg *config.Config) *ImageService {
	return &ImageService{
		config:     cfg,
		staticPath: "static/images",
	}
}

// SaveImage saves an uploaded image file and returns the URL and local path
func (s *ImageService) SaveImage(file multipart.File, header *multipart.FileHeader, subfolder string) (*UploadedImage, error) {
	// Create subfolder if it doesn't exist
	folderPath := filepath.Join(s.staticPath, subfolder)
	if err := os.MkdirAll(folderPath, 0755); err != nil {
		return nil, fmt.Errorf("failed to create directory: %w", err)
	}

	// Generate unique filename based on content hash and timestamp
	content, err := io.ReadAll(file)
	if err != nil {
		return nil, fmt.Errorf("failed to read file content: %w", err)
	}

	hash := fmt.Sprintf("%x", md5.Sum(content))
	timestamp := time.Now().Format("20060102_150405")
	ext := s.getFileExtension(header.Filename)
	filename := fmt.Sprintf("%s_%s%s", hash[:8], timestamp, ext)

	filePath := filepath.Join(folderPath, filename)

	// Write file to disk
	if err := os.WriteFile(filePath, content, 0644); err != nil {
		return nil, fmt.Errorf("failed to save file: %w", err)
	}

	// Generate URL (assuming static files are served from /static/)
	url := fmt.Sprintf("/static/images/%s/%s", subfolder, filename)

	return &UploadedImage{
		URL:  url,
		Path: filePath,
	}, nil
}

// SaveDataURL saves a base64 data URL as an image file
func (s *ImageService) SaveDataURL(dataURL, subfolder string) (*UploadedImage, error) {
	// Create subfolder if it doesn't exist
	folderPath := filepath.Join(s.staticPath, subfolder)
	if err := os.MkdirAll(folderPath, 0755); err != nil {
		return nil, fmt.Errorf("failed to create directory: %w", err)
	}

	// Parse data URL (data:image/png;base64,...)
	parts := strings.Split(dataURL, ",")
	if len(parts) != 2 {
		return nil, fmt.Errorf("invalid data URL format")
	}

	header := parts[0]
	if !strings.HasPrefix(header, "data:image/") {
		return nil, fmt.Errorf("not an image data URL")
	}

	// Extract MIME type and base64 data
	contentType := strings.TrimSuffix(strings.TrimPrefix(header, "data:"), ";base64")
	ext := s.getExtensionFromMIME(contentType)

	// Decode base64
	content, err := base64.StdEncoding.DecodeString(parts[1])
	if err != nil {
		return nil, fmt.Errorf("failed to decode base64: %w", err)
	}

	// Generate unique filename
	hash := fmt.Sprintf("%x", md5.Sum(content))
	timestamp := time.Now().Format("20060102_150405")
	filename := fmt.Sprintf("%s_%s%s", hash[:8], timestamp, ext)

	filePath := filepath.Join(folderPath, filename)

	// Write file to disk
	if err := os.WriteFile(filePath, content, 0644); err != nil {
		return nil, fmt.Errorf("failed to save file: %w", err)
	}

	// Generate URL
	url := fmt.Sprintf("/static/images/%s/%s", subfolder, filename)

	return &UploadedImage{
		URL:  url,
		Path: filePath,
	}, nil
}

// DeleteImage removes an image file from disk
func (s *ImageService) DeleteImage(imagePath string) error {
	// Remove the static/images/ prefix to get the actual file path
	if strings.HasPrefix(imagePath, "/static/images/") {
		imagePath = strings.TrimPrefix(imagePath, "/static/images/")
		imagePath = filepath.Join(s.staticPath, imagePath)
	}

	if err := os.Remove(imagePath); err != nil && !os.IsNotExist(err) {
		return fmt.Errorf("failed to delete image: %w", err)
	}

	return nil
}

// getFileExtension extracts file extension from filename
func (s *ImageService) getFileExtension(filename string) string {
	ext := filepath.Ext(filename)
	if ext == "" {
		return ".jpg" // default extension
	}
	return strings.ToLower(ext)
}

// getExtensionFromMIME converts MIME type to file extension
func (s *ImageService) getExtensionFromMIME(mimeType string) string {
	switch mimeType {
	case "image/jpeg":
		return ".jpg"
	case "image/png":
		return ".png"
	case "image/gif":
		return ".gif"
	case "image/webp":
		return ".webp"
	case "image/svg+xml":
		return ".svg"
	default:
		return ".jpg"
	}
}