package upload

import (
	"bytes"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"github.com/google/uuid"
)

var allowedTypes = map[string]string{
	"image/jpeg": ".jpg",
	"image/png":  ".png",
	"image/webp": ".webp",
	"image/gif":  ".gif",
}

type Storage struct {
	RootDir string
}

func NewStorage(root string) (*Storage, error) {
	if err := os.MkdirAll(root, 0755); err != nil {
		return nil, err
	}
	return &Storage{RootDir: root}, nil
}

func (s *Storage) SaveProductImage(productID int, file multipart.File, header *multipart.FileHeader) (string, error) {
	buf := make([]byte, 512)
	n, err := file.Read(buf)
	if err != nil && err != io.EOF {
		return "", err
	}
	contentType := http.DetectContentType(buf[:n])
	ext, ok := allowedTypes[contentType]
	if !ok {
		return "", fmt.Errorf("недопустимый тип файла: %s", contentType)
	}

	if _, err := file.Seek(0, io.SeekStart); err != nil {
		return "", err
	}

	dir := filepath.Join(s.RootDir, "products", fmt.Sprintf("%d", productID))
	if err := os.MkdirAll(dir, 0755); err != nil {
		return "", err
	}

	name := uuid.New().String() + ext
	fullPath := filepath.Join(dir, name)

	dst, err := os.Create(fullPath)
	if err != nil {
		return "", err
	}
	defer dst.Close()

	if _, err := io.Copy(dst, io.MultiReader(bytes.NewReader(buf[:n]), file)); err != nil {
		os.Remove(fullPath)
		return "", err
	}

	webPath := "/uploads/products/" + fmt.Sprintf("%d", productID) + "/" + name
	_ = header
	return webPath, nil
}

func (s *Storage) Remove(webPath string) error {
	if !strings.HasPrefix(webPath, "/uploads/") {
		return nil
	}
	rel := strings.TrimPrefix(webPath, "/uploads/")
	full := filepath.Join(s.RootDir, rel)
	return os.Remove(full)
}

func (s *Storage) FileServer() http.Handler {
	return http.StripPrefix("/uploads/", http.FileServer(http.Dir(s.RootDir)))
}