package storage

import (
	"crypto/rand"
	"fmt"
	"io"
	"mime/multipart"
	"os"
	"path/filepath"
)

func SaveImage(file multipart.File, header *multipart.FileHeader, uploadDir string) (string, error) {
	if err := os.MkdirAll(uploadDir, 0755); err != nil {
		return "", fmt.Errorf("create upload dir: %w", err)
	}

	ext := filepath.Ext(header.Filename)
	if ext == "" {
		ext = ".png"
	}

	var buf [16]byte
	if _, err := io.ReadFull(rand.Reader, buf[:]); err != nil {
		return "", err
	}
	filename := fmt.Sprintf("%x%s", buf, ext)

	dst, err := os.Create(filepath.Join(uploadDir, filename))
	if err != nil {
		return "", fmt.Errorf("create file: %w", err)
	}
	defer dst.Close()

	if _, err := io.Copy(dst, file); err != nil {
		return "", fmt.Errorf("write file: %w", err)
	}

	return filename, nil
}