package space.anyi.petServiceManagementSystem.server.service.impl;

import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import space.anyi.petServiceManagementSystem.server.common.BusinessException;
import space.anyi.petServiceManagementSystem.server.service.ImageService;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.LocalDate;
import java.util.List;
import java.util.UUID;

@Service
public class ImageServiceImpl implements ImageService {

    private static final List<String> ALLOWED_EXTENSIONS = List.of("jpg", "jpeg", "png", "gif", "webp", "bmp");
    private static final String UPLOAD_DIR = "./upload/";

    @Override
    public String upload(MultipartFile file) {
        if (file == null || file.isEmpty()) {
            throw new BusinessException("上传文件不能为空");
        }

        String originalFilename = file.getOriginalFilename();
        if (originalFilename == null || !originalFilename.contains(".")) {
            throw new BusinessException("文件缺少扩展名");
        }

        String ext = originalFilename.substring(originalFilename.lastIndexOf(".") + 1).toLowerCase();
        if (!ALLOWED_EXTENSIONS.contains(ext)) {
            throw new BusinessException("不支持的图片格式，仅允许: " + String.join(", ", ALLOWED_EXTENSIONS));
        }

        String filename = LocalDate.now() + "_" + UUID.randomUUID() + "." + ext;
        Path uploadPath = Paths.get(UPLOAD_DIR);

        try {
            Files.createDirectories(uploadPath);
            Files.write(uploadPath.resolve(filename), file.getBytes());
        } catch (IOException e) {
            throw new BusinessException("文件上传失败: " + e.getMessage());
        }

        return filename;
    }
}