package xin.merlin.myplayerbackend.service;


import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.Arrays;
import java.util.List;

@Service
@RequiredArgsConstructor
public class UploadService {

    @Value("${resources.user.avatar}")
    private String userAvatarDir;

    @Value("${resources.group.avatar}")
    private String groupAvatarDir;

    @Value("${resources.playroom.avatar}")
    private String playroomAvatarDir;

    @Value("${resources.public}")
    private String publicAvatarDir;

    private static final List<String> AVATAR_ALLOWED_EXTENSIONS = Arrays.asList(".jpg", ".jpeg", ".png", ".gif");

    /**
     * 上传用户、群组、放映室头像
     * @param file  目标文件
     * @param type  上传类型
     * @param influence     受影响的id
     * @return  host后的访问url
     * @throws IOException 抛出io异常
     */
    public String uploadAvatar(MultipartFile file, Integer type,Integer influence) throws IOException {
        String DIR = switch (type) {
            case 1 -> userAvatarDir;
            case 2 -> groupAvatarDir;
            case 3 -> playroomAvatarDir;
            default -> publicAvatarDir;
        };
        String fileName = getFilename(file, influence, DIR);
        Path targetPath = Paths.get(DIR, fileName);
        Files.copy(file.getInputStream(), targetPath, StandardCopyOption.REPLACE_EXISTING);

        return "/resources/user/avatar/" + fileName; // 返回访问 URL
    }

    /**
     *
     * @param file  目标文件
     * @param influence 受影响的id
     * @param DIR   储存的位置
     * @return  fileName 文件在储存之后的名字
     * @throws IOException  抛出io异常
     */
    private static String getFilename(MultipartFile file, Integer influence, String DIR) throws IOException {
        File dir = new File(DIR);
        if (!dir.exists()) dir.mkdirs();

        // 取文件扩展名并检查是否合法
        String originalFileName = file.getOriginalFilename();
        String fileExtension = "";
        if (originalFileName != null && originalFileName.contains(".")) {
            fileExtension = originalFileName.substring(originalFileName.lastIndexOf(".")).toLowerCase();
        }

        if (!AVATAR_ALLOWED_EXTENSIONS.contains(fileExtension)) {
            throw new IOException("仅支持 JPG, PNG, GIF 格式");
        }

        // 以id进行命名，方便直接替换
        return influence.toString() + fileExtension;
    }


}