package com.ard.inspection.service.impl;

import com.ard.inspection.service.IBigFileUploadService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.*;
import java.util.stream.Collectors;

/**
 * @author xia
 */
@Service
@Slf4j
public class BigFileUploadServiceImpl implements IBigFileUploadService {

    @Override
    public Map<String, Object> checkChunk(String fileMd5,String chunkPath) {
        Map<String, Object> result = new HashMap<>();
        try {
            File chunkFolder = new File(chunkPath + File.separator + fileMd5);
            if (!chunkFolder.exists()) {
                result.put("exception", "分片不存在！！！");
                return result;
            }

            File[] chunks = chunkFolder.listFiles();
            if (chunks == null || chunks.length == 0) {
                result.put("exception", "无分片！！！");
                return result;
            }

            List<Integer> uploadedChunks = Arrays.stream(chunks)
                    .map(file -> Integer.parseInt(file.getName().split("\\.")[0]))
                    .collect(Collectors.toList());
            result.put("message", uploadedChunks);
            return result;
        } catch (Exception e) {
            log.error("检查分片失败", e);
            result.put("exception", "检查分片失败！！！");
            return result;
        }
    }

    @Override
    public Map<String, Object> uploadChunk(MultipartFile file,
                              Integer chunkNumber,
                              String fileMd5,
                              String chunkPath) {
        Map<String, Object> result = new HashMap<>();
        try {
            // 验证参数
            if (file.isEmpty()) {
                result.put("exception", "文件不能为空！！！");
                return result;
            }

            // 创建分片目录
            String chunkDirPath = chunkPath + File.separator + fileMd5;
            File chunkDir = new File(chunkDirPath);
            if (!chunkDir.exists()) {
                chunkDir.mkdirs();
            }

            // 保存分片
            String chunkFileName = chunkNumber + ".part";
            File chunkFile = new File(chunkDir, chunkFileName);
            file.transferTo(chunkFile);

            result.put("message", "分片上传成功！！！");
            return result;
        } catch (IOException e) {
            log.error("分片上传失败", e);
            result.put("exception", "分片上传失败！！！");
            return result;
        }
    }

    @Override
    public Map<String, Object> mergeChunks(String md5,String fileName,String uploadPath) {
        Map<String, Object> result = new HashMap<>();
        // 临时目录
        String chunkDir = uploadPath + File.separator + md5;
        File dir = new File(chunkDir);
        if (!dir.exists()) {
            result.put("exception", "切片目录不存在");
            return result;
        }
        // 获取所有切片文件
        File[] chunks = dir.listFiles();
        if (chunks == null || chunks.length == 0) {
            result.put("exception", "没有切片文件");
            return result;
        }
        // 按照切片索引排序
        Arrays.sort(chunks, (a, b) -> {
            int aIndex = Integer.parseInt(a.getName().split("\\.")[0]);
            int bIndex = Integer.parseInt(b.getName().split("\\.")[0]);
            return aIndex - bIndex;
        });

        // 合并后的文件，这里使用原始文件名，为了避免重名，可以加上时间戳或使用UUID
        // 这里根据业务需求，可以保存到数据库，记录文件路径等信息
        String ext = fileName.substring(fileName.lastIndexOf("."));
        String newFileName = UUID.randomUUID().toString().replace("-", "") + ext; // 生成新文件名
        File mergeFile = new File(uploadPath, newFileName);

        try (RandomAccessFile randomAccessFile = new RandomAccessFile(mergeFile, "rw")) {
            byte[] buffer = new byte[1024 * 1024]; // 1MB缓冲区
            for (File chunk : chunks) {
                try (RandomAccessFile chunkFile = new RandomAccessFile(chunk, "r")) {
                    int len;
                    while ((len = chunkFile.read(buffer)) != -1) {
                        randomAccessFile.write(buffer, 0, len);
                    }
                }
                // 删除切片文件
                chunk.delete();
            }
            // 删除临时目录
            dir.delete();
        } catch (IOException e) {
            log.error("合并文件失败", e);
            result.put("exception", "合并文件失败");
            return result;
        }

        // 这里可以保存文件信息到数据库，例如文件路径、文件名、md5等
        // fileService.saveFileInfo(...);

        result.put("message", "文件合并成功");
        return result;
    }

}