package com.yj.earth.business.controller;

import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.crypto.digest.DigestUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.yj.earth.business.domain.FileInfo;
import com.yj.earth.business.service.FileInfoService;
import com.yj.earth.common.util.ApiResponse;
import com.yj.earth.vo.FileInfoVo;
import io.swagger.v3.oas.annotations.Operation;
import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.tags.Tag;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpHeaders;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

@Tag(name = "文件数据管理")
@RestController
@RequestMapping("/fileInfo")
public class FileInfoController {

    @Resource
    private FileInfoService fileInfoService;

    @Value("${file.upload.path}")
    private String uploadPath;

    // 获取项目根目录
    private String getProjectRootPath() {
        return System.getProperty("user.dir");
    }

    // 获取完整的上传目录路径
    private String getFullUploadPath() {
        // 拼接项目根目录和配置的上传路径
        return getProjectRootPath() + File.separator + uploadPath;
    }

    @Operation(summary = "文件上传")
    @PostMapping("/upload")
    public ApiResponse uploadFiles(@Parameter(description = "上传的文件数组", required = true) @RequestParam("files") MultipartFile[] files) throws IOException {

        // 校验文件数组是否为空
        if (files == null || files.length == 0) {
            return ApiResponse.failure("上传文件不能为空");
        }

        // 获取完整的上传目录路径
        String fullUploadPath = getFullUploadPath();

        List<FileInfoVo> fileInfoVoList = new ArrayList<>();

        // 遍历处理每个文件
        for (MultipartFile file : files) {
            // 跳过空文件
            if (file.isEmpty()) {
                continue;
            }

            // 获取原始文件名和后缀
            String originalFilename = file.getOriginalFilename();
            String fileSuffix = FileUtil.extName(originalFilename);
            String contentType = file.getContentType();

            // 生成唯一文件名、避免重复
            String uniqueFileName = IdUtil.simpleUUID() + "." + fileSuffix;

            // 创建文件存储目录（如果不存在则自动创建）
            File uploadDir = new File(fullUploadPath);
            FileUtil.mkdir(uploadDir);

            // 构建完整文件路径
            String filePath = fullUploadPath + File.separator + uniqueFileName;
            File destFile = new File(filePath);

            // 使用Hutool工具类保存文件
            FileUtil.writeBytes(file.getBytes(), destFile);

            // 计算文件MD5（用于校验文件完整性）
            String fileMd5 = DigestUtil.md5Hex(destFile);

            // 查询有没有文件名一样并且 MD5 也一样的数据
            LambdaQueryWrapper<FileInfo> queryWrapper = new LambdaQueryWrapper<>();
            queryWrapper.eq(FileInfo::getFileName, originalFilename).eq(FileInfo::getFileMd5, fileMd5);
            if (fileInfoService.count(queryWrapper) > 0) {  // 修复了此处的bug、添加了queryWrapper参数
                return ApiResponse.failure("已存在文件名相同且内容完全一致的文件");
            }

            // 保存文件信息到数据库
            FileInfo fileInfo = new FileInfo();
            fileInfo.setFileName(originalFilename);
            fileInfo.setFileSuffix(fileSuffix);
            fileInfo.setContentType(contentType);
            fileInfo.setFileSize(file.getSize());
            fileInfo.setFilePath(uniqueFileName);  // 只保存相对文件名、不保存完整路径
            fileInfo.setFileMd5(fileMd5);

            // 保存文件信息并获取ID
            fileInfoService.save(fileInfo);

            // 构建并设置预览URL和下载URL
            String previewUrl = "/fileInfo/preview/" + fileInfo.getId();
            String downloadUrl = "/fileInfo/download/" + fileInfo.getId();

            FileInfoVo fileInfoVo = new FileInfoVo();
            BeanUtils.copyProperties(fileInfo, fileInfoVo);
            fileInfoVo.setPreviewUrl(previewUrl);
            fileInfoVo.setDownloadUrl(downloadUrl);

            fileInfoVoList.add(fileInfoVo);
        }

        if (fileInfoVoList.isEmpty()) {
            return ApiResponse.failure("未成功上传任何文件");
        }

        return ApiResponse.success(fileInfoVoList);
    }

    @Operation(summary = "文件下载")
    @GetMapping("/download/{id}")
    public void downloadFile(@Parameter(description = "文件ID", required = true) @PathVariable String id, HttpServletResponse response) throws IOException {
        // 根据ID查询文件信息
        FileInfo fileInfo = fileInfoService.getById(id);
        if (fileInfo == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        // 构建完整文件路径
        String fullPath = getFullUploadPath() + File.separator + fileInfo.getFilePath();
        File file = new File(fullPath);

        // 校验文件是否存在
        if (!file.exists()) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        // 设置响应头
        response.setContentType(fileInfo.getContentType());
        response.setContentLengthLong(fileInfo.getFileSize());
        String encodedFileName = URLEncoder.encode(fileInfo.getFileName(), StandardCharsets.UTF_8.name());
        response.setHeader(HttpHeaders.CONTENT_DISPOSITION,
                "attachment; filename=\"" + encodedFileName + "\"; filename*=UTF-8''" + encodedFileName);

        // 使用 Hutool 工具类复制文件流到响应输出流
        try (OutputStream os = response.getOutputStream()) {
            FileUtil.writeToStream(file, os);
        }
    }

    @Operation(summary = "文件预览")
    @GetMapping("/preview/{id}")
    public void previewFile(
            @Parameter(description = "文件ID", required = true)
            @PathVariable String id,
            HttpServletResponse response) throws IOException {

        // 根据ID查询文件信息
        FileInfo fileInfo = fileInfoService.getById(id);
        if (fileInfo == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        // 构建完整文件路径
        String fullPath = getFullUploadPath() + File.separator + fileInfo.getFilePath();
        File file = new File(fullPath);

        // 校验文件是否存在
        if (!file.exists()) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        // 设置响应头（不设置 attachment、让浏览器直接显示）
        response.setContentType(fileInfo.getContentType());
        response.setContentLengthLong(fileInfo.getFileSize());

        // 使用 Hutool 工具类复制文件流到响应输出流
        try (OutputStream os = response.getOutputStream()) {
            FileUtil.writeToStream(file, os);
        }
    }

    @Operation(summary = "文件列表")
    @GetMapping("/list")
    public ApiResponse getFileList(
            @Parameter(description = "页码", required = true) Integer pageNum,
            @Parameter(description = "每页条数", required = true) Integer pageSize,
            @Parameter(description = "文件名称") String fileName) {

        // 创建分页对象
        Page<FileInfo> page = new Page<>(pageNum, pageSize);
        // 构建查询条件
        LambdaQueryWrapper<FileInfo> queryWrapper = new LambdaQueryWrapper<>();
        if (fileName != null && !fileName.isEmpty()) {
            queryWrapper.like(FileInfo::getFileName, fileName);
        }
        // 按创建时间倒序排列、最新上传的文件在前
        queryWrapper.orderByDesc(FileInfo::getCreatedAt);

        // 执行分页查询
        IPage<FileInfo> fileInfoPage = fileInfoService.page(page, queryWrapper);

        // 转换为VO对象并设置URL
        List<FileInfoVo> records = fileInfoPage.getRecords().stream().map(fileInfo -> {
            FileInfoVo vo = new FileInfoVo();
            BeanUtils.copyProperties(fileInfo, vo);
            vo.setPreviewUrl("/fileInfo/preview/" + fileInfo.getId());
            vo.setDownloadUrl("/fileInfo/download/" + fileInfo.getId());
            return vo;
        }).collect(Collectors.toList());

        // 构建分页结果
        Page<FileInfoVo> resultPage = new Page<>();
        resultPage.setRecords(records);
        resultPage.setTotal(fileInfoPage.getTotal());
        resultPage.setSize(fileInfoPage.getSize());
        resultPage.setCurrent(fileInfoPage.getCurrent());
        resultPage.setPages(fileInfoPage.getPages());
        return ApiResponse.success(resultPage);
    }
}