package com.mokee.admin.controller;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.mokee.admin.service.FileService;
import com.mokee.common.Result;
import com.mokee.common.annotation.OperationLog;
import com.mokee.common.entity.SysFile;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.RequiredArgsConstructor;
import org.springframework.http.HttpHeaders;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;

/**
 * 文件管理控制器
 * <p>
 * 文件二进制数据存储于本地磁盘，数据库仅保存元信息。
 * 向下兼容存量 BLOB 数据（file_data 非空时优先读磁盘，磁盘无文件则回退 DB BLOB）。
 * <p>
 * 请求路径前缀：{@code /zgapi/v1/admin/file}
 *
 * @author mokee
 */
@RestController
@RequestMapping("/zgapi/v1/admin/file")
@RequiredArgsConstructor
public class FileController {
    private final FileService fileService;

    /**
     * 上传文件（管理后台）
     * <p>
     * 上传者显示名从请求头 X-User-Name 获取（由网关 HeaderInjectFilter 注入，已 URL 解码）。
     */
    @OperationLog(module = "文件管理", action = "上传")
    @PostMapping("/upload")
    public Result<SysFile> upload(@RequestParam("file") MultipartFile file,
                                  @RequestParam(defaultValue = "other") String fileType,
                                  @RequestParam(required = false) String systemId,
                                  HttpServletRequest request) throws IOException {
        String userId = request.getHeader("X-User-Id");
        // X-User-Name 经网关 URL 编码（防 HTTP 转发中文损坏），需解码
        String userName = decodeHeader(request.getHeader("X-User-Name"));
        if (userName == null || userName.isEmpty()) {
            userName = request.getHeader("X-User-Account");
        }
        SysFile sf = fileService.upload(file, fileType, systemId, userId, userName);
        sf.setFileData(null); // 不返回二进制数据
        return Result.ok(sf);
    }

    /**
     * 分页查询文件列表（不含 file_data）
     */
    @PostMapping("/page")
    public Result<IPage<SysFile>> page(@RequestBody java.util.Map<String, Object> params) {
        Integer page = params.get("page") != null ? ((Number) params.get("page")).intValue() : 1;
        Integer size = params.get("pageSize") != null ? ((Number) params.get("pageSize")).intValue() : 10;
        String fileType = (String) params.get("fileType");
        String fileName = (String) params.get("fileName");
        String uploadUserName = (String) params.get("uploadUserName");
        String systemId = params.get("systemId") != null ? params.get("systemId").toString() : null;
        return Result.ok(fileService.page(page, size, fileType, fileName, uploadUserName, systemId));
    }

    /**
     * 文件列表查询（不分页，不含 file_data）
     */
    @GetMapping("/list")
    public Result<List<SysFile>> list(@RequestParam(required = false) String fileType,
                                      @RequestParam(required = false) String systemId) {
        return Result.ok(fileService.list(fileType, systemId));
    }

    /**
     * 获取文件元信息（不含二进制数据）
     */
    @GetMapping("/{id}")
    public Result<SysFile> getById(@PathVariable String id) {
        return Result.ok(fileService.getMetaById(id));
    }

    /**
     * 预览文件 — 直接输出文件流
     * <p>
     * 优先读磁盘文件；磁盘文件不存在时回退到 DB BLOB（存量兼容）。
     * 设置 CORS 和缓存头，支持被 img 标签跨域引用。
     */
    @GetMapping("/{id}/view")
    public void view(@PathVariable String id, HttpServletResponse response) throws IOException {
        SysFile sf = fileService.getById(id);
        if (sf == null) { response.setStatus(404); return; }

        Path diskPath = fileService.getDiskPath(sf);
        if (!Files.exists(diskPath)) {
            response.setStatus(404);
            response.getWriter().write("File not found");
            return;
        }

        byte[] data = Files.readAllBytes(diskPath);
        response.setHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*");
        String mimeType = sf.getMimeType() != null ? sf.getMimeType() : "application/octet-stream";
        response.setContentType(mimeType);
        response.setHeader(HttpHeaders.CACHE_CONTROL, "public, max-age=86400");
        response.setContentLengthLong(data.length);
        response.getOutputStream().write(data);
        response.getOutputStream().flush();
    }

    /**
     * 下载文件 — 触发浏览器下载
     * <p>
     * 与 view 逻辑相同，额外设置 Content-Disposition: attachment 头。
     */
    @GetMapping("/{id}/download")
    public void download(@PathVariable String id, HttpServletResponse response) throws IOException {
        SysFile sf = fileService.getById(id);
        if (sf == null) { response.setStatus(404); return; }

        Path diskPath = fileService.getDiskPath(sf);
        if (!Files.exists(diskPath)) {
            response.setStatus(404);
            response.getWriter().write("File not found");
            return;
        }

        byte[] data = Files.readAllBytes(diskPath);
        // Content-Disposition: filename=ASCII兜底, filename*=UTF-8编码的原始文件名
        String safeName = "download" + ext(sf.getFileName());
        String encodedName = URLEncoder.encode(sf.getFileName(), StandardCharsets.UTF_8)
                .replace("+", "%20");
        response.setContentType("application/octet-stream");
        response.setHeader(HttpHeaders.CONTENT_DISPOSITION,
                "attachment; filename=\"" + safeName + "\"; filename*=UTF-8''" + encodedName);
        response.setContentLengthLong(data.length);
        response.getOutputStream().write(data);
        response.getOutputStream().flush();
    }

    /** 从文件名提取扩展名（含点） */
    private static String ext(String name) {
        if (name == null) return "";
        int i = name.lastIndexOf('.');
        return i > 0 ? name.substring(i) : "";
    }

    /**
     * 删除文件 — 删磁盘文件 + DB 记录
     */
    @OperationLog(module = "文件管理", action = "删除")
    @DeleteMapping("/{id}")
    public Result<?> delete(@PathVariable String id) throws IOException {
        fileService.delete(id);
        return Result.ok();
    }

    /** URL 解码 HTTP 头值（网关对中文值做了 URL 编码） */
    private String decodeHeader(String value) {
        if (value == null) return null;
        try {
            return URLDecoder.decode(value, StandardCharsets.UTF_8);
        } catch (Exception e) {
            return value;
        }
    }
}