package com.guahao.h5.zip;


import org.springframework.http.*;
import org.springframework.web.bind.annotation.*;
import org.springframework.core.io.InputStreamResource;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.file.*;
import java.util.Objects;

@RestController
@RequestMapping("/find")
/**
 * 对账平台接口
 */
public class DownloadZipController {

    // ZIP 文件所在目录
    private static final String DOWNLOAD_DIR = "/root/ccbwlpt/download";

    /**
     * 接口：下载指定 ZIP 文件
     * URL: GET /api/download/{fileName}
     */
    @GetMapping("/download/{fileName}")
    public ResponseEntity<InputStreamResource> downloadZip(
            @PathVariable String fileName) {

        // 1. 构建完整文件路径
        Path filePath = Paths.get(DOWNLOAD_DIR, fileName);

        // 2. 验证文件是否存在且为普通文件
        if (!Files.exists(filePath)) {
            return ResponseEntity.status(HttpStatus.NOT_FOUND)
                    .body(null);
        }
        if (!Files.isRegularFile(filePath)) {
            return ResponseEntity.badRequest()
                    .body(null);
        }

        // 3. 验证文件确实是 ZIP（可选安全检查）
        if (!isZipFile(filePath)) {
            return ResponseEntity.badRequest()
                    .header("X-Error", "File is not a ZIP file")
                    .body(null);
        }

        try {
            // 4. 打开输入流
            InputStreamResource resource = new InputStreamResource(Files.newInputStream(filePath));

            // 5. 构造响应头
            HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
            headers.add("Content-Type", "application/zip");
            headers.setContentLength(Files.size(filePath));

            return ResponseEntity.ok()
                    .headers(headers)
                    .contentLength(Files.size(filePath))
                    .contentType(MediaType.APPLICATION_OCTET_STREAM)
                    .body(resource);

        } catch (IOException e) {
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
                    .header("X-Error", "Failed to read file: " + e.getMessage())
                    .body(null);
        } catch (SecurityException e) {
            return ResponseEntity.status(HttpStatus.FORBIDDEN)
                    .header("X-Error", "Permission denied: " + e.getMessage())
                    .body(null);
        }
    }

    /**
     * 简单判断是否为 ZIP 文件（检查文件头）
     */
    private boolean isZipFile(Path path) {
        try (RandomAccessFile raf = new RandomAccessFile(path.toFile(), "r")) {
            if (raf.length() < 4) return false;
            int magic = raf.readInt();
            return magic == 0x504B0304 || magic == 0x504B0506 || magic == 0x504B0708;
        } catch (IOException e) {
            return false;
        }
    }
}