src/main/java/com/example/g8backend/controller/TrackerController.java

package com.example.g8backend.controller;

import com.example.g8backend.dto.AnnounceRequestDTO;
import com.example.g8backend.dto.AnnounceResponseDTO;
import com.example.g8backend.util.BencodeUtil;
import jakarta.servlet.http.HttpServletRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import com.example.g8backend.service.ITrackerService;

@RestController
@RequestMapping("/tracker")
public class TrackerController {

    private static final Logger logger = LoggerFactory.getLogger(TrackerController.class);

    @Autowired
    private ITrackerService trackerService;

    @GetMapping(value = "/announce/{passkey}", produces = "application/x-bittorrent")
    public ResponseEntity<byte[]> getAnnouncements(
            HttpServletRequest request,
            @RequestParam("info_hash") String infoHash,
            @RequestParam("peer_id") String peerId,
            @RequestParam("port") int port,
            @RequestParam("uploaded") double uploaded,
            @RequestParam("downloaded") double downloaded,
            @RequestParam(value = "event", required = false) String event,
            @RequestParam(value = "left", required = false) Double left,
            @RequestParam(value = "compact", required = false) Integer compact,
            @PathVariable String passkey) {

        logger.info("Announce request received: info_hash={}, peer_id={}, port={}, uploaded={}, downloaded={}, event={}, left={}, compact={}, passkey={}",
                infoHash, peerId, port, uploaded, downloaded, event, left, compact, passkey);

        AnnounceRequestDTO requestDTO = new AnnounceRequestDTO();
        requestDTO.setPasskey(passkey);
        requestDTO.setInfoHash(infoHash);
        requestDTO.setPeerId(peerId);
        requestDTO.setPort(port);
        requestDTO.setUploaded(uploaded);
        requestDTO.setDownloaded(downloaded);
        requestDTO.setEvent(event);
        requestDTO.setLeft(left != null ? left : 0.0);
        requestDTO.setCompact(compact);

        String ipAddress = extractClientIp(request);
        requestDTO.setIp(ipAddress);

        AnnounceResponseDTO responseDTO = trackerService.handleAnnounce(requestDTO);

        byte[] bencoded = BencodeUtil.encodeAnnounceResponse(responseDTO);
        return ResponseEntity
                .ok()
                .header("Content-Type", "application/x-bittorrent")
                .body(bencoded);
    }

    /**
     * 提取客户端 IP，支持 X-Forwarded-For
     */
    private String extractClientIp(HttpServletRequest request) {
        String xfHeader = request.getHeader("X-Forwarded-For");
        if (xfHeader != null && !xfHeader.isEmpty()) {
            return xfHeader.split(",")[0].trim();
        }
        return request.getRemoteAddr();
    }
}