package com.guwan.backend.controller;

import com.guwan.backend.entity.Video;
import com.guwan.backend.service.HdfsStorageService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.ResourceRegion;
import org.springframework.http.*;
import org.springframework.web.bind.annotation.*;

import java.io.IOException;
import java.io.InputStream;

@Slf4j
@RestController
@RequestMapping("/api/stream")
@RequiredArgsConstructor
public class VideoStreamController {

    private final HdfsStorageService hdfsStorageService;
    private static final long CHUNK_SIZE = 1024 * 1024; // 1MB chunks

    @GetMapping("/video/{id}")
    public ResponseEntity<ResourceRegion> streamVideo(
            @PathVariable Long id,
            @RequestHeader(value = "Range", required = false) String rangeHeader) {
        try {
            // 获取视频路径
            Video video = videoMapper.selectById(id);
            if (video == null) {
                return ResponseEntity.notFound().build();
            }

            // 获取视频流
            InputStream videoStream = hdfsStorageService.getVideoStream(video.getUrl());
            InputStreamResource resource = new InputStreamResource(videoStream);

            // 获取视频元数据
            VideoMetadata metadata = hdfsStorageService.getVideoMetadata(video.getUrl());
            long contentLength = metadata.getSize();

            // 处理Range请求
            HttpRange range = rangeHeader == null ? null : HttpRange.parseRanges(rangeHeader).get(0);
            ResourceRegion region;

            if (range != null) {
                long start = range.getRangeStart(contentLength);
                long end = range.getRangeEnd(contentLength);
                long rangeLength = Math.min(CHUNK_SIZE, end - start + 1);
                region = new ResourceRegion(resource, start, rangeLength);
            } else {
                long rangeLength = Math.min(CHUNK_SIZE, contentLength);
                region = new ResourceRegion(resource, 0, rangeLength);
            }

            return ResponseEntity.status(HttpStatus.PARTIAL_CONTENT)
                    .contentType(MediaTypeFactory.getMediaType(resource).orElse(MediaType.APPLICATION_OCTET_STREAM))
                    .body(region);

        } catch (IOException e) {
            log.error("视频流处理失败", e);
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
        }
    }
}