import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { prisma } from '@/lib/prisma'

// GET - 获取弹幕列表（支持SSE）
export async function GET(request: NextRequest) {
  try {
    const searchParams = request.nextUrl.searchParams
    const isSSE = searchParams.get('sse') === 'true'

    if (isSSE) {
      // Server-Sent Events 实时推送
      const encoder = new TextEncoder()
      
      const stream = new ReadableStream({
        async start(controller) {
          // 发送初始弹幕（限制数量，减少数据传输）
          const initialDanmakus = await prisma.danmaku.findMany({
            orderBy: { createdAt: 'desc' },
            take: 30, // 减少初始数据量
            select: {
              id: true,
              content: true,
              username: true,
              createdAt: true,
            }
          })
          
          controller.enqueue(
            encoder.encode(`data: ${JSON.stringify(initialDanmakus)}\n\n`)
          )

          // 记录最后一条弹幕的ID，避免重复推送
          let lastDanmakuId = initialDanmakus[0]?.id || null
          
          // 轮询新弹幕（优化：只查询新弹幕）
          const interval = setInterval(async () => {
            try {
              const latestDanmaku = await prisma.danmaku.findFirst({
                where: lastDanmakuId ? {
                  id: { not: lastDanmakuId }
                } : undefined,
                orderBy: { createdAt: 'desc' },
                select: {
                  id: true,
                  content: true,
                  username: true,
                  createdAt: true,
                }
              })
              
              if (latestDanmaku) {
                lastDanmakuId = latestDanmaku.id
                controller.enqueue(
                  encoder.encode(`data: ${JSON.stringify(latestDanmaku)}\n\n`)
                )
              }
            } catch (error) {
              console.error('[Danmaku] SSE error:', error)
              // 出错时关闭连接，避免资源泄漏
              clearInterval(interval)
              controller.close()
            }
          }, 2000) // 增加轮询间隔到2秒，减少数据库压力

          // 清理
          request.signal.addEventListener('abort', () => {
            clearInterval(interval)
            controller.close()
          })
        }
      })

      return new NextResponse(stream, {
        headers: {
          'Content-Type': 'text/event-stream',
          'Cache-Control': 'no-cache',
          'Connection': 'keep-alive',
        },
      })
    }

    // 普通GET请求（支持分页）
    const limit = Math.min(parseInt(searchParams.get('limit') || '50', 10), 100) // 最大100条
    const danmakus = await prisma.danmaku.findMany({
      orderBy: { createdAt: 'desc' },
      take: limit,
      select: {
        id: true,
        content: true,
        username: true,
        createdAt: true,
        // 不返回userId，保护隐私
      }
    })

    return NextResponse.json(danmakus)
  } catch (error) {
    console.error('Get danmaku error:', error)
    return NextResponse.json(
      { error: '获取弹幕失败' },
      { status: 500 }
    )
  }
}

// POST - 发送弹幕
export async function POST(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

    if (!session) {
      return NextResponse.json(
        { error: '请先登录' },
        { status: 401 }
      )
    }

    const { content } = await request.json()

    if (!content || content.trim().length === 0) {
      return NextResponse.json(
        { error: '弹幕内容不能为空' },
        { status: 400 }
      )
    }

    if (content.length > 100) {
      return NextResponse.json(
        { error: '弹幕内容不能超过100字' },
        { status: 400 }
      )
    }

    // 生成随机匿名用户名
    const randomNames = [
      '神秘访客', '路过的设计师', '热心网友', '匿名用户', 
      '悄悄路过', '神秘嘉宾', '隐身大佬', '低调看客',
      '默默围观', '潜水员', '匿名网友', '神秘人士'
    ]
    const anonymousName = randomNames[Math.floor(Math.random() * randomNames.length)]
    
    const danmaku = await prisma.danmaku.create({
      data: {
        content: content.trim(),
        username: anonymousName, // 使用匿名名称
        userId: (session.user as any).id
      }
    })

    return NextResponse.json(danmaku)
  } catch (error) {
    console.error('Send danmaku error:', error)
    return NextResponse.json(
      { error: '发送弹幕失败' },
      { status: 500 }
    )
  }
}