/**
 * 视频转码 API
 * 
 * 处理视频素材的转码任务：
 * - 生成 540P 预览视频
 * - 生成 10 秒超小预览片段
 * - 从视频中截取封面图（如果用户没有上传）
 */

import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { isCurrentSuperAdmin } from '@/lib/admin-permissions'
import { prisma } from '@/lib/prisma'
import { enqueueVideoTranscodeJob, recoverStaleVideoTranscodeJobs } from '@/lib/video-transcode-service'

export const dynamic = 'force-dynamic'
export const maxDuration = 3600 // 1 hour timeout for transcode

function getSessionUser(session: unknown) {
  return (session as any)?.user as { id?: string; role?: string } | undefined
}

function canManageTranscode(session: unknown, material: { userId?: string | null; createdByUserId?: string | null }) {
  const user = getSessionUser(session)
  if (!user?.id) return false
  if (user.role === 'ADMIN') return true
  return material.userId === user.id || material.createdByUserId === user.id
}

/**
 * GET /api/materials/transcode?materialId=xxx
 * 查询视频转码状态
 */
export async function GET(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)
    if (!getSessionUser(session)?.id) {
      return NextResponse.json(
        { error: '请先登录' },
        { status: 401 }
      )
    }

    const { searchParams } = new URL(req.url)
    const materialId = searchParams.get('materialId')

    if (!materialId) {
      return NextResponse.json(
        { error: '缺少素材ID' },
        { status: 400 }
      )
    }

    const material = await prisma.material.findUnique({
      where: { id: materialId },
      select: {
        id: true,
        userId: true,
        createdByUserId: true,
        videoProcessingStatus: true,
        videoPreview540Url: true,
        videoPreviewClipUrl: true,
        videoCoverUrl: true,
        videoDuration: true,
      },
    })

    if (!material) {
      return NextResponse.json(
        { error: '素材不存在' },
        { status: 404 }
      )
    }

    if (!canManageTranscode(session, material)) {
      return NextResponse.json(
        { error: '无权查看该素材的转码状态' },
        { status: 403 }
      )
    }

    return NextResponse.json({
      materialId: material.id,
      status: material.videoProcessingStatus || 'pending',
      hasPreview540: !!material.videoPreview540Url,
      hasClip: !!material.videoPreviewClipUrl,
      hasCover: !!material.videoCoverUrl,
      duration: material.videoDuration,
    })
  } catch (error) {
    console.error('[Transcode] GET error:', error)
    return NextResponse.json(
      { error: '查询转码状态失败' },
      { status: 500 }
    )
  }
}

/**
 * POST /api/materials/transcode
 * 触发视频转码任务
 */
export async function POST(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)
    if (!getSessionUser(session)?.id) {
      return NextResponse.json(
        { error: '请先登录' },
        { status: 401 }
      )
    }

    const body = await req.json().catch(() => ({}))
    const { materialId } = body

    if (!materialId) {
      return NextResponse.json(
        { error: '缺少素材ID' },
        { status: 400 }
      )
    }

    // 获取素材信息
    const material = await prisma.material.findUnique({
      where: { id: materialId },
      select: {
        id: true,
        userId: true,
        createdByUserId: true,
        materialKind: true,
        videoSourceUrl: true,
        videoCoverUrl: true,
        videoProcessingStatus: true,
        materialType: true,
      },
    })

    if (!material) {
      return NextResponse.json(
        { error: '素材不存在' },
        { status: 404 }
      )
    }

    if (!canManageTranscode(session, material)) {
      return NextResponse.json(
        { error: '无权触发该素材的转码任务' },
        { status: 403 }
      )
    }

    // 检查是否为视频素材
    const materialKind = (material as any).materialKind || ''
    const isVideo = materialKind.toUpperCase() === 'VIDEO' || material.materialType === '视频'
    if (!isVideo) {
      return NextResponse.json(
        { error: '此素材不是视频类型' },
        { status: 400 }
      )
    }

    // 检查是否已有源视频
    if (!material.videoSourceUrl) {
      return NextResponse.json(
        { error: '未找到源视频文件' },
        { status: 400 }
      )
    }

    // 检查转码状态
    const forceRetry = body.forceRetry === true // 允许强制重新转码
    
    if (material.videoProcessingStatus === 'processing' && !forceRetry) {
      return NextResponse.json(
        { error: '转码任务正在进行中', materialId },
        { status: 409 }
      )
    }

    if (material.videoProcessingStatus === 'done' && !forceRetry) {
      return NextResponse.json(
        { message: '转码已完成', materialId },
        { status: 200 }
      )
    }
    
    // 如果强制重试，重置状态
    if (forceRetry && material.videoProcessingStatus === 'done') {
      console.log(`[Transcode] Force retry requested for material ${materialId}`)
    }

    await enqueueVideoTranscodeJob({
      materialId,
      videoSourceUrl: material.videoSourceUrl,
      needsCoverImage: !material.videoCoverUrl,
      forceRetry,
    })

    return NextResponse.json({
      message: '转码任务已启动',
      materialId,
      status: 'pending',
    })
  } catch (error) {
    console.error('[Transcode] API error:', error)
    return NextResponse.json(
      { error: '转码任务启动失败' },
      { status: 500 }
    )
  }
}

export async function PATCH(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)
    if (!(await isCurrentSuperAdmin(session))) {
      return NextResponse.json(
        { error: '无权限' },
        { status: 403 }
      )
    }

    const body = await req.json().catch(() => ({}))
    if (body.action !== 'recover') {
      return NextResponse.json(
        { error: '不支持的操作' },
        { status: 400 }
      )
    }

    const result = await recoverStaleVideoTranscodeJobs()
    return NextResponse.json({
      message: '已触发转码任务恢复',
      ...result,
    })
  } catch (error) {
    console.error('[Transcode] Recovery error:', error)
    return NextResponse.json(
      { error: '转码任务恢复失败' },
      { status: 500 }
    )
  }
}