import { db } from '~/drizzle/db'
import { schedules, semesters, songs, votes } from '~/drizzle/schema'
import { and, count, eq } from 'drizzle-orm'
import { createSongVotedNotification } from '../../services/notificationService'
import {
  isSongProtected,
  getSongProtectRemainingSeconds,
  recordSongVote,
  recordUserVoteActivity
} from '~~/server/services/securityService'
import { getClientIP } from '~~/server/utils/ip-utils'
import { createApiError } from '~~/server/utils/apiError'

export default defineEventHandler(async (event) => {
  // 检查用户认证
  const user = event.context.user

  if (!user) {
    throw createApiError(401, 'SONG_LOGIN_REQUIRED_VOTE', '需要登录才能投票')
  }

  const body = await readBody(event)
  const clientIP = getClientIP(event)

  if (!body.songId) {
    throw createApiError(400, 'SONG_ID_REQUIRED', '歌曲ID不能为空')
  }

  const isUnvote = body.unvote === true

  try {
    // 检查歌曲是否存在
    const songResult = await db.select().from(songs).where(eq(songs.id, body.songId)).limit(1)

    const song = songResult[0]

    if (!song) {
      throw createApiError(404, 'SONG_NOT_FOUND', '歌曲不存在')
    }

    // 检查学期
    const currentSemesterResult = await db
      .select()
      .from(semesters)
      .where(eq(semesters.isActive, true))
      .limit(1)
    const currentSemester = currentSemesterResult[0]

    if (!currentSemester) {
      throw createApiError(400, 'SONG_NO_ACTIVE_SEMESTER_VOTE', '未设置活跃学期，无法进行投票操作')
    }

    if (song.semester !== currentSemester.name) {
      throw createApiError(400, 'SONG_INACTIVE_SEMESTER_VOTE', '非活跃学期，无法进行投票操作')
    }

    // 检查歌曲是否已播放
    if (song.played) {
      throw createApiError(400, 'SONG_PLAYED_NO_VOTE', '该歌曲已播放，无法进行投票操作')
    }

    // 检查歌曲是否已排期（只检查已发布的排期，草稿不算）
    const schedulesResult = await db
      .select()
      .from(schedules)
      .where(and(eq(schedules.songId, body.songId), eq(schedules.isDraft, false)))
      .limit(1)

    if (schedulesResult.length > 0) {
      throw createApiError(400, 'SONG_SCHEDULED_NO_VOTE', '该歌曲已排期，无法进行投票操作')
    }

    // 检查是否是自己的歌曲
    if (song.requesterId === user.id) {
      throw createApiError(400, 'SONG_CANNOT_SELF_VOTE', '不允许自己给自己投票')
    }

    if (isSongProtected(body.songId)) {
      const remain = getSongProtectRemainingSeconds(body.songId)
      throw createApiError(423, 'SONG_TEMP_PROTECTED_SECONDS', `该歌曲处于临时保护期，剩余 ${Math.max(remain, 1)} 秒`, { params: [Math.max(remain, 1)] })
    }

    // 检查用户是否已经投过票
    const existingVoteResult = await db
      .select()
      .from(votes)
      .where(and(eq(votes.songId, body.songId), eq(votes.userId, user.id)))
      .limit(1)

    const existingVote = existingVoteResult[0]

    if (isUnvote) {
      // 撤销投票逻辑
      if (!existingVote) {
        throw createApiError(400, 'SONG_VOTE_NOT_FOUND', '你尚未为这首歌投票，无法取消')
      }

      // 删除投票
      await db.delete(votes).where(eq(votes.id, existingVote.id))

      // 获取投票总数
      const voteCountResult = await db
        .select({ count: count() })
        .from(votes)
        .where(eq(votes.songId, body.songId))

      const voteCount = voteCountResult[0].count

      return {
        success: true,
        message: '取消投票成功',
        song: {
          id: song.id,
          title: song.title,
          artist: song.artist,
          voteCount
        }
      }
    } else {
      // 正常投票逻辑
      if (existingVote) {
        throw createApiError(409, 'SONG_ALREADY_VOTED', '你已经为这首歌投过票了')
      }

      // 创建新的投票
      const newVote = await db
        .insert(votes)
        .values({
          songId: body.songId,
          userId: user.id
        })
        .returning()

      // 获取投票总数
      const voteCountResult = await db
        .select({ count: count() })
        .from(votes)
        .where(eq(votes.songId, body.songId))

      const voteCount = voteCountResult[0].count

      // 发送通知（异步，不阻塞响应）
      if (song.requesterId !== user.id) {
        createSongVotedNotification(body.songId, user.id).catch(() => {
          // 发送通知失败不影响主流程
        })
      }

      const protectedTriggered = recordSongVote(body.songId, clientIP, user.id)
      recordUserVoteActivity(user.id, song.title)

      return {
        success: true,
        message: '投票成功',
        song: {
          id: song.id,
          title: song.title,
          artist: song.artist,
          voteCount
        }
      }
    }
  } catch (error: any) {
    if (error.statusCode) {
      throw error
    } else if (error.code === '23505') {
      throw createApiError(409, 'SONG_ALREADY_VOTED', '你已经为这首歌投过票了')
    } else {
      throw createApiError(500, 'SONG_OPERATION_FAILED', '操作失败，请稍后重试')
    }
  }
})