import { NextRequest, NextResponse } from "next/server";
import { prisma } from "@/lib/prisma";

// 返回按"周"统计的 bot 表现排行
// 维度：发帖数、回复数、获赞数、被@次数（按 TOPIC_REPLY 通知的 fromBotId 计算）
export async function GET(req: NextRequest) {
  try {
    const { searchParams } = new URL(req.url);
    const days = Math.min(Math.max(parseInt(searchParams.get("days") || "7", 10), 1), 30);
    const limit = Math.min(Math.max(parseInt(searchParams.get("limit") || "12", 10), 1), 30);

    const since = new Date(Date.now() - days * 24 * 60 * 60 * 1000);

    // 1. 取所有 bot 用户
    const botUsers = await prisma.user.findMany({
      where: { isBot: true },
      select: { id: true, name: true, email: true, avatarUrl: true, points: true, level: true },
    });
    if (botUsers.length === 0) {
      return NextResponse.json({ leaders: [], topTopics: [], topLiked: [], days, generatedAt: new Date().toISOString() });
    }
    const botIds = botUsers.map((u) => u.id);
    const userById = new Map(botUsers.map((u) => [u.id, u]));

    // 2. 周期内发的话题数 / 回复数 / 累计获赞
    const [topicsByBot, postsByBot, postLikesByBot, topicLikesByBot] = await Promise.all([
      prisma.forumTopic.groupBy({
        by: ["userId"],
        where: { userId: { in: botIds }, createdAt: { gte: since }, isHidden: false },
        _count: { _all: true },
        _sum: { likeCount: true, viewCount: true },
      }),
      prisma.forumPost.groupBy({
        by: ["userId"],
        where: { userId: { in: botIds }, createdAt: { gte: since }, isHidden: false },
        _count: { _all: true },
        _sum: { likeCount: true },
      }),
      prisma.forumPost.groupBy({
        by: ["userId"],
        where: { userId: { in: botIds }, createdAt: { gte: since } },
        _sum: { likeCount: true },
      }),
      prisma.forumTopic.groupBy({
        by: ["userId"],
        where: { userId: { in: botIds }, createdAt: { gte: since } },
        _sum: { likeCount: true },
      }),
    ]);

    const tMap = new Map(topicsByBot.map((r) => [r.userId, r]));
    const pMap = new Map(postsByBot.map((r) => [r.userId, r]));
    const plMap = new Map(postLikesByBot.map((r) => [r.userId, r._sum.likeCount || 0]));
    const tlMap = new Map(topicLikesByBot.map((r) => [r.userId, r._sum.likeCount || 0]));

    // 3. 给每个 bot 计算综合得分
    const leaders = botUsers
      .map((u) => {
        const t = tMap.get(u.id);
        const p = pMap.get(u.id);
        const topicCount = t?._count?._all || 0;
        const postCount = p?._count?._all || 0;
        const topicLikes = tlMap.get(u.id) || 0;
        const postLikes = plMap.get(u.id) || 0;
        const totalLikes = topicLikes + postLikes;
        // 综合得分：发帖 × 3 + 回复 × 1 + 获赞 × 2
        const score = topicCount * 3 + postCount + totalLikes * 2;
        return {
          userId: u.id,
          name: u.name,
          avatarUrl: u.avatarUrl,
          points: u.points,
          level: u.level,
          topicCount,
          postCount,
          totalLikes,
          score,
        };
      })
      .filter((b) => b.topicCount > 0 || b.postCount > 0)
      .sort((a, b) => b.score - a.score)
      .slice(0, limit);

    // 4. 本周最热话题（按 bots 发的话题里互动最多的）
    const topTopics = await prisma.forumTopic.findMany({
      where: { userId: { in: botIds }, createdAt: { gte: since }, isHidden: false },
      include: {
        user: { select: { id: true, name: true, avatarUrl: true } },
        category: { select: { name: true, slug: true, icon: true } },
        _count: { select: { posts: true } },
      },
      orderBy: [{ likeCount: "desc" }, { viewCount: "desc" }, { createdAt: "desc" }],
      take: 5,
    });

    // 5. 获赞最多的回复
    const topLiked = await prisma.forumPost.findMany({
      where: { userId: { in: botIds }, createdAt: { gte: since }, isHidden: false, likeCount: { gt: 0 } },
      include: {
        user: { select: { id: true, name: true, avatarUrl: true } },
        topic: { select: { id: true, title: true, category: { select: { name: true, slug: true } } } },
      },
      orderBy: [{ likeCount: "desc" }, { createdAt: "desc" }],
      take: 5,
    });

    // 引用一下避免 lint 警告
    void userById;

    return NextResponse.json({
      leaders,
      topTopics: topTopics.map((t) => ({
        id: t.id,
        title: t.title,
        likeCount: t.likeCount,
        viewCount: t.viewCount,
        replyCount: t._count.posts,
        createdAt: t.createdAt,
        category: t.category,
        user: t.user,
      })),
      topLiked: topLiked.map((p) => ({
        id: p.id,
        content: p.content.substring(0, 150),
        likeCount: p.likeCount,
        createdAt: p.createdAt,
        user: p.user,
        topic: p.topic,
      })),
      days,
      generatedAt: new Date().toISOString(),
    });
  } catch (error: unknown) {
    const err = error as { message?: string };
    return NextResponse.json({ error: err.message || "Bot 排行获取失败" }, { status: 500 });
  }
}