import { NextResponse } from "next/server";
import { getRoomData } from "@/lib/store";
import type { MatchType } from "@/types";

export async function GET(
  _req: Request,
  { params }: { params: Promise<{ id: string }> },
) {
  const { id } = await params;

  try {
    const data = await getRoomData(id);

    if (!data) {
      return NextResponse.json(
        { error: "房间不存在或已过期" },
        { status: 404 },
      );
    }

    const total = data.restaurants.length;
    const allFinished =
      data.users.length > 0 &&
      data.users.every((u) => (data.swipeCounts[u] ?? 0) >= total);

    let match = data.match;
    let matchType: MatchType = null;
    let matchLikes = 0;

    if (match) {
      matchType = "unanimous";
      matchLikes = data.users.length;
    } else if (allFinished && data.restaurants.length > 0) {
      const best = findBestMatch(data.likes, data.restaurants);
      match = best.id;
      matchType = "best";
      matchLikes = best.likes;
    }

    const likeCounts: Record<string, number> = {};
    for (const [rid, users] of Object.entries(data.likes)) {
      if (users.length > 0) {
        likeCounts[rid] = users.length;
      }
    }

    return NextResponse.json({
      roomId: id,
      userCount: data.users.length,
      match,
      matchType,
      matchLikes,
      likeCounts,
      swipeCounts: data.swipeCounts,
      restaurants: data.restaurants,
    });
  } catch (e) {
    console.error("Failed to get room:", e);
    return NextResponse.json(
      { error: "获取房间信息失败" },
      { status: 500 },
    );
  }
}

function findBestMatch(
  likes: Record<string, string[]>,
  restaurants: { id: string; rating: number }[],
): { id: string; likes: number } {
  let bestId = restaurants[0].id;
  let bestLikes = 0;
  let bestRating = restaurants[0].rating;

  for (const r of restaurants) {
    const count = likes[r.id]?.length ?? 0;

    if (
      count > bestLikes ||
      (count === bestLikes && r.rating > bestRating)
    ) {
      bestId = r.id;
      bestLikes = count;
      bestRating = r.rating;
    }
  }

  return { id: bestId, likes: bestLikes };
}