import Link from "next/link";
import type { Metadata } from "next";
import { cookies } from "next/headers";
import { PenSquare, MessagesSquare, ChevronRight } from "lucide-react";
import { fetchPosts, fetchBoards } from "@/lib/api";
import { authCookieHeader } from "@/lib/cookies";
import { getMeCached } from "@/lib/serverData";
import Pagination from "@/components/Pagination";
import PostRow from "@/components/PostRow";
import PinnedPosts from "@/components/PinnedPosts";
import FeedNewTip from "@/components/home/FeedNewTip";

interface PageProps {
  params: Promise<{ id: string }>;
  searchParams: Promise<{ page?: string }>;
}

export async function generateMetadata({ params }: PageProps): Promise<Metadata> {
  const { id } = await params;
  const { boards } = await fetchBoards();
  const board = boards.find((b) => b.id === Number(id));
  return {
    title: board ? `${board.name} · 姜十三论坛` : "板块 · 姜十三论坛",
    description: board?.description || "板块帖子列表",
  };
}

export default async function BoardPage({ params, searchParams }: PageProps) {
  const { id } = await params;
  const { page: pageStr } = await searchParams;
  const page = Math.max(1, parseInt(pageStr || "1", 10) || 1);
  const cookie = authCookieHeader(await cookies());
  const [postsData, boardsData, me] = await Promise.all([
    fetchPosts(page, 20, Number(id), "latest", "", false, cookie),
    fetchBoards(),
    getMeCached(cookie || undefined),
  ]);
  const boardIndex = boardsData.boards.findIndex((b) => b.id === Number(id));
  const board = boardIndex >= 0 ? boardsData.boards[boardIndex] : null;
  const user = me.user;

  // 第一页：置顶帖独立成区，列表只保留非置顶
  const pinned = page === 1 ? postsData.posts.filter((p) => p.pinned > 0) : [];
  const rows = page === 1 ? postsData.posts.filter((p) => p.pinned <= 0) : postsData.posts;

  return (
    <div>
      {/* 面包屑 */}
      <nav className="meta mb-5 flex items-center gap-1.5 text-[13px]">
        <Link href="/" className="hover:text-[var(--accent)] transition-colors">首页</Link>
        <ChevronRight size={13} />
        <span style={{ color: "var(--accent)" }}>{board?.name || "未知板块"}</span>
      </nav>

      <div className="panel p-6 sm:p-7 mb-6 relative overflow-hidden">
        <span
          aria-hidden
          className="absolute -top-16 -right-12 w-48 h-48 rounded-full"
          style={{ background: "var(--accent-soft)" }}
        />
        <div className="relative flex items-end justify-between gap-4 flex-wrap">
          <div className="flex items-center gap-4">
            <span
              className={`av-${Math.max(0, boardIndex) % 8} w-14 h-14 sm:w-16 sm:h-16 rounded-2xl flex items-center justify-center text-2xl font-extrabold shrink-0`}
            >
              {board?.name.slice(0, 1) || "?"}
            </span>
            <div>
              <h1 className="text-2xl sm:text-[28px] font-extrabold tracking-tight" style={{ color: "var(--ink)" }}>
                {board?.name || "未知板块"}
              </h1>
              {board?.description && (
                <p className="mt-1 text-sm" style={{ color: "var(--ink-2)" }}>
                  {board.description}
                </p>
              )}
              <p className="meta mt-1.5">{postsData.total} 篇讨论</p>
            </div>
          </div>
          <Link href={`/compose?board=${id}`} className="btn btn-primary">
            <PenSquare size={15} /> 在此板块发帖
          </Link>
        </div>
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-[1fr_290px] gap-6">
        <div>
          <PinnedPosts posts={pinned} showBoard={false} />
          {rows.length > 0 ? (
            <div className="panel overflow-hidden">
              <div className="px-4 sm:px-5 py-3.5 flex items-center justify-between" style={{ borderBottom: "1px solid var(--line)" }}>
                <span className="font-bold text-[15px]" style={{ color: "var(--ink)" }}>全部讨论</span>
                <span className="meta text-xs">第 {page} 页</span>
              </div>
              {user && (
                <div className="pt-2.5">
                  <FeedNewTip
                    sort="latest"
                    boardId={Number(id)}
                    page={page}
                    userId={user.id}
                  />
                </div>
              )}
              {rows.map((post, i) => (
                <PostRow key={post.id} post={post} index={i} />
              ))}
            </div>
          ) : (
            pinned.length === 0 && (
              <div className="panel text-center py-20 px-6">
                <span
                  className="inline-flex w-14 h-14 rounded-full items-center justify-center mb-4"
                  style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
                >
                  <MessagesSquare size={26} />
                </span>
                <p className="font-bold text-lg" style={{ color: "var(--ink)" }}>该板块还没有帖子</p>
                <p className="meta mt-1.5">来发第一篇，抢占沙发</p>
                <Link href={`/compose?board=${id}`} className="btn btn-primary mt-6">
                  <PenSquare size={15} /> 写新帖
                </Link>
              </div>
            )
          )}
          <Pagination total={postsData.total} page={page} size={20} basePath={`/board/${id}`} />
        </div>

        <aside>
          <div className="panel p-5">
            <p className="font-bold text-[15px] mb-3.5" style={{ color: "var(--ink)" }}>其他板块</p>
            <div className="space-y-1">
              {boardsData.boards
                .map((b, i) => ({ b, i }))
                .filter(({ b }) => b.id !== Number(id))
                .map(({ b, i }) => (
                  <Link
                    key={b.id}
                    href={`/board/${b.id}`}
                    className="group flex items-center gap-3 py-1.5 px-2 -mx-2 rounded-xl transition-colors hover:bg-[var(--accent-soft)] focus-visible:bg-[var(--accent-soft)]"
                  >
                    <span className={`av-${i % 8} w-8 h-8 rounded-xl flex items-center justify-center text-[13px] font-bold shrink-0`}>
                      {b.name.slice(0, 1)}
                    </span>
                    <span className="text-sm font-medium flex-1 truncate group-hover:text-[var(--accent)] transition-colors" style={{ color: "var(--ink)" }}>
                      {b.name}
                    </span>
                  </Link>
                ))}
            </div>
          </div>
        </aside>
      </div>
    </div>
  );
}