import Link from "next/link";
import {
  Flame,
  Users,
  MessageCircle,
  Heart,
  UserPlus,
  Link2,
  Megaphone,
  BarChart3,
  PenLine,
} from "lucide-react";
import type {
  PostListItem,
  ActiveUser,
  OverviewStats,
  AnnouncementSummary,
  NewUser,
  CheckinStatus,
} from "@/lib/api";
import Avatar from "@/components/Avatar";
import CheckinCard from "./CheckinCard";
import { FRIEND_LINKS } from "@/lib/friendLinks";
import { formatCompact, formatShortDate } from "@/lib/format";

/* ---------- 站点数据（2×2 极简统计表） ---------- */

function StatCell({
  index,
  label,
  value,
  foot,
}: {
  index: number;
  label: string;
  value: string;
  foot: string;
}) {
  const rightCol = index % 2 === 1;
  const bottomRow = index >= 2;
  return (
    <div
      className="min-w-0 py-3.5"
      style={{
        borderLeft: rightCol ? "1px solid var(--line)" : undefined,
        borderTop: bottomRow ? "1px solid var(--line)" : undefined,
        paddingLeft: rightCol ? 14 : 0,
        paddingRight: rightCol ? 0 : 14,
      }}
    >
      <p className="text-[12px]" style={{ color: "var(--ink-3)" }}>
        {label}
      </p>
      <p
        className="mt-1.5 text-[20px] font-semibold leading-none tracking-tight tabular-nums"
        style={{ color: "var(--ink)" }}
      >
        {value}
      </p>
      <p className="mt-2 text-[11px] tabular-nums" style={{ color: "var(--ink-3)" }}>
        {foot}
      </p>
    </div>
  );
}

function PulseCard({ stats }: { stats: OverviewStats }) {
  return (
    <section className="j13-module" aria-label="站点数据">
      <div className="flex items-center justify-between">
        <p className="j13-module-title">
          <BarChart3 size={15} style={{ color: "var(--accent)" }} /> 站点数据
        </p>
        <span
          className="inline-flex items-center gap-1.5 text-[11px] font-normal normal-case tracking-normal"
          style={{ color: "var(--ink-3)" }}
          title="近 5 分钟在线"
        >
          <span className="h-1.5 w-1.5 rounded-full" style={{ background: "var(--ok)" }} />
          实时
        </span>
      </div>
      <div className="mt-2 grid grid-cols-2">
        <StatCell index={0} label="注册用户" value={formatCompact(stats.users)} foot={`+${stats.today_users} 今日`} />
        <StatCell index={1} label="话题总数" value={formatCompact(stats.posts)} foot={`+${stats.today_posts} 今日`} />
        <StatCell index={2} label="回复总数" value={formatCompact(stats.comments)} foot={`+${stats.today_comments} 今日`} />
        <StatCell index={3} label="在线用户" value={formatCompact(stats.online)} foot={`峰值 ${formatCompact(stats.peak_online)}`} />
      </div>
    </section>
  );
}

/* ---------- 站点公告 ---------- */

function Announcements({ items }: { items: AnnouncementSummary[] }) {
  return (
    <section className="j13-module" aria-label="站点公告">
      <p className="j13-module-title mb-2">
        <Megaphone size={15} style={{ color: "var(--accent)" }} /> 站点公告
      </p>
      {items.length === 0 ? (
        <p className="meta px-1 py-1.5">暂无公告</p>
      ) : (
        <ul>
          {items.map((a) => (
            <li key={a.id}>
              <Link
                href={`/announcement/${a.id}`}
                className="group block -mx-1.5 rounded-lg px-1.5 py-1.5 transition-colors hover:bg-[var(--panel-2)]"
              >
                <span className="flex items-center justify-between gap-2">
                  <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
                  <span className="meta shrink-0 text-[11px] tabular-nums">
                    {formatShortDate(a.created_at)}
                  </span>
                </span>
                <span
                  className="mt-1.5 block truncate text-[13px] leading-snug transition-colors group-hover:text-[var(--accent)]"
                  style={{ color: "var(--ink)" }}
                  title={a.title}
                >
                  {a.title}
                </span>
              </Link>
            </li>
          ))}
        </ul>
      )}
    </section>
  );
}

/* ---------- 热门榜 ---------- */

function HotRanking({ posts }: { posts: PostListItem[] }) {
  return (
    <section className="j13-module" aria-label="热门讨论">
      <p className="j13-module-title mb-1.5">
        <Flame size={15} style={{ color: "var(--clay)" }} /> 热门讨论
      </p>
      {posts.length === 0 ? (
        <p className="meta px-1.5 py-3">还没有热门讨论</p>
      ) : (
        <ol className="j13-ranklist">
          {posts.map((p, i) => (
            <li key={p.id}>
              <Link href={`/post/${p.id}`} className="j13-rank group" title={p.title}>
                <span className="j13-rank-no">{i + 1}</span>
                <span className="min-w-0 flex-1">
                  <span
                    className="block truncate text-[13px] font-normal leading-snug transition-colors group-hover:text-[var(--accent)]"
                    style={{ color: "var(--ink)" }}
                  >
                    {p.title}
                  </span>
                  <span className="mt-1 flex items-center gap-2.5 meta text-[11.5px]">
                    <span className="inline-flex items-center gap-1">
                      <MessageCircle size={11.5} /> {p.comment_count}
                    </span>
                    <span className="inline-flex items-center gap-1">
                      <Heart size={11.5} /> {p.like_count}
                    </span>
                  </span>
                </span>
              </Link>
            </li>
          ))}
        </ol>
      )}
    </section>
  );
}

/* ---------- 最新注册 ---------- */

function NewUsers({ users }: { users: NewUser[] }) {
  if (users.length === 0) return null;
  return (
    <section className="j13-module" aria-label="最新注册">
      <p className="j13-module-title mb-3">
        <UserPlus size={15} style={{ color: "var(--accent)" }} /> 最新注册
      </p>
      <ul className="grid grid-cols-4 gap-y-3">
        {users.map((u) => {
          const name = u.nickname || u.username;
          return (
            <li key={u.id}>
              <Link
                href={`/u/${u.id}`}
                className="flex flex-col items-center gap-1.5 rounded-lg px-1 py-1 transition-colors hover:bg-[var(--panel-2)]"
              >
                <Avatar name={name} src={u.avatar} size={38} />
                <span
                  className="w-full truncate text-center text-[11px]"
                  style={{ color: "var(--ink-2)" }}
                  title={name}
                >
                  {name}
                </span>
              </Link>
            </li>
          );
        })}
      </ul>
    </section>
  );
}

/* ---------- 活跃成员（本周发帖 / 回复） ---------- */

function ActiveUsers({ users }: { users: ActiveUser[] }) {
  return (
    <section className="j13-module" aria-label="本周活跃成员">
      <p className="j13-module-title mb-2">
        <Users size={15} style={{ color: "var(--accent)" }} /> 活跃成员
        <span className="ml-auto font-normal normal-case tracking-normal text-[11px]" style={{ color: "var(--ink-3)" }}>
          本周
        </span>
      </p>
      {users.length === 0 ? (
        <p className="meta px-1.5 py-2">本周还没有人互动</p>
      ) : (
        <ul className="space-y-0.5">
          {users.map((u) => {
            const name = u.nickname || u.username;
            return (
              <li key={u.id}>
                <Link href={`/u/${u.id}`} className="j13-raillink" title={name}>
                  <Avatar name={name} src={u.avatar} size={30} />
                  <span className="flex-1 min-w-0">
                    <span
                      className="block truncate text-[13px] font-semibold leading-tight"
                      style={{ color: "var(--ink)" }}
                    >
                      {name}
                    </span>
                    <span className="mt-px flex items-center gap-2.5 text-[11px] meta">
                      <span className="inline-flex items-center gap-1">
                        <PenLine size={10.5} /> 发帖 {u.post_count}
                      </span>
                      <span className="inline-flex items-center gap-1">
                        <MessageCircle size={10.5} /> 回复 {u.comment_count}
                      </span>
                    </span>
                  </span>
                  <span
                    className="shrink-0 text-[13px] font-extrabold tabular-nums"
                    style={{ color: "var(--accent)" }}
                    aria-label={`本周共 ${u.post_count + u.comment_count} 次互动`}
                  >
                    {u.post_count + u.comment_count}
                  </span>
                </Link>
              </li>
            );
          })}
        </ul>
      )}
    </section>
  );
}

/* ---------- 友情链接 ---------- */

function FriendLinks() {
  return (
    <section className="j13-module" aria-label="友情链接">
      <p className="j13-module-title mb-3">
        <Link2 size={15} style={{ color: "var(--accent)" }} /> 友情链接
        <Link
          href="/compose"
          className="meta ml-auto text-[12px] font-normal transition-colors hover:text-[var(--accent)]"
        >
          申请
        </Link>
      </p>
      <div className="flex flex-wrap gap-2">
        {FRIEND_LINKS.map((l) =>
          l.href.startsWith("http") ? (
            <a
              key={l.name}
              href={l.href}
              target="_blank"
              rel="noopener noreferrer"
              className="j13-chip"
            >
              {l.name}
            </a>
          ) : (
            <span key={l.name} className="j13-chip" title="友链待配置">
              {l.name}
            </span>
          )
        )}
      </div>
    </section>
  );
}

/* ---------- 桌面 / 移动两种装配 ---------- */

type PanelsProps = {
  stats: OverviewStats;
  hot: PostListItem[];
  activeUsers: ActiveUser[];
  announcements: AnnouncementSummary[];
  newUsers: NewUser[];
  checkin?: CheckinStatus | null;
};

export function CommunityPanels({
  stats,
  hot,
  activeUsers,
  announcements,
  newUsers,
  checkin,
}: PanelsProps) {
  return (
    <aside className="hidden w-[280px] shrink-0 lg:block xl:w-[300px]" aria-label="社区面板">
      <div className="sticky top-24 space-y-4">
        <PulseCard stats={stats} />
        <Announcements items={announcements} />
        <CheckinCard initial={checkin} />
        <HotRanking posts={hot} />
        <NewUsers users={newUsers} />
        <ActiveUsers users={activeUsers} />
        <FriendLinks />
      </div>
    </aside>
  );
}

export function CommunityPanelsMobile({
  hot,
  activeUsers,
  announcements,
  newUsers,
  checkin,
}: Omit<PanelsProps, "stats">) {
  return (
    <div className="space-y-4 lg:hidden" aria-label="社区面板">
      <Announcements items={announcements} />
      <CheckinCard initial={checkin} />
      <HotRanking posts={hot} />
      <NewUsers users={newUsers} />
      <ActiveUsers users={activeUsers} />
      <FriendLinks />
    </div>
  );
}