import Link from "next/link";
import {
  Flame,
  Users,
  MessageCircle,
  Heart,
  Shield,
  LayoutGrid,
  PenLine,
  PenSquare,
  BarChart3,
  TrendingUp,
} from "lucide-react";
import type {
  PostListItem,
  ActiveUser,
  BoardWithCount,
  BoardModerator,
  BoardSidebarStats,
  CheckinStatus,
} from "@/lib/api";
import Avatar from "@/components/Avatar";
import { PulseCheckin } from "./CheckinCard";
import { formatCompact } from "@/lib/format";

/* ---------- 1. 板块管理员 ---------- */

function Moderators({ items }: { items: BoardModerator[] }) {
  return (
    <section className="j13-module" aria-label="板块管理员">
      <p className="j13-module-title mb-2">
        <Shield size={15} style={{ color: "var(--accent)" }} /> 板块管理员
      </p>
      {items.length === 0 ? (
        <p className="meta px-0.5 py-1.5">暂无板块管理员</p>
      ) : (
        <ul className="space-y-0.5">
          {items.map((u) => {
            const name = u.nickname || u.username;
            return (
              <li key={u.id}>
                <Link href={`/u/${u.id}`} className="j13-raillink" data-tip={name}>
                  <Avatar name={name} src={u.avatar || undefined} size={30} />
                  <span className="min-w-0 flex-1 truncate text-[13px] font-medium" style={{ color: "var(--ink)" }}>
                    {name}
                  </span>
                </Link>
              </li>
            );
          })}
        </ul>
      )}
    </section>
  );
}

/* ---------- 2. 板块概况 ---------- */

function BoardIntro({ board }: { board: BoardWithCount }) {
  return (
    <section className="j13-module" aria-label="板块概况">
      <p className="j13-module-title mb-2">
        <LayoutGrid size={15} style={{ color: "var(--accent)" }} /> 板块概况
      </p>
      <p className="text-[15px] font-medium leading-snug" style={{ color: "var(--ink)" }}>
        {board.name}
      </p>
      {board.description ? (
        <p className="meta mt-1.5 text-[12.5px] leading-relaxed line-clamp-3">{board.description}</p>
      ) : (
        <p className="meta mt-1.5">暂无板块介绍</p>
      )}
      <p className="meta mt-2 tabular-nums">讨论 {formatCompact(board.post_count)} 篇</p>
      <div className="mt-3">
        <Link href={`/compose?board=${board.id}`} className="btn btn-primary btn-sm w-full justify-center">
          <PenSquare size={14} /> 在此发帖
        </Link>
      </div>
    </section>
  );
}

/* ---------- 3. 板块数据 + 签到 ---------- */

function BoardPulse({
  stats,
  checkin,
}: {
  stats: BoardSidebarStats;
  checkin?: CheckinStatus | null;
}) {
  const cells = [
    {
      icon: <PenLine size={12.5} />,
      label: "话题总数",
      value: formatCompact(stats.post_count),
      foot: `+${formatCompact(stats.today_posts)} 今日`,
      up: true,
    },
    {
      icon: <TrendingUp size={12.5} />,
      label: "今日新帖",
      value: formatCompact(stats.today_posts),
      foot: "本日新增",
      up: stats.today_posts > 0,
    },
    {
      icon: <MessageCircle size={12.5} />,
      label: "回复总数",
      value: formatCompact(stats.comment_count),
      foot: `+${formatCompact(stats.today_comments)} 今日`,
      up: true,
    },
    {
      icon: <Heart size={12.5} />,
      label: "今日回复",
      value: formatCompact(stats.today_comments),
      foot: "本日新增",
      up: stats.today_comments > 0,
    },
  ];
  return (
    <section className="j13-module" aria-label="板块数据">
      <p className="j13-module-title">
        <BarChart3 size={15} style={{ color: "var(--accent)" }} /> 板块数据
      </p>
      <div className="j13-pulse">
        {cells.map((c) => (
          <div key={c.label} className="j13-pulse-cell">
            <p className="j13-pulse-lab">
              <span style={{ color: "var(--accent)" }} aria-hidden="true">
                {c.icon}
              </span>
              {c.label}
            </p>
            <p className="j13-pulse-num">{c.value}</p>
            <p className={`j13-pulse-foot${c.up ? " is-up" : ""}`}>
              {c.up && <TrendingUp size={10.5} aria-hidden="true" />}
              {c.foot}
            </p>
          </div>
        ))}
      </div>
      <div className="j13-pulse-checkin">
        <PulseCheckin initial={checkin} />
      </div>
    </section>
  );
}

/* ---------- 4. 本板热门 ---------- */

function BoardHot({ posts }: { posts: PostListItem[] }) {
  return (
    <section className="j13-module" aria-label="本板热门">
      <p className="j13-module-title mb-1.5">
        <Flame size={15} style={{ color: "var(--clay)" }} /> 本板热门
      </p>
      {posts.length === 0 ? (
        <p className="meta px-1.5 py-3">本板还没有热门讨论</p>
      ) : (
        <ol className="j13-ranklist">
          {posts.map((p, i) => (
            <li key={p.id}>
              <Link href={`/post/${p.id}`} className="j13-rank" data-tip={p.title}>
                <span className="j13-rank-no">{i + 1}</span>
                <span className="min-w-0 flex-1">
                  <span className="j13-rank-title truncate">
                    {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>
  );
}

/* ---------- 5. 本板活跃 ---------- */

function BoardActive({ users }: { users: ActiveUser[] }) {
  return (
    <section className="j13-module" aria-label="本板活跃成员">
      <p className="j13-module-title mb-2">
        <Users size={15} style={{ color: "var(--accent)" }} /> 本板活跃
        <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">本周本板还没有人互动</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" data-tip={name}>
                  <Avatar name={name} src={u.avatar || undefined} size={30} />
                  <span className="flex-1 min-w-0">
                    <span
                      className="block truncate text-[13px] font-medium 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] 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>
  );
}

/* ---------- 装配 ---------- */

type BoardPanelsProps = {
  board: BoardWithCount;
  moderators: BoardModerator[];
  stats: BoardSidebarStats;
  hot: PostListItem[];
  activeUsers: ActiveUser[];
  checkin?: CheckinStatus | null;
};

function BoardPanelsBody(props: BoardPanelsProps) {
  return (
    <>
      <Moderators items={props.moderators} />
      <BoardIntro board={props.board} />
      <BoardPulse stats={props.stats} checkin={props.checkin} />
      <BoardHot posts={props.hot} />
      <BoardActive users={props.activeUsers} />
    </>
  );
}

export function BoardPanels(props: BoardPanelsProps) {
  return (
    <aside className="hidden w-[280px] shrink-0 lg:block xl:w-[300px]" aria-label="板块面板">
      <div className="sticky top-24 space-y-4">
        <BoardPanelsBody {...props} />
      </div>
    </aside>
  );
}

export function BoardPanelsMobile(props: BoardPanelsProps) {
  return (
    <div className="space-y-4 lg:hidden" aria-label="板块面板">
      <BoardPanelsBody {...props} />
    </div>
  );
}

/** 板块不存在时的简卡 */
export function BoardMissingPanel() {
  return (
    <aside className="hidden w-[280px] shrink-0 lg:block xl:w-[300px]" aria-label="板块面板">
      <div className="sticky top-24">
        <section className="j13-module">
          <p className="j13-module-title mb-2">
            <LayoutGrid size={15} style={{ color: "var(--ink-3)" }} /> 板块
          </p>
          <p className="meta">板块不存在或已删除</p>
          <Link href="/" className="btn btn-line btn-sm mt-3 w-full justify-center">
            返回全部讨论
          </Link>
        </section>
      </div>
    </aside>
  );
}