"use client";

import Link from "next/link";
import { useSearchParams } from "next/navigation";
import { useCallback, useEffect, useRef, useState, type ReactNode } from "react";
import { Bookmark, Home, LayoutGrid, Menu, ShieldCheck } from "lucide-react";
import type { BoardWithCount, User } from "@/lib/api";
import { isStaff } from "@/lib/roles";
import BoardIcon, { boardColor } from "@/components/BoardIcon";
import { useUrlStyle } from "@/components/SiteBrandProvider";
import { userPath } from "@/lib/urlStyle";
import { RailDrawerPanel, useDrawerChrome } from "@/components/MobileRailDrawers";

// 首页壳内板块切换：仅替换中栏帖子流，不离开工作台
function boardHref(id: number) {
  return `/?board=${id}`;
}

// 板块目录裸面板：只有 j13-module 本体，不含外层 nav / 宽度 / sticky 类，
// 供侧栏注册表按管理端配置在任意侧栏渲染。
export function WorkspaceNavPanel({
  boards,
  user,
}: {
  boards: BoardWithCount[];
  user?: User | null;
}) {
  const params = useSearchParams();
  const urlStyle = useUrlStyle();
  const activeBoard = Number(params.get("board")) || 0;
  const showAdmin = !!user && isStaff(user.role);

  return (
    <section className="j13-module flex max-h-[var(--rail-max-h)] flex-col overflow-hidden" aria-label="板块目录">
      <div className="j13-rail-scroll j13-board-list min-h-0 flex-1">
        <p className="j13-rail-group">浏览</p>
        <Link
          href="/"
          className="j13-bcard"
          aria-current={activeBoard === 0 ? "page" : undefined}
        >
          <span
            className="j13-bcard-ico"
            style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
            aria-hidden="true"
          >
            <Home size={15} />
          </span>
          <span className="j13-bcard-name flex-1 truncate">全部讨论</span>
        </Link>

        {user ? (
          <Link href={`${userPath(urlStyle, user.id)}?tab=favorites`} className="j13-bcard">
            <span
              className="j13-bcard-ico"
              style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
              aria-hidden="true"
            >
              <Bookmark size={15} />
            </span>
            <span className="j13-bcard-name flex-1 truncate">我的收藏</span>
          </Link>
        ) : null}

        {boards.length > 0 ? (
          <>
            <p className="j13-rail-group">板块</p>
            {boards.map((b) => (
              <Link
                key={b.id}
                href={boardHref(b.id)}
                className="j13-bcard"
                aria-current={activeBoard === b.id ? "page" : undefined}
                aria-label={`${b.name}板块，${b.post_count} 篇讨论`}
              >
                <span className={`av-${boardColor(b)} j13-bcard-ico`} aria-hidden="true">
                  <BoardIcon icon={b.icon} name={b.name} size={15} />
                </span>
                <span className="min-w-0 flex-1 flex items-center justify-between gap-2">
                  <span className="j13-bcard-name truncate">{b.name}</span>
                  <span className="meta shrink-0 text-[11px] tabular-nums">{b.post_count} 篇</span>
                </span>
              </Link>
            ))}
          </>
        ) : null}
      </div>

      {showAdmin ? (
        <div className="shrink-0 mt-1.5 pt-1.5" style={{ borderTop: "1px solid var(--line)" }}>
          <Link href="/admin" className="j13-bcard">
            <span
              className="j13-bcard-ico"
              style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
              aria-hidden="true"
            >
              <ShieldCheck size={15} />
            </span>
            <span className="j13-bcard-name flex-1 truncate">管理面板</span>
          </Link>
        </div>
      ) : null}
    </section>
  );
}

// 桌面左栏：整块模块，与右栏 j13-module 对齐
export function WorkspaceNav({ boards, user }: { boards: BoardWithCount[]; user?: User | null }) {
  return (
    // sticky 必须挂在 flex 子项上：父级 items-start 会把内层缩成内容高，失去粘滞行程
    <nav
      className="hidden lg:block w-56 xl:w-60 shrink-0 sticky top-[var(--rail-top)] max-h-[var(--rail-max-h)]"
      aria-label="工作台导航"
    >
      <WorkspaceNavPanel boards={boards} user={user} />
    </nav>
  );
}

// 移动端：横向滑动板块条（两端渐隐指示「可左右滑动」）；发帖入口由底部公共菜单承载。
// 板块条两端嵌左右抽屉入口（☰ 导航 / ▦ 面板），与书籍阅读页的左右工具栏同构：
// 左抽屉 = 桌面左栏（板块目录 + 工作台），右抽屉 = 桌面右栏面板；内容为空则对应入口不渲染
export function WorkspaceNavMobile({
  boards,
  left,
  right,
}: {
  boards: BoardWithCount[];
  /** 左抽屉内容（桌面左栏，服务端渲染节点） */
  left?: ReactNode;
  /** 右抽屉内容（桌面右栏，服务端渲染节点） */
  right?: ReactNode;
}) {
  const params = useSearchParams();
  const activeBoard = Number(params.get("board")) || 0;
  const scrollRef = useRef<HTMLDivElement>(null);
  const [canScrollLeft, setCanScrollLeft] = useState(false);
  const [canScrollRight, setCanScrollRight] = useState(false);
  const [drawer, setDrawer] = useState<"left" | "right" | null>(null);
  useDrawerChrome(drawer !== null, () => setDrawer(null));

  const updateScrollState = useCallback(() => {
    const el = scrollRef.current;
    if (!el) return;
    const max = el.scrollWidth - el.clientWidth;
    setCanScrollLeft(el.scrollLeft > 4);
    setCanScrollRight(max > 4 && el.scrollLeft < max - 4);
  }, []);

  useEffect(() => {
    updateScrollState();
    const el = scrollRef.current;
    if (!el || typeof ResizeObserver === "undefined") return;
    const ro = new ResizeObserver(updateScrollState);
    ro.observe(el);
    return () => ro.disconnect();
  }, [boards, updateScrollState]);

  // 进页 / 切板块时把激活 chip 滚到可视区中央
  useEffect(() => {
    const el = scrollRef.current;
    if (!el) return;
    el.querySelector<HTMLElement>('[aria-current="page"]')?.scrollIntoView({
      block: "nearest",
      inline: "center",
    });
  }, [activeBoard, boards]);

  const triggerBtn =
    "relative inline-flex h-7 w-7 shrink-0 items-center justify-center rounded-full border transition-colors hover:bg-[var(--panel-2)] active:scale-95 " +
    // 视觉 28px、触控热区扩到 44px（HIG 最小触控目标），仅扩大命中范围不改变外观
    "before:absolute before:-inset-2 before:rounded-full before:content-['']";

  return (
    <div className="lg:hidden -mx-4 sm:-mx-6 px-4 sm:px-6 bg-[var(--main-bg)] border-b border-[var(--line)] py-2.5">
      <div className="relative flex items-center gap-1.5">
        {left ? (
          <button
            type="button"
            className={triggerBtn}
            style={{ borderColor: "var(--line)", color: "var(--ink-2)" }}
            onClick={() => setDrawer("left")}
            aria-haspopup="dialog"
            aria-label="打开导航抽屉"
          >
            <Menu size={15} aria-hidden />
          </button>
        ) : null}

        <div className="relative min-w-0 flex-1">
          <div
            ref={scrollRef}
            className="j13-chips"
            onScroll={updateScrollState}
          >
            <Link
              href="/"
              className="j13-chip"
              aria-current={activeBoard === 0 ? "page" : undefined}
            >
              <Home size={13} /> 全部
            </Link>
            {boards.map((b) => (
              <Link
                key={b.id}
                href={boardHref(b.id)}
                className="j13-chip"
                aria-current={activeBoard === b.id ? "page" : undefined}
              >
                <BoardIcon icon={b.icon} name={b.name} size={13} />
                {b.name}
              </Link>
            ))}
          </div>
          {/* 渐隐滑动指示：遮罩与背景同色，pointer-events-none 不挡触控 */}
          <div
            className={`j13-chip-fade j13-chip-fade-left ${canScrollLeft ? "is-on" : ""}`}
            aria-hidden="true"
          />
          <div
            className={`j13-chip-fade j13-chip-fade-right ${canScrollRight ? "is-on" : ""}`}
            aria-hidden="true"
          />
        </div>

        {right ? (
          <button
            type="button"
            className={triggerBtn}
            style={{ borderColor: "var(--line)", color: "var(--ink-2)" }}
            onClick={() => setDrawer("right")}
            aria-haspopup="dialog"
            aria-label="打开面板抽屉"
          >
            <LayoutGrid size={15} aria-hidden />
          </button>
        ) : null}
      </div>

      {/* 左右抽屉：内容由服务端渲染后传入；lg 起隐藏（桌面用常驻侧栏） */}
      {left ? (
        <RailDrawerPanel side="left" title="导航" open={drawer === "left"} onClose={() => setDrawer(null)}>
          {left}
        </RailDrawerPanel>
      ) : null}
      {right ? (
        <RailDrawerPanel side="right" title="面板" open={drawer === "right"} onClose={() => setDrawer(null)}>
          {right}
        </RailDrawerPanel>
      ) : null}
    </div>
  );
}