"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import { useEffect, useState } from "react";
import type { LucideIcon } from "lucide-react";
import {
  LayoutDashboard,
  Users,
  Megaphone,
  Palette,
  ShieldCheck,
  ArrowLeft,
  Coins,
  Globe,
  FolderOpen,
} from "lucide-react";
import type { User } from "@/lib/api";
import { apiAdminPendingCounts } from "@/lib/api";
import {
  canModerateAny,
  isAdminOrAbove,
  isSuperOrOwner,
  type RoleUserLike,
} from "@/lib/roles";
import { realtime, RT_MODERATION_CHANGED } from "@/lib/realtime";
import { onDocumentVisible } from "@/lib/visibilityReconcile";
import Avatar from "@/components/Avatar";
import RoleBadge from "@/components/RoleBadge";

interface NavItem {
  href: string;
  label: string;
  icon: LucideIcon;
  exact?: boolean;
  visible: (u: RoleUserLike) => boolean;
  pendingBadge?: boolean;
}

interface NavGroup {
  title: string;
  items: NavItem[];
}

// 分组导航：概览 → 内容运营 → 成员经济 → 站点配置，便于后期在组内扩展
const NAV_GROUPS: NavGroup[] = [
  {
    title: "概览",
    items: [
      { href: "/admin", label: "仪表盘", icon: LayoutDashboard, exact: true, visible: () => true },
    ],
  },
  {
    title: "内容",
    items: [
      {
        href: "/admin/content",
        label: "内容管理",
        icon: FolderOpen,
        visible: (u) => canModerateAny(u),
        pendingBadge: true,
      },
      {
        href: "/admin/announcements",
        label: "公告管理",
        icon: Megaphone,
        visible: (u) => isAdminOrAbove(u.role),
      },
    ],
  },
  {
    title: "成员与经济",
    items: [
      {
        href: "/admin/users",
        label: "用户权限",
        icon: Users,
        visible: (u) => isSuperOrOwner(u.role),
      },
      {
        href: "/admin/economy",
        label: "积分看板",
        icon: Coins,
        visible: (u) => isAdminOrAbove(u.role),
      },
    ],
  },
  {
    title: "站点",
    items: [
      {
        href: "/admin/settings",
        label: "站点设置",
        icon: Globe,
        visible: (u) => isSuperOrOwner(u.role),
      },
      {
        href: "/admin/appearance",
        label: "外观",
        icon: Palette,
        visible: (u) => isSuperOrOwner(u.role),
      },
    ],
  },
];

function isActive(pathname: string, href: string, exact?: boolean) {
  return exact ? pathname === href : pathname === href || pathname.startsWith(`${href}/`);
}

function usePendingCounts(enabled: boolean) {
  const [counts, setCounts] = useState({ posts: 0, comments: 0 });
  useEffect(() => {
    if (!enabled) return;
    let alive = true;
    const load = () => {
      apiAdminPendingCounts()
        .then((c) => {
          if (alive) setCounts(c);
        })
        .catch(() => {});
    };
    load();
    const off = realtime.on(RT_MODERATION_CHANGED, () => load());
    const offVisible = onDocumentVisible(load);
    return () => {
      alive = false;
      off();
      offVisible();
    };
  }, [enabled]);
  return counts.posts + counts.comments;
}

function PendingBadge({ count }: { count: number }) {
  if (count <= 0) return null;
  return (
    <span
      className="ml-auto shrink-0 min-w-[20px] h-5 px-1.5 rounded-full inline-flex items-center justify-center text-[10.5px] font-medium tabular-nums"
      style={{ background: "var(--gold-soft)", color: "var(--gold)" }}
      aria-label={`${count} 条待审核`}
    >
      {count > 99 ? "99+" : count}
    </span>
  );
}

function visibleGroups(user: RoleUserLike) {
  return NAV_GROUPS.map((g) => ({
    ...g,
    items: g.items.filter((i) => i.visible(user)),
  })).filter((g) => g.items.length > 0);
}

function flatItems(user: RoleUserLike) {
  return visibleGroups(user).flatMap((g) => g.items);
}

export function AdminSidebar({ user }: { user: User }) {
  const pathname = usePathname();
  const groups = visibleGroups(user);
  const pendingTotal = usePendingCounts(flatItems(user).some((i) => i.pendingBadge));

  return (
    <div className="panel p-3">
      <div className="flex items-center gap-2.5 px-2 pt-1.5 pb-3.5" style={{ borderBottom: "1px solid var(--line)" }}>
        <span
          className="w-9 h-9 rounded-xl flex items-center justify-center shrink-0"
          style={{ background: "var(--accent)", color: "var(--accent-on)" }}
        >
          <ShieldCheck size={18} />
        </span>
        <span className="leading-tight min-w-0">
          <span className="block text-[14.5px] font-extrabold tracking-tight truncate" style={{ color: "var(--ink)" }}>
            管理面板
          </span>
          <span className="block text-[10.5px] mt-0.5 tracking-wide" style={{ color: "var(--ink-3)" }}>
            J13 ADMIN
          </span>
        </span>
      </div>

      <nav className="flex flex-col gap-3 pt-3 pb-2" aria-label="后台导航">
        {groups.map((group) => (
          <div key={group.title}>
            <p className="field-label px-2 pb-1.5" style={{ marginBottom: 0 }}>
              {group.title}
            </p>
            <div className="flex flex-col gap-1">
              {group.items.map((item) => {
                const active = isActive(pathname, item.href, item.exact);
                const Icon = item.icon;
                return (
                  <Link
                    key={item.href}
                    href={item.href}
                    aria-current={active ? "page" : undefined}
                    className="flex items-center gap-2.5 px-3 py-2.5 rounded-xl text-[13.5px] font-medium transition-colors"
                    style={
                      active
                        ? { background: "var(--nav-active-bg)", color: "var(--nav-active-ink)" }
                        : { color: "var(--ink-2)" }
                    }
                  >
                    <Icon
                      size={16}
                      className="shrink-0"
                      style={{ color: active ? "var(--nav-active-ink)" : "var(--ink-3)" }}
                    />
                    {item.label}
                    {item.pendingBadge && <PendingBadge count={pendingTotal} />}
                  </Link>
                );
              })}
            </div>
          </div>
        ))}
      </nav>

      <div className="pt-2" style={{ borderTop: "1px solid var(--line)" }}>
        <Link
          href="/"
          className="flex items-center gap-2.5 px-3 py-2.5 rounded-xl text-[13.5px] transition-colors hover:bg-[var(--panel-2)]"
          style={{ color: "var(--ink-2)" }}
        >
          <ArrowLeft size={16} className="shrink-0" style={{ color: "var(--ink-3)" }} />
          返回站点
        </Link>
      </div>

      <div className="flex items-center gap-2.5 mt-2 px-2.5 py-2.5 rounded-xl" style={{ background: "var(--panel-2)" }}>
        <Avatar name={user.nickname || user.username} src={user.avatar || undefined} size={32} />
        <div className="min-w-0 leading-tight">
          <p className="text-[13px] font-medium truncate" style={{ color: "var(--ink)" }}>
            {user.nickname}
          </p>
          <p className="text-[11px] truncate" style={{ color: "var(--ink-3)" }}>
            @{user.username}
          </p>
        </div>
        <span className="ml-auto shrink-0">
          <RoleBadge role={user.role} boardIds={user.board_ids} size={11} />
        </span>
      </div>
    </div>
  );
}

export function AdminNavMobile({ user }: { user: User }) {
  const pathname = usePathname();
  const items = flatItems(user);
  const pendingTotal = usePendingCounts(items.some((i) => i.pendingBadge));

  return (
    <div
      className="lg:hidden sticky z-30 -mx-4 sm:-mx-6 px-4 sm:px-6 py-2.5 mb-4"
      style={{
        top: 68,
        background: "color-mix(in srgb, var(--bg) 88%, transparent)",
        backdropFilter: "blur(14px)",
        WebkitBackdropFilter: "blur(14px)",
        borderBottom: "1px solid var(--line)",
      }}
    >
      <nav className="flex items-center gap-2 overflow-x-auto" aria-label="后台导航">
        {items.map((item) => {
          const active = isActive(pathname, item.href, item.exact);
          const Icon = item.icon;
          return (
            <Link
              key={item.href}
              href={item.href}
              aria-current={active ? "page" : undefined}
              className="admin-seg shrink-0"
              style={
                active
                  ? undefined
                  : { background: "var(--panel)", border: "1px solid var(--line)" }
              }
            >
              <Icon size={14} />
              {item.label}
              {item.pendingBadge && pendingTotal > 0 && (
                <span className="admin-seg-count">{pendingTotal > 99 ? "99+" : pendingTotal}</span>
              )}
            </Link>
          );
        })}
        <Link
          href="/"
          className="admin-seg shrink-0"
          style={{ background: "var(--panel)", border: "1px solid var(--line)" }}
        >
          <ArrowLeft size={14} />
          返回站点
        </Link>
      </nav>
    </div>
  );
}