"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import type { LucideIcon } from "lucide-react";
import {
  LayoutDashboard,
  Users,
  Megaphone,
  Palette,
  ShieldCheck,
  ArrowLeft,
} from "lucide-react";
import type { User } from "@/lib/api";
import Avatar from "@/components/Avatar";

// 后台导航项：exact 为精确匹配（仪表盘 /admin），其余按路径前缀匹配
const NAV_ITEMS: { href: string; label: string; icon: LucideIcon; exact?: boolean }[] = [
  { href: "/admin", label: "仪表盘", icon: LayoutDashboard, exact: true },
  { href: "/admin/users", label: "用户管理", icon: Users },
  { href: "/admin/announcements", label: "公告管理", icon: Megaphone },
  { href: "/admin/appearance", label: "外观设置", icon: Palette },
];

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

/**
 * 桌面端后台侧边栏：品牌头 + 分组导航 + 返回站点 + 管理员身份卡。
 * 选中态复用全站导航语言（--nav-active-bg 淡底 + accent 文字），
 * 与 j13-bcard / 顶部 pill 保持一致。
 */
export function AdminSidebar({ user }: { user: User }) {
  const pathname = usePathname();

  return (
    <div className="panel p-3">
      {/* 品牌头 */}
      <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] font-semibold mt-0.5 tracking-wide" style={{ color: "var(--ink-3)" }}>
            J13 ADMIN
          </span>
        </span>
      </div>

      {/* 导航 */}
      <nav className="flex flex-col gap-1 pt-3 pb-2" aria-label="后台导航">
        <p className="field-label px-2 pb-1.5" style={{ marginBottom: 0 }}>
          站点管理
        </p>
        {NAV_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-semibold 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}
            </Link>
          );
        })}
      </nav>

      {/* 返回前台 */}
      <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] font-semibold 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>

      {/* 管理员身份卡 */}
      <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-bold truncate" style={{ color: "var(--ink)" }}>
            {user.nickname}
          </p>
          <p className="text-[11px] font-semibold truncate" style={{ color: "var(--ink-3)" }}>
            @{user.username}
          </p>
        </div>
        <span
          className="ml-auto shrink-0 inline-flex items-center gap-1 rounded-full px-2 py-0.5 text-[10.5px] font-bold leading-[1.6]"
          style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
        >
          <ShieldCheck size={11} />
          管理员
        </span>
      </div>
    </div>
  );
}

/**
 * 移动端后台导航：横向滚动 pill，吸附在全站 Header 下方，
 * 窄屏下保持与桌面侧栏同等的切换能力且不占垂直空间。
 */
export function AdminNavMobile() {
  const pathname = usePathname();

  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">
        {NAV_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="shrink-0 inline-flex items-center gap-1.5 px-3.5 py-2 rounded-full text-[13px] font-semibold transition-colors"
              style={
                active
                  ? { background: "var(--nav-active-bg)", color: "var(--nav-active-ink)" }
                  : { color: "var(--ink-2)", background: "var(--panel)", border: "1px solid var(--line)" }
              }
            >
              <Icon size={14} />
              {item.label}
            </Link>
          );
        })}
        <Link
          href="/"
          className="shrink-0 inline-flex items-center gap-1.5 px-3.5 py-2 rounded-full text-[13px] font-semibold transition-colors"
          style={{ color: "var(--ink-2)", background: "var(--panel)", border: "1px solid var(--line)" }}
        >
          <ArrowLeft size={14} />
          返回站点
        </Link>
      </nav>
    </div>
  );
}