"use client";

import Link from "next/link";
import { useRouter } from "next/navigation";
import { useState, useEffect } from "react";
import { Menu, X, Sun, Moon, LogIn, UserPlus, LogOut, PenSquare, Search, Settings } from "lucide-react";
import { apiMe, apiLogout, type User } from "@/lib/api";
import NotificationBell from "./NotificationBell";

export default function Header() {
  const router = useRouter();
  const [menuOpen, setMenuOpen] = useState(false);
  const [theme, setTheme] = useState<"light" | "dark">("light");
  const [user, setUser] = useState<User | null>(null);
  const [searchQuery, setSearchQuery] = useState("");

  const handleSearch = (e: React.FormEvent) => {
    e.preventDefault();
    const q = searchQuery.trim();
    if (q) {
      router.push(`/?q=${encodeURIComponent(q)}`);
    }
  };

  useEffect(() => {
    // 读取主题
    const savedTheme = document.documentElement.classList.contains("dark") ? "dark" : "light";
    setTheme(savedTheme);

    // 从后端获取登录态（HttpOnly cookie 自动携带）
    apiMe()
      .then((res) => setUser(res.user || null))
      .catch(() => setUser(null));
  }, []);

  const toggleTheme = () => {
    const newTheme = theme === "dark" ? "light" : "dark";
    setTheme(newTheme);
    document.documentElement.classList.toggle("dark", newTheme === "dark");
    document.cookie = `j13-theme=${newTheme}; path=/; max-age=31536000`;
  };

  const handleLogout = async () => {
    try {
      await apiLogout();
    } catch {
      /* ignore */
    }
    setUser(null);
    setMenuOpen(false);
    router.refresh();
  };

  return (
    <header className="sticky top-0 z-50 border-b" style={{ borderColor: "var(--border)", background: "var(--bg)" }}>
      <div className="max-w-5xl mx-auto px-4 h-14 flex items-center justify-between">
        <Link href="/" className="font-bold text-lg" style={{ color: "var(--primary)" }}>
          姜十三论坛
        </Link>

        {/* 桌面端导航 */}
        <nav className="hidden md:flex items-center gap-4">
          <form onSubmit={handleSearch} className="relative">
            <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2" style={{ color: "var(--text-secondary)" }} />
            <input
              type="text"
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              placeholder="搜索帖子..."
              className="pl-9 pr-3 py-1.5 rounded-lg text-sm w-44 focus:outline-none focus:w-56 transition-all"
              style={{ background: "var(--bg-secondary)", color: "var(--text)", border: "1px solid var(--border)" }}
            />
          </form>
          <Link href="/" className="hover:opacity-80" style={{ color: "var(--text)" }}>首页</Link>
          {user && (
            <Link href="/compose" className="flex items-center gap-1 hover:opacity-80" style={{ color: "var(--text)" }}>
              <PenSquare size={16} /> 发帖
            </Link>
          )}
          <button onClick={toggleTheme} className="p-2 rounded-lg hover:opacity-80" style={{ color: "var(--text)" }}>
            {theme === "dark" ? <Sun size={18} /> : <Moon size={18} />}
          </button>
          {user && <NotificationBell />}
          {user ? (
            <div className="flex items-center gap-3">
              <span className="text-sm" style={{ color: "var(--text-secondary)" }}>{user.nickname}</span>
              <Link href="/settings" className="flex items-center gap-1 text-sm hover:opacity-80" style={{ color: "var(--text-secondary)" }}>
                <Settings size={14} /> 设置
              </Link>
              <button onClick={handleLogout} className="flex items-center gap-1 text-sm hover:opacity-80" style={{ color: "var(--text-secondary)" }}>
                <LogOut size={14} /> 退出
              </button>
            </div>
          ) : (
            <div className="flex items-center gap-2">
              <Link href="/login" className="flex items-center gap-1 px-3 py-1.5 rounded-lg text-sm" style={{ background: "var(--bg-secondary)", color: "var(--text)" }}>
                <LogIn size={14} /> 登录
              </Link>
              <Link href="/register" className="flex items-center gap-1 px-3 py-1.5 rounded-lg text-sm text-white" style={{ background: "var(--primary)" }}>
                <UserPlus size={14} /> 注册
              </Link>
            </div>
          )}
        </nav>

        {/* 移动端菜单按钮 */}
        <button onClick={() => setMenuOpen(!menuOpen)} className="md:hidden p-2" style={{ color: "var(--text)" }}>
          {menuOpen ? <X size={20} /> : <Menu size={20} />}
        </button>
      </div>

      {/* 移动端下拉菜单 */}
      {menuOpen && (
        <div className="md:hidden border-t px-4 py-3 space-y-2" style={{ borderColor: "var(--border)", background: "var(--bg)" }}>
          <form onSubmit={(e) => { handleSearch(e); setMenuOpen(false); }} className="relative">
            <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2" style={{ color: "var(--text-secondary)" }} />
            <input
              type="text"
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              placeholder="搜索帖子..."
              className="w-full pl-9 pr-3 py-2 rounded-lg text-sm"
              style={{ background: "var(--bg-secondary)", color: "var(--text)", border: "1px solid var(--border)" }}
            />
          </form>
          <Link href="/" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>首页</Link>
          {user && (
            <Link href="/compose" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>发帖</Link>
          )}
          <button onClick={toggleTheme} className="block py-2 w-full text-left" style={{ color: "var(--text)" }}>
            {theme === "dark" ? "切换亮色主题" : "切换暗色主题"}
          </button>
          {user ? (
            <Link href="/notifications" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>通知中心</Link>
          ) : null}
          {user ? (
            <>
              <Link href="/settings" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>账号设置</Link>
              <button onClick={handleLogout} className="block py-2 w-full text-left" style={{ color: "var(--text)" }}>退出登录</button>
            </>
          ) : (
            <>
              <Link href="/login" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>登录</Link>
              <Link href="/register" onClick={() => setMenuOpen(false)} className="block py-2" style={{ color: "var(--text)" }}>注册</Link>
            </>
          )}
        </div>
      )}
    </header>
  );
}