import { useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { User, Lock, Palette, Check, Loader2, AlertCircle } from 'lucide-react';
import { useUserStore } from '@/store';
import { userApi } from '@/services/api';
import { useTheme, THEME_OPTIONS } from '@/hooks/useTheme';
import { cn } from '@/lib/utils';
import {
  DropdownMenu,
  DropdownMenuTrigger,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
} from '@/components/ui/dropdown-menu';

/* ---------- Floating background orbs (themed light spots) ---------- */
const ORBS = [
  {
    top: '-10%',
    left: '-5%',
    size: 520,
    color: 'var(--dg-blue)',
    opacity: 0.22,
    blur: 90,
    animation: 'login-orb-1 18s ease-in-out infinite',
  },
  {
    bottom: '-15%',
    right: '-8%',
    size: 480,
    color: 'var(--dg-purple)',
    opacity: 0.2,
    blur: 100,
    animation: 'login-orb-2 22s ease-in-out infinite',
  },
  {
    top: '30%',
    right: '10%',
    size: 320,
    color: 'var(--dg-cyan)',
    opacity: 0.16,
    blur: 70,
    animation: 'login-orb-3 16s ease-in-out infinite',
  },
  {
    bottom: '10%',
    left: '8%',
    size: 380,
    color: 'var(--dg-gradient-start)',
    opacity: 0.18,
    blur: 80,
    animation: 'login-orb-4 20s ease-in-out infinite',
  },
];

const ANIMATIONS = `
  @keyframes login-orb-1 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(40px, -50px) scale(1.12); }
    66% { transform: translate(-30px, 35px) scale(0.92); }
  }
  @keyframes login-orb-2 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(-50px, 25px) scale(1.18); }
  }
  @keyframes login-orb-3 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(30px, 45px) scale(0.88); }
  }
  @keyframes login-orb-4 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(25px, -30px) scale(1.1); }
  }
  @keyframes login-card-enter {
    from { opacity: 0; transform: translateY(24px) scale(0.97); }
    to { opacity: 1; transform: translateY(0) scale(1); }
  }
  @keyframes login-fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
  }
`;

export function Login() {
  const navigate = useNavigate();
  const { theme, setTheme } = useTheme();
  const [username, setUsername] = useState('admin');
  const [password, setPassword] = useState('123456');
  const [showPassword, setShowPassword] = useState(false);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setError('');
    setLoading(true);
    try {
      const result = await userApi.login(username, password);
      useUserStore.getState().login(result.user, result.token);
      localStorage.setItem('token', result.token); // backward compat
      navigate('/', { replace: true });
    } catch (err: unknown) {
      const message = err instanceof Error ? err.message : '登录失败，请检查用户名和密码';
      setError(message);
    } finally {
      setLoading(false);
    }
  };

  return (
    <>
      <style>{ANIMATIONS}</style>

      <div
        className="relative min-h-screen flex items-center justify-center px-4 overflow-hidden"
        style={{
          background:
            'linear-gradient(135deg, var(--dg-bg-primary) 0%, var(--dg-bg-secondary) 100%)',
        }}
      >
        {/* -------- Floating themed light spots -------- */}
        {ORBS.map((orb, i) => (
          <div
            key={`orb-${i}`}
            aria-hidden="true"
            className="pointer-events-none absolute"
            style={{
              top: orb.top,
              left: orb.left,
              bottom: orb.bottom,
              right: orb.right,
              width: orb.size,
              height: orb.size,
              borderRadius: '50%',
              background: `radial-gradient(circle, ${orb.color} 0%, transparent 70%)`,
              opacity: orb.opacity,
              filter: `blur(${orb.blur}px)`,
              animation: orb.animation,
              willChange: 'transform',
            }}
          />
        ))}

        {/* -------- Theme switcher (top-right) -------- */}
        <div
          className="fixed top-4 right-4 z-50"
          style={{ animation: 'login-fade-in 0.6s ease-out' }}
        >
          <DropdownMenu>
            <DropdownMenuTrigger asChild>
              <button
                type="button"
                aria-label="切换主题"
                className={cn(
                  'inline-flex items-center justify-center size-10 rounded-full',
                  'border transition-all duration-200 hover:scale-105 active:scale-95'
                )}
                style={{
                  background: 'color-mix(in srgb, var(--dg-bg-secondary) 70%, transparent)',
                  borderColor: 'var(--dg-border)',
                  color: 'var(--dg-text-secondary)',
                  backdropFilter: 'blur(12px)',
                  WebkitBackdropFilter: 'blur(12px)',
                }}
              >
                <Palette className="size-5" />
              </button>
            </DropdownMenuTrigger>
            <DropdownMenuContent align="end" className="w-60">
              <DropdownMenuLabel>主题切换</DropdownMenuLabel>
              <DropdownMenuSeparator />
              {THEME_OPTIONS.map((option) => (
                <DropdownMenuItem
                  key={option.id}
                  className="flex items-center gap-2.5 cursor-pointer"
                  onClick={() => setTheme(option.id)}
                >
                  <span
                    className="size-3.5 rounded-full shrink-0 ring-2"
                    style={{
                      backgroundColor: option.primaryColor,
                      // @ts-expect-error css var in style string
                      '--tw-ring-color': 'var(--dg-bg-primary)',
                    }}
                  />
                  <div className="flex-1 min-w-0">
                    <span className="text-sm font-medium block">{option.name}</span>
                    <span className="text-xs opacity-60 block truncate">
                      {option.description}
                    </span>
                  </div>
                  {theme === option.id && <Check className="size-4 shrink-0" />}
                </DropdownMenuItem>
              ))}
            </DropdownMenuContent>
          </DropdownMenu>
        </div>

        {/* -------- Login card -------- */}
        <div
          className="relative z-10 w-full max-w-md"
          style={{
            background:
              'color-mix(in srgb, var(--dg-bg-secondary) 75%, transparent)',
            backdropFilter: 'blur(24px)',
            WebkitBackdropFilter: 'blur(24px)',
            border: '1px solid var(--dg-border)',
            borderRadius: 24,
            boxShadow:
              '0 8px 48px rgba(0,0,0,0.28), 0 0 0 1px rgba(255,255,255,0.02)',
            padding: '40px 36px',
            animation: 'login-card-enter 0.6s cubic-bezier(0.16, 1, 0.3, 1)',
          }}
        >
          {/* Brand */}
          <div className="text-center mb-8">
            <div
              className="inline-flex items-center justify-center size-14 rounded-2xl mb-4 shadow-lg"
              style={{
                background:
                  'linear-gradient(135deg, var(--dg-gradient-start), var(--dg-gradient-end))',
                boxShadow: '0 8px 24px color-mix(in srgb, var(--dg-gradient-start) 35%, transparent)',
              }}
            >
              <svg
                className="size-7 text-white"
                fill="none"
                viewBox="0 0 24 24"
                stroke="currentColor"
                strokeWidth={1.8}
                strokeLinecap="round"
                strokeLinejoin="round"
              >
                <path d="M3 12h4l3-8 4 16 3-8h4" />
              </svg>
            </div>
            <h1 className="text-3xl font-bold dg-gradient-text tracking-tight">
              AIOps
            </h1>
            <p
              className="mt-2 text-sm"
              style={{ color: 'var(--dg-text-secondary)' }}
            >
              智能运维 · 全栈可观测平台
            </p>
          </div>

          {/* Form */}
          <form onSubmit={handleSubmit} className="flex flex-col gap-4">
            {/* Error */}
            {error && (
              <div
                className="flex items-start gap-2 rounded-lg px-4 py-3 text-sm"
                style={{
                  background: 'color-mix(in srgb, var(--dg-red) 12%, transparent)',
                  border: '1px solid color-mix(in srgb, var(--dg-red) 30%, transparent)',
                  color: 'var(--dg-red)',
                  animation: 'login-fade-in 0.25s ease-out',
                }}
              >
                <AlertCircle className="size-4 shrink-0 mt-0.5" />
                <span>{error}</span>
              </div>
            )}

            {/* Username */}
            <div>
              <label
                className="block text-sm font-medium mb-1.5"
                style={{ color: 'var(--dg-text-secondary)' }}
              >
                用户名
              </label>
              <div className="relative">
                <User
                  className="absolute left-3.5 top-1/2 -translate-y-1/2 size-4 pointer-events-none"
                  style={{ color: 'var(--dg-text-muted)' }}
                />
                <input
                  type="text"
                  value={username}
                  onChange={(e) => setUsername(e.target.value)}
                  placeholder="请输入用户名"
                  autoComplete="username"
                  autoFocus
                  className="dg-input w-full rounded-lg py-2.5 pl-10 pr-4 text-sm transition-colors"
                />
              </div>
            </div>

            {/* Password */}
            <div>
              <label
                className="block text-sm font-medium mb-1.5"
                style={{ color: 'var(--dg-text-secondary)' }}
              >
                密码
              </label>
              <div className="relative">
                <Lock
                  className="absolute left-3.5 top-1/2 -translate-y-1/2 size-4 pointer-events-none"
                  style={{ color: 'var(--dg-text-muted)' }}
                />
                <input
                  type={showPassword ? 'text' : 'password'}
                  value={password}
                  onChange={(e) => setPassword(e.target.value)}
                  placeholder="请输入密码"
                  autoComplete="current-password"
                  className="dg-input w-full rounded-lg py-2.5 pl-10 pr-12 text-sm transition-colors"
                />
                <button
                  type="button"
                  onClick={() => setShowPassword((v) => !v)}
                  className="absolute right-3 top-1/2 -translate-y-1/2 text-xs font-medium transition-colors"
                  style={{ color: 'var(--dg-text-muted)' }}
                >
                  {showPassword ? '隐藏' : '显示'}
                </button>
              </div>
            </div>

            {/* Submit */}
            <button
              type="submit"
              disabled={loading || !username || !password}
              className={cn(
                'dg-gradient-bg w-full rounded-lg py-3 mt-2 text-white font-semibold text-[15px]',
                'transition-all duration-200 active:scale-[0.98]',
                'disabled:cursor-not-allowed'
              )}
              style={{
                opacity: loading || !username || !password ? 0.6 : 1,
                boxShadow:
                  '0 6px 24px color-mix(in srgb, var(--dg-gradient-start) 30%, transparent)',
              }}
            >
              {loading ? (
                <span className="inline-flex items-center justify-center gap-2">
                  <Loader2 className="size-4 animate-spin" />
                  登录中…
                </span>
              ) : (
                '登 录'
              )}
            </button>
          </form>

          {/* Hints */}
          <div
            className="mt-6 pt-5 text-center text-xs space-y-1"
            style={{
              borderTop: '1px solid var(--dg-border-light)',
              color: 'var(--dg-text-muted)',
            }}
          >
            <p>
              默认管理员账号 <span className="font-medium" style={{ color: 'var(--dg-text-secondary)' }}>admin / 123456</span>
            </p>
            <p>LDAP 用户可直接使用域账号登录</p>
          </div>
        </div>

        {/* Footer */}
        <p
          className="absolute bottom-4 left-0 right-0 text-center text-xs"
          style={{ color: 'var(--dg-text-muted)', opacity: 0.7 }}
        >
          © AIOps · 智能运维平台
        </p>
      </div>
    </>
  );
}