import { useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { useTranslation } from 'react-i18next';
import { User, Lock, Palette, Check, Loader2, AlertCircle, Eye, EyeOff, Languages, Activity } from 'lucide-react';
import { useUserStore, useLanguageStore } from '@/store';
import { authApi } from '@/api';
import { useTheme } from '@/hooks/useTheme';
import { ThemePicker } from '@/components/layout/ThemePicker';
import { cn } from '@/lib/utils';
import { SUPPORTED_LANGUAGES, type AppLanguage } from '@/i18n';
import {
  DropdownMenu,
  DropdownMenuTrigger,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
} from '@/components/ui/dropdown-menu';

/** 登录页 — 克制企业风，无渐变/粉彩色光球 // Logan.Li */
export function Login() {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const { theme, setTheme } = useTheme();
  const { language, setLanguage } = useLanguageStore();
  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 authApi.login(username, password) as { user: { id: number; username: string }; token: string; permissions?: string[] };
      useUserStore.getState().login(result.user, result.token, result.permissions ?? null);
      localStorage.setItem('token', result.token);
      navigate('/', { replace: true });
    } catch (err) {
      const message = err instanceof Error ? err.message : t('login.loginFailed');
      setError(message);
    } finally {
      setLoading(false);
    }
  };

  return (
    <div className="relative min-h-screen flex items-center justify-center px-4 bg-[var(--surface-canvas)]">
      {/* 极弱品牌氛围 — 单色径向，非彩色光球 // Logan.Li */}
      <div
        aria-hidden
        className="pointer-events-none absolute inset-0"
        style={{
          background: 'radial-gradient(ellipse 80% 50% at 50% -10%, color-mix(in srgb, var(--brand) 6%, transparent), transparent)',
        }}
      />

      {/* 语言 / 主题 */}
      <div className="fixed top-4 right-4 z-50 flex items-center gap-2">
        <DropdownMenu>
          <DropdownMenuTrigger asChild>
            <button
              type="button"
              aria-label={t('header.language')}
              className="dg-btn-secondary h-9 w-9 p-0 rounded-lg"
            >
              <Languages className="size-4" />
            </button>
          </DropdownMenuTrigger>
          <DropdownMenuContent
            align="end"
            className="w-40 bg-[var(--surface-raised)] border-[var(--border-default)]"
            style={{ boxShadow: 'var(--shadow-dropdown)' }}
          >
            <DropdownMenuLabel className="text-[var(--text-secondary)]">{t('header.languageSwitch')}</DropdownMenuLabel>
            <DropdownMenuSeparator className="bg-[var(--border-default)]" />
            {SUPPORTED_LANGUAGES.map((lang) => (
              <DropdownMenuItem
                key={lang.code}
                className={cn(
                  'flex items-center gap-2.5 cursor-pointer',
                  language === lang.code ? 'text-[var(--text-primary)]' : 'dg-text-secondary',
                )}
                onClick={() => setLanguage(lang.code as AppLanguage)}
              >
                <span className="text-base">{lang.flag}</span>
                <span className="flex-1 text-sm">{lang.label}</span>
                {language === lang.code && <Check className="size-4 shrink-0 text-[var(--brand)]" />}
              </DropdownMenuItem>
            ))}
          </DropdownMenuContent>
        </DropdownMenu>

        <DropdownMenu>
          <DropdownMenuTrigger asChild>
            <button
              type="button"
              aria-label={t('header.theme')}
              className="dg-btn-secondary h-9 w-9 p-0 rounded-lg"
            >
              <Palette className="size-4" />
            </button>
          </DropdownMenuTrigger>
          <DropdownMenuContent
            align="end"
            className="w-60 bg-[var(--surface-raised)] border-[var(--border-default)]"
            style={{ boxShadow: 'var(--shadow-dropdown)' }}
          >
            <DropdownMenuLabel className="text-[var(--text-secondary)]">{t('header.themeSwitch')}</DropdownMenuLabel>
            <ThemePicker value={theme} onChange={setTheme} />
          </DropdownMenuContent>
        </DropdownMenu>
      </div>

      {/* 登录卡片 */}
      <div className="relative z-10 w-full max-w-md dg-card rounded-xl p-10 animate-fade-in">
        <div className="text-center mb-8">
          <div className="dg-icon-box w-14 h-14 rounded-xl mx-auto mb-4">
            <Activity className="size-7" />
          </div>
          <h1 className="text-2xl font-bold text-[var(--text-primary)] tracking-tight">
            AIOps
          </h1>
          <p className="mt-2 text-sm dg-text-secondary">
            {t('login.subtitle')}
          </p>
        </div>

        <form onSubmit={handleSubmit} className="flex flex-col gap-4">
          {error && (
            <div className="flex items-start gap-2.5 rounded-lg px-4 py-3 text-sm dg-alert-banner border-[var(--alert-error-border)] bg-[var(--alert-error-bg)] text-[var(--alert-error-text)]">
              <AlertCircle className="size-4 shrink-0 mt-0.5" />
              <span>{error}</span>
            </div>
          )}

          <div className="space-y-1.5">
            <label className="block text-sm font-medium dg-text-secondary">
              {t('login.username')}
            </label>
            <div className="relative">
              <User className="absolute left-3.5 top-1/2 -translate-y-1/2 size-4 pointer-events-none dg-text-muted" />
              <input
                type="text"
                value={username}
                onChange={(e) => setUsername(e.target.value)}
                placeholder={t('login.usernamePlaceholder')}
                autoComplete="username"
                autoFocus
                className="dg-input w-full py-2.5 pl-10 pr-4 text-sm"
              />
            </div>
          </div>

          <div className="space-y-1.5">
            <label className="block text-sm font-medium dg-text-secondary">
              {t('login.password')}
            </label>
            <div className="relative">
              <Lock className="absolute left-3.5 top-1/2 -translate-y-1/2 size-4 pointer-events-none dg-text-muted" />
              <input
                type={showPassword ? 'text' : 'password'}
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                placeholder={t('login.passwordPlaceholder')}
                autoComplete="current-password"
                className="dg-input w-full py-2.5 pl-10 pr-12 text-sm"
              />
              <button
                type="button"
                onClick={() => setShowPassword((v) => !v)}
                className="absolute right-3 top-1/2 -translate-y-1/2 dg-text-muted hover:dg-text-secondary transition-colors"
                tabIndex={-1}
              >
                {showPassword ? <EyeOff className="size-4" /> : <Eye className="size-4" />}
              </button>
            </div>
          </div>

          <button
            type="submit"
            disabled={loading || !username || !password}
            className="dg-btn-primary w-full rounded-lg py-2.5 mt-1 text-[15px] font-semibold disabled:cursor-not-allowed"
          >
            {loading ? (
              <span className="inline-flex items-center justify-center gap-2">
                <Loader2 className="size-4 animate-spin" />
                {t('login.loggingIn')}
              </span>
            ) : (
              t('login.loginButton')
            )}
          </button>
        </form>

        <div className="mt-6 pt-5 text-center text-xs space-y-1 border-t border-[var(--border-subtle)] dg-text-muted">
          <p>
            默认管理员账号{' '}
            <span className="font-medium dg-text-secondary">admin / 123456</span>
          </p>
          <p>LDAP 用户可直接使用域账号登录</p>
        </div>
      </div>

      <p className="absolute bottom-4 left-0 right-0 text-center text-xs dg-text-muted opacity-60">
        &copy; AIOps 智能运维平台
      </p>
    </div>
  );
}