'use client';

import { zodResolver } from '@hookform/resolvers/zod';
import { useMutation, useQuery } from '@tanstack/react-query';
import Link from 'next/link';
import { useRouter, useSearchParams } from 'next/navigation';
import { useState } from 'react';
import { useForm } from 'react-hook-form';
import { z } from 'zod';

import { InlineMessage } from '@/components/feedback/inline-message';
import { useAuth } from '@/components/providers/auth-provider';
import { AppCard } from '@/components/ui/app-card';
import { login } from '@/features/auth/api/auth';
import { getPublicStatus } from '@/features/auth/api/public';
import {
  AuthButton,
  AuthFormField,
  AuthInput,
  SecondaryButton,
} from '@/features/auth/components/auth-form-primitives';
import { PublicAuthGuard } from '@/features/auth/components/public-auth-guard';

const loginSchema = z.object({
  username: z.string().min(1, '请输入用户名'),
  password: z.string().min(1, '请输入密码'),
});

type LoginFormValues = z.infer<typeof loginSchema>;

export function LoginForm() {
  const router = useRouter();
  const searchParams = useSearchParams();
  const { setUser } = useAuth();
  const [errorMessage, setErrorMessage] = useState('');
  const redirect = searchParams?.get('redirect') || '/';

  const form = useForm<LoginFormValues>({
    resolver: zodResolver(loginSchema),
    defaultValues: {
      username: '',
      password: '',
    },
  });

  const statusQuery = useQuery({
    queryKey: ['public-status'],
    queryFn: getPublicStatus,
  });

  const loginMutation = useMutation({
    mutationFn: login,
    onSuccess: (user) => {
      setUser(user);
      router.replace(redirect);
    },
    onError: (error: Error) => {
      setErrorMessage(error.message || '登录失败，请稍后重试。');
    },
  });

  const handleSubmit = form.handleSubmit((values) => {
    setErrorMessage('');
    loginMutation.mutate(values);
  });

  const handleGitHubLogin = () => {
    const clientId = statusQuery.data?.github_client_id;
    if (!clientId) {
      setErrorMessage('GitHub 登录当前不可用。');
      return;
    }

    const authorizeUrl = new URL('https://github.com/login/oauth/authorize');
    authorizeUrl.searchParams.set('client_id', clientId);
    authorizeUrl.searchParams.set('scope', 'user:email');
    window.location.href = authorizeUrl.toString();
  };

  return (
    <PublicAuthGuard>
      <AppCard title='用户登录'>
        <form className='space-y-4' onSubmit={handleSubmit}>
          <AuthFormField label='用户名'>
            <AuthInput placeholder='请输入用户名' {...form.register('username')} />
            {form.formState.errors.username ? (
              <span className='text-xs text-[var(--status-danger-foreground)]'>
                {form.formState.errors.username.message}
              </span>
            ) : null}
          </AuthFormField>

          <AuthFormField label='密码'>
            <AuthInput type='password' placeholder='请输入密码' {...form.register('password')} />
            {form.formState.errors.password ? (
              <span className='text-xs text-[var(--status-danger-foreground)]'>
                {form.formState.errors.password.message}
              </span>
            ) : null}
          </AuthFormField>

          {errorMessage ? <InlineMessage tone='danger' message={errorMessage} /> : null}

          <div className='flex flex-col gap-3 sm:flex-row'>
            <AuthButton type='submit' disabled={loginMutation.isPending}>
              {loginMutation.isPending ? '登录中...' : '登录'}
            </AuthButton>
            {statusQuery.data?.github_oauth ? (
              <SecondaryButton type='button' onClick={handleGitHubLogin} className='w-full sm:w-auto'>
                GitHub 登录
              </SecondaryButton>
            ) : null}
          </div>
        </form>

        <div className='mt-6 flex flex-wrap gap-3 text-sm text-[var(--foreground-secondary)]'>
          <Link href='/reset' className='text-[var(--brand-primary)] transition hover:opacity-80'>
            忘记密码？
          </Link>
          <span>·</span>
          <Link href='/register' className='text-[var(--brand-primary)] transition hover:opacity-80'>
            注册
          </Link>
        </div>
      </AppCard>
    </PublicAuthGuard>
  );
}