'use client';

import {useMutation} from '@tanstack/react-query';
import {useRouter, useSearchParams} from 'next/navigation';
import {useEffect, useRef, useState} from 'react';

import {InlineMessage} from '@/components/feedback/inline-message';
import {LoadingState} from '@/components/feedback/loading-state';
import {useAuth} from '@/components/providers/auth-provider';
import {AppCard} from '@/components/ui/app-card';
import {exchangeGitHubCode} from '@/features/auth/api/auth';

export function GitHubOAuthCallback() {
  const router = useRouter();
  const searchParams = useSearchParams();
  const { setUser } = useAuth();
  const handledCodeRef = useRef<string | null>(null);
  const [prompt, setPrompt] = useState('正在处理 GitHub 授权结果...');
  const [message, setMessage] = useState<{
    tone: 'danger' | 'success';
    text: string;
  } | null>(null);
  const code = searchParams?.get('code')?.trim() ?? '';

  const mutation = useMutation({
    mutationFn: exchangeGitHubCode,
    onSuccess: (user) => {
      setUser(user);
      setMessage({ tone: 'success', text: '登录成功，正在跳转...' });
      router.replace('/');
    },
    onError: (error: Error) => {
      setPrompt('授权处理失败');
      setMessage({
        tone: 'danger',
        text: error.message || 'GitHub 授权失败，请稍后重试。',
      });
    },
  });

  useEffect(() => {
    if (!code) {
      setPrompt('缺少授权 code');
      setMessage({
        tone: 'danger',
        text: '未收到 GitHub 授权参数，请返回登录页重试。',
      });
      return;
    }

    if (handledCodeRef.current === code) {
      return;
    }

    handledCodeRef.current = code;
    mutation.mutate(code);
  }, [code, mutation]);

  return (
    <AppCard title="GitHub OAuth 回调" description={prompt}>
      <div className="space-y-4">
        {mutation.isPending ? <LoadingState /> : null}
        {message ? (
          <InlineMessage tone={message.tone} message={message.text} />
        ) : null}
      </div>
    </AppCard>
  );
}