import React from 'react';
import { useEffect } from 'react';
import { useLocation, useNavigate } from 'react-router-dom';
import { useTranslation } from 'react-i18next';
import { Card } from '@tamagui/card';
import { YStack } from '@tamagui/stacks';
import { SizableText as Text } from '@tamagui/text';
import { Spinner } from 'tamagui';
import { ADMIN_LOGIN_PATH } from '../constants';
import { useAdminTheme } from './theme';
import { useDocumentTitle } from './hooks/useDocumentTitle';

export default function LoginStartPage(): React.ReactElement {
  const location = useLocation();
  const navigate = useNavigate();
  const { t } = useTranslation('auth');
  const { textStrong, muted, border, surface, shadow, appBackground } = useAdminTheme();
  const safeAreaStyle: React.CSSProperties = {
    paddingTop: 'calc(env(safe-area-inset-top, 0px) + 16px)',
    paddingBottom: 'calc(env(safe-area-inset-bottom, 0px) + 16px)',
  };

  useDocumentTitle(t('redirecting', 'Redirecting to login …'));

  useEffect(() => {
    const params = new URLSearchParams(location.search);
    const returnTo = params.get('return_to');
    const target = new URL(ADMIN_LOGIN_PATH, window.location.origin);
    if (returnTo) {
      target.searchParams.set('return_to', returnTo);
    }

    navigate(`${target.pathname}${target.search}`, { replace: true });
  }, [location.search, navigate]);

  return (
    <YStack
      alignItems="center"
      justifyContent="center"
      padding="$4"
      style={{ minHeight: '100vh', backgroundImage: appBackground, ...safeAreaStyle }}
      backgroundColor={surface}
    >
      <Card
        borderRadius={22}
        borderWidth={2}
        borderColor={border}
        backgroundColor={surface}
        padding="$3"
        shadowColor={shadow}
        shadowOpacity={0.16}
        shadowRadius={16}
        shadowOffset={{ width: 0, height: 10 }}
      >
        <YStack alignItems="center" space="$2">
          <Spinner size="small" color={textStrong} />
          <Text fontSize="$sm" fontWeight="700" color={textStrong}>
            {t('redirecting', 'Redirecting to login …')}
          </Text>
          <Text fontSize="$xs" color={muted}>
            {t('redirectingHint', 'One moment, preparing the login screen.')}
          </Text>
        </YStack>
      </Card>
    </YStack>
  );
}