'use client';

import { useState, useEffect } from 'react';
import type { CustomerOAuthProvider } from 'brainerce';
import { getClient } from '@/core/lib/brainerce';
import { useTranslations } from '@/core/lib/translations';
import { cn } from '@/core/lib/utils';
import { LoadingSpinner } from '@/ui/shared/loading-spinner';

const PROVIDER_CONFIG: Record<CustomerOAuthProvider, { labelKey: string; icon: React.ReactNode }> =
  {
    GOOGLE: {
      labelKey: 'google',
      icon: (
        <svg className="h-5 w-5" viewBox="0 0 24 24" fill="currentColor">
          <path
            d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92a5.06 5.06 0 01-2.2 3.32v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.1z"
            fill="#4285F4"
          />
          <path
            d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z"
            fill="#34A853"
          />
          <path
            d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"
            fill="#FBBC05"
          />
          <path
            d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"
            fill="#EA4335"
          />
        </svg>
      ),
    },
    FACEBOOK: {
      labelKey: 'facebook',
      icon: (
        <svg className="h-5 w-5" viewBox="0 0 24 24" fill="#1877F2">
          <path d="M24 12.073c0-6.627-5.373-12-12-12s-12 5.373-12 12c0 5.99 4.388 10.954 10.125 11.854v-8.385H7.078v-3.47h3.047V9.43c0-3.007 1.792-4.669 4.533-4.669 1.312 0 2.686.235 2.686.235v2.953H15.83c-1.491 0-1.956.925-1.956 1.874v2.25h3.328l-.532 3.47h-2.796v8.385C19.612 23.027 24 18.062 24 12.073z" />
        </svg>
      ),
    },
    GITHUB: {
      labelKey: 'github',
      icon: (
        <svg className="h-5 w-5" viewBox="0 0 24 24" fill="currentColor">
          <path d="M12 0C5.374 0 0 5.373 0 12c0 5.302 3.438 9.8 8.207 11.387.599.111.793-.261.793-.577v-2.234c-3.338.726-4.033-1.416-4.033-1.416-.546-1.387-1.333-1.756-1.333-1.756-1.089-.745.083-.729.083-.729 1.205.084 1.839 1.237 1.839 1.237 1.07 1.834 2.807 1.304 3.492.997.107-.775.418-1.305.762-1.604-2.665-.305-5.467-1.334-5.467-5.931 0-1.311.469-2.381 1.236-3.221-.124-.303-.535-1.524.117-3.176 0 0 1.008-.322 3.301 1.23A11.509 11.509 0 0112 5.803c1.02.005 2.047.138 3.006.404 2.291-1.552 3.297-1.23 3.297-1.23.653 1.653.242 2.874.118 3.176.77.84 1.235 1.911 1.235 3.221 0 4.609-2.807 5.624-5.479 5.921.43.372.823 1.102.823 2.222v3.293c0 .319.192.694.801.576C20.566 21.797 24 17.3 24 12c0-6.627-5.373-12-12-12z" />
        </svg>
      ),
    },
  };

interface OAuthButtonsProps {
  className?: string;
}

export function OAuthButtons({ className }: OAuthButtonsProps) {
  const t = useTranslations('auth');
  const [providers, setProviders] = useState<CustomerOAuthProvider[]>([]);
  const [loading, setLoading] = useState(true);
  const [redirecting, setRedirecting] = useState<CustomerOAuthProvider | null>(null);
  const [failedProvider, setFailedProvider] = useState<CustomerOAuthProvider | null>(null);

  useEffect(() => {
    async function fetchProviders() {
      try {
        const client = getClient();
        const result = await client.getAvailableOAuthProviders();
        // `redirectReady` is per storefront address: a provider can be enabled
        // while the sales channel has nowhere to send the session back to
        // (TEST channel, no domain, this preview URL not registered). The
        // authorize call would 400 on click, so render nothing — and tell the
        // builder why, in dev only, since only the merchant can fix it.
        // Read through a local shape rather than the SDK type: the scaffold pins
        // an SDK that may predate the field, and `=== false` keeps an older
        // backend (which omits it) behaving exactly as before.
        const readiness = result as { redirectReady?: boolean; redirectBlockedReason?: string };
        if (readiness.redirectReady === false) {
          if (process.env.NODE_ENV !== 'production') {
            console.warn(
              `[brainerce] Social login hidden: this storefront's address (${window.location.origin}) ` +
                `is not registered on the sales channel (reason: ${readiness.redirectBlockedReason}). ` +
                'Add it under Dashboard → Sales Channels → Domains.'
            );
          }
          setProviders([]);
          return;
        }
        setProviders(result.providers);
      } catch {
        // OAuth not available - silently hide buttons
        setProviders([]);
      } finally {
        setLoading(false);
      }
    }

    fetchProviders();
  }, []);

  async function handleOAuthClick(provider: CustomerOAuthProvider) {
    if (redirecting) return;

    try {
      setRedirecting(provider);
      setFailedProvider(null);
      const client = getClient();
      const redirectUrl = window.location.origin + '/api/auth/oauth-callback';
      const result = await client.getOAuthAuthorizeUrl(provider, { redirectUrl });
      window.location.href = result.authorizationUrl;
    } catch (err) {
      // The 400 body is a rule for the merchant (`redirect_not_allowed` and
      // which channel setting to fix) — the shopper gets store-language copy,
      // never the English policy text.
      console.error('OAuth redirect failed:', err);
      setFailedProvider(provider);
      setRedirecting(null);
    }
  }

  if (loading) {
    return null;
  }

  if (providers.length === 0) {
    return null;
  }

  return (
    <div className={cn('space-y-3', className)}>
      <div className="relative">
        <div className="absolute inset-0 flex items-center">
          <div className="border-border w-full border-t" />
        </div>
        <div className="relative flex justify-center text-xs uppercase">
          <span className="bg-background text-muted-foreground px-2">{t('orContinueWith')}</span>
        </div>
      </div>

      {failedProvider && (
        <div
          role="alert"
          className="bg-destructive/10 border-destructive/20 text-destructive rounded-lg border px-4 py-3 text-sm"
        >
          {t('socialLoginUnavailable', {
            provider: t(PROVIDER_CONFIG[failedProvider].labelKey as 'google' | 'facebook' | 'github'),
          })}
        </div>
      )}

      <div className="grid gap-2">
        {providers.map((provider) => {
          const config = PROVIDER_CONFIG[provider];
          if (!config) return null;

          const isRedirecting = redirecting === provider;

          return (
            <button
              key={provider}
              type="button"
              onClick={() => handleOAuthClick(provider)}
              disabled={!!redirecting}
              className="border-border text-foreground bg-background hover:bg-muted flex h-10 w-full items-center justify-center gap-2 rounded border text-sm font-medium transition-colors disabled:cursor-not-allowed disabled:opacity-50"
            >
              {isRedirecting ? <LoadingSpinner size="sm" /> : config.icon}
              {t(config.labelKey as 'google' | 'facebook' | 'github')}
            </button>
          );
        })}
      </div>
    </div>
  );
}