import { useState, useEffect } from 'react'
import { Button } from '@/components/ui/button'
import { Separator } from '@/components/ui/separator'
import { apiService } from '@/lib/api'

export function OAuthButtons() {
  const [providers, setProviders] = useState<string[]>([])
  const [loading, setLoading] = useState<string | null>(null)

  useEffect(() => {
    const fetchProviders = async () => {
      try {
        const response = await apiService.getOAuthProviders()
        setProviders(response.providers)
      } catch (error) {
        console.error('Failed to fetch OAuth providers:', error)
      }
    }

    fetchProviders()
  }, [])

  const handleOAuthLogin = async (provider: string) => {
    setLoading(provider)
    try {
      const response = await apiService.getOAuthUrl(provider)
      
      // Store state in sessionStorage for verification
      sessionStorage.setItem('oauth_state', response.state)
      
      // Redirect to OAuth provider
      window.location.href = response.authorization_url
    } catch (error) {
      console.error(`${provider} OAuth failed:`, error)
      setLoading(null)
    }
  }

  const getProviderIcon = (provider: string) => {
    switch (provider) {
      case 'google':
        return (
          <svg className="w-5 h-5" viewBox="0 0 24 24">
            <path
              fill="currentColor"
              d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92c-.26 1.37-1.04 2.53-2.21 3.31v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.09z"
            />
            <path
              fill="currentColor"
              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"
            />
            <path
              fill="currentColor"
              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"
            />
            <path
              fill="currentColor"
              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"
            />
          </svg>
        )
      case 'github':
        return (
          <svg className="w-5 h-5" viewBox="0 0 24 24" fill="currentColor">
            <path d="M12 0c-6.626 0-12 5.373-12 12 0 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 1.23.957-.266 1.983-.399 3.003-.404 1.02.005 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 .319.192.694.801.576 4.765-1.589 8.199-6.086 8.199-11.386 0-6.627-5.373-12-12-12z" />
          </svg>
        )
      default:
        return null
    }
  }

  const getProviderName = (provider: string) => {
    return provider.charAt(0).toUpperCase() + provider.slice(1)
  }

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

  return (
    <div className="space-y-4">
      <div className="relative">
        <div className="absolute inset-0 flex items-center">
          <Separator className="w-full" />
        </div>
        <div className="relative flex justify-center text-xs uppercase">
          <span className="bg-white dark:bg-gray-900 px-2 text-gray-500 dark:text-gray-400">
            Or continue with
          </span>
        </div>
      </div>
      
      <div className="grid grid-cols-1 gap-3">
        {providers.map((provider) => (
          <Button
            key={provider}
            variant="outline"
            type="button"
            disabled={loading !== null}
            onClick={() => handleOAuthLogin(provider)}
            className="w-full"
          >
            {loading === provider ? (
              <div className="w-5 h-5 border-2 border-current border-t-transparent rounded-full animate-spin" />
            ) : (
              getProviderIcon(provider)
            )}
            <span className="ml-2">
              {loading === provider 
                ? 'Connecting...' 
                : `Continue with ${getProviderName(provider)}`
              }
            </span>
          </Button>
        ))}
      </div>
    </div>
  )
}