import { useState } from 'react'
import { Link, useNavigate, useLocation } from 'react-router-dom'
import { useAuth } from '../contexts/AuthContext'

const isLocalDev = import.meta.env['VITE_SUPABASE_URL']?.includes('localhost') ?? false

export function Login() {
  const [email, setEmail] = useState('')
  const [password, setPassword] = useState('')
  const [totpCode, setTotpCode] = useState('')
  const [error, setError] = useState<string | null>(null)
  const [loading, setLoading] = useState(false)
  const [showMfaChallenge, setShowMfaChallenge] = useState(false)
  const { signInWithEmail, signInWithGoogle, signInWithDiscord, verifyMfa } = useAuth()
  const navigate = useNavigate()
  const location = useLocation()

  const from = (location.state as { from?: { pathname: string } })?.from?.pathname ?? '/'

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault()
    setError(null)
    setLoading(true)

    const { error, requiresMfa } = await signInWithEmail(email, password)
    setLoading(false)

    if (error) {
      setError(error.message)
    } else if (requiresMfa) {
      setShowMfaChallenge(true)
    } else {
      navigate(from, { replace: true })
    }
  }

  async function handleMfaSubmit(e: React.FormEvent) {
    e.preventDefault()
    setError(null)
    setLoading(true)

    const { error } = await verifyMfa(totpCode)
    setLoading(false)

    if (error) {
      setError(error.message)
      setTotpCode('')
    } else {
      navigate(from, { replace: true })
    }
  }

  async function handleGoogleLogin() {
    setError(null)
    const { error } = await signInWithGoogle()
    if (error) setError(error.message)
  }

  async function handleDiscordLogin() {
    setError(null)
    const { error } = await signInWithDiscord()
    if (error) setError(error.message)
  }

  if (showMfaChallenge) {
    return (
      <div className="min-h-[80vh] flex items-center justify-center px-4">
        <div className="w-full max-w-sm space-y-6">
          <div className="text-center">
            <h1 className="text-2xl font-bold">Two-Factor Authentication</h1>
            <p className="text-text-secondary mt-1">Enter the code from your authenticator app</p>
          </div>

          {error && (
            <div className="bg-red-500/10 border border-red-500/20 text-red-400 px-4 py-3 rounded-lg text-sm">
              {error}
            </div>
          )}

          <form onSubmit={handleMfaSubmit} className="space-y-4">
            <div>
              <label
                htmlFor="totp-code"
                className="block text-sm font-medium text-text-secondary mb-1"
              >
                Authentication code
              </label>
              <input
                id="totp-code"
                type="text"
                inputMode="numeric"
                pattern="[0-9]*"
                maxLength={6}
                value={totpCode}
                onChange={(e) => setTotpCode(e.target.value.replace(/\D/g, ''))}
                autoFocus
                className="w-full px-3 py-2 bg-surface-2 border border-border-default rounded-lg focus:outline-none focus:ring-2 focus:ring-accent-500 text-center text-lg tracking-widest font-mono"
                autoComplete="one-time-code"
              />
            </div>

            <button
              type="submit"
              disabled={totpCode.length !== 6 || loading}
              className="w-full py-2 px-4 bg-accent-600 hover:bg-accent-700 disabled:opacity-50 disabled:cursor-not-allowed text-white font-medium rounded-lg transition-colors"
            >
              {loading ? 'Verifying...' : 'Verify'}
            </button>
          </form>

          <button
            type="button"
            onClick={() => {
              setShowMfaChallenge(false)
              setTotpCode('')
              setError(null)
            }}
            className="w-full text-center text-sm text-text-secondary hover:text-text-primary"
          >
            Back to login
          </button>
        </div>
      </div>
    )
  }

  return (
    <div className="min-h-[80vh] flex items-center justify-center px-4">
      <div className="w-full max-w-sm space-y-6">
        <div className="text-center">
          <h1 className="text-2xl font-bold">Welcome back</h1>
          <p className="text-text-secondary mt-1">Sign in to your account</p>
        </div>

        {error && (
          <div className="bg-red-500/10 border border-red-500/20 text-red-400 px-4 py-3 rounded-lg text-sm">
            {error}
          </div>
        )}

        <form onSubmit={handleSubmit} className="space-y-4">
          <div>
            <label htmlFor="email" className="block text-sm font-medium text-text-secondary mb-1">
              Email
            </label>
            <input
              id="email"
              type="email"
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              required
              className="w-full px-3 py-2 bg-surface-2 border border-border-default rounded-lg focus:outline-none focus:ring-2 focus:ring-accent-500 focus:border-transparent"
            />
          </div>

          <div>
            <label
              htmlFor="password"
              className="block text-sm font-medium text-text-secondary mb-1"
            >
              Password
            </label>
            <input
              id="password"
              type="password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              required
              className="w-full px-3 py-2 bg-surface-2 border border-border-default rounded-lg focus:outline-none focus:ring-2 focus:ring-accent-500 focus:border-transparent"
            />
          </div>

          <button
            type="submit"
            disabled={loading}
            className="w-full py-2 px-4 bg-accent-600 hover:bg-accent-700 disabled:opacity-50 disabled:cursor-not-allowed text-white font-medium rounded-lg transition-colors"
          >
            {loading ? 'Signing in...' : 'Sign in'}
          </button>
        </form>

        <div className="relative">
          <div className="absolute inset-0 flex items-center">
            <div className="w-full border-t border-border-default" />
          </div>
          <div className="relative flex justify-center text-sm">
            <span className="px-2 bg-surface-0 text-text-tertiary">Or continue with</span>
          </div>
        </div>

        <div className="grid grid-cols-2 gap-3">
          <button
            type="button"
            onClick={handleGoogleLogin}
            disabled={isLocalDev}
            title={isLocalDev ? 'OAuth not available in local dev' : undefined}
            className="flex items-center justify-center gap-2 py-2 px-4 bg-surface-2 hover:bg-surface-3 border border-border-default rounded-lg transition-colors disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:bg-surface-2"
          >
            <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>
            Google
          </button>
          <button
            type="button"
            onClick={handleDiscordLogin}
            disabled={isLocalDev}
            title={isLocalDev ? 'OAuth not available in local dev' : undefined}
            className="flex items-center justify-center gap-2 py-2 px-4 bg-surface-2 hover:bg-surface-3 border border-border-default rounded-lg transition-colors disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:bg-surface-2"
          >
            <svg className="w-5 h-5" viewBox="0 0 24 24" fill="currentColor">
              <path d="M20.317 4.37a19.791 19.791 0 0 0-4.885-1.515.074.074 0 0 0-.079.037c-.21.375-.444.864-.608 1.25a18.27 18.27 0 0 0-5.487 0 12.64 12.64 0 0 0-.617-1.25.077.077 0 0 0-.079-.037A19.736 19.736 0 0 0 3.677 4.37a.07.07 0 0 0-.032.027C.533 9.046-.32 13.58.099 18.057a.082.082 0 0 0 .031.057 19.9 19.9 0 0 0 5.993 3.03.078.078 0 0 0 .084-.028c.462-.63.874-1.295 1.226-1.994a.076.076 0 0 0-.041-.106 13.107 13.107 0 0 1-1.872-.892.077.077 0 0 1-.008-.128 10.2 10.2 0 0 0 .372-.292.074.074 0 0 1 .077-.01c3.928 1.793 8.18 1.793 12.062 0a.074.074 0 0 1 .078.01c.12.098.246.198.373.292a.077.077 0 0 1-.006.127 12.299 12.299 0 0 1-1.873.892.077.077 0 0 0-.041.107c.36.698.772 1.362 1.225 1.993a.076.076 0 0 0 .084.028 19.839 19.839 0 0 0 6.002-3.03.077.077 0 0 0 .032-.054c.5-5.177-.838-9.674-3.549-13.66a.061.061 0 0 0-.031-.03zM8.02 15.33c-1.183 0-2.157-1.085-2.157-2.419 0-1.333.956-2.419 2.157-2.419 1.21 0 2.176 1.096 2.157 2.42 0 1.333-.956 2.418-2.157 2.418zm7.975 0c-1.183 0-2.157-1.085-2.157-2.419 0-1.333.955-2.419 2.157-2.419 1.21 0 2.176 1.096 2.157 2.42 0 1.333-.946 2.418-2.157 2.418z" />
            </svg>
            Discord
          </button>
        </div>
        {isLocalDev && (
          <p className="text-center text-xs text-text-tertiary">
            OAuth providers are not available in local development. Use email/password instead.
          </p>
        )}

        <p className="text-center text-sm text-text-secondary">
          Don&apos;t have an account?{' '}
          <Link to="/signup" className="text-accent-400 hover:text-accent-300">
            Sign up
          </Link>
        </p>
      </div>
    </div>
  )
}