import { useState } from 'react'
import { useNavigate } from 'react-router-dom'
import { useAuthStore } from '../hooks/useAuth'
import { useQuery } from '@tanstack/react-query'
import api from '../utils/api'

const AUTH_ERRORS = {
  not_authorized: "Your account isn't permitted to access MileVault — ask the admin to add you to the allowed group.",
  passkey_in_use: "That passkey is already linked to another account. Sign in to that account, or have an admin remove it on the Users page, then try linking again.",
  link_failed: "Couldn't link the passkey. Please try again.",
  invalid_state: "Your sign-in link expired or was invalid. Please try signing in again.",
  no_identity: "Couldn't read your identity from the provider. Please try again.",
}

export default function LoginPage() {
  const [username, setUsername] = useState('')
  const [password, setPassword] = useState('')
  const authError = new URLSearchParams(window.location.search).get('auth_error')
  const [error, setError] = useState(AUTH_ERRORS[authError] || '')
  const { login, isLoading } = useAuthStore()
  const navigate = useNavigate()

  const { data: pocketidData } = useQuery({
    queryKey: ['pocketid-available'],
    queryFn: () => api.get('/auth/pocketid/available').then(r => r.data),
  })

  const handleSubmit = async (e) => {
    e.preventDefault()
    setError('')
    try {
      await login(username, password)
      navigate('/')
    } catch (err) {
      setError(err.response?.data?.detail || 'Login failed')
    }
  }

  const handlePocketID = async () => {
    const { data } = await api.get('/auth/pocketid/login-url')
    window.location.href = data.url
  }

  return (
    <div className="min-h-screen bg-gray-950 flex items-center justify-center px-4">
      <div className="w-full max-w-sm">
        <div className="text-center mb-8">
          <h1 className="text-3xl font-bold text-white">
            <span className="text-blue-400">Mile</span>Vault
          </h1>
          <p className="text-gray-500 mt-2 text-sm">Your personal fitness dashboard</p>
        </div>

        <div className="bg-gray-900 rounded-2xl p-6 border border-gray-800">
          <form onSubmit={handleSubmit} className="space-y-4">
            <div>
              <label className="block text-xs text-gray-400 mb-1">Username</label>
              <input
                type="text"
                value={username}
                onChange={e => setUsername(e.target.value)}
                className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2.5 text-sm text-white focus:outline-none focus:ring-2 focus:ring-blue-500"
                autoComplete="username"
                required
              />
            </div>
            <div>
              <label className="block text-xs text-gray-400 mb-1">Password</label>
              <input
                type="password"
                value={password}
                onChange={e => setPassword(e.target.value)}
                className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2.5 text-sm text-white focus:outline-none focus:ring-2 focus:ring-blue-500"
                autoComplete="current-password"
                required
              />
            </div>

            {error && (
              <p className="text-red-400 text-xs">{error}</p>
            )}

            <button
              type="submit"
              disabled={isLoading}
              className="w-full bg-blue-600 hover:bg-blue-700 disabled:opacity-50 text-white font-medium py-2.5 rounded-lg text-sm transition-colors"
            >
              {isLoading ? 'Signing in…' : 'Sign in'}
            </button>
          </form>

          {pocketidData?.available && (
            <>
              <div className="flex items-center gap-3 my-4">
                <div className="flex-1 h-px bg-gray-800" />
                <span className="text-xs text-gray-600">or</span>
                <div className="flex-1 h-px bg-gray-800" />
              </div>
              <button
                onClick={handlePocketID}
                className="w-full bg-gray-800 hover:bg-gray-700 text-gray-300 font-medium py-2.5 rounded-lg text-sm transition-colors flex items-center justify-center gap-2"
              >
                🔑 Sign in with passkey
              </button>
            </>
          )}
        </div>
      </div>
    </div>
  )
}