'use client'

import { Suspense, useState } from 'react'
import { useRouter, useSearchParams } from 'next/navigation'
import Link from 'next/link'
import { Heart } from 'lucide-react'
import { Button, Input, Card, showToast } from '@/components/ui'

function LoginForm() {
  const router = useRouter()
  const searchParams = useSearchParams()
  const redirectTo = searchParams.get('redirect')
  const [email, setEmail] = useState('')
  const [password, setPassword] = useState('')
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState('')

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()
    setError('')
    setLoading(true)

    try {
      const response = await fetch('/api/auth/login', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({ email, password }),
      })

      const data = await response.json()

      if (!response.ok) {
        setError(data.error || 'Login failed')
        return
      }

      // Check if user needs to change password
      if (data.forcePasswordReset) {
        showToast('Please change your password to continue', 'info')
        router.push('/change-password')
        router.refresh()
        return
      }

      const sessionResponse = await fetch('/api/auth/me', {
        credentials: 'include',
        cache: 'no-store',
      })

      if (!sessionResponse.ok) {
        throw new Error('Your session was created but is not available yet. Please try again.')
      }

      showToast('Welcome back!', 'success')
      // If there's a redirect param (e.g., from invite link), go there
      router.push(redirectTo || '/today')
      router.refresh()
    } catch {
      setError('Something went wrong. Please try again.')
    } finally {
      setLoading(false)
    }
  }

  return (
    <div className="min-h-screen bg-background flex flex-col items-center justify-center p-4">
      <div className="w-full max-w-sm">
        {/* Logo */}
        <div className="text-center mb-8">
          <div className="w-16 h-16 bg-primary-500 rounded-2xl flex items-center justify-center mx-auto mb-4">
            <Heart className="w-8 h-8 text-white" />
          </div>
          <h1 className="text-2xl font-bold text-secondary-900">Next Step</h1>
          <p className="text-secondary-500 mt-1">Health management made simple</p>
        </div>

        <Card className="mb-6">
          <form onSubmit={handleSubmit} className="space-y-4">
            <Input
              label="Email"
              type="email"
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              placeholder="you@example.com"
              required
              autoComplete="email"
            />
            <Input
              label="Password"
              type="password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              placeholder="••••••••"
              required
              autoComplete="current-password"
            />

            {error && (
              <p className="text-sm text-red-600 bg-red-50 px-3 py-2 rounded-button">
                {error}
              </p>
            )}

            <Button type="submit" fullWidth loading={loading}>
              Sign In
            </Button>
          </form>
        </Card>

        <p className="text-center text-secondary-500">
          Don't have an account?{' '}
          <Link href="/register" className="text-primary-600 font-medium hover:text-primary-700">
            Create one
          </Link>
        </p>
      </div>
    </div>
  )
}

export default function LoginPage() {
  return (
    <Suspense fallback={
      <div className="min-h-screen bg-background flex items-center justify-center">
        <div className="w-8 h-8 border-2 border-primary-500 border-t-transparent rounded-full animate-spin" />
      </div>
    }>
      <LoginForm />
    </Suspense>
  )
}