'use client'

import { useState, useEffect } from 'react'
import { useRouter, useSearchParams } from 'next/navigation'
import Link from 'next/link'
import { createClient } from '@/lib/supabase/client'

export default function SignupPage() {
  const router = useRouter()
  const searchParams = useSearchParams()
  // Pre-fill email if provided in URL (from invite link)
  const [email, setEmail] = useState(searchParams.get('email') ?? '')
  const [password, setPassword] = useState('')
  const [confirmPassword, setConfirmPassword] = useState('')
  const [error, setError] = useState<string | null>(null)
  const [loading, setLoading] = useState(false)

  useEffect(() => {
    // Handle invite/signup token from URL hash
    // Supabase adds tokens to the URL hash after redirect
    const handleTokenFromUrl = async () => {
      const hash = window.location.hash
      if (hash) {
        const params = new URLSearchParams(hash.substring(1))
        const accessToken = params.get('access_token')
        const refreshToken = params.get('refresh_token')
        const type = params.get('type')

        if (accessToken && refreshToken && (type === 'invite' || type === 'signup')) {
          const supabase = createClient()
          const { error } = await supabase.auth.setSession({
            access_token: accessToken,
            refresh_token: refreshToken,
          })

          if (error) {
            setError('Invalid or expired invite link. Please request a new invitation.')
            return
          }

          // Get the user's email from the session
          const { data: { user } } = await supabase.auth.getUser()
          if (user?.email) {
            setEmail(user.email)
          }
        }
      }
    }

    handleTokenFromUrl()
  }, [searchParams])

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

    // Validate passwords match
    if (password !== confirmPassword) {
      setError('Passwords do not match')
      return
    }

    // Validate password length
    if (password.length < 6) {
      setError('Password must be at least 6 characters')
      return
    }

    setLoading(true)

    const supabase = createClient()

    // Check if user already has a session (from invite link)
    const { data: { session } } = await supabase.auth.getSession()

    if (session) {
      // User was invited and has a session - update their password
      const { error: updateError } = await supabase.auth.updateUser({
        password,
      })

      if (updateError) {
        setError(updateError.message)
        setLoading(false)
        return
      }

      // Create profile record
      const { error: profileError } = await supabase.from('profiles').upsert({
        id: session.user.id,
        email: session.user.email,
        display_name: session.user.email?.split('@')[0] || 'User',
        is_admin: false,
      })

      if (profileError) {
        setError(profileError.message)
        setLoading(false)
        return
      }

      router.push('/dashboard')
    } else {
      // Regular signup flow (if allowed)
      const { data, error } = await supabase.auth.signUp({
        email,
        password,
      })

      if (error) {
        setError(error.message)
        setLoading(false)
        return
      }

      if (data.user) {
        // Create profile record
        const { error: profileError } = await supabase.from('profiles').upsert({
          id: data.user.id,
          email: data.user.email,
          display_name: email.split('@')[0] || 'User',
          is_admin: false,
        })

        if (profileError) {
          setError(profileError.message)
          setLoading(false)
          return
        }

        router.push('/dashboard')
      }
    }
  }

  return (
    <div className="flex min-h-screen items-center justify-center bg-zinc-50 px-4 dark:bg-zinc-950">
      <div className="w-full max-w-md space-y-8">
        <div className="text-center">
          <h1 className="text-3xl font-bold tracking-tight text-zinc-900 dark:text-zinc-50">
            WebVNWrite
          </h1>
          <p className="mt-2 text-sm text-zinc-600 dark:text-zinc-400">
            Complete your account setup
          </p>
        </div>

        <form onSubmit={handleSubmit} className="mt-8 space-y-6">
          {error && (
            <div className="rounded-md bg-red-50 p-4 dark:bg-red-900/20">
              <p className="text-sm text-red-700 dark:text-red-400">{error}</p>
            </div>
          )}

          <div className="space-y-4">
            <div>
              <label
                htmlFor="email"
                className="block text-sm font-medium text-zinc-700 dark:text-zinc-300"
              >
                Email address
              </label>
              <input
                id="email"
                name="email"
                type="email"
                autoComplete="email"
                required
                value={email}
                onChange={(e) => setEmail(e.target.value)}
                className="mt-1 block w-full rounded-md border border-zinc-300 bg-white px-3 py-2 text-zinc-900 placeholder-zinc-400 shadow-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 dark:border-zinc-700 dark:bg-zinc-800 dark:text-zinc-50 dark:placeholder-zinc-500"
                placeholder="you@example.com"
              />
            </div>

            <div>
              <label
                htmlFor="password"
                className="block text-sm font-medium text-zinc-700 dark:text-zinc-300"
              >
                Password
              </label>
              <input
                id="password"
                name="password"
                type="password"
                autoComplete="new-password"
                required
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                className="mt-1 block w-full rounded-md border border-zinc-300 bg-white px-3 py-2 text-zinc-900 placeholder-zinc-400 shadow-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 dark:border-zinc-700 dark:bg-zinc-800 dark:text-zinc-50 dark:placeholder-zinc-500"
                placeholder="••••••••"
              />
            </div>

            <div>
              <label
                htmlFor="confirmPassword"
                className="block text-sm font-medium text-zinc-700 dark:text-zinc-300"
              >
                Confirm password
              </label>
              <input
                id="confirmPassword"
                name="confirmPassword"
                type="password"
                autoComplete="new-password"
                required
                value={confirmPassword}
                onChange={(e) => setConfirmPassword(e.target.value)}
                className="mt-1 block w-full rounded-md border border-zinc-300 bg-white px-3 py-2 text-zinc-900 placeholder-zinc-400 shadow-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 dark:border-zinc-700 dark:bg-zinc-800 dark:text-zinc-50 dark:placeholder-zinc-500"
                placeholder="••••••••"
              />
            </div>
          </div>

          <button
            type="submit"
            disabled={loading}
            className="flex w-full justify-center rounded-md bg-blue-600 px-4 py-2 text-sm font-semibold text-white shadow-sm hover:bg-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 dark:focus:ring-offset-zinc-950"
          >
            {loading ? 'Creating account...' : 'Create account'}
          </button>

          <p className="text-center text-sm text-zinc-600 dark:text-zinc-400">
            Already have an account?{' '}
            <Link
              href="/login"
              className="font-medium text-blue-600 hover:text-blue-500 dark:text-blue-400 dark:hover:text-blue-300"
            >
              Sign in
            </Link>
          </p>
        </form>
      </div>
    </div>
  )
}