"use client"

import { useState } from "react"
import { signIn } from "next-auth/react"
import Link from "next/link"
import { Loader2 } from "lucide-react"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"

/**
 * Signup form for an invited user.
 *
 * The invite token is deliberately absent: it lives in an HttpOnly cookie set by
 * /invite/<token>, and the register route reads it server-side. Nothing here can
 * see or forge it.
 */
export function JoinForm() {
  const [name, setName] = useState("")
  const [email, setEmail] = useState("")
  const [password, setPassword] = useState("")
  const [confirmPassword, setConfirmPassword] = useState("")
  const [error, setError] = useState("")
  const [loading, setLoading] = useState(false)

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

    if (password !== confirmPassword) {
      setError("Passwords do not match")
      return
    }
    if (password.length < 10) {
      setError("Password must be at least 10 characters")
      return
    }
    if (!/[a-z]/.test(password) || !/[A-Z]/.test(password) || !/[0-9]/.test(password)) {
      setError("Password must contain lowercase, uppercase, and a number")
      return
    }

    setLoading(true)

    try {
      const res = await fetch("/api/auth/register", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ name, email, password }),
      })
      const data = await res.json()

      if (!res.ok) {
        setError(data.error || "Registration failed")
        setLoading(false)
        return
      }

      await signIn("credentials", { email, password, callbackUrl: "/dashboard" })
    } catch {
      setError("Something went wrong. Please try again.")
      setLoading(false)
    }
  }

  return (
    <>
      <form onSubmit={handleSubmit} className="space-y-4">
        {error && (
          <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive">
            {error}
          </div>
        )}

        <div className="space-y-2">
          <Label htmlFor="name">Name</Label>
          <Input
            id="name"
            type="text"
            placeholder="Your name"
            value={name}
            onChange={(e) => setName(e.target.value)}
            required
            maxLength={100}
            disabled={loading}
          />
        </div>

        <div className="space-y-2">
          <Label htmlFor="email">Email</Label>
          <Input
            id="email"
            type="email"
            placeholder="you@example.com"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
            required
            disabled={loading}
          />
        </div>

        <div className="space-y-2">
          <Label htmlFor="password">Password</Label>
          <Input
            id="password"
            type="password"
            placeholder="Min 10 chars, upper+lower+number"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            required
            minLength={10}
            maxLength={128}
            disabled={loading}
          />
        </div>

        <div className="space-y-2">
          <Label htmlFor="confirmPassword">Confirm Password</Label>
          <Input
            id="confirmPassword"
            type="password"
            placeholder="Confirm your password"
            value={confirmPassword}
            onChange={(e) => setConfirmPassword(e.target.value)}
            required
            minLength={10}
            disabled={loading}
          />
        </div>

        <Button type="submit" className="w-full" disabled={loading}>
          {loading ? <Loader2 className="h-4 w-4 animate-spin mr-2" /> : null}
          Create Account
        </Button>
      </form>

      <p className="mt-4 text-center text-sm text-muted-foreground">
        Already have an account?{" "}
        <Link href="/login" className="text-primary underline-offset-4 hover:underline">
          Sign in
        </Link>
      </p>
    </>
  )
}