'use client';

import Link from 'next/link';
import { useSearchParams } from 'next/navigation';
import { useState } from 'react';
import { CheckCircle2, Loader2 } from 'lucide-react';

import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';

interface PasswordSetFormProps {
  /** API endpoint that accepts `{ token, password }` and sets / resets the password. */
  endpoint: string;
  title: string;
  description: string;
  successTitle: string;
  successDescription: string;
  submitLabel: string;
}

const MIN_LENGTH = 12;

/**
 * Shared form used by both the activation and password-reset flows. The
 * activation token is read from the `?token=` query string. Empty / missing
 * tokens land the user in an explicit error state instead of submitting a
 * doomed request.
 */
export function PasswordSetForm({
  endpoint,
  title,
  description,
  successTitle,
  successDescription,
  submitLabel,
}: PasswordSetFormProps) {
  const search = useSearchParams();
  const token = search.get('token') ?? '';

  const [password, setPassword] = useState('');
  const [confirm, setConfirm] = useState('');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');
  const [done, setDone] = useState(false);

  const tooShort = password.length > 0 && password.length < MIN_LENGTH;
  const mismatch = confirm.length > 0 && password !== confirm;
  const canSubmit = !!token && password.length >= MIN_LENGTH && password === confirm && !loading;

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    if (!canSubmit) return;
    setLoading(true);
    setError('');
    try {
      const res = await fetch(endpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ token, password }),
      });
      if (!res.ok) {
        const data = await res.json().catch(() => ({}));
        setError((data as { error?: string }).error ?? 'Something went wrong. Please try again.');
        return;
      }
      setDone(true);
    } catch {
      setError('Unable to connect. Please try again.');
    } finally {
      setLoading(false);
    }
  }

  if (!token) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gray-50 px-4">
        <div className="w-full max-w-md text-center space-y-3">
          <h1 className="text-xl font-semibold text-gray-900">Link is missing or invalid</h1>
          <p className="text-sm text-gray-500">
            Please use the link from the email we sent you. If the link is broken, request a new
            one.
          </p>
          <Link
            href="/portal/forgot-password"
            className="inline-block text-sm text-[#1e2844] hover:underline"
          >
            Request a new link
          </Link>
        </div>
      </div>
    );
  }

  if (done) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gray-50 px-4">
        <div className="w-full max-w-md text-center">
          <div className="inline-flex items-center justify-center w-14 h-14 rounded-full bg-green-50 mb-4">
            <CheckCircle2 className="h-7 w-7 text-green-600" />
          </div>
          <h1 className="text-xl font-semibold text-gray-900 mb-2">{successTitle}</h1>
          <p className="text-gray-500 text-sm">{successDescription}</p>
          <Link
            href="/portal/login"
            className="mt-6 inline-block text-sm text-[#1e2844] hover:underline"
          >
            Sign in
          </Link>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen flex items-center justify-center bg-gray-50 px-4">
      <div className="w-full max-w-sm">
        <div className="bg-white rounded-lg border p-8 shadow-sm">
          <div className="mb-6">
            <h1 className="text-xl font-semibold text-gray-900">{title}</h1>
            <p className="text-sm text-gray-500 mt-1">{description}</p>
          </div>

          <form onSubmit={handleSubmit} className="space-y-4">
            <div className="space-y-1.5">
              <Label htmlFor="password">New password</Label>
              <Input
                id="password"
                type="password"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                required
                autoFocus
                autoComplete="new-password"
                minLength={MIN_LENGTH}
                disabled={loading}
              />
              <p className="text-xs text-gray-500">At least {MIN_LENGTH} characters.</p>
              {tooShort && (
                <p className="text-xs text-red-600">
                  Password must be at least {MIN_LENGTH} characters.
                </p>
              )}
            </div>

            <div className="space-y-1.5">
              <Label htmlFor="confirm">Confirm password</Label>
              <Input
                id="confirm"
                type="password"
                value={confirm}
                onChange={(e) => setConfirm(e.target.value)}
                required
                autoComplete="new-password"
                disabled={loading}
              />
              {mismatch && <p className="text-xs text-red-600">Passwords don&apos;t match.</p>}
            </div>

            {error && <p className="text-sm text-red-600">{error}</p>}

            <Button
              type="submit"
              className="w-full bg-[#1e2844] hover:bg-[#1e2844]/90 text-white"
              disabled={!canSubmit}
            >
              {loading ? (
                <>
                  <Loader2 className="h-4 w-4 mr-2 animate-spin" />
                  Saving…
                </>
              ) : (
                submitLabel
              )}
            </Button>
          </form>
        </div>
      </div>
    </div>
  );
}