<?php


use Gregwar\Captcha\CaptchaBuilder;
use Lewp\Resolve;

return new class extends Lewp\Module
{

    const KEY_CSRF_TOKEN = 'csrf_token';
    const KEY_CAPTCHA_PHRASE = 'captcha_phrase';
    const KEY_POST_EMAIL = 'email';
    const KEY_POST_NAME = 'name';
    const KEY_POST_MESSAGE = 'message';
    const OPTIONS_REDIRECT_URI = 'location_on_success';
    const OPTIONS_MAIL_FROM = 'mail_from';
    const OPTIONS_MAIL_TO = 'mail_to';

    private function createForm(bool $group_input_and_labels = true)
    {
        $form = $this->createAndSetupElement(
            'form',
            '',
            [
                'method' => 'post',
                'action' => '',
            ]
        );

        // LABEL NAME
        $label_name = $this->createAndSetupElement(
            'label',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'name'
            ])),
            [
                'for' => 'name',
            ]
        );
        // NAME INPUT
        $name = $this->createAndSetupElement(
            'input',
            '',
            [
                'id' => 'name',
                'name' => 'name',
                'type' => 'text',
                'value' => $_POST[self::KEY_POST_NAME] ?? '',
                'required' => 'required',
                'placeholder' => ' ',
            ]
        );
        // LABEL Email
        $label_email = $this->createAndSetupElement(
            'label',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'email'
            ])),
            [
                'for' => 'email'
            ]
        );
        // EMAIL INPUT
        $email = $this->createAndSetupElement(
            'input',
            '',
            [
                'id' => 'email',
                'name' => 'email',
                'type' => 'email',
                'value' => $_POST[self::KEY_POST_EMAIL] ?? '',
                'required' => 'required',
                'placeholder' => ' ',
            ]
        );
        // LABEL Message
        $label_message = $this->createAndSetupElement(
            'label',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'message'
            ])),
            [
                'for' => 'message'
            ]
        );
        // MESSAGE INPUT
        $message = $this->createAndSetupElement(
            'textarea',
            $_POST[self::KEY_POST_MESSAGE] ?? '',
            [
                'id' => 'message',
                'name' => 'message',
                'required' => 'required',
                'placeholder' => ' ',
            ]
        );
        // LABEL Captcha
        $label_captcha = $this->createAndSetupElement(
            'label',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'captcha'
            ])),
            [
                'for' => self::KEY_CAPTCHA_PHRASE
            ]
        );
        // CAPTCHA INPUT
        $captcha = $this->createAndSetupElement(
            'input',
            '',
            [
                'id' => self::KEY_CAPTCHA_PHRASE,
                'name' => self::KEY_CAPTCHA_PHRASE,
                'type' => 'text',
                'required' => 'required',
                'placeholder' => ' ',
            ]
        );
        // SUBMIT BUTTON
        $submit = $this->createAndSetupElement(
            'button',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'submit'
            ])),
            [
                'id' => 'submit',
                'type' => 'submit',
            ]
        );

        // APPEND THEM TO DOCUMENT
        if ($group_input_and_labels) {
            $div = $this->createAndSetupElement(
                'div', '', ['class' => 'fieldwrapper']
            );
            $div->appendChild($name);
            $div->appendChild($label_name);
            $form->appendChild($div);
            $div = $this->createAndSetupElement(
                'div', '', ['class' => 'fieldwrapper']
            );
            $div->appendChild($email);
            $div->appendChild($label_email);
            $form->appendChild($div);
            $div = $this->createAndSetupElement(
                'div', '', ['class' => 'fieldwrapper']
            );
            $div->appendChild($message);
            $div->appendChild($label_message);
            $form->appendChild($div);
        } else {
            $form->appendChild($label_name);
            $form->appendChild($name);
            $form->appendChild($label_email);
            $form->appendChild($email);
            $form->appendChild($label_message);
            $form->appendChild($message);
        }
        $form->appendChild($this->generateCaptcha());
        if ($group_input_and_labels) {
            $div = $this->createAndSetupElement(
                'div', '', ['class' => 'fieldwrapper']
            );
            $div->appendChild($captcha);
            $div->appendChild($label_captcha);
            $form->appendChild($div);
        } else {
            $form->appendChild($label_captcha);
            $form->appendChild($captcha);
        }

        $form->appendChild($submit);
        // ADD CSRF CHECK
        $form->appendChild($this->generateCsrfInput());
        return $form;
    }

    private function generateCsrfInput()
    {
        // create token and save to session
        $token = bin2hex(random_bytes(6));
        $this->getSession()->set(self::KEY_CSRF_TOKEN, $token);
        return $this->createAndSetupElement(
            'input',
            '',
            [
                'type' => 'hidden',
                'name' => self::KEY_CSRF_TOKEN,
                'value' => $token,
            ]
        );
    }

    private function validateCsrfInput() : bool
    {
        if (!$this->formSubmitted()) {
            return true;
        }

        $token = $this->getSession()->get(self::KEY_CSRF_TOKEN);
        if (
            is_null($_POST[self::KEY_CSRF_TOKEN])
            || $_POST[self::KEY_CSRF_TOKEN] !== $token
        ) {
            return false;
        }
        return true;
    }

    private function generateCaptcha()
    {
        $builder = new CaptchaBuilder();
        $builder->build();
        $this->getSession()->set(self::KEY_CAPTCHA_PHRASE, $builder->getPhrase());
        $img_captcha = $this->createAndSetupElement(
            'img',
            '',
            [
                'id' => 'captcha',
                'src' => $builder->inline(),
            ]
        );
        return $img_captcha;
    }

    private function validateCaptcha() : bool
    {
        if (!$this->formSubmitted()) {
            return true;
        }

        $valid_phrase = $this->getSession()->get(self::KEY_CAPTCHA_PHRASE);
        if (
            is_null($_POST[self::KEY_CAPTCHA_PHRASE])
            || $_POST[self::KEY_CAPTCHA_PHRASE] !== $valid_phrase
        ) {
            return false;
        }
        return true;
    }

    private function formSubmitted()
    {
        return (
            !is_null($_POST['name'])
            || !is_null($_POST['email'])
            || !is_null($_POST['message'])
        ) ? true : false;
    }

    private function sendMail($payload, $options)
    {
        mail(
            $options[self::OPTIONS_MAIL_TO],
            '['.$this->getTLD().'] '.$payload[self::KEY_POST_NAME],
            $payload[self::KEY_POST_MESSAGE],
            'From: '.$options[self::OPTIONS_MAIL_FROM]
            ."\r\n"
            .'Reply-To: '.$payload[self::KEY_POST_EMAIL]
            ."\r\n"
            .'MIME-Version: 1.0'
            ."\r\n"
            .'Content-type: text/plain; charset=UTF-8'
            ."\r\n"
        );
    }

    public function run(array $options = []) : bool
    {

        // set default options
        $options += [
            self::OPTIONS_REDIRECT_URI => "/"
        ];

        if (!$this->validateCsrfInput()) {
            $this->getSession()->getFlashBag()->add(
                'error',
                $this->loadTextFile(Resolve::arrayToId([
                    $this->getLanguage(),
                    'flashmessages',
                    'error',
                    'csrf-failed'
                ]))
            );
        }
        if (!$this->validateCaptcha()) {
            $this->getSession()->getFlashBag()->add(
                'error',
                $this->loadTextFile(Resolve::arrayToId([
                    $this->getLanguage(),
                    'flashmessages',
                    'error',
                    'captcha-failed'
                ]))
            );
        }

        // send form again if captcha or csrf not valid, or form not submitted yet
        if (
            !$this->validateCaptcha()
            || !$this->validateCsrfInput()
            || !$this->formSubmitted()
        ) {
            $form = $this->createForm();
            $this->appendChild($form);
            return true;
        }

        // send email
        if (
            !is_null($options[self::OPTIONS_MAIL_TO])
            || !is_null($options[self::OPTIONS_MAIL_FROM])
        ) {
            $this->sendMail($_POST, $options);
        }
        // notify user about success
        $this->getSession()->getFlashBag()->add(
            'success',
            $this->loadTextFile(Resolve::arrayToId([
                $this->getLanguage(),
                'flashmessages',
                'success',
                'thanks-for-message'
            ]))
        );

        header('Location: '.$options[self::OPTIONS_REDIRECT_URI]);
        exit; // if not present, session gets not saved


        return true;
    }

    public function onWebsocketRequest(
        \Lewp\Websocket\Message $message
    ) : \Lewp\Websocket\Message {
    }
};