<?php

require 'settings.php';
require 'vendor/autoload.php';

function create_response($response) {
    @header('Content-Type: application/json');
    return json_encode($response);
};

// Фильтрация значений полей //

function has_correct_value($name, $value, $filters) {

    foreach ($filters as $filter) {

        if (!$filter($value)) {
            return false;
        }

    };

    return true;
};

function send_message($array) {
    global $alias;
    global $settings;

    $message = "
        <p>" . $settings["mail"]["message"] . "</p>
        <br>
        <p><strong>Дата обращения: </strong>" . date('d.m.Y H:i:s') .  "</p>
    ";
    foreach($array as $field) {
        $name = $field["name"];
        $value = $field["value"];

        if ($name !== "g-recaptcha-response" && $name !== "agreement") {
            $message .= "<p><strong>" . $alias[$name] . ":</strong> " . $value . "</p>";
        }
    };
    $message .= "<br><br><p>Это письмо сгенерировано автоматически. Пожалуйста, не отвечайте на него.</p>";

    $mail = new PHPMailer;

    $mail->isSMTP();
    $mail->Host = 'smtp.yandex.ru';
    $mail->SMTPAuth = true;
    $mail->Username = $settings["mail"]["auth"]["username"];
    $mail->Password = $settings["mail"]["auth"]["password"];
    $mail->SMTPSecure = "tsl";
    $mail->Port = 587;
    $mail->CharSet = "UTF-8";

    $mail->Subject = $settings["mail"]["subject"];
    $mail->SetFrom($settings["mail"]["sender"]["address"], $settings["mail"]["sender"]["alias"]);
    $mail->MsgHTML($message);
    $mail->AddAddress($settings["mail"]["receiver"]["address"], $settings["mail"]["receiver"]["alias"]);

    $mail->send();
};

// Функции — Фильтры //

$is_filled_string = function($string) {
    return !(preg_match("/^\s+$/", $string) || strlen($string) === 0);
};

$is_phone = function($string) {
    return preg_match("/^\+?(\d.*){3,}$/", $string);
};

$is_email = function($string) {
    return preg_match("/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i", $string);
};

$is_correct_contact = function($string) {
    global $is_email;
    global $is_phone;

    return $is_email($string) || $is_phone($string);
};

$is_agree = function($value) {
    return $value === true;
};

$is_shorter_than = function($string) {
    return strlen($string) <= 180;
};

$is_correct_captcha = function($public_key) {
    global $settings;

    $secretKey = $settings["captcha"]["secret_key"];
    $ip = $_SERVER['REMOTE_ADDR'];

    $postdata = http_build_query(array(
            'secret' => $secretKey,
            'response' => $public_key,
            'remoteip' => $ip,
        ));

    $opts = array(
        'http' =>
        array(
            'method'  => 'POST',
            'header'  => 'Content-type: application/x-www-form-urlencoded',
            'content' => $postdata
        )
    );

    $context  = stream_context_create($opts);
    $response = file_get_contents("https://www.google.com/recaptcha/api/siteverify", false, $context);
    $responseKeys = json_decode($response,true);

    return $responseKeys["success"];
};

// Настройки //

$JSON_request = json_decode(file_get_contents('php://input'), true);
$response = array();
$filters = array(
    "name" => array(
        $is_filled_string,
        $is_shorter_than
    ),
    "contact" => array(
        $is_filled_string,
        $is_correct_contact
    ),
    "point" => array(
        $is_filled_string,
        $is_shorter_than
    ),
    "agreement" => array(
        $is_filled_string,
        $is_agree
    ),
    "g-recaptcha-response" => array(
        $is_filled_string,
        $is_correct_captcha
    )
);
$alias = array(
    "name" => "Имя",
    "contact" => "Email или номер телефона",
    "point" => "Текст вопроса"
);

foreach($JSON_request as $field) {
    $name = $field["name"];
    $value = $field["value"];

    if ( !has_correct_value($name, $value, $filters[$name]) ) {
        array_push($response, $name);
    }
};

if (empty($response)) {
    send_message($JSON_request);
};

echo create_response($response);

?>