[laimas]

<?php
$check = array(
    'sex'       => array(
        'filter'    => FILTER_VALIDATE_INT, 
        'flags'     => FILTER_REQUIRE_SCALAR, 
        'options'   => array('min_range' => 1, 'max_range' => 2)
    ),
    'email'     => FILTER_VALIDATE_EMAIL,
    'worker'    => FILTER_VALIDATE_INT,
    'message'   => FILTER_SANITIZE_SPECIAL_CHARS
);

$error_message = array(
    'sex'       => 'Некорректное значение поля «Пол»!',
    'email'     => 'Некорректное значение поля «Адрес почты»!',
    'worker'    => 'Некорректное значение поля «Сотрудник»!',
    'message'   => 'Некорректное значение поля «Сообощение»!',
);

$errors = array();

$post = array_map('trim', $_POST);
if(array_diff_key($post, $check)) exit;
$data = filter_var_array($post, $check);
$errors +=  array_intersect_key($error_message, array_filter($data, function($v) { return !$v; }));
if($errors) { 
    header('Content-Type: application/json');
    exit(json_encode(array('result'=> 'error', 'data'=>  array_values($errors))));
} else {
    
    $sex = array(1 => 'мужчина', 'женщина');
    $worker = array(1 => 'Сергей', 'Иван', 'Николай', 'Антон', 'Виктор');
    
    if(!$name = $worker[$data['worker']]) exit;
    
    $text = 'Текстовый вариант';
    $html = "<p><b>Пол:</b> " . $sex[$data['sex']] . "</p>
    <p><b>E-mail:</b> " . $data['email'] . "</p>
    <p><b>Сотрудник:</b> " . $name . "</p>
    <p><b>Сообщение:</b> " . $data['message'] . "</p>";
    
    $to             = 'pochta@mail.ru';
    $subject        = '=?utf-8?b?' . base64_encode($data['subject']) . '?=';
    $headers        = 'From: =?utf-8?B?' . base64_encode($name) . '?= <' . $data['email'] . '>' . PHP_EOL;
    $headers       .= 'Reply-To: receiver@domain3.com' .  PHP_EOL;
    $headers       .= 'X-Mailer: PHP/' . phpversion() . PHP_EOL;
    $headers       .= 'Mime-Version: 1.0' . PHP_EOL;
    $headers       .= 'Content-Type: multipart/alternative; boundary="==boundary-2"' . PHP_EOL.PHP_EOL;
    $body          .= '--==boundary-2' . PHP_EOL.PHP_EOL;
    $body          .= 'Content-type: text/plain; charset="utf-8"' . PHP_EOL;
    $body          .= 'Content-Transfer-Encoding: 8bit' . PHP_EOL.PHP_EOL;
    $body          .= $text . PHP_EOL; //текстовая версия
    $body          .= '--==boundary-2' . PHP_EOL;
    $body          .= 'Content-Type: multipart/related; boundary="==boundary-1"; type="text/html"' . PHP_EOL.PHP_EOL;
    $body          .= '--==boundary-1' . PHP_EOL;
    $body          .= 'Content-type: text/html; charset="utf-8"' . PHP_EOL;
    $body          .= 'Content-Transfer-Encoding: base64' . PHP_EOL.PHP_EOL;
    $body          .= chunk_split(base64_encode($html)) . PHP_EOL.PHP_EOL; //html версия
    $body          .= '--==boundary-1--' . PHP_EOL;
    $body          .= '--==boundary-2--' . PHP_EOL;
    
    mail($to, $subject, $body, $headers);
    
    header('Content-Type: application/json');
    exit(json_encode(array('result'=> 'done', 'data'=>  array('Письмо отправлено'))));
}