<?php
/**
 * The Strangecode Codebase - a general application development framework for PHP
 * For details visit the project site: <http://trac.strangecode.com/codebase/>
 * Copyright 2001-2012 Strangecode, LLC
 *
 * This file is part of The Strangecode Codebase.
 *
 * The Strangecode Codebase is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * The Strangecode Codebase is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * The Strangecode Codebase. If not, see <http://www.gnu.org/licenses/>.
 */

/*
* Email.inc.php
*
* Easy email template usage.
*
* @author  Quinn Comendant <quinn@strangecode.com>
* @version 1.0
*
* Example of use:
---------------------------------------------------------------------
// Setup email object.
$email = new Email(array(
    'to' => array($frm['email'], 'q@lovemachine.local'),
    'from' => sprintf('"%s" <%s>', addcslashes($app->getParam('site_name'), '"'), $app->getParam('site_email')),
    'subject' => 'Your account has been activated',
));
$email->setTemplate('email_registration_confirm.ihtml');
// $email->setString('Or you can pass your message body as a string, also with {VARIABLES}.');
$email->replace(array(
    'site_name' => $app->getParam('site_name'),
    'site_url' => $app->getParam('site_url'),
    'username' => $frm['username'],
    'password' => $frm['password1'],
));
if ($email->send()) {
    $app->raiseMsg(sprintf(_("A confirmation email has been sent to %s."), $frm['email']), MSG_SUCCESS, __FILE__, __LINE__);
} else {
    $app->logMsg(sprintf('Error sending confirmation email to address %s', $frm['email']), LOG_NOTICE, __FILE__, __LINE__);
}
---------------------------------------------------------------------
*/

class Email
{

    // Default parameters, to be overwritten by setParam() and read with getParam()
    protected $_params = array(
        'to' => null,
        'from' => null,
        'subject' => null,
        'headers' => null,
        'envelope_sender_address' => null, // AKA the bounce-to address. Will default to 'from' if left null.
        'regex' => null,

        // A single carriage return (\n) should terminate lines for locally injected mail.
        // A carriage return + line-feed (\r\n) should be used if sending mail directly with SMTP.
        'crlf' => "\n",

        // RFC 2822 says line length MUST be no more than 998 characters, and SHOULD be no more than 78 characters, excluding the CRLF.
        // http://mailformat.dan.info/body/linelength.html
        'wrap' => true,
        'line_length' => 75,

        'sandbox_mode' => null,
        'sandbox_to_addr' => null,
    );

    // String that contains the email body.
    protected $_template;

    // String that contains the email body after replacements.
    protected $_template_replaced;

    // Email debug modes.
    const SANDBOX_MODE_REDIRECT = 1; // Send all mail to 'sandbox_to_addr'
    const SANDBOX_MODE_STDERR = 2; // Log all mail to stderr

    /**
     * Constructor.
     *
     * @access  public
     * @param   array   $params     Array of object parameters.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   28 Nov 2005 12:59:41
     */
    public function __construct($params=null)
    {
        // The regex used in validEmail(). Set here instead of in the default _params above so we can use the concatenation . dot.
        // This matches a (valid) email address as complex as:
        //      "Jane & Bob Smith" <bob&smith's/dep=sales!@smith-wick.ca.us > (Sales department)
        // ...and something as simple as:
        //      x@x.com
        $this->setParam(array('regex' => '/^(?:(?:"[^"]*?"\s*|[^,@]*)(<\s*)|(?:"[^"]*?"|[^,@]*)\s+|)'   // Display name
        . '((?:[^.<>\s@",\[\]]+[^<>\s@",\[\]])*[^.<>\s@",\[\]]+)'       // Local-part
        . '@'                                                           // @
        . '((?:(\[)|[A-Z0-9]?)'                                         // Domain, first char
        . '(?(4)'                                                       // Domain conditional for if first domain char is [
        . '(?:[0-9]{1,3}\.){3}[0-9]{1,3}\]'                             // TRUE, matches IP address
        . '|'
        . '[.-]?(?:[A-Z0-9]+[-.])*(?:[A-Z0-9]+\.)+[A-Z]{2,6}))'         // FALSE, matches domain name
        . '(?(1)'                                                       // Comment conditional for if initial < exists
        . '(?:\s*>\s*|>\s+\([^,@]+\)\s*)'                               // TRUE, ensure ending >
        . '|'
        . '(?:|\s*|\s+\([^,@]+\)\s*))$/i'));                            // FALSE ensure there is no ending >

        if (isset($params)) {
            $this->setParam($params);
        }
    }

    /**
     * Set (or overwrite existing) parameters by passing an array of new parameters.
     *
     * @access public
     * @param  array    $params     Array of parameters (key => val pairs).
     */
    public function setParam($params)
    {
        $app =& App::getInstance();

        if (isset($params) && is_array($params)) {
            // Enforce valid email addresses.
            if (isset($params['to']) && !$this->validEmail($params['to'])) {
                $params['to'] = null;
            }
            if (isset($params['from']) && !$this->validEmail($params['from'])) {
                $params['from'] = null;
            }
            if (isset($params['envelope_sender_address']) && !$this->validEmail($params['envelope_sender_address'])) {
                $params['envelope_sender_address'] = null;
            }

            // Merge new parameters with old overriding only those passed.
            $this->_params = array_merge($this->_params, $params);
        } else {
            $app->logMsg(sprintf('Parameters are not an array: %s', $params), LOG_ERR, __FILE__, __LINE__);
        }
    }

    /**
     * Return the value of a parameter, if it exists.
     *
     * @access public
     * @param string $param        Which parameter to return.
     * @return mixed               Configured parameter value.
     */
    public function getParam($param)
    {
        $app =& App::getInstance();

        if (array_key_exists($param, $this->_params)) {
            return $this->_params[$param];
        } else {
            $app->logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__);
            return null;
        }
    }

    /**
     * Loads template from file to generate email body.
     *
     * @access  public
     * @param   string  $template   Filename of email template.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   28 Nov 2005 12:56:23
     */
    public function setTemplate($template)
    {
        $app =& App::getInstance();

        // Load file, using include_path.
        if (!$this->_template = file_get_contents($template, true)) {
            $app->logMsg(sprintf('Email template file does not exist: %s', $template), LOG_ERR, __FILE__, __LINE__);
            $this->_template = null;
            $this->_template_replaced = null;
            return false;
        }

        // Ensure template is UTF-8.
        $detected_encoding = mb_detect_encoding($this->_template, array('UTF-8', 'ISO-8859-1', 'WINDOWS-1252'), true);
        if ('UTF-8' != strtoupper($detected_encoding)) {
            $this->_template = mb_convert_encoding($this->_template, 'UTF-8', $detected_encoding);
        }

        // This could be a new template, so reset the _template_replaced.
        $this->_template_replaced = null;
        return true;
    }

    /**
     * Loads template from string to generate email body.
     *
     * @access  public
     * @param   string  $template   Filename of email template.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   28 Nov 2005 12:56:23
     */
    public function setString($string)
    {
        $app =& App::getInstance();

        if ('' == trim($string)) {
            $app->logMsg(sprintf('Empty string provided.', null), LOG_ERR, __FILE__, __LINE__);
            $this->_template_replaced = null;
            return false;
        } else {
            $this->_template = $string;
            // This could be a new template, so reset the _template_replaced.
            $this->_template_replaced = null;
            return true;
        }
    }

    /**
     * Replace variables in template with argument data.
     *
     * @access  public
     * @param   array   $replacements   Array keys are the values to search for, array vales are the replacement values.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   28 Nov 2005 13:08:51
     */
    public function replace($replacements)
    {
        $app =& App::getInstance();

        // Ensure template exists.
        if (!isset($this->_template)) {
            $app->logMsg(sprintf('Cannot replace variables, no template defined.', null), LOG_ERR, __FILE__, __LINE__);
            return false;
        }

        // Ensure replacements argument is an array.
        if (!is_array($replacements)) {
            $app->logMsg(sprintf('Cannot replace variables, invalid replacements.', null), LOG_ERR, __FILE__, __LINE__);
            return false;
        }

        // Apply regex pattern to search elements.
        $search = array_keys($replacements);
        array_walk($search, create_function('&$v', '$v = "{" . mb_strtoupper($v) . "}";'));

        // Replacement values.
        $replace = array_values($replacements);

        // Search and replace all values at once.
        $this->_template_replaced = str_replace($search, $replace, $this->_template);
    }

    /*
    * Returns the body of the current email. This can be used to store the message that is being sent.
    * It will use the original template, or the replaced template if it has been processed.
    * You can also use this function to do post-processing on the email body before sending it,
    * like removing extraneous lines:
    * $email->setString(preg_replace('/(?:(?:\r\n|\r|\n)\s*){2}/s', "\n\n", $email->getBody()));
    *
    * @access   public
    * @return   string  Message body.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    18 Nov 2014 21:15:19
    */
    public function getBody()
    {
        $app =& App::getInstance();

        $final_body = isset($this->_template_replaced) ? $this->_template_replaced : $this->_template;
        // Ensure all placeholders have been replaced. Find anything with {...} characters.
        if (preg_match('/({[^}]+})/', $final_body, $unreplaced_match)) {
            unset($unreplaced_match[0]);
            $app->logMsg(sprintf('Cannot get email body. Unreplaced variables in template: %s', getDump($unreplaced_match)), LOG_ERR, __FILE__, __LINE__);
            return false;
        }
        return $final_body;
    }

    /**
     * Send email using PHP's mail() function.
     *
     * @access  public
     * @param   string  $to
     * @param   string  $from
     * @param   string  $subject
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   28 Nov 2005 12:56:09
     */
    public function send($to=null, $from=null, $subject=null, $headers=null)
    {
        $app =& App::getInstance();

        // Use arguments if provided.
        if (isset($to)) {
            $this->setParam(array('to' => $to));
        }
        if (isset($from)) {
            $this->setParam(array('from' => $from));
        }
        if (isset($subject)) {
            $this->setParam(array('subject' => $subject));
        }
        if (isset($headers)) {
            $this->setParam(array('headers' => $headers));
        }

        // Ensure required values exist.
        if (!isset($this->_params['subject'])) {
            $app->logMsg('Cannot send email. SUBJECT not defined.', LOG_ERR, __FILE__, __LINE__);
            return false;
        } else if (!isset($this->_template)) {
            $app->logMsg(sprintf('Cannot send email: "%s". Template not set.', $this->_params['subject']), LOG_ERR, __FILE__, __LINE__);
            return false;
        } else if (!isset($this->_params['to'])) {
            $app->logMsg(sprintf('Cannot send email: "%s". TO not defined.', $this->_params['subject']), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        } else if (!isset($this->_params['from'])) {
            $app->logMsg(sprintf('Cannot send email: "%s". FROM not defined.', $this->_params['subject']), LOG_ERR, __FILE__, __LINE__);
            return false;
        }

        // Wrap email text body, using _template_replaced if replacements have been used, or just a fresh _template if not.
        $final_body = isset($this->_template_replaced) ? $this->_template_replaced : $this->_template;
        if (false !== $this->getParam('wrap')) {
            $final_body = wordwrap($final_body, $this->getParam('line_length'), $this->getParam('crlf'));
        }

        // Ensure all placeholders have been replaced. Find anything with {...} characters.
        if (preg_match('/({[^}]+})/', $final_body, $unreplaced_match)) {
            unset($unreplaced_match[0]);
            $app->logMsg(sprintf('Cannot send email. Unreplaced variables in template: %s', getDump($unreplaced_match)), LOG_ERR, __FILE__, __LINE__);
            return false;
        }

        // Final "to" header can have multiple addresses if in an array.
        $final_to = is_array($this->_params['to']) ? join(', ', $this->_params['to']) : $this->_params['to'];

        // From headers are custom headers.
        $headers = array('From' => $this->_params['from']);

        // Additional headers.
        if (isset($this->_params['headers']) && is_array($this->_params['headers'])) {
            $headers = array_merge($this->_params['headers'], $headers);
        }

        // Process headers.
        $final_headers = array();
        foreach ($headers as $key => $val) {
            // Validate key and values.
            if (empty($val)) {
                $app->logMsg(sprintf('Empty email header provided: %s', $key), LOG_DEBUG, __FILE__, __LINE__);
                continue;
            }
            if (empty($key) || !is_string($key) || !is_string($val) || preg_match("/[\n\r]/", $key . $val) || preg_match('/[^\w-]/', $key)) {
                $app->logMsg(sprintf('Broken email header provided: %s=%s', $key, $val), LOG_WARNING, __FILE__, __LINE__);
                continue;
            }
            // If the envelope_sender_address was given as a header, move it to the correct place.
            if ('envelope_sender_address' == strtolower($key)) {
                $this->_params['envelope_sender_address'] = isset($this->_params['envelope_sender_address']) ? $this->_params['envelope_sender_address'] : $val;
                continue;
            }
            // If we're sending in sandbox mode, remove any headers with recipient addresses.
            if ($this->getParam('sandbox_mode') == self::SANDBOX_MODE_REDIRECT && in_array(strtolower($key), array('to', 'cc', 'bcc')) && mb_strpos($val, '@') !== false) {
                // Don't carry this into the $final_headers.
                $app->logMsg(sprintf('Skipping header in sandbox mode: %s=%s', $key, $val), LOG_DEBUG, __FILE__, __LINE__);
                continue;
            }
            $final_headers[] = sprintf('%s: %s', $key, $val);
        }
        $final_headers = join($this->getParam('crlf'), $final_headers);

        // This is the address where delivery problems are sent to. We must strip off everything except the local@domain part.
        if (isset($this->_params['envelope_sender_address'])) {
            $envelope_sender_address = sprintf('<%s>', trim($this->_params['envelope_sender_address'], '<>'));
        } else {
            $envelope_sender_address = preg_replace('/^.*<?([^\s@\[\]<>()]+\@[A-Za-z0-9.-]{1,}\.[A-Za-z]{2,5})>?$/iU', '$1', $this->_params['from']);
        }
        if ('' != $envelope_sender_address && $this->validEmail($envelope_sender_address)) {
            $additional_parameter = sprintf('-f %s', $envelope_sender_address);
        } else {
            $additional_parameter = '';
        }

        // Check for mail header injection attacks.
        $full_mail_content = join($this->getParam('crlf'), array($final_to, $this->_params['subject'], $final_body));
        if (preg_match("/(^|[\n\r])(Content-Type|MIME-Version|Content-Transfer-Encoding|Bcc|Cc)\s*:/i", $full_mail_content)) {
            $app->logMsg(sprintf('Mail header injection attack in content: %s', $full_mail_content), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        // Enter sandbox mode, if specified.
        switch ($this->getParam('sandbox_mode')) {
        case self::SANDBOX_MODE_REDIRECT:
            if (!$this->getParam('sandbox_to_addr')) {
                $app->logMsg(sprintf('Email sandbox_mode is SANDBOX_MODE_REDIRECT but sandbox_to_addr is not set.', null), LOG_ERR, __FILE__, __LINE__);
                break;
            }
            $final_to = $this->getParam('sandbox_to_addr');
            break;

        case self::SANDBOX_MODE_STDERR:
            file_put_contents('php://stderr', sprintf("Subject: %s\nTo: %s\n%s\n\n%s", $this->getParam('subject'), $final_to, str_replace($this->getParam('crlf'), "\n", $final_headers), $final_body), FILE_APPEND);
            return true;
        }

        // Send email without 5th parameter if safemode is enabled.
        if (ini_get('safe_mode')) {
            $ret = mb_send_mail($final_to, $this->_params['subject'], $final_body, $final_headers);
        } else {
            $ret = mb_send_mail($final_to, $this->_params['subject'], $final_body, $final_headers, $additional_parameter);
        }

        // Ensure message was successfully accepted for delivery.
        if ($ret) {
            $app->logMsg(sprintf('Email successfully sent to %s', $final_to), LOG_INFO, __FILE__, __LINE__);
            return true;
        } else {
            $app->logMsg(sprintf('Email failure: %s, %s, %s, %s', $final_to, $this->_params['subject'], str_replace("\r\n", '\r\n', $final_headers), $additional_parameter), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }
    }

    /**
     * Validates an email address based on the recommendations in RFC 3696.
     * Is more loose than restrictive, to allow the many valid variants of
     * email addresses while catching the most common mistakes. Checks an array too.
     * http://www.faqs.org/rfcs/rfc822.html
     * http://www.faqs.org/rfcs/rfc2822.html
     * http://www.faqs.org/rfcs/rfc3696.html
     * http://www.faqs.org/rfcs/rfc1035.html
     *
     * @access  public
     * @param   mixed  $email  Address to check, string or array.
     * @return  bool    Validity of address.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   30 Nov 2005 22:00:50
     */
    public function validEmail($email)
    {
        $app =& App::getInstance();

        // If an array, check values recursively.
        if (is_array($email)) {
            foreach ($email as $e) {
                if (!$this->validEmail($e)) {
                    return false;
                }
            }
            return true;
        } else {
            // To be valid email address must match regex and fit within the length constraints.
            if (preg_match($this->getParam('regex'), $email, $e_parts) && mb_strlen($e_parts[2]) < 64 && mb_strlen($e_parts[3]) < 255) {
                return true;
            } else {
                $app->logMsg(sprintf('Invalid email address: %s', $email), LOG_INFO, __FILE__, __LINE__);
                return false;
            }
        }
    }
}