<?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/>.
 */

/**
 * PayPal.inc.php
 *
 * The PayPal class provides functions for creating PayPal buttons and for
 * receiving PayPal's Instant Payment Notification (IPN) service.
 *
 * @author  Quinn Comendant <quinn@strangecode.com>
 * @version 1.0
 */
class PayPal
{

    // General object parameters.
    protected $_params = array(
        'paypal_url' => 'https://www.paypal.com/cgi-bin/webscr',
        'test_mode' => false,
    );

    // Options used for specific buttons and links.
    protected $_default_button_options = array();

    // Array of buttons created by newButton().
    protected $_buttons = array();

    // Store the response from the last IPN.
    protected $_ipn_response;

    /**
     * Constructor.
     *
     * @param   bool    $test_mode  Use PayPal sandbox for testing.
     */
    public function __construct($test_mode=false)
    {
        if ($test_mode) {
            $this->setParam(array('test_mode' => true));
            // Use PayPal sandbox when in test mode.
            $url = 'www.sandbox.paypal.com';
        } else {
            $url = 'www.paypal.com';
        }

        $this->_default_button_options = array(
            '_global' => array(
                'business' => null,
            ),
            'web_accept' => array(
                'cmd' => '_xclick',
                'button_url' => 'https://' . $url . '/cgi-bin/webscr',
                'link_url' => 'https://' . $url . '/xclick/',
                'submit_img' => 'https://' . $url . '/en_US/i/btn/x-click-but23.gif',
                'submit_text' => _("Pay with PayPal"),
            ),
            'subscriptions' => array(
                'cmd' => '_xclick-subscriptions',
                'button_url' => 'https://' . $url . '/cgi-bin/webscr',
                'link_url' => 'https://' . $url . '/subscriptions/',
                'submit_img' => 'https://' . $url . '/en_US/i/btn/x-click-but20.gif',
                'submit_text' => _("Subscribe with PayPal"),
            ),
        );
    }

    /**
     * Updates the _default_button_options array with options used for
     * specific buttons, or all buttons if $type is null.
     *
     * @access  public
     *
     * @param   mixed   $type       The type of button to set defaults. If null,
     *                              sets the global button types.
     * @param   array   $options    Options to set for button.
     *
     * @return  bool    True on success, false on failure.
     */
    public function setButtonDefaults($type, $options)
    {
        $app =& App::getInstance();

        if (!is_array($options) || empty($options)) {
            $app->logMsg(sprintf('Invalid options: %s', truncate(getDump($options, true), 128, 'end')), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        if (is_null($type) || '_global' == $type) {
            $this->_default_button_options['_global'] = array_merge($this->_default_button_options['_global'], $options);
        } else if (!isset($this->_default_button_options[$type])) {
            $app->logMsg(sprintf('Invalid button type: %s', $type), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        $this->_default_button_options[$type] = array_merge($this->_default_button_options[$type], $options);
        return true;
    }

    /**
     * Creates a new element in the _buttons array. Uses _default_button_options
     * merged with provided options.
     *
     * @access  public
     *
     * @param   string  $type       Type of button to create.
     * @param   string  $name       Name of button to create.
     * @param   array   $options    Options of button. Overwrites _default_button_options.
     *
     * @return  bool    True on success, false on failure.
     */
    public function newButton($type, $name, $options=null)
    {
        $app =& App::getInstance();

        if (!isset($this->_default_button_options[$type])) {
            $app->logMsg(sprintf('Invalid button type: %s', $type), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        if (!is_array($options) || empty($options)) {
            $app->logMsg(sprintf('Invalid options: %s', truncate(getDump($options, true), 128, 'end')), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        if (isset($this->_buttons[$name])) {
            $app->logMsg(sprintf('Overwriting existing button name: %s', truncate(getDump($this->_buttons[$name], true), 128, 'end')), LOG_DEBUG, __FILE__, __LINE__);
        }

        $this->_buttons[$name] = array(
            'type' => $type,
            'options' => array_merge($this->_default_button_options['_global'], $this->_default_button_options[$type], $options)
        );

        return true;
    }

    /**
     * Returns the URL link for specified button.
     *
     * @access  public
     *
     * @param   string  $name   Name of button for which to generate link.
     *
     * @return  mixed   Link of button, or false on failure.
     */
    public function getLink($name)
    {
        $app =& App::getInstance();

        if (!isset($this->_buttons[$name])) {
            $app->logMsg(sprintf('Button does not exist: %s', $name), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        $query_string = '';
        $delim = '';
        if (is_array($this->_buttons[$name]['options']) && !empty($this->_buttons[$name]['options'])) {
            foreach ($this->_buttons[$name]['options'] as $key=>$val) {
                if (!in_array($key, array('button_url', 'link_url', 'cmd', 'submit_img', 'submit_text'))) {
                    $query_string .= $delim . $key . '=' . urlencode($val);
                    $delim = '&';
                }
            }
        }

        // PayPal links do not like urlencoded slashes for some stupid reason.
        $search = array('/%2F/');
        $replace = array('/');

        return $this->_buttons[$name]['options']['link_url'] . preg_replace($search, $replace, $query_string);
    }

    /**
     * Prints the link returned by getLink().
     *
     * @access  public
     *
     * @param   string  $name   Name of button for which to generate link.
     */
    public function printLink($name)
    {
        echo $this->getLink($name);
    }

    /**
     * Prints button with specified name.
     *
     * @access  public
     *
     * @param   string  $name   Name of button to print.
     */
    public function printButton($name)
    {
        ?>
        <form action="<?php echo oTxt($this->_buttons[$name]['options']['button_url']); ?>" method="post">
        <?php
        if (is_array($this->_buttons[$name]['options']) && !empty($this->_buttons[$name]['options'])) {
            foreach ($this->_buttons[$name]['options'] as $key=>$val) {
                if (!in_array($key, array('button_url', 'link_url', 'submit_img', 'submit_text'))) {
                    ?>
                    <input type="hidden" name="<?php echo oTxt($key); ?>" value="<?php echo oTxt($val); ?>" />
                    <?php
                }
            }
        }
        ?>
        <input type="image" src="<?php echo oTxt($this->_buttons[$name]['options']['submit_img']); ?>" border="0" name="submit" alt="<?php echo oTxt($this->_buttons[$name]['options']['submit_text']); ?>" />
        </form>
        <?php
    }

    /**
     * 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)) {
            // 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;
        }
    }

    /**
     * Tests if the HTTP request is a valid IPN request from PayPal.
     *
     * @access  public
     *
     * @return  bool    True if valid, false if invalid.
     */
    public function incomingIPNRequest()
    {
        if ($_SERVER['REQUEST_METHOD'] == 'POST'
        && $_SERVER['CONTENT_TYPE'] == 'application/x-www-form-urlencoded'
        && !empty($_POST)) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * Process incoming IPN.
     *
     * @access  public
     *
     * @return  bool    True on success, false on failure.
     */
    public function processIPN()
    {
        $app =& App::getInstance();

        if (getPost('test_ipn') == '1' || $this->getParam('test_mode')) {
            $app->logMsg(sprintf('Processing PayPal IPN in test mode: %s', truncate(getDump(getFormData(), true), 128, 'end')), LOG_DEBUG, __FILE__, __LINE__);
            $url = parse_url('https://www.sandbox.paypal.com/cgi-bin/webscr');
        } else {
            $app->logMsg(sprintf('Processing PayPal IPN: %s', truncate(getDump(getFormData(), true), 128, 'end')), LOG_DEBUG, __FILE__, __LINE__);
            $url = parse_url($this->getParam('paypal_url'));
        }

        // Read POST request and add 'cmd'.
        $received_data = getPost();
        $return_data = 'cmd=_notify-validate';
        foreach ($received_data as $post_key => $post_val) {
            $return_data .= '&' . $post_key . '=' . urlencode($post_val);
        }

        // Set the port number based on the scheme.
        if ($url['scheme'] == "https") {
            $url['port'] = 443;
            $ssl = 'ssl://';
        } else {
            $url['port'] = 80;
            $ssl = '';
        }

        // Open connection to PayPal server.
        $fp = fsockopen($ssl . $url['host'], $url['port'], $errnum, $errstr, 30);

        if (!$fp) {
            $app->logMsg(sprintf('Connection to PayPal URL %s failed with error: %s (%s)', $ssl . $url['host'], $errstr, $errnum), LOG_WARNING, __FILE__, __LINE__);
            return false;
        } else {
            fputs($fp, "POST {$url['path']} HTTP/1.1\r\n");
            fputs($fp, "Host: {$url['host']}\r\n");
            fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
            fputs($fp, "Content-length: " . mb_strlen($return_data) . "\r\n");
            fputs($fp, "Connection: close\r\n\r\n");
            fputs($fp, $return_data . "\r\n\r\n");

            // Loop through the response lines from the server.
            $this->_ipn_response = '';
            while (!feof($fp)) {
                $this->_ipn_response .= fgets($fp, 1024);
            }
            fclose($fp);

            $app->logMsg(sprintf('IPN response received: %s', $this->_ipn_response), LOG_NOTICE, __FILE__, __LINE__);
            return true;
        }
    }

    /**
     * Checks the response received from PayPal's IPN upon calling processIPN().
     *
     * @access  public
     *
     * @return  bool    True if response contains VERIFIED, false otherwise.
     */
    public function verifiedIPN()
    {
        $app =& App::getInstance();

        if (!isset($this->_ipn_response)) {
            $app->logMsg(sprintf('Cannot verify IPN, response not received.', null), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        if (empty($this->_ipn_response)) {
            $app->logMsg(sprintf('Cannot verify IPN, response empty.', null), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        if (preg_match('/VERIFIED/', $this->_ipn_response)) {
            $app->logMsg(sprintf('IPN verified!', null), LOG_DEBUG, __FILE__, __LINE__);
            return true;
        } else if (preg_match('/INVALID/', $this->_ipn_response)) {
            $app->logMsg(sprintf('IPN invalid.', null), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        } else {
            $app->logMsg(sprintf('IPN unknown.', null), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }
    }


} // End of class.