<?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/>.
 */

/**
 * PageSequence.inc.php
 *
 * The PageSequence class provides an interface to simplify the creation of a multi-step form.
 *
 * @requires  This class requires Prefs.inc.php
 * @author    Quinn Comendant <quinn@strangecode.com>
 * @version   1.01
 */

require_once dirname(__FILE__) . '/Prefs.inc.php';

class PageSequence
{
    public $current_step_id = 0;
    public $start_url;
    public $sequence_title = '';
    public $seq = '_sequence_';
    public $idle_timeout;

    /**
     * Constructor. Sets the title of this sequence and initializes session variables.
     *
     * @param  array $params   An associative array of PageSequence parameters.
     * @access public
     */
    public function __construct($params)
    {
        if (isset($params['sequence_title'])) {
            $this->sequence_title = $params['sequence_title'];
            $this->seq .= $params['sequence_title'];
        }

        // How long before resetting session? 60 minutes.
        $this->idle_timeout = isset($params['idle_timeout']) ? $params['idle_timeout'] : 3600;

        // Where is user to be redirected after startOver function call?
        $this->start_url = isset($params['start_url']) ? $params['start_url'] : $_SERVER['PHP_SELF'];

        // Initialize vars if not set.
        if (!isset($_SESSION[$this->seq]['steps'])) {
            $_SESSION[$this->seq]['steps'] = array();
        }
        if (!isset($_SESSION[$this->seq]['data'])) {
            $_SESSION[$this->seq]['data'] = array();
        }
        if (!isset($_SESSION[$this->seq]['defaults'])) {
            $_SESSION[$this->seq]['defaults'] = array();
        }

        // Manage timeout.
        $this->_auto_timeout();
    }

    /**
     * Create a new step at the end (or specified position) of the $steps array.
     *
     * @param  string $step_id      Uniqie identifyer for this step.
     * @param  array  $params       Values for the creation of the step.
     *
     * @return boolean    Success of the addition
     * @access public
     */
    public function addStep($step_id, $params)
    {
        // Keys for the steps array cannot be numeric.
        if (is_numeric($step_id)) {
            trigger_error('Step ID for function addStep cannot be numeric.', E_USER_WARNING);
        }
        // This step ID already exists.
        if (!is_null($this->getPosition($step_id))) {
            return false;
        }
        $_SESSION[$this->seq]['steps'][] = array(
            'id'        => $step_id,
            'title'     => isset($params['title'])     ? $params['title']     : '',
            'active'    => isset($params['active'])    ? $params['active']    : false,
            'form_tpl'  => isset($params['form_tpl'])  ? $params['form_tpl']  : '',
            'disp_tpl'  => isset($params['disp_tpl'])  ? $params['disp_tpl']  : '',
            'required'  => isset($params['required'])  ? $params['required']  : false,
            'completed' => isset($params['completed']) ? $params['completed'] : false,
            'editable'  => isset($params['editable'])  ? $params['editable']  : true,
        );
    }

    /**
     * Set the features of a step. Current step if step_id not specified.
     *
     * @param  string $page_id    ID of page. Leave null if modifying current step features.
     * @param  array  $feature    Array of feature keys and values to set.
     *
     * @return bool true on success, false on failure
     */
    public function setFeature($step_id=null, $features)
    {
        $pos = isset($step_id) ? $this->getPosition($step_id) : $this->getPosition();

        if (isset($features) && is_array($features) && isset($_SESSION[$this->seq]['steps'][$pos])) {
            $_SESSION[$this->seq]['steps'][$pos] = array_merge($_SESSION[$this->seq]['steps'][$pos], $features);
        }
    }

    /**
     * Returns a specified value from a registered step.
     *
     * @access public
     *
     * @param string $step_id  Id of step with feature to return.
     * @param string $key      Which value to return.
     * @param mixed  $default  Value to return if key not found in user_data.
     *
     * @return mixed          Value stored in session.
     */
    public function getFeature($step_id, $key, $default='')
    {
        $pos = isset($step_id) ? $this->getPosition($step_id) : $this->getPosition();
        if (isset($_SESSION[$this->seq]['steps'][$pos][$key])) {
            return $_SESSION[$this->seq]['steps'][$pos][$key];
        } else {
            return $default;
        }
    }

    /**
     * Set the current step id. Which step are we on?
     *
     * @param  string $step_id      ID or number of current step.
     * @return string    Actual step ID
     * @access public
     */
    public function setCurrent($step_id)
    {
        $app =& App::getInstance();

        if (false !== ($pos = $this->getPosition($step_id))) {
            // Specified step exists (even if numeric).
            $this->current_step_id = $this->getID($pos);
        } else {
            // Step with specified key does not exist.
            $app->logMsg(sprintf('Step %s not defined in sequence %s', $step_id, $this->sequence_title), LOG_INFO, __FILE__, __LINE__);
            return false;
        }
    }

    /**
     * Get the current step id.
     *
     * @return int $pos    Actual step position
     * @access public
     */
    public function getID($pos=null)
    {
        if (isset($pos)) {
            return $_SESSION[$this->seq]['steps'][$pos]['id'];
        } else {
            return $this->current_step_id;
        }
    }

    /**
     * Get the current step number.
     *
     * @param  string $step_id      ID or number of step to convert to position.
     *
     * @return string               Actual step number
     * @access public
     */
    public function getPosition($step_id=null)
    {
        // Get current step id if step not provided.
        if (!isset($step_id)) {
            $step_id = $this->current_step_id;
        }
        if (is_numeric($step_id) && isset($_SESSION[$this->seq]['steps'][$step_id])) {
            // Step ID provided is a number...go directly to key.
            return $step_id;
        } else {
            // Step ID is a string. Loop through searching for match.
            foreach ($_SESSION[$this->seq]['steps'] as $pos=>$step) {
                if ($step['id'] == $step_id) {
                    return $pos;
                }
            }
            // Step not found matching ID.
            return null;
        }
    }

    /**
     * Returns the ID of the step with required=true and completed=false
     * and active=true that falls before specified step_id.
     *
     * @param  string $curr_step_id ID or number of current step.
     * @return string               Prerequisite step ID or false if none.
     * @access public
     */
    public function getRequiredID($curr_step_id)
    {
        if ('' === $curr_step_id) {
            return $this->current_step_id;
        }
        foreach ($_SESSION[$this->seq]['steps'] as $pos=>$step) {
            if (is_numeric($curr_step_id) && $pos == $curr_step_id && $step['active']) {
                return $curr_step_id;
            } else if ($step['id'] == $curr_step_id && $step['active']) {
                return $curr_step_id;
            }
            if ($step['active'] && $step['required'] && !$step['completed']) {
                return $step['id'];
            }
        }
        return $curr_step_id;
    }

    /**
     * Returns the next step in the steps array or the first active required
     * uncompleted step.
     *
     * @return string  Step identifier of the next step.
     * @access public
     */
    public function getNextID()
    {
        // Loop through all steps.
        foreach ($_SESSION[$this->seq]['steps'] as $pos=>$step) {
            // If a step is found that is active, required, and not completed, we must do that one.
            if ($step['active'] && $step['required'] && !$step['completed']) {
                return $step['id'];
            }
            // Otherwise do the first step after the current one that is active.
            if ($step['active'] && $pos > $this->getPosition()) {
                return $step['id'];
            }
        }
        return null;
    }

    /**
     * To set a set as 'completed'.
     * @return string  Step identifier of the next step.
     * @access public
     */
    public function complete($step_id=null)
    {
        $pos = isset($step_id) ? $this->getPosition($step_id) : $this->getPosition();
        $_SESSION[$this->seq]['steps'][$pos]['completed'] = true;
    }

    /**
     * Prints the a link that returns to the form for a step.
     *
     * @param  string $form_type  'form' or 'disp'.
     * @param  string $step_id    ID of step.
     * @return string             Filename of template.
     * @access public
     */
    public function printEditLink($step_id=null)
    {
        $app =& App::getInstance();

        $pos = isset($step_id) ? $this->getPosition($step_id) : $this->getPosition();
        if ($_SESSION[$this->seq]['steps'][$pos]['editable']) {
            printf('[<a href="%s">%s</a>]', $app->oHREF($_SERVER['PHP_SELF'] . '?step=' . $pos . '&boomerang=confirmation'), _("edit"));
        }
    }

    /**
     * Saves given $step_data (usually coming from $_POST) into $_SESSION
     * array with the $step_id as the key.
     *
     * @param  string $step_id   ID of current step.
     * @param  mixed  $step_data Data to place into session storage.
     * @return string  Step identifier of the next step.
     * @access public
     */
    public function setDataDefault($data_key, $data_val)
    {
        if (!isset($_SESSION[$this->seq]['data'][$data_key])) {
            $_SESSION[$this->seq]['data'][$data_key] = $data_val;
            $_SESSION[$this->seq]['defaults'][$data_key] = $data_val;
        }
    }

    /**
     * Returns the value saved in $_SESSION for a specific data key.
     *
     * @param  mixed  $data_key  Key of data to return from session data.
     * @access public
     */
    public function getData($data_key=null)
    {
        if (!isset($data_key)) {
            return $_SESSION[$this->seq]['data'];
        }
        if (isset($_SESSION[$this->seq]['data'][$data_key])) {
            return $_SESSION[$this->seq]['data'][$data_key];
        } else {
            return null;
        }
    }

    /**
     * Deletes all data saved in $_SESSION.
     *
     * @param  mixed  $data_key  Key of data to return from session data.
     * @access public
     */
    public function clearData($data_key=null)
    {
        if (isset($data_key)) {
            // Clear a specific key.
            $_SESSION[$this->seq]['data'][$key] = array();
        } else {
            // Clear the whole thing.
            $_SESSION[$this->seq]['data'] = array();
        }
    }

    /**
     * Deletes all data that are older than auto_timeout. Set current time if not not expired or not set.
     */
    protected function _auto_timeout()
    {
        $app =& App::getInstance();

        if (isset($_SESSION[$this->seq]['last_access_time'])
        && $_SESSION[$this->seq]['last_access_time'] < time() - $this->idle_timeout) {
            // Session has expired, flush all vars to start over.
            $this->startOver();
            $app->dieURL($this->start_url);
        } else {
            // Set timer.
            $_SESSION[$this->seq]['last_access_time'] = time();
        }
    }

    /**
     * Saves given array (usually coming from $_POST) into $_SESSION
     *
     * @param  mixed  $step_data  Array of data to merge with session data.
     * @access public
     */
    public function registerData($step_data)
    {
        $_SESSION[$this->seq]['data'] = array_merge($_SESSION[$this->seq]['data'], $step_data);
    }

    /**
     * Reset all vars.
     *
     */
    public function startOver()
    {
        $this->current_step_id = 0;
        $_SESSION[$this->seq]['steps'] = array();
        $_SESSION[$this->seq]['data'] = array();
        $_SESSION[$this->seq]['defaults'] = array();
        $_SESSION[$this->seq]['last_access_time'] = time();
    }

} // END CLASS