<?php
/**
 * Slim - a micro PHP 5 framework
 *
 * @author      Josh Lockhart <info@slimframework.com>
 * @copyright   2011 Josh Lockhart
 * @link        http://www.slimframework.com
 * @license     http://www.slimframework.com/license
 * @version     1.6.0
 * @package     Slim
 *
 * MIT LICENSE
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

 /**
  * Flash
  *
  * This is middleware for a Slim application that enables
  * Flash messaging between HTTP requests. This allows you
  * set Flash messages for the current request, for the next request,
  * or to retain messages from the previous request through to
  * the next request.
  *
  * @package    Slim
  * @author     Josh Lockhart
  * @since      1.5.2
  */
class Slim_Middleware_Flash extends Slim_Middleware implements ArrayAccess {
    /**
     * @var array
     */
    protected $settings;

    /**
     * @var array
     */
    protected $messages;

    /**
     * Constructor
     * @param   Slim  $app
     * @param   array $settings
     * @return  void
     */
    public function __construct( $settings = array() ) {
        $this->settings = array_merge(array('key' => 'slim.flash'), $settings);
        $this->messages = array(
            'prev' => array(), //flash messages from prev request (loaded when middleware called)
            'next' => array(), //flash messages for next request
            'now' => array() //flash messages for current request
        );
    }

    /**
     * Call
     * @return  void
     */
    public function call() {
        //Read flash messaging from previous request if available
        $this->loadMessages();

        //Prepare flash messaging for current request
        $env = $this->app->environment();
        $env['slim.flash'] = $this;
        $this->next->call();
        $this->save();
    }

    /**
     * Now
     *
     * Specify a flash message for a given key to be shown for the current request
     *
     * @param   string $key
     * @param   string $value
     * @return  void
     */
    public function now( $key, $value ) {
        $this->messages['now'][(string)$key] = $value;
    }

    /**
     * Set
     *
     * Specify a flash message for a given key to be shown for the next request
     *
     * @param   string $key
     * @param   string $value
     * @return  void
     */
    public function set( $key, $value ) {
        $this->messages['next'][(string)$key] = $value;
    }

    /**
     * Keep
     *
     * Retain flash messages from the previous request for the next request
     *
     * @return  void
     */
    public function keep() {
        foreach ( $this->messages['prev'] as $key => $val ) {
            $this->messages['next'][$key] = $val;
        }
    }

    /**
     * Save
     */
    public function save() {
        $_SESSION[$this->settings['key']] = $this->messages['next'];
    }

    /**
     * Load messages
     *
     * Load messages from previous request if available
     */
    public function loadMessages() {
        if ( isset($_SESSION[$this->settings['key']]) ) {
            $this->messages['prev'] = $_SESSION[$this->settings['key']];
        }
    }

    /**
     * Get messages
     *
     * Return array of flash messages to be shown for the current request
     *
     * @return array
     */
    public function getMessages() {
        return array_merge($this->messages['prev'], $this->messages['now']);
    }

    /**
     * Array Access: Offset Exists
     */
    public function offsetExists( $offset ) {
        $messages = $this->getMessages();
        return isset($messages[$offset]);
    }

    /**
     * Array Access: Offset Get
     */
    public function offsetGet( $offset ) {
        $messages = $this->getMessages();
        return isset($messages[$offset]) ? $messages[$offset] : null;
    }

    /**
     * Array Access: Offset Set
     */
    public function offsetSet( $offset, $value ) {
        $this->now($offset, $value);
    }

    /**
     * Array Access: Offset Unset
     */
    public function offsetUnset( $offset ) {
        unset($this->messages['prev'][$offset], $this->messages['now'][$offset]);
    }
}