<?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/>.
 */

/**
 * Cart.inc.php
 *
 * Class description goes here...
 *
 * @author  Quinn Comendant <quinn@strangecode.com>
 * @version 1.0
 *
 * Example of use:
---------------------------------------------------------------------
$cart = new Cart();

switch (getFormData('op')) {
case 'add' :
    // User clicks an "Add to cart" button.
    if ($product_id = getFormData('product_id')) {
        $qid = $db->query("SELECT * FROM product_tbl WHERE product_id = '" . $db->escapeString($product_id) . "'");
        if ($p = mysql_fetch_assoc($qid)) {
            $cart->add($product_id, $p['price'], 1, array(
                'name' => $p['name'],
                'shipping' => $p['shipping'],
                'weight' => $p['weight'],
            ));
        }
    }
    break;

case 'remove' :
    // User clicks a "Remove item" button.
    $cart->remove(getFormData('product_id'));
    break;

case 'qty' :
    // User changes the quantity of an item.
    $cart->setQty(getFormData('product_id'), getFormData('qty'));
    break;

case 'view' :
default :
    // User views cart.
    foreach ($cart->getList() as $item) {
        printf("Item: %s\nQty: %s\nPrice: %s\n\n", $item['name'], $item['quantity'], $item['price']);
    }
    break;
}
---------------------------------------------------------------------
 */
class Cart
{

    // Namespace of this instance.
    protected $_ns;

    // Configuration parameters for this object.
    protected $_params = array(
    );

    /**
     * Cart constructor.
     */
    public function __construct($namespace='')
    {
        $app =& App::getInstance();

        $this->_ns = $namespace;

        // Initialize.
        if (!isset($_SESSION['_cart'][$this->_ns])) {
            $this->clear();
        }
    }

    /**
     * Set the params of this object.
     *
     * @param  array $params   Array of param keys and values to set.
     */
    public function setParam($params=null)
    {
        if (isset($params) && is_array($params)) {
            // Merge new parameters with old overriding only those passed.
            $this->_params = array_merge($this->_params, $params);
        }
    }

    /**
     * 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;
        }
    }

    /*
    * Add an item to the cart. If called twice for one item it will add the quantities together.
    *
    * @access   public
    * @param    string  $item_id    A unique ID for the item
    * @param    float   $price      Price-per-quantity-unit for the item
    * @param    float   $quantity   Quantity of items (can be fractional unites?)
    * @param    array   $specs      An array of additional specifications (name, weight, etc)
    * @return   float               The new adjusted quantity of this item.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    11 Mar 2008 18:59:37
    */
    public function add($item_id, $price, $quantity=1, $specs=array())
    {
        $app =& App::getInstance();

        // Include any previously added items in the total quantity.
        $quantity += isset($_SESSION['_cart'][$this->_ns]['items'][$item_id]) ? $_SESSION['_cart'][$this->_ns]['items'][$item_id]['quantity'] : 0;

        // Add item with adjusted quantity and merge in additional specs.
        $_SESSION['_cart'][$this->_ns]['items'][$item_id] = array_merge($specs, array(
            'quantity' => $quantity,
            'price' => $price,
            'extended_price' => $quantity * $price,
        ));

        $app->logMsg(sprintf('Added %s %s to cart (%s)', $quantity, $item_id, truncate(getDump($specs, true), 128, 'end')), LOG_DEBUG, __FILE__, __LINE__);

        return $quantity;
    }

    /*
    * Set the absolute quantity value of a specified item in a cart.
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    10 May 2008 16:42:25
    */
    public function setQty($item_id, $quantity)
    {
        if ($quantity <= 0) {
            $this->remove($item_id);
        } else {
            if (isset($_SESSION['_cart'][$this->_ns]['items'][$item_id])) {
                $item = $_SESSION['_cart'][$this->_ns]['items'][$item_id];
                $_SESSION['_cart'][$this->_ns]['items'][$item_id] = array_merge($item, array(
                    'quantity' => $quantity,
                    'extended_price' => $quantity * $item['price'],
                ));
                return true;
            } else {
                return false;
            }
            return true;
        }
    }

    /*
    * Set the absolute price value of a specified item in a cart.
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    10 May 2008 16:42:25
    */
    public function setPrice($item_id, $price)
    {
        if (isset($_SESSION['_cart'][$this->_ns]['items'][$item_id])) {
            $item = $_SESSION['_cart'][$this->_ns]['items'][$item_id];
            $_SESSION['_cart'][$this->_ns]['items'][$item_id] = array_merge($item, array(
                'price' => $price,
                'extended_price' => $price * $item['quantity'],
            ));
            return true;
        } else {
            return false;
        }
    }

    /*
    * Remove an item from the cart.
    *
    * @access   public
    * @param    string  $item_id    Item to remove from cart.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    11 Mar 2008 18:59:48
    */
    public function remove($item_id)
    {
        $app =& App::getInstance();

        if (isset($_SESSION['_cart'][$this->_ns]['items'][$item_id])) {
            unset($_SESSION['_cart'][$this->_ns]['items'][$item_id]);
            $app->logMsg(sprintf('Removed %s from cart', $item_id), LOG_DEBUG, __FILE__, __LINE__);
            return true;
        } else {
            return false;
        }
    }

    /*
    * Return the value matching key for a specified item.
    *
    * @access   public
    * @param    string  $item_id    The ID of the cart item to retrieve.
    * @param    string  $spec_key   The key of the value to return.
    * @return   mixed               The value, or false if not found.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    11 Mar 2008 18:59:55
    */
    public function get($item_id, $spec_key)
    {
        if (isset($_SESSION['_cart'][$this->_ns]['items'][$item_id][$spec_key])) {
            return $_SESSION['_cart'][$this->_ns]['items'][$item_id][$spec_key];
        }
        return false;
    }

    /*
    * Return an array of the items in cart.
    *
    * @access   public
    * @return   array   Array of cart items.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    11 Mar 2008 18:59:55
    */
    public function getList()
    {
        return $_SESSION['_cart'][$this->_ns]['items'];
    }

    /*
    * Return the sum of the numeric values stored under the specified key for cart items.
    * 0 will be returned if key is invalid or not filled with numeric values.
    * Most commonly, $cart->sum() will be called when checking out to retrieve the total
    * cost of the items in the cart.
    *
    * @access   public
    * @param    string  $key    The spec key to sum.
    * @return   float           The total added by all the found values.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    11 Mar 2008 19:00:12
    */
    public function sum($key='extended_price')
    {
        $sum = 0;
        switch ($key) {
        case 'items' :
            $sum = sizeof($_SESSION['_cart'][$this->_ns]['items']);
            break;

        case 'extended_price' :
            foreach ($_SESSION['_cart'][$this->_ns]['items'] as $item_id => $specs) {
                $sum += isset($specs[$key]) && is_numeric($specs[$key]) ? $specs[$key] : 0;
            }
            break;

        default :
            // Retrieve arbitrary values stored in the cart (shipping, air miles, etc).
            foreach ($_SESSION['_cart'][$this->_ns]['items'] as $item_id => $specs) {
                $sum += isset($specs[$key]) && is_numeric($specs[$key]) ? $specs[$key] * $specs['quantity'] : 0;
            }
            break;
        }

        return $sum;
    }

    /**
     * Resets the $_SESSION cart array. This should be executed with the same consideration
     * as $auth->clear(), such as when logging out.
     */
    public function clear()
    {
        $app =& App::getInstance();

        $_SESSION['_cart'][$this->_ns] = array(
            'items' => array(),
        );

        $app->logMsg(sprintf('Cleared %s cart', $this->_ns), LOG_DEBUG, __FILE__, __LINE__);
    }
}