<?php
/**
 * Cart.inc.php 
 * Code by Strangecode :: www.strangecode.com :: This document contains copyrighted information
 */

class Cart {
	var $items;			// array of items
	var $subtotals;		// array of subtotals
	var $errors;		// array of errors
	var $total;			// total of the cart
	var $weight;		// total weight of the cart
	var $tax;			// tax, a percentage of the total
	var $delivery;		// delivery price, it depends on the weight
	var $final_price;	// $final_price = $total + $tax + $delivery
	
	var $we_charge_tax;             // bool
	var $taxrate;                   // array, key is location identifyer (state, etc) val is the percentage (7.25, etc)
	var $default_delivery_method;   // string, an identifyer for default shipping
	var $default_delivery_zone;     // integer, the default world zone for calculating shipping before the customer specifies actual
	var $shiprate;                  // array, shipping rates. See below.
	
    /* Shipping rates are built upon a threshold algorithm. The lowest array (0) is tested first,
     * and if the actual weight and price are lower, we continue, otherwise that rate is used.
     * When the weight and price are not lower, we take the last matched delivery cost.
     * Examples: */
     
    /* 100g */
    // $this->shiprate["French_Postal"][1][0]["maxweight"]	= 100;
    // $this->shiprate["French_Postal"][1][0]["cost"]		= 1.04;
    // $this->shiprate["French_Postal"][2][0]["maxweight"]	= 100;
    // $this->shiprate["French_Postal"][2][0]["cost"]		= 1.14;
    
    /* 200g */
    // $this->shiprate["French_Postal"][1][1]["maxweight"]	= 200;
    // $this->shiprate["French_Postal"][1][1]["cost"]		= 1.98;
    // $this->shiprate["French_Postal"][2][1]["maxweight"]	= 200;
    // $this->shiprate["French_Postal"][2][1]["cost"]		= 2.06;
	
    function Cart()
    {
        $this->init();
    }
    
    /**
     * initialize (and reset) a shopping cart
     */
    function init()
    {
        $this->items = array();
        $this->subtotals = array();
        $this->total = 0;
        $this->weight = 0;
        $this->tax = 0;
        $this->delivery = 0;
        $this->final_price = 0;
    }
    
    /**
     * Checks item quantity in stock to make sure there are enough. Returns 
     * the total number of items in stock.
     *
     * @param  mixed $product_id   id of the item to check
     *
     * @return int   the number of items in stock, 0 if none
     */
    function inventory($product_id)
    {
        $qid = dbQuery("SELECT qty_in_stock FROM product_tbl WHERE product_id = '$product_id'");
        $in_stock = mysql_fetch_row($qid);
        return $in_stock[0];
    }
    
    /**
     * Add $qty items to the shopping cart, adding to the number already selected.
     * If there are not enough items in stock, the total number of items in stock are set.
     * Returns the quantity it was set to.
     *
     * @param  mixed $product_id   the id of the item to add
     * @param  int   $qty         the quantity of items to add
     *
     * @return int    the number of items that were added. May not be the
     *                same number as were requested if not enough are available
     */
    function addItem(&$product_id, $qty)
    {
        $in_stock = $this->inventory($product_id);
        $new_qty = $this->items[$product_id] + $qty;
        if ($new_qty <= $in_stock && isset($product_id)) {
            /* If there are enough items in stock and the product id is specified, we add them to the cart */
            $this->items[$product_id] = $new_qty;
        } else {
            /* Otherwise we set the qty to the actual number of items in stock */
            $new_qty = $in_stock;
            $this->items[$product_id] = $new_qty;
        }
        return $new_qty;
    }
    
    /**
     * Set the quantity of a product in the cart to a specified value.
     * Returns the quantity it was set to.
     *
     * @param  mixed $product_id   the id of the item to set
     * @param  int   $new_qty      the quantity of items to set
     *
     * @return int    the number of items that the cart was set to. May not be the
     *                same number as were requested if not enough are available
     */
    function setItemQty(&$product_id, $new_qty)
    {
        $in_stock = $this->inventory($product_id);
        if ($new_qty <= $in_stock && isset($product_id)) {
            $this->items[$product_id] = (int) $new_qty;
        } else {
            $new_qty = $in_stock;
            $this->items[$product_id] = $new_qty;
        }
        return $new_qty;
    }
    
    /**
     * this function will remove a given product from the cart
     *
     * @param  mixed $product_id   item id to remove
     */
    function removeItem(&$product_id)
    {
        if (isset($product_id)) {
            unset($this->items[$product_id]);
        }
    }
    
    /**
     * this function will clean up the cart, removing items with invalid product
     * id's (non-numeric ones) and products with quantities less than 1.
     */
    function cleanup()
    {
        foreach ($this->items as $product_id => $qty) {
            if ($qty < 1) {
                unset($this->items[$product_id]);
            }
        }
    }
    
    /**
     * Returns the total number of individual items in the shopping cart 
     * (note, this takes into account the quantities of the items as well).
     * If a product_id is specified, returns the count of just that item.
     *
     * @param  mixed $product_id   optional id of item to count
     *
     * @return int      the number of items in the cart
     */
    function itemCount($product_id='')
    {
        $count = 0;
        
        if (empty($product_id)) {
            foreach ($this->items as $item => $qty) {
                $count += $qty;
            }
        } else {
            foreach ($this->items as $item => $qty) {
                if ($product_id == $item) {
                    $count += $qty;
                }
            }
        }
    
        return $count;
    }
    
    /**
     * Return a comma delimited list of all the products in the cart, this will
     * be used for queries, eg. SELECT id, price FROM products WHERE id IN ...
     *
     * @return string    a comma delimited list of the item ids in the cart
     */
    function getProductidList()
    {
        $comma = '';
        foreach ($this->items as $product_id => $qty) {
            $product_id_list .= $comma . "'" . $product_id . "'";
            $comma = ',';
        }
        return $product_id_list;
    }
    
    /**
     * return an array of all the items in the shopping cart 
     *
     * @return array    a 2-dimentional array, containing the result set of the query
     */
    function getCartItems()
    {    
        $in_clause = $this->getProductidList();
        if (empty($in_clause)) {
            return array();
        }
        $qid = dbQuery("
            SELECT *
            FROM product_tbl
            WHERE product_id IN ($in_clause)
        ");
        while ($row = mysql_fetch_assoc($qid)) {
            $ret[] = $row;
        }
        return $ret;
    }
    
    /**
     * recalculate the total for the shopping cart, we will also do some cleanup
     * and remove invalid items from the cart.  we have to query the database to
     * get the prices, so instead of making one query for each product in the
     * basket, we will gather up all the ID's we are interested in and run one
     * query to get all the products we care about (using $in_clause).
     *
     * @return bool true on success, false on failure
     */
    function recalculateTotal()
    {
        $this->total = 0;
        $this->weight = 0;
        $this->tax = 0;
        $this->delivery = 0;
        $this->final_price = 0;
    
        $in_clause = $this->getProductidList();
        if (empty($in_clause)) {
            return;
        }
    
        $qid = dbQuery("SELECT product_id, retail_price, weight FROM product_tbl WHERE product_id IN ($in_clause)");
        while ($product = mysql_fetch_object($qid)) {
            $this->subtotals[$product->product_id] = $this->items[$product->product_id] * $product->retail_price;
            $this->total += $this->subtotals[$product->product_id];
            $this->weight += $this->items[$product->product_id] * $product->weight;
        }
        
        $this->delivery = $this->getDeliveryCost($this->weight);
        $this->tax = $this->getTaxCost($this->total);
    
        $this->final_price = $this->total + $this->tax + $this->delivery;
    }
    
    /**
     * Returns the cost of delivery based on the supplied variables.
     *
     * @param  float  $total_weight   weight of all items combined
     *
     * @param  string $delivery_type  optional delivery type to return the cost 
     *                                for this type of delivery. could be used
     *                                to show a price for each method available.
     *                                
     * @param  string $zone           optional zone for getting a specific price
     *
     * @return float  the cost of delivery
     */
    function getDeliveryCost($total_weight, $delivery_type='', $zone='')
    {
        global $_SESSION;
        
        if ($total_weight == 0) {
            return 0;
        }
        
        setDefault($_SESSION['app']['orderinfo']['delivery_type'], $this->default_delivery_method);
        if (empty($delivery_type)) { $delivery_type = $_SESSION['app']['orderinfo']['delivery_type']; }
        
        setDefault($_SESSION['app']['orderinfo']['delivery_zone'], $this->default_delivery_zone);
        if (empty($zone)) { $zone = $_SESSION['app']['orderinfo']['delivery_zone'];	}
        
        if ($zone == 0) { $zone = $this->default_delivery_zone; }
        for ($i=sizeof($this->shiprate[$delivery_type][$zone]); $i>=0; $i--) {
            if ($total_weight <= $this->shiprate[$delivery_type][$zone][$i]['maxweight']) { // && $this->total <= $this->shiprate[$delivery_type][$zone][$i]['maxprice']
                $delivery_cost = $this->shiprate[$delivery_type][$zone][$i]['cost'];
            }
        }
        
        return $delivery_cost;
    }
    
    /**
     * Returns the cost of tax based on the default US billing state. CA is set here.
     *
     * @param  float $total   the total cost of this order before tax or shipping
     *
     * @return float    the cost of the tax
     */
    function getTaxCost($total)
    {
        global $_SESSION;
        
        if (!$this->we_charge_tax) {
            return 0;
        }
        
        setDefault($_SESSION['app']['orderinfo']['bill_state'], 'CA');
        
        foreach ($this->taxrate as $state => $rate) {
            if (eregi($state, $_SESSION['app']['orderinfo']['bill_state'])) {
                $tax = ($rate / 100) * $total;
                break;
            } else {
                $tax = 0;
            }
        }
        
        return $tax;
    }
}

?>