<?php
/**
 * Abstract Product Class
 *
 * The WooCommerce product class handles individual product data.
 *
 * @class 		WC_Product
 * @version		1.6.4
 * @package		WooCommerce/Classes
 * @author 		WooThemes
 */
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

abstract class WC_Product {

	/** @var int The product (post) ID. */
	var $id;

	/** @var array Array of custom fields (meta) containing product data. */
	var $product_custom_fields;

	/** @var array Array of product attributes. */
	var $attributes;

	/** @var object The actual post object. */
	var $post;

	/** @var string "Yes" for downloadable products. */
	var $downloadable;

	/** @var string "Yes" for virtual products. */
	var $virtual;

	/** @var string The product SKU (stock keeping unit). */
	var $sku;

	/** @var string The product price. */
	var $price;

	/** @var string The product's visibility. */
	var $visibility;

	/** @var string The product's stock level (if applicable). */
	var $stock;

	/** @var string The product's stock status (instock or outofstock). */
	var $stock_status;

	/** @var string The product's backorder status. */
	var $backorders;

	/** @var bool True if the product is stock managed. */
	var $manage_stock;

	/** @var string The product's sale price. */
	var $sale_price;

	/** @var string The product's regular non-sale price. */
	var $regular_price;

	/** @var string The product's weight. */
	var $weight;

	/** @var string The product's length. */
	var $length;

	/** @var string The product's width. */
	var $width;

	/** @var string The product's height. */
	var $height;

	/** @var string The product's tax status. */
	var $tax_status;

	/** @var string The product's tax class. */
	var $tax_class;

	/** @var array Array of product ID's being up-sold. */
	var $upsell_ids;

	/** @var array Array of product ID's being cross-sold. */
	var $crosssell_ids;

	/** @var string The product's type (simple, variable etc). */
	var $product_type;

	/** @var string Date a sale starts. */
	var $sale_price_dates_from;

	/** @var string Data a sale ends. */
	var $sale_price_dates_to;

	/** @var string "Yes" for featured products. */
	var $featured;

	/** @var string Shipping class slug for the product. */
	var $shipping_class;

	/** @var int Shipping class ID for the product. */
	var $shipping_class_id;

	/** @var string Formatted LxWxH. */
	var $dimensions;


	/**
	 * __construct function.
	 *
	 * @access public
	 * @param mixed $product
	 */
	function __construct( $product ) {
		if ( is_object( $product ) ) {
			$this->id = absint( $product->ID );
			$this->post = $product;
		} else {
			$this->id = absint( $product );
		}
	}


	/**
	 * Load the data from the custom fields
	 *
	 * @access public
	 * @param mixed $fields
	 * @return void
	 */
	function load_product_data( $fields ) {
		if ( $fields )
			foreach ( $fields as $key => $default )
				$this->$key = isset( $this->product_custom_fields[ '_' . $key ][0] ) && $this->product_custom_fields[ '_' . $key ][0] !== '' ? $this->product_custom_fields[ '_' . $key ][0] : $default;
	}


	/**
     * Get SKU (Stock-keeping unit) - product unique ID.
     *
     * @return string
     */
    function get_sku() {
        return $this->sku;
    }


    /**
     * Returns number of items available for sale.
     *
     * @access public
     * @return int
     */
    function get_stock_quantity() {
    	if ( ! $this->managing_stock() )
    		return '';

        return apply_filters( 'woocommerce_stock_amount', $this->stock );
    }


    /**
     * Get total stock.
     *
     * @access public
     * @return int
     */
    function get_total_stock() {
		return $this->get_stock_quantity();
    }


	/**
	 * Reduce stock level of the product.
	 *
	 * @access public
	 * @param int $by (default: 1) Amount to reduce by.
	 * @return int Stock
	 */
	function reduce_stock( $by = 1 ) {
		global $woocommerce;

		if ( $this->managing_stock() ) {
			$this->stock = $this->stock - $by;
			update_post_meta( $this->id, '_stock', $this->stock );

			// Out of stock attribute
			if ( $this->managing_stock() && ! $this->backorders_allowed() && $this->get_total_stock() <= 0 )
				$this->set_stock_status( 'outofstock' );

			$woocommerce->clear_product_transients( $this->id ); // Clear transient

			do_action(  );

			return $this->get_stock_quantity();
		}
	}


	/**
	 * Increase stock level of the product.
	 *
	 * @access public
	 * @param int $by (default: 1) Amount to increase by
	 * @return int Stock
	 */
	function increase_stock( $by = 1 ) {
		global $woocommerce;

		if ( $this->managing_stock() ) {
			$this->stock = $this->stock + $by;
			update_post_meta( $this->id, '_stock', $this->stock );

			// Out of stock attribute
			if ( $this->managing_stock() && ( $this->backorders_allowed() || $this->get_total_stock() > 0 ) )
				$this->set_stock_status( 'instock' );

			$woocommerce->clear_product_transients( $this->id ); // Clear transient

			return $this->get_stock_quantity();
		}
	}


	/**
	 * set_stock_status function.
	 *
	 * @access public
	 * @return void
	 */
	function set_stock_status( $status ) {
		$status = 'outofstock' ? 'outofstock' : 'instock';

		if ( $this->stock_status != $status ) {
			update_post_meta( $this->id, '_stock_status', $status );

			do_action( 'woocommerce_product_set_stock_status', $this->id, $status );
		}
	}


	/**
	 * Checks the product type.
	 *
	 * Backwards compat with downloadable/virtual.
	 *
	 * @access public
	 * @param mixed $type Array or string of types
	 * @return bool
	 */
	function is_type( $type ) {
		if ( $this->product_type == $type || ( is_array( $type ) && in_array( $this->product_type, $type ) ) ) return true;
		return false;
	}


	/**
	 * Checks if a product is downloadable
	 *
	 * @access public
	 * @return bool
	 */
	function is_downloadable() {
		return $this->downloadable == 'yes' ? true : false;
	}


	/**
	 * Check if downloadable product has a file attached.
	 *
	 * @since 1.6.2
	 *
	 * @access public
	 * @param string $download_id file identifier
	 * @return bool Whether downloadable product has a file attached.
	 */
	function has_file( $download_id = '' ) {
		if ( ! $this->is_downloadable() )
			return false;

		if ( $this->get_file_download_path( $download_id ) )
			return true;

		return false;
	}


	/**
	 * Get file download path identified by $download_id
	 *
	 * @access public
	 * @param string $download_id file identifier
	 * @return array
	 */
	function get_file_download_path( $download_id ) {

		$file_paths = isset( $this->product_custom_fields['_file_paths'][0] ) ? $this->product_custom_fields['_file_paths'][0] : '';
		$file_paths = apply_filters( 'woocommerce_file_download_paths', $file_paths, $this->id, null, null );

		if ( ! $download_id && count( $file_paths ) == 1 ) {
			// backwards compatibility for old-style download URLs and template files
			$file_path = array_shift( $file_paths );
		} elseif ( isset( $file_paths[ $download_id ] ) ) {
			$file_path = $file_paths[ $download_id ];
		} else {
			$file_path = '';
		}

		// allow overriding based on the particular file being requested
		return apply_filters( 'woocommerce_file_download_path', $file_path, $this->id, $download_id );
	}


	/**
	 * Checks if a product is virtual (has no shipping).
	 *
	 * @access public
	 * @return bool
	 */
	function is_virtual() {
		return $this->virtual == 'yes' ? true : false;
	}


	/**
	 * Checks if a product needs shipping.
	 *
	 * @access public
	 * @return bool
	 */
	function needs_shipping() {
		return $this->is_virtual() ? false : true;
	}


	/**
	 * Check if a product is sold individually (no quantities)
	 *
	 * @access public
	 * @return bool
	 */
	function is_sold_individually() {
		$return = false;

		// Sold individually if downloadable, virtual, and the option is enabled OR if intentionally a singular item
		if ( 'yes' == get_post_meta( $this->id, '_sold_individually', true ) || ( $this->is_downloadable() && $this->is_virtual() && get_option('woocommerce_limit_downloadable_product_qty') == 'yes'  ) || ( ! $this->backorders_allowed() && $this->get_stock_quantity() == 1 ) ) {
			$return = true;
		}

		return apply_filters( 'woocommerce_is_sold_individually', $return, $this );
	}

	/**
	 * get_children function.
	 *
	 * @access public
	 * @return bool
	 */
	function get_children() {
		return array();
	}


	/**
	 * Returns whether or not the product has any child product.
	 *
	 * @access public
	 * @return bool
	 */
	function has_child() {
		return false;
	}


	/**
	 * Returns whether or not the product post exists.
	 *
	 * @access public
	 * @return bool
	 */
	function exists() {
		global $wpdb;

		return ! empty( $this->post ) || $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE ID = %d LIMIT 1;", $this->id ) ) > 0 ? true : false;
	}


	/**
	 * Returns whether or not the product is taxable.
	 *
	 * @access public
	 * @return bool
	 */
	function is_taxable() {
		return $this->tax_status == 'taxable' && get_option('woocommerce_calc_taxes') == 'yes' ? true : false;
	}


	/**
	 * Returns whether or not the product shipping is taxable.
	 *
	 * @access public
	 * @return bool
	 */
	function is_shipping_taxable() {
		return $this->tax_status=='taxable' || $this->tax_status=='shipping' ? true : false;
	}


	/**
	 * Get the product's post data.
	 *
	 * @access public
	 * @return object
	 */
	function get_post_data() {
		if ( empty( $this->post ) )
			$this->post = get_post( $this->id );
		return $this->post;
	}


	/**
	 * Get the title of the post.
	 *
	 * @access public
	 * @return string
	 */
	function get_title() {
		$this->get_post_data();
		return apply_filters( 'woocommerce_product_title', apply_filters( 'the_title', $this->post->post_title, $this->id ), $this );
	}


	/**
	 * Get the parent of the post.
	 *
	 * @access public
	 * @return int
	 */
	function get_parent() {
		$this->get_post_data();
		return apply_filters('woocommerce_product_parent', $this->post->post_parent, $this);
	}


	/**
	 * Get the add to url.
	 *
	 * @access public
	 * @return string
	 */
	function add_to_cart_url() {
		return apply_filters( 'woocommerce_add_to_cart_url', add_query_arg( 'add-to-cart', $this->id ) );
	}


	/**
	 * Returns whether or not the product is stock managed.
	 *
	 * @access public
	 * @return bool
	 */
	function managing_stock() {
		if ( ! isset( $this->manage_stock ) || $this->manage_stock == 'no' ) return false;
		if ( get_option('woocommerce_manage_stock') == 'yes' ) return true;
		return false;
	}


	/**
	 * Returns whether or not the product is in stock.
	 *
	 * @access public
	 * @return bool
	 */
	function is_in_stock() {
		if ( $this->managing_stock() ) :
			if ( ! $this->backorders_allowed() ) :
				if ( $this->get_total_stock() <  1 ) :
					return false;
				else :
					if ( $this->stock_status == 'instock' ) return true;
					return false;
				endif;
			else :
				return true;
			endif;
		endif;
		if ( $this->stock_status == 'instock' ) return true;
		return false;
	}


	/**
	 * Returns whether or not the product can be backordered.
	 *
	 * @access public
	 * @return bool
	 */
	function backorders_allowed() {
		return $this->backorders=='yes' || $this->backorders=='notify' ? true : false;
	}


	/**
	 * Returns whether or not the product needs to notify the customer on backorder.
	 *
	 * @access public
	 * @return bool
	 */
	function backorders_require_notification() {
		return $this->managing_stock() && $this->backorders=='notify' ? true : false;
	}


	/**
	 * is_on_backorder function.
	 *
	 * @access public
	 * @param int $qty_in_cart (default: 0)
	 * @return bool
	 */
	function is_on_backorder( $qty_in_cart = 0 ) {
		return $this->managing_stock() && $this->backorders_allowed() && ( $this->get_total_stock() - $qty_in_cart ) < 0 ? true : false;
	}


	/**
	 * Returns whether or not the product has enough stock for the order.
	 *
	 * @access public
	 * @param mixed $quantity
	 * @return bool
	 */
	function has_enough_stock( $quantity ) {
		return ! $this->managing_stock() || $this->backorders_allowed() || $this->stock >= $quantity ? true : false;
	}


	/**
	 * Returns the availability of the product.
	 *
	 * @access public
	 * @return string
	 */
	function get_availability() {

		$availability = "";
		$class = "";

		if (!$this->managing_stock()) :
			if (!$this->is_in_stock()) :
				$availability = __( 'Out of stock', 'woocommerce' );
				$class = 'out-of-stock';
			endif;
		else :
			if ($this->is_in_stock()) :
				if ( $this->get_total_stock() > 0 ) :

					$format_option = get_option( 'woocommerce_stock_format' );

					switch ( $format_option ) {
						case 'no_amount' :
							$format = __( 'In stock', 'woocommerce' );
						break;
						case 'low_amount' :
							$low_amount = get_option( 'woocommerce_notify_low_stock_amount' );

							$format = ( $this->get_total_stock() <= $low_amount ) ? __( 'Only %s left in stock', 'woocommerce' ) : __( 'In stock', 'woocommerce' );
						break;
						default :
							$format = __( '%s in stock', 'woocommerce' );
						break;
					}

					$availability = sprintf( $format, $this->stock );

					if ($this->backorders_allowed() && $this->backorders_require_notification()) :
						$availability .= ' ' . __( '(backorders allowed)', 'woocommerce' );
					endif;

				else :

					if ($this->backorders_allowed()) :
						if ($this->backorders_require_notification()) :
							$availability = __( 'Available on backorder', 'woocommerce' );
							$class = 'available-on-backorder';
						else :
							$availability = __( 'In stock', 'woocommerce' );
						endif;
					else :
						$availability = __( 'Out of stock', 'woocommerce' );
						$class = 'out-of-stock';
					endif;

				endif;
			else :
				if ($this->backorders_allowed()) :
					$availability = __( 'Available on backorder', 'woocommerce' );
					$class = 'available-on-backorder';
				else :
					$availability = __( 'Out of stock', 'woocommerce' );
					$class = 'out-of-stock';
				endif;
			endif;
		endif;

		return apply_filters( 'woocommerce_get_availability', array( 'availability' => $availability, 'class' => $class ), $this );
	}


	/**
	 * Returns whether or not the product is featured.
	 *
	 * @access public
	 * @return bool
	 */
	function is_featured() {
		return $this->featured == 'yes' ? true : false;
	}


	/**
	 * Returns whether or not the product is visible.
	 *
	 * @access public
	 * @return bool
	 */
	function is_visible() {

		$visible = true;

		// Out of stock visibility
		if ( get_option( 'woocommerce_hide_out_of_stock_items' ) == 'yes' && ! $this->is_in_stock() ) $visible = false;

		// visibility setting
		elseif ( $this->visibility == 'hidden' ) $visible = false;
		elseif ( $this->visibility == 'visible' ) $visible = true;

		// Visibility in loop
		elseif ( $this->visibility == 'search' && is_search() ) $visible = true;
		elseif ( $this->visibility == 'search' && ! is_search() ) $visible = false;
		elseif ( $this->visibility == 'catalog' && is_search() ) $visible = false;
		elseif ( $this->visibility == 'catalog' && ! is_search() ) $visible = true;

		return apply_filters( 'woocommerce_product_is_visible', $visible, $this->id );
	}


	/**
	 * Returns whether or not the product is on sale.
	 *
	 * @access public
	 * @return bool
	 */
	function is_on_sale() {
		return $this->sale_price && $this->sale_price == $this->price ? true : false;
	}


	/**
	 * Returns the product's weight.
	 *
	 * @access public
	 * @return string
	 */
	function get_weight() {
		if ( $this->weight ) return $this->weight;
	}


	/**
	 * Set a products price dynamically.
	 *
	 * @access public
	 * @param float $price Price to set.
	 * @return void
	 */
	function set_price( $price ) {
		$this->price = $price;
	}


	/**
	 * Adjust a products price dynamically.
	 *
	 * @access public
	 * @param float $price Price to increase by.
	 * @return void
	 */
	function adjust_price( $price ) {
		if ( $price > 0 ) :
			$this->price += $price;
		endif;
	}


	/**
	 * Returns the product's price.
	 *
	 * @access public
	 * @return string
	 */
	function get_price() {
		return apply_filters( 'woocommerce_get_price', $this->price, $this );
	}


	/**
	 * Returns false if the product cannot be bought.
	 *
	 * @access public
	 * @return cool
	 */
	function is_purchasable() {

		$purchasable = true;

		// Products must exist of course
		if ( ! $this->exists() )
			$purchasable = false;

		// Other products types need a price to be set
		elseif ( $this->get_price() === '' )
			$purchasable = false;

		return apply_filters( 'woocommerce_is_purchasable', $purchasable, $this );
	}


	/**
	 * Returns the price (excluding tax) - ignores tax_class filters since the price may *include* tax and thus needs subtracting.
	 *
	 * @access public
	 * @return string
	 */
	function get_price_excluding_tax() {

		$price = $this->get_price();

		if ( $this->is_taxable() && get_option('woocommerce_prices_include_tax')=='yes' ) :

			$_tax = new WC_Tax();

			$tax_rates 		= $_tax->get_shop_base_rate( $this->tax_class );
			$taxes 			= $_tax->calc_tax( $price, $tax_rates, true );
			$tax_amount		= $_tax->get_tax_total( $taxes );
			$price 			= round( $price - $tax_amount, 2);

		endif;

		return apply_filters( 'woocommerce_get_price_excluding_tax', $price, $this );
	}


	/**
	 * Returns the tax class.
	 *
	 * @access public
	 * @return string
	 */
	function get_tax_class() {
		return apply_filters( 'woocommerce_product_tax_class', $this->tax_class, $this );
	}


	/**
	 * Returns the tax status.
	 *
	 * @access public
	 * @return string
	 */
	function get_tax_status() {
		return $this->tax_status;
	}


	/**
	 * Returns the price in html format.
	 *
	 * @access public
	 * @param string $price (default: '')
	 * @return string
	 */
	function get_price_html( $price = '' ) {

		if ( $this->price > 0 ) {
			if ( $this->is_on_sale() && isset( $this->regular_price ) ) {

				$price .= $this->get_price_html_from_to( $this->regular_price, $this->get_price() );

				$price = apply_filters( 'woocommerce_sale_price_html', $price, $this );

			} else {

				$price .= woocommerce_price( $this->get_price() );

				$price = apply_filters( 'woocommerce_price_html', $price, $this );

			}
		} elseif ($this->price === '' ) {

			$price = apply_filters( 'woocommerce_empty_price_html', '', $this );

		} elseif ($this->price == 0 ) {

			if ( $this->is_on_sale() && isset( $this->regular_price ) ) {

				$price .= $this->get_price_html_from_to( $this->regular_price, __( 'Free!', 'woocommerce' ) );

				$price = apply_filters( 'woocommerce_free_sale_price_html', $price, $this );

			} else {

				$price = __( 'Free!', 'woocommerce' );

				$price = apply_filters( 'woocommerce_free_price_html', $price, $this );

			}

		}

		return apply_filters( 'woocommerce_get_price_html', $price, $this );
	}


	/**
	 * Functions for getting parts of a price, in html, used by get_price_html.
	 *
	 * @access public
	 * @return string
	 */
	function get_price_html_from_text() {
		return '<span class="from">' . _x('From:', 'min_price', 'woocommerce') . ' </span>';
	}


	/**
	 * Functions for getting parts of a price, in html, used by get_price_html.
	 *
	 * @access public
	 * @return string
	 */
	function get_price_html_from_to( $from, $to ) {
		return '<del>' . ((is_numeric($from)) ? woocommerce_price( $from ) : $from) . '</del> <ins>' . ((is_numeric($to)) ? woocommerce_price( $to ) : $to) . '</ins>';
	}


	/**
	 * Returns the product rating in html format - ratings are stored in transient cache.
	 *
	 * @access public
	 * @param string $location (default: '')
	 * @return void
	 */
	function get_rating_html( $location = '' ) {

		if ( $location )
			$location = '_' . $location;

		$star_size = apply_filters( 'woocommerce_star_rating_size' . $location, 16 );

		if ( false === ( $average_rating = get_transient( 'wc_average_rating_' . $this->id ) ) ) {

			global $wpdb;

			$count = $wpdb->get_var( $wpdb->prepare("
				SELECT COUNT(meta_value) FROM $wpdb->commentmeta
				LEFT JOIN $wpdb->comments ON $wpdb->commentmeta.comment_id = $wpdb->comments.comment_ID
				WHERE meta_key = 'rating'
				AND comment_post_ID = %d
				AND comment_approved = '1'
				AND meta_value > 0
			"), $this->id );

			$ratings = $wpdb->get_var( $wpdb->prepare("
				SELECT SUM(meta_value) FROM $wpdb->commentmeta
				LEFT JOIN $wpdb->comments ON $wpdb->commentmeta.comment_id = $wpdb->comments.comment_ID
				WHERE meta_key = 'rating'
				AND comment_post_ID = %d
				AND comment_approved = '1'
			"), $this->id );

			if ( $count > 0 )
				$average_rating = number_format($ratings / $count, 2);
			else
				$average_rating = '';

			set_transient( 'wc_average_rating_' . $this->id, $average_rating );
		}

		if ( $average_rating > 0 )
			return '<div class="star-rating" title="' . sprintf( __( 'Rated %s out of 5', 'woocommerce' ), $average_rating ) . '"><span style="width:' . ( $average_rating * $star_size ) . 'px"><span class="rating">' . $average_rating . '</span> ' . __( 'out of 5', 'woocommerce' ) . '</span></div>';
		else
			return '';
	}


	/**
	 * Returns the upsell product ids.
	 *
	 * @access public
	 * @return array
	 */
	function get_upsells() {
		return (array) maybe_unserialize( $this->upsell_ids );
	}


	/**
	 * Returns the crosssell product ids.
	 *
	 * @access public
	 * @return array
	 */
	function get_cross_sells() {
		return (array) maybe_unserialize( $this->crosssell_ids );
	}


	/**
	 * Returns the product categories.
	 *
	 * @access public
	 * @param string $sep (default: ')
	 * @param mixed '
	 * @param string $before (default: '')
	 * @param string $after (default: '')
	 * @return array
	 */
	function get_categories( $sep = ', ', $before = '', $after = '' ) {
		return get_the_term_list( $this->id, 'product_cat', $before, $sep, $after );
	}


	/**
	 * Returns the product tags.
	 *
	 * @access public
	 * @param string $sep (default: ')
	 * @param mixed '
	 * @param string $before (default: '')
	 * @param string $after (default: '')
	 * @return array
	 */
	function get_tags( $sep = ', ', $before = '', $after = '' ) {
		return get_the_term_list($this->id, 'product_tag', $before, $sep, $after);
	}


	/**
	 * Returns the product shipping class.
	 *
	 * @access public
	 * @return string
	 */
	function get_shipping_class() {
		if ( ! $this->shipping_class ) {
			$classes = get_the_terms( $this->id, 'product_shipping_class' );
			if ( $classes && ! is_wp_error( $classes ) )
				$this->shipping_class = current( $classes )->slug;
			else
				$this->shipping_class = '';
		}
		return $this->shipping_class;
	}


	/**
	 * Returns the product shipping class ID.
	 *
	 * @access public
	 * @return int
	 */
	function get_shipping_class_id() {
		if ( ! $this->shipping_class_id ) :
			$classes = get_the_terms( $this->id, 'product_shipping_class' );
			if ( $classes && ! is_wp_error( $classes ) )
				$this->shipping_class_id = current( $classes )->term_id;
			else
				$this->shipping_class_id = 0;
		endif;
		return absint( $this->shipping_class_id );
	}


	/**
	 * Get and return related products.
	 *
	 * @access public
	 * @param int $limit (default: 5)
	 * @return array Array of post IDs
	 */
	function get_related( $limit = 5 ) {
		global $woocommerce;

		// Related products are found from category and tag
		$tags_array = array(0);
		$cats_array = array(0);

		// Get tags
		$terms = wp_get_post_terms($this->id, 'product_tag');
		foreach ($terms as $term) $tags_array[] = $term->term_id;

		// Get categories
		$terms = wp_get_post_terms($this->id, 'product_cat');
		foreach ($terms as $term) $cats_array[] = $term->term_id;

		// Don't bother if none are set
		if ( sizeof($cats_array)==1 && sizeof($tags_array)==1 ) return array();

		// Meta query
		$meta_query = array();
		$meta_query[] = $woocommerce->query->visibility_meta_query();
	    $meta_query[] = $woocommerce->query->stock_status_meta_query();

		// Get the posts
		$related_posts = get_posts( apply_filters('woocommerce_product_related_posts', array(
			'orderby' 		=> 'rand',
			'posts_per_page'=> $limit,
			'post_type' 	=> 'product',
			'fields' 		=> 'ids',
			'meta_query' 	=> $meta_query,
			'tax_query' 	=> array(
				'relation' => 'OR',
				array(
					'taxonomy' 	=> 'product_cat',
					'field' 	=> 'id',
					'terms' 	=> $cats_array
				),
				array(
					'taxonomy' 	=> 'product_tag',
					'field' 	=> 'id',
					'terms' 	=> $tags_array
				)
			)
		) ) );

		$related_posts = array_diff( $related_posts, array( $this->id ), $this->get_upsells() );

		return $related_posts;
	}


	/**
	 * Returns a single product attribute.
	 *
	 * @access public
	 * @param mixed $attr
	 * @return mixed
	 */
	function get_attribute( $attr ) {
		$attributes = $this->get_attributes();

		$attr = sanitize_title( $attr );

		if ( isset( $attributes[ $attr ] ) || isset( $attributes[ 'pa_' . $attr ] ) ) {

			$attribute = isset( $attributes[ $attr ] ) ? $attributes[ $attr ] : $attributes[ 'pa_' . $attr ];

			if ( $attribute['is_taxonomy'] ) {

				return implode( ', ', woocommerce_get_product_terms( $this->id, $attribute['name'], 'names' ) );

			} else {

				return $attribute['value'];

			}

		}

		return false;
	}


	/**
	 * Returns product attributes.
	 *
	 * @access public
	 * @return array
	 */
	function get_attributes() {

		if ( ! is_array( $this->attributes ) ) {

			if (isset($this->product_custom_fields['_product_attributes'][0]))
				$this->attributes = maybe_unserialize( maybe_unserialize( $this->product_custom_fields['_product_attributes'][0] ));
			else
				$this->attributes = array();
		}

		return (array) $this->attributes;
	}


	/**
	 * Returns whether or not the product has any attributes set.
	 *
	 * @access public
	 * @return mixed
	 */
	function has_attributes() {
		if ( sizeof( $this->get_attributes() ) > 0 ) {
			foreach ( $this->get_attributes() as $attribute ) {
				if ( isset( $attribute['is_visible'] ) && $attribute['is_visible'] )
					return true;
			}
		}
		return false;
	}


	/**
	 * Returns whether or not we are showing dimensions on the product page.
	 *
	 * @access public
	 * @return bool
	 */
	function enable_dimensions_display() {
		return get_option( 'woocommerce_enable_dimension_product_attributes' ) == 'yes' ? true : false;
	}


	/**
	 * Returns whether or not the product has dimensions set.
	 *
	 * @access public
	 * @return bool
	 */
	function has_dimensions() {
		return $this->get_dimensions() ? true : false;
	}


	/**
	 * Returns whether or not the product has weight set.
	 *
	 * @access public
	 * @return bool
	 */
	function has_weight() {
		return $this->get_weight() ? true : false;
	}


	/**
	 * Returns dimensions.
	 *
	 * @access public
	 * @return string
	 */
	function get_dimensions() {
		if ( ! $this->dimensions ) :
			$this->dimensions = '';

			// Show length
			if ( $this->length ) {
				$this->dimensions = $this->length;
				// Show width also
				if ( $this->width ) {
					$this->dimensions .= ' x ' . $this->width;
					// Show height also
					if ( $this->height ) {
						$this->dimensions .= ' x ' . $this->height;
					}
				}
				// Append the unit
				$this->dimensions .= ' '.get_option('woocommerce_dimension_unit');
			}
		endif;
		return $this->dimensions;
	}


	/**
	 * Lists a table of attributes for the product page.
	 *
	 * @access public
	 * @return void
	 */
	function list_attributes() {
		woocommerce_get_template( 'single-product/product-attributes.php', array(
			'product' => $this
		) );
	}


    /**
     * Returns the main product image
     *
     * @access public
     * @param string $size (default: 'shop_thumbnail')
     * @return string
     */
    function get_image( $size = 'shop_thumbnail' ) {
    	global $woocommerce;

    	$image = '';

		if ( has_post_thumbnail( $this->id ) ) {
			$image = get_the_post_thumbnail( $this->id, $size );
		} elseif ( ( $parent_id = wp_get_post_parent_id( $this->id ) ) && has_post_thumbnail( $parent_id ) ) {
			$image = get_the_post_thumbnail( $parent_id, $size );
		} else {
			$image = woocommerce_placeholder_img( $size );
		}

		return $image;
    }


    /**
     * Checks sale data to see if the product is due to go on sale/sale has expired, and updates the main price.
     *
     * @access public
     * @return void
     */
    function check_sale_price() {

    	if ( $this->sale_price_dates_from && $this->sale_price_dates_from < current_time('timestamp') ) {

    		if ( $this->sale_price && $this->price !== $this->sale_price ) {

    			// Update price
    			$this->price = $this->sale_price;
    			update_post_meta( $this->id, '_price', $this->price );
    		}

    	}

    	if ( $this->sale_price_dates_to && $this->sale_price_dates_to < current_time('timestamp') ) {

    		if ( $this->regular_price && $this->price !== $this->regular_price ) {

    			$this->price = $this->regular_price;
    			update_post_meta( $this->id, '_price', $this->price );

				// Sale has expired - clear the schedule boxes
				update_post_meta( $this->id, '_sale_price', '' );
				update_post_meta( $this->id, '_sale_price_dates_from', '' );
				update_post_meta( $this->id, '_sale_price_dates_to', '' );
			}

    	}
    }
}