Section214 / PrintCenter

includes/vendors/class.product-vendors.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 21 and the first side effect is on line 12.

/**
 * Bootstraps the Vendor system
 *
 * @package     PrintCenter\Vendor
 * @since       1.0.0
 */


// Exit if accessed directly
if( ! defined( 'ABSPATH' ) ) {
	exit;
}


/**
 * The main WooCommerce_Product_Vendors class
 *
 * @since       1.0.0
 */
class WooCommerce_Product_Vendors {


	/**
	 * @access      private
	 * @since       1.0.0
	 * @var         string $dir The directory containing this file
	 */
	private $dir;


	/**
	 * @access      private
	 * @since       1.0.0
	 * @var         string $file This file
	 */
	private $file;


	/**
	 * @access      private
	 * @since       1.0.0
	 * @var         string $assets_dir The directory containing the vendor assets
	 */
	private $assets_dir;


	/**
	 * @access      private
	 * @since       1.0.0
	 * @var         string $assets_url The URL of the directory containing the vendor assets
	 */
	private $assets_url;


	/**
	 * @access      public
	 * @since       1.0.0
	 * @var         string $token The prefix for vendor related hooks
	 */
	public $token;


	/**
	 * Get things started
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       string $file This file
	 * @return      void

Adding a @return annotation to constructors is generally not recommended as a constructor does not have a meaningful return value.

	 */
	public function __construct( $file ) {
		$this->dir = dirname( $file );
		$this->file = $file;
		$this->assets_dir = trailingslashit( $this->dir ) . 'assets';
		$this->assets_url = esc_url( trailingslashit( plugins_url( '/assets/', $file ) ) );
		$this->token = 'shop_vendor';

		// Register new taxonomy
		add_action( 'init', array( $this, 'register_vendors_taxonomy' ) );

		// Process commissions for order
		add_action( 'woocommerce_order_status_completed', array( $this, 'process_commissions' ), 10, 1 );
		add_action( 'woocommerce_order_status_refunded', array( $this, 'cancel_commission' ), 10, 1 );
		add_action( 'woocommerce_order_status_cancelled', array( $this, 'cancel_commission' ), 10, 1 );

		// Allow vendors access to the WP dashboard
		add_filter( 'woocommerce_prevent_admin_access', array( $this, 'allow_vendor_admin_access' ) );

		// Vendor report: Total earnings
		add_shortcode( 'product_vendors_total_earnings', array( $this, 'vendor_total_earnings_report' ) );

		// Vendor report: This month's earnings
		add_shortcode( 'product_vendors_month_earnings', array( $this, 'vendor_month_earnings' ) );

		// Setup vendor shop page (taxonomy archive)
		add_action( 'template_redirect', array( $this, 'load_product_archive_template' ) );
		add_filter( 'body_class', array( $this, 'set_product_archive_class' ) );
		add_action( 'woocommerce_archive_description', array( $this, 'product_archive_vendor_info' ) );

		// Handle commission setting on product edit page
		add_action( 'woocommerce_product_options_general_product_data', array( $this, 'add_product_settings' ) );
		add_action( 'woocommerce_process_product_meta', array( $this, 'process_product_settings' ), 10, 2 );
		add_action( 'woocommerce_product_after_variable_attributes', array( $this, 'add_variation_settings' ), 10, 2 );
		add_action( 'woocommerce_process_product_meta_variable', array( $this, 'process_variation_settings' ) );

		// Add fields to taxonomy
		add_action( $this->token . '_add_form_fields' , array( $this , 'add_vendor_fields' ) , 1 , 1 );
		add_action( $this->token . '_edit_form_fields' , array( $this , 'edit_vendor_fields' ) , 1 , 1 );
		add_action( 'edited_' . $this->token , array( $this , 'save_vendor_fields' ) , 10 , 2 );
		add_action( 'created_' . $this->token , array( $this , 'save_vendor_fields' ) , 10 , 2 );

		// Make vendor selection use checkboxes
		add_action( 'admin_menu', array( $this, 'remove_meta_box' ) );
		add_action( 'add_meta_boxes', array( $this, 'add_meta_box' ) );
		add_action( 'wp_ajax_add-' . $this->token , '_wp_ajax_add_non_hierarchical_term' );

		// Only show vendor's products in dashboard
		add_filter( 'request', array( $this, 'filter_product_list' ) );
		add_action( 'current_screen', array( $this, 'restrict_products' ) );
		add_filter( 'wp_count_posts', array( $this, 'list_table_product_counts' ), 10, 3 );
		add_filter( 'wp_count_attachments', array( $this, 'list_table_media_counts'), 10, 2 );
		add_filter( 'views_upload', array( $this, 'remove_unattached_attachments' ), 10, 1 );

		// Handle saving posts for vendors
		add_action( 'save_post', array( $this, 'add_vendor_to_product' ) );

		// Add pages to menu
		add_action( 'admin_menu', array( $this, 'vendor_menu_items' ) );

		// Handle media library restrictions
		add_filter( 'request', array( $this, 'restrict_media_library' ), 10, 1 );
		add_filter( 'ajax_query_attachments_args', array( $this, 'restrict_media_library_modal' ), 10, 1 );

		// Save vendor details
		add_action( 'admin_init', array( $this, 'vendor_details_page_save' ) );

		// Integration for WooCommerce Bookings
		add_action( 'woocommerce_new_booking', array( $this, 'add_vendor_to_booking' ), 10, 1 );
		add_filter( 'get_booking_products_args', array( $this, 'restrict_booking_products' ) );
		add_filter( 'request', array( $this, 'filter_booking_list' ) );
		add_filter( 'get_bookings_in_date_range_args', array( $this, 'filter_booking_calendar' ) );
		add_filter( 'wp_count_posts', array( $this, 'list_table_booking_counts' ), 10, 3 );

		// Add vendor pages to WooCommerce screen IDs
		add_filter( 'woocommerce_screen_ids', array( $this, 'screen_ids' ), 10, 1 );

		// Add reports to WP dashboard
		add_filter( 'woocommerce_reports_charts', array( $this, 'add_reports' ) );

		// Display admin page notices
		add_action( 'admin_notices', array( $this, 'admin_notices' ) );

		// Add settings link to plugin page
		add_filter( 'plugin_action_links_' . plugin_basename( $this->file ), array( $this, 'add_settings_link' ) );

		// Add extension settings to WooCommerce General settings tab
		add_filter( 'woocommerce_general_settings', array( $this, 'add_settings' ), 10, 1 );

		// Filter products in non-vendor shop loops
		add_action( 'pre_get_posts', array( $this, 'hide_vendor_products' ) );

		// If Product Enquiry Form is active then send enquiries to the product vendors too
		add_filter( 'product_enquiry_send_to', array( $this, 'wc_product_enquiry_to_vendor' ), 10, 2 );

		// Flush rewrite rules on plugin activation
		register_activation_hook( $this->file, array( $this, 'rewrite_flush' ) );
	}


	/**
	 * Register taxonomy for vendors
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function register_vendors_taxonomy() {
		$labels = array(
			'name'                       => __( 'Product Vendors' , 'printcenter' ),
			'singular_name'              => __( 'Vendor', 'printcenter' ),
			'menu_name'                  => __( 'Vendors' , 'printcenter' ),
			'search_items'               => __( 'Search Vendors' , 'printcenter' ),
			'all_items'                  => __( 'All Vendors' , 'printcenter' ),
			'parent_item'                => __( 'Parent Vendor' , 'printcenter' ),
			'parent_item_colon'          => __( 'Parent Vendor:' , 'printcenter' ),
			'view_item'                  => __( 'View Vendor' , 'printcenter' ),
			'edit_item'                  => __( 'Edit Vendor' , 'printcenter' ),
			'update_item'                => __( 'Update Vendor' , 'printcenter' ),
			'add_new_item'               => __( 'Add New Vendor' , 'printcenter' ),
			'new_item_name'              => __( 'New Vendor Name' , 'printcenter' ),
			'popular_items'              => __( 'Popular Vendors' , 'printcenter' ),
			'separate_items_with_commas' => __( 'Separate vendors with commas' , 'printcenter' ),
			'add_or_remove_items'        => __( 'Add or remove vendors' , 'printcenter' ),
			'choose_from_most_used'      => __( 'Choose from most used vendors' , 'printcenter' ),
			'not_found'                  => __( 'No vendors found' , 'printcenter' ),
		);

		$vendor_slug = apply_filters( 'product_vendors_vendor_slug', 'vendor' );

		$args = array(
			'public'            => true,
			'hierarchical'      => false,
			'rewrite'           => array( 'slug' => $vendor_slug ),
			'show_admin_column' => true,
			'labels'            => $labels
		);

		register_taxonomy( $this->token, 'product', $args );
	}


	/**
	 * Add vendor settings to products
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function add_product_settings() {
		global $post, $woocommerce;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		if( ! printcenter_vendor_access() ) {

			// Get current commission setting
			$commission = get_post_meta( $post->ID , '_product_vendors_commission', true );

			// Print out options fields
			$html = '<div class="options_group">
						<p class="form-field _product_vendors_commission_field">
							<label for="_product_vendors_commission">' . __( 'Vendor Commission', 'printcenter' ) . '</label>
							<input class="short" size="6" placeholder="0" type="number" name="_product_vendors_commission" id="_product_vendors_commission" value="' . $commission . '" />&nbsp;&nbsp;%
							<span class="description">' . __( 'OPTIONAL: Enter the percentage of the sale price that will go to each product vendor. If no value is entered then the vendor\'s default commission will be used.', 'printcenter' ) . '</span>
						</p>
					</div>';

			echo $html;
		}
    }


	/**
	 * Update product settings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $post_id ID of product
	 * @param       obj $post Product post object
	 * @return      void
	 */
	public function process_product_settings( $post_id, $post ) {

The parameter $post is not used and could be removed.

		$commission = 0;

		if( isset( $_POST['_product_vendors_commission'] ) ) {
			$commission = $_POST['_product_vendors_commission'];
		}

		update_post_meta( $post_id , '_product_vendors_commission' , $commission );
	}


	/**
	 * Add vendor settings to product variations
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $loop Current variation loop
	 * @param       obj $variation_data Variation data object
	 * @return      void
	 */
	public function add_variation_settings( $loop, $variation_data ) {
		$commission = isset( $variation_data['_product_vendors_commission'] ) ? $variation_data['_product_vendors_commission'] : '';

		if( isset( $commission[0] ) ) {
			$commission = $commission[0];
		}

		$html = '<tr>
					<td>
						<div class="_product_vendors_commission">
							<label for="_product_vendors_commission_' . $loop . '">' . __( 'Vendor Commission', 'printcenter' ) . ':</label>
							<input size="4" type="text" name="variable_product_vendors_commission[' . $loop . ']" id="_product_vendors_commission_' . $loop . '" value="' . $commission . '" />
						</div>
					</td>
				</tr>';

		echo $html;
	}


	/**
	 * Update product variation settings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function process_variation_settings() {
		if( isset( $_POST['variable_post_id'] ) && is_array( $_POST['variable_post_id'] ) ) {
			foreach( $_POST['variable_post_id'] as $k => $id ) {
				$commission = $_POST['variable_product_vendors_commission'][$k];
				update_post_meta( $id , '_product_vendors_commission' , $commission );
			}
		}
	}


	/**
	 * Removing default vendor meta box
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function remove_meta_box() {
		remove_meta_box( 'tagsdiv-' . $this->token, 'product', 'normal' );
	}


	/**
	 * Add new vendor meta box
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function add_meta_box() {
		if( ! printcenter_vendor_access() ) {
			$tax = get_taxonomy( $this->token );
			add_meta_box( 'tagdiv-' . $this->token, $tax->labels->name, array( $this, 'metabox_content' ), 'product', 'side', 'core' );
		}
	}

	/**
	 * Generate metabox content
	 *
	 * @access      public
	 * @param       object $post Current post object
	 * @return      void
	 */
	public function metabox_content( $post ) {
		$taxonomy = $this->token;
		$tax = get_taxonomy( $taxonomy );
		?>
		<div id="taxonomy-<?php echo $taxonomy; ?>" class="categorydiv">
			<ul id="<?php echo $taxonomy; ?>-tabs" class="category-tabs">
				<li class="tabs"><a href="#<?php echo $taxonomy; ?>-all"><?php echo $tax->labels->all_items; ?></a></li>
				<li class="hide-if-no-js"><a href="#<?php echo $taxonomy; ?>-pop"><?php _e( 'Most Used' ); ?></a></li>
			</ul>

			<div id="<?php echo $taxonomy; ?>-pop" class="tabs-panel" style="display: none;">
				<ul id="<?php echo $taxonomy; ?>checklist-pop" class="categorychecklist form-no-clear">
					<?php $popular_ids = wp_popular_terms_checklist( $taxonomy ); ?>
				</ul>
			</div>

			<div id="<?php echo $taxonomy; ?>-all" class="tabs-panel">
				<input type="hidden" name="tax_input[<?php echo $taxonomy; ?>][]" value="0" />
				<?php
				if( class_exists( 'Walker_Tag_Checklist' ) ) {
					$walker = new Walker_Tag_Checklist;
				}
				?>
				<ul id="<?php echo $taxonomy; ?>checklist" data-wp-lists="list:<?php echo $taxonomy; ?>" class="categorychecklist form-no-clear">
					<?php wp_terms_checklist($post->ID, array( 'taxonomy' => $taxonomy, 'popular_cats' => $popular_ids , 'walker' => $walker ) ) ?>

The variable $walker does not seem to be defined for all execution paths leading up to this point.

				</ul>
			</div>
			<?php if ( current_user_can($tax->cap->edit_terms) ) : ?>
				<div id="<?php echo $taxonomy; ?>-adder" class="wp-hidden-children">
					<h4>
						<a id="<?php echo $taxonomy; ?>-add-toggle" href="#<?php echo $taxonomy; ?>-add" class="hide-if-no-js">
							<?php
							/* translators: %s: add new taxonomy label */
							printf( __( '+ %s' ), $tax->labels->add_new_item );
							?>
						</a>
					</h4>
					<p id="<?php echo $taxonomy; ?>-add" class="category-add wp-hidden-child">
						<label class="screen-reader-text" for="new<?php echo $taxonomy; ?>"><?php echo $tax->labels->add_new_item; ?></label>
						<input type="text" name="new<?php echo $taxonomy; ?>" id="new<?php echo $taxonomy; ?>" class="form-required form-input-tip" value="<?php echo esc_attr( $tax->labels->new_item_name ); ?>" aria-required="true"/>
						<input type="button" id="<?php echo $taxonomy; ?>-add-submit" data-wp-lists="add:<?php echo $taxonomy ?>checklist:<?php echo $taxonomy ?>-add" class="button category-add-submit" value="<?php echo esc_attr( $tax->labels->add_new_item ); ?>" />
						<?php wp_nonce_field( 'add-' . $taxonomy, '_ajax_nonce-add-' . $taxonomy, false ); ?>
						<span id="<?php echo $taxonomy; ?>-ajax-response"></span>
					</p>
				</div>
			<?php endif; ?>
		</div>
		<?php
	}


	/**
	 * Add items to dashboard menu
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function vendor_menu_items() {
		if( printcenter_vendor_access() ) {
			add_submenu_page( 'edit.php?post_type=product', __( 'Vendor Details', 'printcenter' ), __( 'Vendor Details', 'printcenter' ), 'edit_products', 'vendor_details', array( $this, 'vendor_details_page' ) );
		}
	}

	/**
	 * Only show current vendor's media in the media library
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $request Default request arguments
	 * @return      array Modified request arguments
	 */
	public function restrict_media_library( $request = array() ) {
		if( ! is_admin() ) {
			return $request;
		}

		$screen = get_current_screen();

		if( in_array( $screen->id, array( 'upload', 'product' ) ) ) {
			if( printcenter_vendor_access() ) {
				$vendor_id = printcenter_is_vendor();

				if( ! $vendor_id ) {
					return;
				}

				$vendor_admins = printcenter_get_vendor_admins( $vendor_id );

				if( ! $vendor_admins ) {

The expression $vendor_admins of type array is implicitly converted to a boolean; are you sure this is intended? If so, consider using empty($expr) instead to make it clear that you intend to check for an array without elements.

					return;
				}

				$admins = array();

				foreach( $vendor_admins as $admin ) {
					if( ! $admin->ID ) {
						continue;
					}

					$admins[] = $admin->ID;
				}

				if( 0 == count( $admins ) ) {
					return;
				}

				$request['author__in'] = $admins;
			}
		}

		return $request;
	}


	/**
	 * Only show current vendor's media in the media library modal on the product edit screen
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $query Default query arguments
	 * @return      array Modified query arguments
	 */
	public function restrict_media_library_modal( $query = array() ) {
		if( ! is_admin() ) {
			return $query;
		}

		$screen = get_current_screen();

		if( printcenter_vendor_access() ) {
			$vendor_id = printcenter_is_vendor();

			if( ! $vendor_id ) {
				return;
			}

			$vendor_admins = printcenter_get_vendor_admins( $vendor_id );

			if( ! $vendor_admins ) {

The expression $vendor_admins of type array is implicitly converted to a boolean; are you sure this is intended? If so, consider using empty($expr) instead to make it clear that you intend to check for an array without elements.

				return;
			}

			$admins = array();

			foreach( $vendor_admins as $admin ) {
				if( ! $admin->ID ) {
					continue;
				}

				$admins[] = $admin->ID;
			}

			if( 0 == count( $admins ) ) {
				return;
			}

			$query['author__in'] = $admins;
		}

		return $query;
	}


	/**
	 * Create vendor details page for vendors to edit their own details
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function vendor_details_page() {
		$vendor         = printcenter_get_user_vendor();
		$vendor_data    = get_option( $this->token . '_' . $vendor->ID );
		$vendor_info    = printcenter_get_vendor( $vendor->ID );
		$paypal_address = '';

		if( isset( $vendor_data['paypal_email'] ) ) {
			$paypal_address = $vendor_data['paypal_email'];
		}

		echo '<div class="wrap" id="vendor_details">
				<div class="icon32" id="icon-options-general"><br/></div>
				<h2>' . __( 'Vendor Details', 'printcenter' ) . '</h2>
				<form method="post" action="" enctype="multipart/form-data">
					<input type="hidden" name="update_vendor_id" value="' . esc_attr( $vendor->ID ) . '" />
					' . wp_nonce_field( 'vendor_update', 'vendor_update_nonce', true, false ) . '
					<p class="form-field"><label for="vendor_paypal_address">' . __( 'PayPal account email address:', 'printcenter' ) . '</label> <input id="vendor_paypal_address" type="text" name="woo_vendors_paypal_address_' . $vendor->ID . '" value="' . $paypal_address . '" class="regular-text" style="width:auto;"/></p>
					<p class="form-field">
						<label for="vendor_description" style="vertical-align:top">' . __( 'Vendor description:', 'printcenter' ) . '</label>
						<textarea id="vendor_description" name="woo_vendors_description_' . $vendor->ID . '" rows="10" cols="50" class="large-text">' . $vendor_info->description . '</textarea>
					</p>';

		do_action( 'product_vendors_details_fields', $vendor->ID );

		echo '      <p class="submit">
						<input name="Submit" type="submit" class="button-primary" value="' . esc_attr( __( 'Save Details', 'printcenter' ) ) . '" />
					</p>
				</form>
			</div>';
	}


	/**
	 * Process save on vendor details submit
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function vendor_details_page_save() {
		if( isset( $_POST[ 'vendor_update_nonce' ] ) && isset( $_POST['update_vendor_id'] ) ) {
			if( ! wp_verify_nonce( $_POST['vendor_update_nonce'], 'vendor_update' ) ) {
				wp_die( __( 'Cheatin&#8217; uh?', 'printcenter' ) );
			}

			$vendor_id = $_POST['update_vendor_id'];

			if( ! $vendor_id ) {
				return;
			}

			// PayPal account email address
			$paypal_address              = $_POST[ 'woo_vendors_paypal_address_' . $vendor_id ];
			$vendor_data['paypal_email'] = $paypal_address;

$vendor_data was never initialized. Although not strictly required by PHP, it is generally a good practice to add $vendor_data = array(); before regardless.

			update_option( $this->token . '_' . $vendor_id, $vendor_data );

			// Vendor description
			$args = array(
				'description' => $_POST[ 'woo_vendors_description_' . $vendor_id ]
			);
			wp_update_term( $vendor_id, $this->token, $args );

			do_action( 'product_vendors_details_fields_save', $vendor_id, $_POST );

			$redirect = add_query_arg( 'message', 1, $_POST['_wp_http_referer'] );
			wp_safe_redirect( $redirect );
			exit;

The method vendor_details_page_save() contains an exit expression.

		}
	}


	/**
	 * Add fields to vendor taxonomy (add new vendor screen)
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       str $taxonomy Current taxonomy name
	 * @return      void
	 */
	public function add_vendor_fields( $taxonomy ) {

The parameter $taxonomy is not used and could be removed.

		global $woocommerce;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		wp_enqueue_script( 'chosen' );
		wp_enqueue_script( 'ajax-chosen' );

		$commission = 50;

		?>
		<div class="form-field">
			<label for="vendor_admins"><?php _e( 'Vendor admins (optional)', 'printcenter' ); ?></label>
			<select name="vendor_data[admins][]" id="vendor_admins" class="ajax_chosen_select_customer" multiple="multiple" style="width:95%;" placeholder="Search for users"></select><br/>
			<span class="description"><?php _e( 'A list of users who can manage this vendor\'s products and view the sales reports.', 'printcenter' ); ?></span>
		</div>

		<div class="form-field">
			<label for="vendor_commission"><?php _e( 'Commission', 'printcenter' ); ?></label>
			<input type="number" class="regular-text" name="vendor_data[commission]" id="vendor_commission" value="<?php echo esc_attr( $commission ); ?>" /> %<br/>
			<span class="description"><?php _e( 'The percent of the total sale price that this vendor will receive - can be modified per product.', 'printcenter' ); ?></span>
		</div>

		<div class="form-field">
			<label for="vendor_paypal_email"><?php _e( 'PayPal email address', 'printcenter' ); ?></label>
			<input type="text" class="regular-text" name="vendor_data[paypal_email]" id="vendor_paypal_email" value="" /><br/>
			<span class="description"><?php _e( 'The PayPal email address of the vendor where their profits will be delivered.', 'printcenter' ); ?></span>
		</div>
		<?php
		$inline_js = "
			jQuery('select.ajax_chosen_select_customer').ajaxChosen({
				method: 		'GET',
				url: 			'" . admin_url('admin-ajax.php') . "',
				dataType: 		'json',
				afterTypeDelay: 100,
				minTermLength: 	1,
				data:		{
					action: 	'woocommerce_json_search_customers',
					security: 	'" . wp_create_nonce("search-customers") . "',
					default: 	''
				}
			}, function (data) {
				var terms = {};

				$.each(data, function (i, val) {
					terms[i] = val;
				});

				return terms;
			});
		";

		// Check WC version for backwards compatibility
		if( version_compare( $woocommerce->version, '2.1-beta-1', ">=" ) ) {
			wc_enqueue_js( $inline_js );
		} else {
			$woocommerce->add_inline_js( $inline_js );
		}
	}


	/**
	 * Add fields to vendor taxonomy (edit vendor screen)
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       obj $vendor Vendor taxonomy object
	 * @return      void
	 */
	public function edit_vendor_fields( $vendor ) {
		global $woocommerce;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		wp_enqueue_script( 'chosen' );
		wp_enqueue_script( 'ajax-chosen' );

		$vendor_id     = $vendor->term_id;
		$vendor_data   = get_option( $this->token . '_' . $vendor_id );
		$vendor_admins = '';

		if( isset( $vendor_data['admins'] ) && count( $vendor_data['admins'] ) > 0 ) {
			$admins = $vendor_data['admins'];

			foreach( $admins as $k => $user_id ) {
				$user           = get_userdata( $user_id );
				$user_display   = $user->display_name . '(#' . $user_id . ' - ' . $user->user_email . ')';
				$vendor_admins .= '<option value="' . esc_attr( $user_id ) . '" selected="selected">' . $user_display . '</option>';
			}
		}

		$commission = 0;
		if( $vendor_data['commission'] || strlen( $vendor_data['commission'] ) > 0 || $vendor_data['commission'] != '' ) {
			$commission = $vendor_data['commission'];
		}

		$paypal_email = '';
		if( $vendor_data['paypal_email'] || strlen( $vendor_data['paypal_email'] ) > 0 || $vendor_data['paypal_email'] != '' ) {
			$paypal_email = $vendor_data['paypal_email'];
		}
		?>
		<tr class="form-field">
			<th scope="row" valign="top"><label for="vendor_admins"><?php _e( 'Vendor admins (optional)', 'printcenter' ); ?></label></th>
			<td>
				<select name="vendor_data[admins][]" id="vendor_admins" class="ajax_chosen_select_customer" multiple="multiple" style="width:95%;" placeholder="Search for users"><?php echo $vendor_admins; ?></select><br/>
				<span class="description"><?php _e( 'A list of users who can manage this vendor\'s products and view the sales reports.', 'printcenter' ); ?></span>
			</td>
		</tr>

		<tr class="form-field">
			<th scope="row" valign="top"><label for="vendor_commission"><?php _e( 'Commission', 'printcenter' ); ?></label></th>
			<td>
				<input type="number" class="regular-text" name="vendor_data[commission]" id="vendor_commission" value="<?php echo esc_attr( $commission ); ?>" /> %<br/>
				<span class="description"><?php _e( 'The percent of the total sale price that this vendor will receive - can be modified per product.', 'printcenter' ); ?></span>
			</td>
		</tr>

		<tr class="form-field">
			<th scope="row" valign="top"><label for="vendor_paypal_email"><?php _e( 'PayPal email address', 'printcenter' ); ?></label></th>
			<td>
				<input type="text" class="regular-text" name="vendor_data[paypal_email]" id="vendor_paypal_email" value="<?php echo esc_attr( $paypal_email ); ?>" /><br/>
				<span class="description"><?php _e( 'The PayPal email address of the vendor where their profits will be delivered.', 'printcenter' ); ?></span>
			</td>
		</tr>
		<?php

		$inline_js = "
			jQuery('select.ajax_chosen_select_customer').ajaxChosen({
				method:         'GET',
				url:            '" . admin_url('admin-ajax.php') . "',
				dataType:       'json',
				afterTypeDelay: 100,
				minTermLength:  1,
				data:       {
					action:     'woocommerce_json_search_customers',
					security:   '" . wp_create_nonce("search-customers") . "',
					default:    ''
				}
			}, function (data) {
				var terms = {};

				$.each(data, function (i, val) {
					terms[i] = val;
				});

				return terms;
			});
		";

		// Check WC version for backwards compatibility
		if( version_compare( $woocommerce->version, '2.1-beta-1', ">=" ) ) {
			wc_enqueue_js( $inline_js );
		} else {
			$woocommerce->add_inline_js( $inline_js );
		}
	}


	/**
	 * Save vendor taxonomy fields
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $vendor_id ID of vendor
	 * @return      void
	 */
	public function save_vendor_fields( $vendor_id ) {
		if ( isset( $_POST['vendor_data'] ) ) {
			$vendor_data = get_option( $this->token . '_' . $vendor_id );
			$keys        = array_keys( $_POST['vendor_data'] );

			foreach( $keys as $key ) {
				if( isset( $_POST['vendor_data'][$key] ) ) {
					$vendor_data[$key] = $_POST['vendor_data'][$key];
				}
			}

			// Get current vendor admins
			$args = array(
				'meta_key'     => 'product_vendor',
				'meta_value'   => $vendor_id,
				'meta_compare' => '='
			);

			$current_vendors = get_users( $args );

			// Remove all current admins (user meta)
			foreach( $current_vendors as $vendor ) {
				delete_user_meta( $vendor->ID, 'product_vendor' );
				$this->remove_vendor_caps( $vendor->ID );
			}

			// Remove all current admins (vendor meta)
			$vendor_data['admins'] = array();
			update_option( $this->token . '_' . $vendor_id, $vendor_data );

			// Only add selected admins
			if( isset( $_POST['vendor_data']['admins'] ) && count( $_POST['vendor_data']['admins'] > 0 ) ) {

				// Add selected admins to vendor
				$vendor_data['admins'] = $_POST['vendor_data']['admins'];

				// Get all vendors
				$vendors = printcenter_get_vendors();

				foreach( $_POST['vendor_data']['admins'] as $user_id ) {
					update_user_meta( $user_id, 'product_vendor', $vendor_id );
					$this->add_vendor_caps( $user_id );

					// Remove user from all other vendors
					if( is_array( $vendors ) && count( $vendors ) > 0 ) {
						foreach( $vendors as $v ) {
							$this_vendor = get_option( $this->token . '_' . $v->ID );

							if( isset( $this_vendor['admins'] ) && is_array( $this_vendor['admins'] ) ) {
								foreach( $this_vendor['admins'] as $k => $admin ) {
									if( $admin == $user_id ) {
										unset( $this_vendor['admins'][ $k ] );
										break;
									}
								}
							}

							update_option( $this->token . '_' . $v->ID, $this_vendor );
						}
					}
				}
			}

			// Update vendor
			update_option( $this->token . '_' . $vendor_id, $vendor_data );
		}
	}

	/**
	 * Add capabilities to vendor admins
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $user_id User ID of vendor admin
	 * @return      void
	 */
	private function add_vendor_caps( $user_id = 0 ) {
		if( $user_id > 0 ) {
			$caps = $this->vendor_caps();
			$user = new WP_User( $user_id );

			foreach( $caps as $cap ) {
				$user->add_cap( $cap );
			}
		}
	}


	/**
	 * Remove capabilities from vendor admins
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $user_id User ID of vendor admin
	 * @return      void
	 */
	private function remove_vendor_caps( $user_id = 0 ) {
		if( $user_id > 0 ) {
			$caps = $this->vendor_caps();
			$user = new WP_User( $user_id );

			foreach( $caps as $cap ) {
				$user->remove_cap( $cap );
			}
		}
	}


	/**
	 * Set up array of vendor admin capabilities
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      array $caps Vendor capabilities
	 */
	private function vendor_caps() {
		$caps = array(
			"edit_product",
			"read_product",
			"delete_product",
			"edit_products",
			"edit_others_products",
			"delete_products",
			"delete_published_products",
			"delete_others_products",
			"edit_published_products",
			"assign_product_terms",
			"upload_files",
			"manage_bookings",
		);

		$skip_review = get_option( 'woocommerce_product_vendors_skip_review' ) == 'yes' ? true : false;

		if( $skip_review ) {
			$caps[] = 'publish_products';
		}

		$caps = apply_filters( 'product_vendors_admin_caps', $caps );

		return $caps;
	}


	/**
	 * Process commission for order
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $order_id ID of order
	 * @return      void
	 */
	public function process_commissions( $order_id ) {

		// Only process commissions once
		$processed = get_post_meta( $order_id, '_commissions_processed', $single = false );

		if( $processed && $processed == 'yes' ) {
			return;
		}

		$order           = new WC_Order( $order_id );
		$include_coupons = get_option( 'woocommerce_product_vendors_include_coupons' ) == 'yes' ? true : false;
		$discounts       = array();

		if( $include_coupons ) {

			// Get order total with tax subtracted and discounts added
			$order_total    = $order->get_total();
			$order_tax      = $order->get_total_tax();
			$order_discount = $order->get_total_discount();
			$order_total    = (float) ( $order_total - $order_tax + $order_discount );
			$order_coupons  = $order->get_used_coupons();

			foreach( $order_coupons as $code ) {
				$coupon = new WC_Coupon( $code );

				if( ! $coupon->id ) {
					continue;
				}

				$coupon_amount   = (float) $coupon->amount;
				$coupon_discount = 0;

				// Work out discount based on coupon type, amount and products specified
				switch( $coupon->type ) {
					case 'fixed_cart':
						if( $coupon_amount >= $order_total ) {
							$coupon_amount = $order_total;
						}

						$coupon_discount = ( $coupon_amount / $order_total ) * 100;

						if( isset( $discounts['all']['percent'] ) ) {
							$coupon_discount += $discounts['all']['percent'];
						}

						$discounts['all']['percent'] = $coupon_discount;
						break;
					case 'percent':
						$coupon_discount = $coupon_amount;

						if( isset( $discounts['all']['percent'] ) ) {
							$coupon_discount += $discounts['all']['percent'];
						}

						$discounts['all']['percent'] = $coupon_discount;
						break;
					case 'fixed_product':
						$products = $coupon->product_ids;

						foreach( $products as $product_id ) {
							$coupon_discount = $coupon_amount;

							if( isset( $discounts[ $product_id ]['fixed'] ) ) {
								$coupon_discount += $discounts[ $product_id ]['fixed'];
							}

							$discounts[ $product_id ]['fixed'] = $coupon_amount;
						}
						break;
					case 'percent_product':
						$products = $coupon->product_ids;

						foreach( $products as $product_id ) {
							$coupon_discount = $coupon_amount;

							if( isset( $discounts[ $product_id ]['percent'] ) ) {
								$coupon_discount += $discounts[ $product_id ]['percent'];
							}

							$discounts[ $product_id ]['percent'] = $coupon_discount;
						}
						break;
				}
			}
		}

		// Get all products in order
		$items = $order->get_items( 'line_item' );

		foreach( $items as $item_id => $item ) {
			$discount_amount = 0;
			$product_id      = $order->get_item_meta( $item_id, '_product_id', true );
			$line_total      = (float) $order->get_line_subtotal( $item, false, true );

			foreach( $discounts as $product => $data ) {
				if( ! in_array( $product, array( 'all', $product_id ) ) ) {
					continue;
				}

				foreach( $data as $type => $amount ) {
					$amount = (float) $amount;

					switch( $type ) {
						case 'fixed':
							$discount_amount += (float) $amount;
							break;
						case 'percent':
							$discount_amount += (float) ( $line_total * ( $amount / 100 ) );
							break;
					}
				}
			}

			if( $product_id && $line_total ) {
				$this->record_commission( $product_id, $line_total, $discount_amount, $order_id );
			}
		}

		// Mark commissions as processed
		update_post_meta( $order_id, '_commissions_processed', 'yes' );

		do_action( 'product_vendors_commissions_processed', $order_id );

	}


	/**
	 * Record individual commission
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $product_id ID of product for commission
	 * @param       int $line_total Line total of product
	 * @param       int $discount   Total discount applied to order
	 * @param       int $order_id   ID of order
	 * @return      void
	 */
	public function record_commission( $product_id = 0, $line_total = 0, $discount = 0, $order_id = 0 ) {
		if( $product_id > 0 && $line_total > 0 ) {
			$vendors = printcenter_get_product_vendors( $product_id );

			if( $vendors ) {
				foreach( $vendors as $vendor ) {

The expression $vendors of type boolean is not traversable.

					// Get percentage for commission
					$commission = (float) printcenter_get_commission_percent( $product_id, $vendor->ID );

					// If commission is 0% then go no further
					if( ! $commission ) {
						continue;
					}

					// Subtract total discount for this line item
					$discounted_total = (float) $line_total - $discount;

					// If total is 0 after discounts then go no further
					if( ! $discounted_total ) {
						continue;
					}

					// Get total amount for commission
					$amount = (float) $discounted_total * ( $commission / 100 );

					// If commission amount is 0 then go no further
					if( ! $amount ) {
						continue;
					}

					$this->create_commission( $vendor->ID, $product_id, $amount, $order_id );
				}
			}
		}
	}


	/**
	 * Create new commission post
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $vendor_id  ID of vendor for commission
	 * @param       int $product_id ID of product for commission
	 * @param       int $amount     Commission total
	 * @param       int $order_id   ID of order
	 * @return      void
	 */
	public function create_commission( $vendor_id = 0, $product_id = 0, $amount = 0, $order_id = 0 ) {
		$commission_data = array(
			'post_type'    => 'shop_commission',
			'post_title'   => sprintf( __( 'Commission - %s', 'printcenter' ), strftime( _x( '%B %e, %Y @ %I:%M %p', 'Commission date parsed by strftime', 'printcenter' ) ) ),
			'post_status'  => 'private',
			'ping_status'  => 'closed',
			'post_excerpt' => '',
			'post_author'  => 1
		);

		$commission_id = wp_insert_post( $commission_data );

		// Add meta data
		if( $vendor_id ) { add_post_meta( $commission_id, '_commission_vendor', $vendor_id ); }
		if( $product_id ) { add_post_meta( $commission_id, '_commission_product', $product_id ); }
		if( $amount ) { add_post_meta( $commission_id, '_commission_amount', $amount ); }
		if( $order_id ) { add_post_meta( $commission_id, '_commission_order', $order_id ); }

		// Mark commission as unpaid
		add_post_meta( $commission_id, '_paid_status', 'unpaid' );

		do_action( 'product_vendors_commission_created', $commission_id );
	}


	/**
	 * Cancel commission (move to trash) - will only work for commissions created in v1.1+
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $order_id ID of orders for commissions to cancal
	 * @return      void
	 */
	public function cancel_commission( $order_id ) {
		// Get all commissions for order
		$args = array(
			'post_type'      => 'shop_commission',
			'posts_per_page' => -1,
			'post_status'    => 'any',
			'meta_key'       => '_commission_order',
			'meta_value_num' => $order_id,
		);

		$commissions = get_posts( $args );

		// Move all commission posts to trash
		foreach( $commissions as $commission ) {
			wp_trash_post( $commission->ID, false );
		}
	}


	/**
	 * Allow vendor admins to access the WP dashboard
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       bool $prevent_access Current setting
	 * @return      bool Modified setitng
	 */
	public function allow_vendor_admin_access( $prevent_access ) {
		if( printcenter_vendor_access() ) {
			$prevent_access = false;
		}

		return apply_filters( 'product_vendors_prevent_admin_access', $prevent_access );
	}


	/**
	 * Only show vendor's products
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $request Current request
	 * @return      array Modified request
	 */
	public function filter_product_list( $request ) {
		global $typenow, $current_user;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		if( is_admin() ) {
			if( ! current_user_can( 'manage_woocommerce' ) ) {
				if( printcenter_vendor_access() ) {
					if( $typenow == 'product' ) {
						wp_get_current_user();

						if( isset( $current_user->ID ) && $current_user->ID > 0 ) {
							$vendor = printcenter_get_user_vendor( $current_user->ID );

							if( $vendor->slug && strlen( $vendor->slug ) > 0 ) {
								$request[ $this->token ] = $vendor->slug;
							}
						}
					}
				}
			}
		}

		return $request;
	}


	/**
	 * Restrict vendors from editing other vendors' products
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function restrict_products() {
		global $typenow, $pagenow, $current_user;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		if( printcenter_is_vendor() && printcenter_vendor_access() ) {
			if( $pagenow == 'post.php' && $typenow == 'product' ) {
				if( isset( $_POST['post_ID'] ) ) {
					return;
				}

				wp_get_current_user();
				$show_product = false;

				if( isset( $current_user->ID ) && $current_user->ID > 0 ) {
					$vendors = printcenter_get_product_vendors( $_GET['post'] );

					if( isset( $vendors ) && is_array( $vendors ) ) {
						foreach( $vendors as $vendor ) {
							$show_product = printcenter_is_vendor_admin( $vendor->ID, $current_user->ID );

							if( $show_product ) {
								break;
							}
						}
					}
				}

				if( ! $show_product ) {
					wp_die( sprintf( __( 'You do not have permission to edit this product. %1$sClick here to view and edit your products%2$s.', 'printcenter' ), '<a href="' . esc_url( 'edit.php?post_type=product' ) . '">', '</a>' ) );
				}
			}
		}

		return;
	}


	/**
	 * Show correct post counts on list table for products
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       object $counts Default status counts
	 * @param       string $type Current post type
	 * @param       string $perm User permission level
	 * @return      object Modified status counts
	 */
	public function list_table_product_counts( $counts, $type, $perm ) {

The parameter $perm is not used and could be removed.

		if( 'product' != $type ) {
			return $counts;
		}

		if( printcenter_vendor_access() ) {
			$vendor_id = printcenter_is_vendor();

			if( ! $vendor_id ) {
				return $counts;
			}

			$vendor_admins = printcenter_get_vendor_admins( $vendor_id );

			if( ! $vendor_admins ) {

The expression $vendor_admins of type array is implicitly converted to a boolean; are you sure this is intended? If so, consider using empty($expr) instead to make it clear that you intend to check for an array without elements.

				return $counts;
			}

			$admins = array();

			foreach( $vendor_admins as $admin ) {
				if( ! $admin->ID ) {
					continue;
				}

				$admins[] = $admin->ID;
			}

			if( 0 == count( $admins ) ) {
				return;
			}

			$args = array(
				'post_type'      => $type,
				'author__in'     => $admins,
				'posts_per_page' => -1
			);

			 // Get all available statuses
			$stati = get_post_stati();

			// Update count object
			foreach( $stati as $status ) {
				$args['post_status'] = $status;
				$posts               = get_posts( $args );
				$counts->$status     = count( $posts );
			}
		}

		return $counts;
	}


	/**
	 * Show correct post counts on list tables for attachments
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       object $counts Default counts
	 * @param       string $mime_type Current MIME type
	 * @return      object Modified counts
	 */
	public function list_table_media_counts( $counts, $mime_type = '' ) {

The parameter $mime_type is not used and could be removed.

		if( printcenter_vendor_access() ) {
			$vendor_id = printcenter_is_vendor();

			if( ! $vendor_id ) {
				return $counts;
			}

			$vendor_admins = printcenter_get_vendor_admins( $vendor_id );

			if( ! $vendor_admins ) {

The expression $vendor_admins of type array is implicitly converted to a boolean; are you sure this is intended? If so, consider using empty($expr) instead to make it clear that you intend to check for an array without elements.

				return $counts;
			}

			$admins = array();

			foreach( $vendor_admins as $admin ) {
				if( ! $admin->ID ) {
					continue;
				}

				$admins[] = $admin->ID;
			}

			if( 0 == count( $admins ) ) {
				return $counts;
			}

			$args = array(
				'post_parent' => null,
				'numberposts' => -1,
				'post_type'   => 'attachment',
				'post_status' => 'any',
				'author__in'  => $admins,
			);

			// Update count object
			foreach( $counts as $mimetype => $num ) {
				$args['post_mime_type'] = $mimetype;
				$attachments            = get_children( $args );
				$counts->$mimetype      = count( $attachments );
			}
		}

		return $counts;
	}


	/**
	 * Remove the 'Unattached' attachment view for vendors
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $views Default views
	 * @return      array Modified views
	 */
	public function remove_unattached_attachments( $views = array() ) {
		if( printcenter_vendor_access() ) {
			unset( $views['detached'] );
		}

		return $views;
	}


	/**
	 * Add vendor to product
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $post_id Product ID
	 * @return      void
	 */
	public function add_vendor_to_product( $post_id ) {
		if( get_post_type( $post_id ) == 'product' ) {
			if ( ! current_user_can( 'edit_post', $post_id ) ) {
				return;
			}

			if( printcenter_vendor_access() ) {
				$vendor = printcenter_get_user_vendor();

				if( isset( $vendor->slug ) && strlen( $vendor->slug ) > 0 ) {
					wp_set_object_terms( $post_id, $vendor->slug, $this->token, false );
				}
			}
		}
	}


	/**
	 * Add Product Vendor reports to WC reports
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $charts Existing reports
	 * @return      array Modified reports
	 */
	public function add_reports( $charts ) {
		$charts['product_vendors'] = array(
			'title'  => __( 'Product Vendors', 'printcenter' ),
			'charts' => array(
				array(
					'title'       => __( 'Overview', 'printcenter' ),
					'description' => '',
					'hide_title'  => true,
					'function'    => 'woocommerce_product_vendors_report_overview'
				),
				array(
					'title'       => __( 'Vendor Sales', 'printcenter' ),
					'description' => '',
					'hide_title'  => false,
					'function'    => 'woocommerce_product_vendors_report_vendor_sales'
				)
			)
		);

		return $charts;
	}


	/**
	 * Detailed report of total vendor earnings for logged in user
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      string Report HTML
	 */
	public function vendor_total_earnings_report() {
		$html      = '';
		$vendor_id = printcenter_is_vendor();

		if( $vendor_id ) {
			$selected_year  = ( isset( $_POST['report_year'] ) && $_POST['report_year'] != 'all' ) ? $_POST['report_year'] : false;
			$selected_month = ( isset( $_POST['report_month'] ) && $_POST['report_month'] != 'all' ) ? $_POST['report_month'] : false;
			$commissions    = printcenter_get_vendor_commissions( $vendor_id, $selected_year, $selected_month, false );
			$total_earnings = 0;

			foreach( $commissions as $commission ) {
				$earnings   = get_post_meta( $commission->ID, '_commission_amount', true );
				$product_id = get_post_meta( $commission->ID, '_commission_product', true );
				$product    = get_product( $product_id );

				if( ! isset( $product ) || ! $product || is_wp_error( $product ) || ! is_object( $product ) ) {
					continue;
				}

				if( ! isset( $data[ $product_id ]['product'] ) ) {
					$data[ $product_id ]['product'] = $product->get_title();

$data was never initialized. Although not strictly required by PHP, it is generally a good practice to add $data = array(); before regardless.

				}

				if( ! isset( $data[ $product_id ]['product_url'] ) ) {
					$data[ $product_id ]['product_url'] = get_permalink( $product_id );

The variable $data does not seem to be defined for all execution paths leading up to this point.

				}

				if( isset( $data[ $product_id ]['sales'] ) ) {
					++$data[ $product_id ]['sales'];
				} else {
					$data[ $product_id ]['sales'] = 1;
				}

				if( isset( $data[ $product_id ]['earnings'] ) ) {
					$data[ $product_id ]['earnings'] += $earnings;
				} else {
					$data[ $product_id ]['earnings'] = $earnings;
				}

				$total_earnings += $earnings;
			}

			$month_options = '<option value="all">' . __( 'All months', 'printcenter' ) . '</option>';

			for( $i = 1; $i <= 12; $i++ ) {
				$month_num      = str_pad( $i, 2, 0, STR_PAD_LEFT );
				$month_name     = date( 'F', mktime( 0, 0, 0, $i + 1, 0, 0 ) );
				$month_options .= '<option value="' . esc_attr( $month_num ) . '" ' . selected( $selected_month, $month_num, false ) . '>' . $month_name . '</option>';
			}

			$year_options = '<option value="all">' . __( 'All years', 'printcenter' ) . '</option>';
			$current_year = date( 'Y' );

			for( $i = $current_year; $i >= ( $current_year - 5 ); $i-- ) {
				$year_options .= '<option value="' . $i . '" ' . selected( $selected_year, $i, false ) . '>' . $i . '</option>';
			}

			$html .= '<div class="product_vendors_report_form">
						<form name="product_vendors_report" action="' . get_permalink() . '" method="post">
							' . __( 'Select report date:', 'printcenter' ) . '
							<select name="report_month">' . $month_options . '</select>
							<select name="report_year">' . $year_options . '</select>
							<input type="submit" class="button" value="Submit" />
						</form>
					</div>';

			$html .= '<table class="shop_table" cellspacing="0">
						<thead>
							<tr>
								<th>' . __( 'Product', 'printcenter' ) . '</th>
								<th>' . __( 'Sales', 'printcenter' ) . '</th>
								<th>' . __( 'Earnings', 'printcenter' ) . '</th>
							</tr>
						</thead>
						<tbody>';

			if( isset( $data ) && is_array( $data ) ) {
				foreach( $data as $product_id => $product ) {
					$html .= '<tr>
								<td><a href="' . esc_url( $product['product_url'] ) . '">' . $product['product'] . '</a></td>
								<td>' . $product['sales'] . '</td>
								<td>' . get_woocommerce_currency_symbol() . number_format( $product['earnings'], 2 ) . '</td>
							</tr>';
				}

				$html .= '<tr>
							<td colspan="2"><b>' . __( 'Total', 'printcenter' ) . '</b></td>
							<td>' . get_woocommerce_currency_symbol() . number_format( $total_earnings, 2 ) . '</td>
						</tr>';
			} else {
				$html .= '<tr><td colspan="3"><em>' . __( 'No sales found', 'printcenter' ) . '</em></td></tr>';
			}

			$html .= '</tbody>
					</table>';
		}

		return $html;
	}


	/**
	 * Quick report of total vendor earnings for the current month
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      string Report HTML
	 */
	public function vendor_month_earnings() {
		$html      = '';
		$vendor_id = printcenter_is_vendor();

		if( $vendor_id ) {
			$commissions = printcenter_get_vendor_commissions( $vendor_id, date( 'Y' ), date( 'm' ), false );

			if( $commissions ) {

The expression $commissions of type array is implicitly converted to a boolean; are you sure this is intended? If so, consider using ! empty($expr) instead to make it clear that you intend to check for an array without elements.

				$month_earnings = 0;

				foreach( $commissions as $commission ) {
					$earnings        = get_post_meta( $commission->ID, '_commission_amount', true );
					$month_earnings += $earnings;
				}

				$html .= sprintf( __( 'This month\'s earnings: %1$s', 'printcenter' ), '<b>' . get_woocommerce_currency_symbol() . number_format( $month_earnings, 2 ) . '</b>' );
			}
		}

		return $html;
	}


	/**
	 * Load product archive template for vendor pages
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function load_product_archive_template() {
		if( is_tax( $this->token ) ) {
			woocommerce_get_template( 'archive-product.php' );
			exit;

The method load_product_archive_template() contains an exit expression.

		}
	}


	/**
	 * Add 'woocommerce' class to body tag for vendor pages
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $classes Existing classes
	 * @return      array Modified classes
	 */
	public function set_product_archive_class( $classes ) {
		if( is_tax( $this->token ) ) {
			// Add generic classes
			$classes[] = 'woocommerce';
			$classes[] = 'product-vendor';

			// Get vendor ID
			$vendor_id = get_queried_object()->term_id;

			// Get vendor info
			$vendor = printcenter_get_vendor( $vendor_id );

			// Add vendor slug as class
			if( '' != $vendor->slug ) {
				$classes[] = $vendor->slug;
			}
		}

		return $classes;
	}


	/**
	 * Add vendor info to top of vendor pages
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function product_archive_vendor_info() {
		if( is_tax( $this->token ) ) {
			// Get vendor ID
			$vendor_id = get_queried_object()->term_id;

			// Get vendor info
			$vendor = printcenter_get_vendor( $vendor_id );

			do_action( 'product_vendors_page_description_before', $vendor_id );

			if( '' != $vendor->description ) {
				echo '<p class="archive-description">' . apply_filters( 'product_vendors_page_description', nl2br( $vendor->description ), $vendor_id ) . '</p>';
			}

			do_action( 'product_vendors_page_description_after', $vendor_id );
		}
	}


	/**
	 * Add vendor ID to booking
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       int $booking_id Booking ID
	 * @return      void
	 */
	public function add_vendor_to_booking( $booking_id = 0 ) {
		if( ! $booking_id ) {
			return;
		}

		$product_id = get_post_meta( $booking_id, '_booking_product_id', true );

		if( ! $product_id ) {
			return;
		}

		$vendors = printcenter_get_product_vendors( $product_id );

		if( ! $vendors ) {
			return;
		}

		foreach( $vendors as $vendor ) {

The expression $vendors of type boolean is not traversable.

			if( ! isset( $vendor->ID ) ) {
				continue;
			}

			update_post_meta( $booking_id, '_booking_vendor', $vendor->ID );
		}
	}


	/**
	 * Restrict booking products lists to current vendor's products
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $args Default query args
	 * @return      array Modified query args
	 */
	public function restrict_booking_products( $args = array() ) {
		if( current_user_can( 'manage_woocommerce' ) ) {
			return $args;
		}

		$vendor_id = printcenter_is_vendor();

		if( $vendor_id ) {
			$args['tax_query'][] = array(
				'taxonomy' => $this->token,
				'field'    => 'id',
				'terms'    => $vendor_id,
			);
		}

		return $args;
	}


	/**
	 * Only show vendor's bookings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $request Current request
	 * @return      array Modified request
	 */
	public function filter_booking_list( $request ) {
		global $typenow, $current_user;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		if( is_admin() ) {
			if( ! current_user_can( 'manage_woocommerce' ) ) {
				if( printcenter_vendor_access() ) {
					if( $typenow == 'wc_booking' ) {
						wp_get_current_user();

						if( isset( $current_user->ID ) && $current_user->ID > 0 ) {
							$vendor = printcenter_get_user_vendor( $current_user->ID );

							if( $vendor->slug && strlen( $vendor->slug ) > 0 ) {
								$request['meta_query'][] = array(
									'key'   => '_booking_vendor',
									'value' => $vendor->ID,
								);
							}
						}
					}
				}
			}
		}

		return $request;
	}


	/**
	 * Restrict booking calendar to current vendor's bookings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $args Default query args
	 * @return      array Modified query args
	 */
	public function filter_booking_calendar( $args = array() ) {
		if( current_user_can( 'manage_woocommerce' ) ) {
			return $args;
		}

		$vendor_id = printcenter_is_vendor();

		if( $vendor_id ) {
			$args['meta_query'][] = array(
				'key'   => '_booking_vendor',
				'value' => $vendor_id,
			);
		}

		return $args;
	}


	/**
	 * Show correct post counts on list table for bookings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       object $counts Default status counts
	 * @param       string $type Current post type
	 * @param       string $perm User permission level
	 * @return      object Modified status counts
	 */
	public function list_table_booking_counts( $counts, $type, $perm ) {

The parameter $perm is not used and could be removed.

		if( 'wc_booking' != $type ) {
			return $counts;
		}

		if( printcenter_vendor_access() ) {
			$vendor_id = printcenter_is_vendor();

			if( ! $vendor_id ) {
				return $counts;
			}

			// Build up query arguments
			$args = array(
				'post_type'      => $type,
				'posts_per_page' => -1,
				'meta_query'     => array(
					array(
						'key'   => '_booking_vendor',
						'value' => $vendor_id,
					),
				),
			);

			// Get all available booking statuses
			$stati = array( 'unpaid', 'pending', 'confirmed', 'paid', 'cancelled', 'complete' );

			// Update count object
			foreach( $stati as $status ) {
				$args['post_status'] = $status;
				$posts               = get_posts( $args );
				$counts->$status     = count( $posts );
			}
		}

		return $counts;
	}


	/**
	 * Hide vendor products from other product loops
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       object $query WP_Query object
	 * @return      void
	 */
	public function hide_vendor_products( $query ) {
		$hide_vendor_products = get_option( 'woocommerce_product_vendors_hide_vendor_products' ) == 'yes' ? true : false;

		if( $hide_vendor_products && ! is_admin() ) {
			if( is_post_type_archive( 'product' ) && ! is_tax( $this->token ) ) {
				// Get all shop_vendor terms
				$vendor_terms_array = get_terms( $this->token, array( 'hide_empty' => false ) );
				$vendor_terms       = array();

				foreach( $vendor_terms_array as $term ) {
					$vendor_terms[] = $term->slug;
				}

				// Set up custom tax query
				$tax_query = array(
					'taxonomy' => $this->token,
					'field'    => 'slug',
					'terms'    => $vendor_terms,
					'operator' => 'NOT IN',
				);

				// Add custom tax query to query
				$query->tax_query->queries[]    = $tax_query;
				$query->query_vars['tax_query'] = $query->tax_query->queries;
			}
		}
	}


	/**
	 * Send product enquiries directly to vendors
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       string $email Default email address for form
	 * @param       int $product_id ID of product
	 * @return      mixed String if no vendors exist for product, otherwise array of vendor email addresses
	 */
	function wc_product_enquiry_to_vendor( $email = '', $product_id = 0 ) {

It is generally recommended to explicitly declare the visibility for methods.

		// Get all vendors for product
		$vendors = printcenter_get_product_vendors( $product_id );

		if ( ! empty( $vendors ) ) {
			$emails = array();

			// Send to default email address
			$emails[] = $email;

			// Also send to vendor email addresses
			foreach( $vendors as $vendor ) {

The expression $vendors of type boolean is not traversable.

				// Get all admins for vendor
				foreach( $vendor->admins as $admin ) {
					$emails[] = $admin->data->user_email;
				}
			}

			return $emails;
		}

		return $email;
	}


	/**
	 * Add extension settings
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $settings Existing settings
	 * @return      array Modified settings
	 */
	public function add_settings( $settings ) {
		$vendors_settings = array(
			array(
				'title' => __( 'Product Vendors', 'printcenter' ),
				'type'  => 'title',
				'id'    => 'product_vendors_options'
			),
			array(
				'title'         => __( 'Product listings', 'printcenter' ),
				'desc'          => __( 'Hide vendor products from other product listings', 'printcenter' ),
				'id'            => 'woocommerce_product_vendors_hide_vendor_products',
				'default'       => 'no',
				'desc_tip'      => __( 'Hide products belonging to vendors from other product listings - this means that vendor products will only be visible on the individual vendor pages.', 'printcenter' ),
				'type'          => 'checkbox',
				'checkboxgroup' => 'start'
			),
			array(
				'title'         => __( 'Admin review', 'printcenter' ),
				'desc'          => __( 'Skip admin review for vendors', 'printcenter' ),
				'id'            => 'woocommerce_product_vendors_skip_review',
				'default'       => 'no',
				'desc_tip'      => __( 'Allow vendors to add products without the need for admin review - after changing this option you will need to resave each vendor.', 'printcenter' ),
				'type'          => 'checkbox',
				'checkboxgroup' => 'start'
			),
			array(
				'title'             => __( 'Base commission', 'woocommerce' ),
				'desc'              => __( 'This sets the default commission percentage that will be applied if no product or vendor commission is specified.', 'printcenter' ),
				'id'                => 'woocommerce_product_vendors_base_commission',
				'css'               => 'width:50px;',
				'default'           => '50',
				'desc_tip'          => true,
				'type'              => 'number',
				'custom_attributes' => array(
					'min'  => 0,
					'max'  => 100,
					'step' => 1
				)
			),
			array(
				'title'         => __( 'Coupon handling', 'printcenter' ),
				'desc'          => __( 'Include coupons in commission calculations', 'printcenter' ),
				'id'            => 'woocommerce_product_vendors_include_coupons',
				'default'       => 'no',
				'desc_tip'      => __( 'Decide whether vendor commissions should take coupons into account or not.', 'printcenter' ),
				'type'          => 'checkbox',
				'checkboxgroup' => 'start'
			),
			array(
				'type' => 'sectionend',
				'id'   => 'product_vendors_options'
			),
		);

		$settings = array_merge( $settings, $vendors_settings );

		return $settings;
	}


	/**
	 * Add Product Vendors pages to WooCommerce screen IDs
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $screen_ids Existing IDs
	 * @return      array Modified IDs
	 */
	public function screen_ids( $screen_ids = array() ) {
		$screen_ids[] = 'edit-shop_vendor';
		$screen_ids[] = 'shop_commission';
		$screen_ids[] = 'edit-shop_commission';
		$screen_ids[] = 'product_page_vendor_details';

		return $screen_ids;
	}


	/**
	 * Display admin notices in the WP dashboard
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function admin_notices() {
		global $current_screen;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

		$message = false;

		if( $current_screen->base == 'product_page_vendor_details' ) {
			if( isset( $_GET['message'] ) ) {
				switch( $_GET['message'] ) {
					case 1: $message = sprintf( __( '%1$sVendor details have been updated.%2$s', 'printcenter' ), '<div id="message" class="updated"><p>', '</p></div>' );
				}
			}
		}

		if( $message ) {

The expression $message of type string|false is loosely compared to true; this is ambiguous if the string can be empty. You might want to explicitly use !== false instead.

			echo $message;
		}
	}


	/**
	 * Flush rewrite rules on plugin activation
	 *
	 * @access      public
	 * @since       1.0.0
	 * @return      void
	 */
	public function rewrite_flush() {
		$this->register_vendors_taxonomy();
		flush_rewrite_rules();
	}


	/**
	 * Add 'Configure' link to plugin listing
	 *
	 * @access      public
	 * @since       1.0.0
	 * @param       array $links Existing links
	 * @return      array Modified links
	 */
	public function add_settings_link( $links ) {
		$custom_links[] = '<a href="' . admin_url( 'edit-tags.php?taxonomy=shop_vendor&post_type=product' ) . '">' . __( 'Vendors', 'printcenter' ) . '</a>';

$custom_links was never initialized. Although not strictly required by PHP, it is generally a good practice to add $custom_links = array(); before regardless.

		$custom_links[] = '<a href="' . admin_url( 'edit.php?post_type=shop_commission' ) . '">' . __( 'Commissions', 'printcenter' ) . '</a>';

		return array_merge( $links, $custom_links );
	}
}