Better Inventory

<?php
/**
 * Gravity Wiz // Gravity Forms // Better Inventory
 *
 * Specify an inventory for any Gravity Forms field.
 *
 * @version   2.20
 * @author    David Smith <david@gravitywiz.com>
 * @license   GPL-2.0+
 * @link      https://gravitywiz.com/better-inventory-with-gravity-forms/
 */
class GW_Inventory {

	public $_args;

	public function __construct( $args ) {

		$this->_args = $this->parse_args( $args );

		add_action( 'init', array( $this, 'init' ) );

	}

	public function init() {

		// make sure we're running the required minimum version of Gravity Forms
		if ( ! property_exists( 'GFCommon', 'version' ) || ! version_compare( GFCommon::$version, '1.8', '>=' ) ) {
			return;
		}

		add_filter( 'gform_pre_render', array( $this, 'limit_by_field_values' ) );
		add_filter( 'gform_validation', array( $this, 'limit_by_field_values_validation' ) );

		// check 'field_group' for date fields; if found, limit based on exhausted inventory days.
		if ( ! empty( $this->_args['field_group'] ) ) {
			add_filter( "gpld_limit_dates_options_{$this->_args['form_id']}", array( $this, 'limit_date_fields' ), 10, 2 );
		}

		// add 'sum' action for [gravityforms] shortcode
		add_filter( 'gform_shortcode_sum', array( $this, 'shortcode_sum' ), 10, 2 );
		add_filter( 'gform_shortcode_remaining', array( $this, 'shortcode_remaining' ), 10, 2 );

		add_action( 'gwinv_before_get_sum', array( $this, 'before_get_sum' ) );
		add_action( 'gwinv_after_get_sum', array( $this, 'after_get_sum' ) );

		add_filter( 'gform_product_info', array( $this, 'handle_calculated_product_fields' ), 10, 3 );

		if ( $this->_args['enable_notifications'] ) {
			$this->enable_notifications();
		}

	}

	public function parse_args( $args ) {

		$args = wp_parse_args( $args, array(
			'form_id'                  => false,
			'field_id'                 => false,
			'input_id'                 => false,
			'stock_qty'                => false,
			'out_of_stock_message'     => __( 'Sorry, this item is out of stock.' ),
			// translators: placeholders are numbers
			'not_enough_stock_message' => __( 'You ordered %1$s of this item but there are only %2$s of this item left.' ),
			'approved_payments_only'   => false,
			'hide_form'                => false,
			'enable_notifications'     => false,
			'field_group'              => array(),
		) );

		/**
		 * @var $stock_qty
		 * @var $field_group
		 */
		// phpcs:ignore WordPress.PHP.DontExtract.extract_extract
		extract( $args );

		if ( ! $stock_qty && isset( $limit ) ) {
			$args['stock_qty'] = $limit;
			unset( $args['limit'] );
		}

		if ( isset( $limit_message ) ) {
			$args['out_of_stock_message'] = $limit_message;
			unset( $args['limit_message'] );
		}

		if ( isset( $validation_message ) ) {
			$args['not_enough_stock_message'] = $validation_message;
			unset( $args['validation_message'] );
		}

		if ( ! $args['input_id'] ) {
			$args['input_id'] = $args['field_id'];
			unset( $args['field_id'] );
		}

		if ( $field_group && ! is_array( $field_group ) ) {
			$args['field_group'] = array( $field_group );
		}

		return $args;
	}

	public function enable_notifications() {

		if ( ! class_exists( 'GW_Notification_Event' ) ) {

			_doing_it_wrong( 'GW_Inventory::$enable_notifications', __( 'Inventory notifications require the \'GW_Notification_Event\' class.' ), '1.0' );

		} else {

			$event_slug = "gwinv_out_of_stock_{$this->_args['input_id']}";
			$event_name = GFForms::get_page() === 'notification_edit' ? $this->get_notification_event_name() : __( 'Event name is only populated on Notification Edit view; saves a DB call to get the form on every ' );

			$this->_notification_event = new GW_Notification_Event( array(
				'form_id'    => $this->_args['form_id'],
				'event_name' => $event_name,
				'event_slug' => $event_slug,
				'trigger'    => array( $this, 'notification_event_listener' ),
			) );

		}

	}

	public function limit_by_field_values( $form ) {

		if ( ! $this->is_applicable_form( $form ) ) {
			return $form;
		}

		if ( $this->is_in_stock() ) {
			return $form;
		}

		if ( $this->_args['hide_form'] ) {
			add_filter( "gform_get_form_filter_{$form['id']}", array( $this, 'get_out_of_stock_message' ) );
		} elseif ( empty( $this->_args['field_group'] ) ) {
			add_filter( 'gform_field_input', array( $this, 'hide_field' ), 10, 2 );
		}

		return $form;
	}

	public function limit_by_field_values_validation( $validation_result ) {

		if ( ! $this->is_applicable_form( $validation_result['form'] ) ) {
			return $validation_result;
		}

		$input_id           = $this->_args['input_id'];
		$limit              = $this->get_stock_quantity();
		$validation_message = $this->_args['not_enough_stock_message'];

		$form           = $validation_result['form'];
		$exceeded_limit = false;

		foreach ( $form['fields'] as &$field ) {

			if ( intval( $field['id'] ) !== intval( $input_id ) ) {
				continue;
			}

			$requested_qty = rgpost( 'input_' . str_replace( '.', '_', $input_id ) );
			$field_sum     = $this->get_sum();

			if ( $field->get_input_type() === 'number' && $field->numberFormat === 'currency' ) {
				$requested_qty = GFCommon::to_number( $requested_qty );
			}

			if ( rgblank( $requested_qty ) || $field_sum + $requested_qty <= $limit ) {
				continue;
			}

			$exceeded_limit = true;
			$stock_left     = $limit - $field_sum >= 0 ? $limit - $field_sum : 0;

			$field['failed_validation']  = true;
			$field['validation_message'] = sprintf( $validation_message, $requested_qty, $stock_left );

		}

		if ( $exceeded_limit && ! empty( $this->_args['field_group'] ) ) {
			foreach ( $form['fields'] as &$field ) {
				if ( in_array( $field->id, $this->_args['field_group'] ) ) {
					$field['failed_validation']  = true;
					$field['validation_message'] = sprintf( $validation_message, $requested_qty, $stock_left );
				}
			}
		}

		$validation_result['form']     = $form;
		$validation_result['is_valid'] = ! $validation_result['is_valid'] ? false : ! $exceeded_limit;

		return $validation_result;
	}

	public function limit_by_field_group( $query, $form_id, $input_id ) {
		global $wpdb;

		if ( $input_id != $this->_args['input_id'] ) {
			return $query;
		}

		$form  = GFAPI::get_form( $form_id );
		$join  = array();
		$where = array();

		foreach ( $this->_args['field_group'] as $index => $field_id ) {

			$field = GFFormsModel::get_field( $form, $field_id );
			$alias = sprintf( 'fgld%d', $index + 1 );

			// Fetch entry from submission if available. Otherwise, get default/dynpop value.
			if ( rgpost( 'gform_submit' ) == $form_id ) {
				$value = $field->get_value_save_entry( GFFormsModel::get_field_value( $field ), $form, null, null, null );
			} else {
				$value = $field->get_value_default_if_empty( GFFormsModel::get_parameter_value( $field->inputName, array(), $field ) );
			}

			$join[] = "\nINNER JOIN {$wpdb->prefix}gf_entry_meta {$alias} ON em.entry_id = {$alias}.entry_id";

			// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			$where[] = $wpdb->prepare( "CAST( {$alias}.meta_key as unsigned ) = %d AND {$alias}.meta_value = %s ", $field_id, $value );

		}

		$query['join']  .= implode( "\n", $join );
		$query['where'] .= sprintf( "\n AND %s", implode( "\nAND ", $where ) );

		return $query;
	}

	public function limit_date_fields( $options, $form ) {
		global $wpdb;

		foreach ( $form['fields'] as $field ) {

			if ( ! in_array( $field->id, $this->_args['field_group'] ) || $field->get_input_type() != 'date' || $field->dateType != 'datepicker' ) {
				continue;
			}

			$query = self::get_sum_query( $field->formId, $this->_args['input_id'] );

			if ( $this->_args['approved_payments_only'] ) {
				$query = $this->limit_by_approved_payments_only( $query );
			}

			if ( ! empty( $this->_args['field_group'] ) ) {

				// add our Date field to the front of the array so we can reliably target it when replacing the queries below
				array_unshift( $this->_args['field_group'], $field->id );
				$this->_args['field_group'] = array_unique( $this->_args['field_group'] );

				$query = $this->limit_by_field_group( $query, $field->formId, $this->_args['input_id'] );

			}

			$regex = sprintf( '/(CAST\( fgld1.meta_key as unsigned \) = %d) AND fgld1.meta_value = \'(?:[\w\d]*)\'/', $field->id );
			preg_match( $regex, $query['where'], $match );
			if ( ! empty( $match ) ) {
				list( $search, $replace ) = $match;
				$query['where']           = str_replace( $search, $replace, $query['where'] );
			}

			$query['select']   = 'SELECT sum( em.meta_value ) as total, fgld1.meta_value as date';
			$query['group_by'] = 'GROUP BY date';
			$query['having']   = sprintf( 'HAVING total >= %d', $this->get_stock_quantity() );

			$sql = implode( "\n", $query );

			// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
			$results = $wpdb->get_results( $sql );

			foreach ( $results as $result ) {
				$options[ $field->id ]['exceptionsMode'] = 'disable';
				if ( ! is_array( $options[ $field->id ]['exceptions'] ) ) {
					$options[ $field->id ]['exceptions'] = array();
				}

				// phpcs:ignore WordPress.DateTime.RestrictedFunctions.date_date
				$options[ $field->id ]['exceptions'][] = date( 'm/d/Y', strtotime( $result->date ) );
			}
		}

		return $options;
	}

	public function get_stock_quantity() {

		$stock = $this->_args['stock_qty'];

		if ( is_callable( $stock ) ) {
			$stock = call_user_func( $stock );
		}

		return $stock;
	}

	public function is_in_stock() {
		$count = $this->get_sum();//self::get_field_values_sum( $this->_args['form_id'], $this->_args['input_id'] );
		return $count < $this->get_stock_quantity();
	}

	public function hide_field( $field_content, $field ) {

		if ( $field['id'] == intval( $this->_args['input_id'] ) ) {

			$quantity_input = '';
			// GF will default to a quantity of 1 if it can't find the input for a Quantity field.
			if ( $field->type === 'quantity' ) {
				$quantity_input = sprintf( '<input type="hidden" name="input_%d_%d" value="0" />', $field->formId, $field->id );
			}

			return sprintf( '<div class="ginput_container">%s%s</div>', $this->_args['out_of_stock_message'], $quantity_input );
		}

		return $field_content;
	}

	public function notification_event_listener() {

		// really is no better hook to use to send custom notifications just yet
		add_filter( "gform_confirmation_{$this->_args['form_id']}", array( $this, 'send_out_of_stock_notifications' ), 10, 3 );

	}

	public function send_out_of_stock_notifications( $return, $form, $entry ) {

		// if product is still in stock or the entry is spam, don't sent notification
		if ( $this->is_in_stock() || $entry['status'] == 'spam' ) {
			return $return;
		}

		// if product is out of stock and no qty of the product is in current order, assume that out of stock notifications have already been sent
		$requested_qty = intval( rgar( $entry, (string) $this->_args['input_id'] ) );
		if ( $requested_qty <= 0 ) {
			return $return;
		}

		$this->_notification_event->send_notifications( $this->_notification_event->get_event_slug(), $form, $entry );

		return $return;
	}

	public function get_notification_event_name() {

		$form  = GFAPI::get_form( $this->_args['form_id'] );
		$field = GFFormsModel::get_field( $form, $this->_args['input_id'] );

		// translators: placeholder is the field label
		$event_name = sprintf( __( '%s: Out of Stock' ), GFCommon::get_label( $field ) );

		return $event_name;
	}

	public function shortcode_sum( $output, $atts ) {

		$atts = shortcode_atts( array(
			'id'       => false,
			'input_id' => false,
		), $atts );

		/**
		 * @var $id
		 * @var $input_id
		 */
		// phpcs:ignore WordPress.PHP.DontExtract.extract_extract
		extract( $atts ); // gives us $id, $input_id

		return intval( self::get_field_values_sum( $id, $input_id ) );
	}

	public function shortcode_remaining( $output, $atts ) {

		/**
		 * @var $id
		 * @var $input_id
		 * @var $limit
		 */
		$atts = shortcode_atts( array(
			'id'       => false,
			'input_id' => false,
			'limit'    => false,
		), $atts );

		// phpcs:ignore WordPress.PHP.DontExtract.extract_extract
		extract( $atts ); // gives us $id, $input_id

		if ( $input_id == $this->_args['input_id'] && $id == $this->_args['form_id'] ) {
			$limit     = $limit ? $limit : $this->get_stock_quantity();
			$remaining = $limit - intval( $this->get_sum() );
			$output    = max( 0, $remaining );
		}

		return $output;
	}

	public function get_sum() {

		if ( $this->_args['approved_payments_only'] ) {
			add_filter( 'gwinv_query', array( $this, 'limit_by_approved_payments_only' ) );
		}

		if ( ! empty( $this->_args['field_group'] ) ) {
			add_filter( 'gwinv_query', array( $this, 'limit_by_field_group' ), 10, 3 );
		}

		$sum = self::get_field_values_sum( $this->_args['form_id'], $this->_args['input_id'] );

		remove_filter( 'gwinv_query', array( $this, 'limit_by_approved_payments_only' ) );
		remove_filter( 'gwinv_query', array( $this, 'limit_by_field_group' ) );

		return $sum;
	}

	public function limit_by_approved_payments_only( $query ) {
		$valid_statuses  = array( 'Approved', /* old */ 'Paid', 'Active' );
		$query['where'] .= sprintf( ' AND ( e.payment_status IN ( %s ) OR e.payment_status IS NULL )', self::prepare_strings_for_mysql_in_statement( $valid_statuses ) );
		return $query;
	}

	public function get_out_of_stock_message() {
		return $this->_args['out_of_stock_message'];
	}

	/**
	 * Calculated Product fields limited by their default quantity should be excluded from the order summary.
	 *
	 * Since their value is calculated post submission, they function uniquely from other product fields.
	 *
	 * @param $order
	 * @param $form
	 * @param $entry
	 *
	 * @return mixed
	 */
	public function handle_calculated_product_fields( $order, $form, $entry ) {

		foreach ( $order['products'] as $field_id => $product ) {

			// Check for if target input ID is for the current field and is targeting a Product field default quantity input (i.e. 1.3).
			if ( $field_id != intval( $this->_args['input_id'] ) || rgar( explode( '.', $this->_args['input_id'] ), 1 ) != '3' ) {
				continue;
			}

			$field = GFAPI::get_field( $form, $field_id );
			if ( $field->get_input_type() !== 'calculation' ) {
				continue;
			}

			if ( ! $this->is_in_stock() ) {
				unset( $order['products'][ $field_id ] );
			}
		}

		return $order;
	}

	public static function get_field_values_sum( $form_id, $input_id ) {
		global $wpdb;

		$query = self::get_sum_query( $form_id, $input_id );
		$sql   = implode( "\n", $query );

		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
		$result = $wpdb->get_var( $sql );

		return intval( $result );
	}

	public static function get_sum_query( $form_id, $input_id, $suppress_filters = false ) {
		global $wpdb;

		$query = array(
			'select' => 'SELECT sum( em.meta_value )',
			'from'   => "FROM {$wpdb->prefix}gf_entry_meta em",
			'join'   => "INNER JOIN {$wpdb->prefix}gf_entry e ON e.id = em.entry_id",
			'where'  => $wpdb->prepare( "
                WHERE em.form_id = %d
                AND em.meta_key = %s
                AND e.status = 'active'\n",
				$form_id, $input_id
			),
		);

		if ( class_exists( 'GF_Partial_Entries' ) ) {
			$query['where'] .= "and em.entry_id NOT IN( SELECT entry_id FROM {$wpdb->prefix}gf_entry_meta WHERE meta_key = 'partial_entry_id' )";
		}

		if ( ! $suppress_filters ) {
			$query = apply_filters( 'gwlimitbysum_query', $query, $form_id, $input_id );
			$query = apply_filters( 'gwinv_query', $query, $form_id, $input_id );
			$query = apply_filters( "gwinv_query_{$form_id}", $query, $form_id, $input_id );
			$query = apply_filters( "gwinv_query_{$form_id}_{$input_id}", $query, $form_id, $input_id );
		}

		return $query;
	}

	public static function prepare_strings_for_mysql_in_statement( $strings ) {
		$wrapped = array();
		foreach ( $strings as $string ) {
			$wrapped[] = sprintf( '"%s"', $string );
		}
		return implode( ', ', $wrapped );
	}

	public function is_applicable_form( $form ) {

		$form_id = isset( $form['id'] ) ? $form['id'] : $form;

		return empty( $this->_args['form_id'] ) || $form_id == $this->_args['form_id'];
	}

}

class GWLimitBySum extends GW_Inventory { }

new GW_Inventory( array(
	'form_id'                  => 123,
	'field_id'                 => 4.3,
	'stock_qty'                => 20,
	'out_of_stock_message'     => 'Sorry, there are no more tickets!',
	'not_enough_stock_message' => 'You ordered %1$s tickets. There are only %2$s tickets left.',
	'approved_payments_only'   => false,
	'hide_form'                => false,
	'enable_notifications'     => false,
) );