<?php
/**
 * WooCommerce Stock Functions
 *
 * Functions used to manage product stock levels.
 *
 * @package WooCommerce/Functions
 * @version 3.4.0
 */

defined( 'ABSPATH' ) || exit;

/**
 * Update a product's stock amount.
 *
 * Uses queries rather than update_post_meta so we can do this in one query (to avoid stock issues).
 *
 * @since  3.0.0 this supports set, increase and decrease.
 *
 * @param  int|WC_Product $product        Product ID or product instance.
 * @param  int|null       $stock_quantity Stock quantity.
 * @param  string         $operation      Type of opertion, allows 'set', 'increase' and 'decrease'.
 *
 * @return bool|int|null
 */
function wc_update_product_stock( $product, $stock_quantity = null, $operation = 'set' ) {
	$product = wc_get_product( $product );

	if ( ! $product ) {
		return false;
	}

	if ( ! is_null( $stock_quantity ) && $product->managing_stock() ) {
		// Some products (variations) can have their stock managed by their parent. Get the correct ID to reduce here.
		$product_id_with_stock = $product->get_stock_managed_by_id();
		$data_store            = WC_Data_Store::load( 'product' );
		$data_store->update_product_stock( $product_id_with_stock, $stock_quantity, $operation );
		delete_transient( 'wc_low_stock_count' );
		delete_transient( 'wc_outofstock_count' );
		delete_transient( 'wc_product_children_' . ( $product->is_type( 'variation' ) ? $product->get_parent_id() : $product->get_id() ) );
		wp_cache_delete( 'product-' . $product_id_with_stock, 'products' );

		// Re-read product data after updating stock, then have stock status calculated and saved.
		$product_with_stock = wc_get_product( $product_id_with_stock );
		$product_with_stock->set_stock_status();
		$product_with_stock->set_date_modified( current_time( 'timestamp', true ) );
		$product_with_stock->save();

		if ( $product_with_stock->is_type( 'variation' ) ) {
			do_action( 'woocommerce_variation_set_stock', $product_with_stock );
		} else {
			do_action( 'woocommerce_product_set_stock', $product_with_stock );
		}

		return $product_with_stock->get_stock_quantity();
	}
	return $product->get_stock_quantity();
}

/**
 * Update a product's stock status.
 *
 * @param  int $product_id Product ID.
 * @param  int $status     Status.
 */
function wc_update_product_stock_status( $product_id, $status ) {
	$product = wc_get_product( $product_id );
	if ( $product ) {
		$product->set_stock_status( $status );
		$product->save();
	}
}

/**
 * When a payment is complete, we can reduce stock levels for items within an order.
 *
 * @since 3.0.0
 * @param int $order_id Order ID.
 */
function wc_maybe_reduce_stock_levels( $order_id ) {
	$order = wc_get_order( $order_id );

	if ( ! $order ) {
		return;
	}

	$stock_reduced  = $order->get_data_store()->get_stock_reduced( $order_id );
	$trigger_reduce = apply_filters( 'woocommerce_payment_complete_reduce_order_stock', ! $stock_reduced, $order_id );

	// Only continue if we're reducing stock.
	if ( ! $trigger_reduce ) {
		return;
	}

	wc_reduce_stock_levels( $order );

	// Ensure stock is marked as "reduced" in case payment complete or other stock actions are called.
	$order->get_data_store()->set_stock_reduced( $order_id, true );
}
add_action( 'woocommerce_payment_complete', 'wc_maybe_reduce_stock_levels' );
add_action( 'woocommerce_order_status_completed', 'wc_maybe_reduce_stock_levels' );
add_action( 'woocommerce_order_status_processing', 'wc_maybe_reduce_stock_levels' );
add_action( 'woocommerce_order_status_on-hold', 'wc_maybe_reduce_stock_levels' );

/**
 * When a payment is cancelled, restore stock.
 *
 * @since 3.0.0
 * @param int $order_id Order ID.
 */
function wc_maybe_increase_stock_levels( $order_id ) {
	$order = wc_get_order( $order_id );

	if ( ! $order ) {
		return;
	}

	$stock_reduced  = $order->get_data_store()->get_stock_reduced( $order_id );
	$trigger_reduce = (bool) $stock_reduced;

	// Only continue if we're reducing stock.
	if ( ! $trigger_reduce ) {
		return;
	}

	wc_increase_stock_levels( $order );

	// Ensure stock is marked as "reduced" in case payment complete or other stock actions are called.
	$order->get_data_store()->set_stock_reduced( $order_id, false );
}
add_action( 'woocommerce_order_status_cancelled', 'wc_maybe_increase_stock_levels' );
add_action( 'woocommerce_order_status_pending', 'wc_maybe_increase_stock_levels' );

/**
 * Reduce stock levels for items within an order, if stock has not already been reduced for the items.
 *
 * @since 3.0.0
 * @param int|WC_Order $order_id Order ID or order instance.
 */
function wc_reduce_stock_levels( $order_id ) {
	if ( is_a( $order_id, 'WC_Order' ) ) {
		$order    = $order_id;
		$order_id = $order->get_id();
	} else {
		$order = wc_get_order( $order_id );
	}
	// We need an order, and a store with stock management to continue.
	if ( ! $order || 'yes' !== get_option( 'woocommerce_manage_stock' ) || ! apply_filters( 'woocommerce_can_reduce_order_stock', true, $order ) ) {
		return;
	}

	$changes = array();

	// Loop over all items.
	foreach ( $order->get_items() as $item ) {
		if ( ! $item->is_type( 'line_item' ) ) {
			continue;
		}

		// Only reduce stock once for each item.
		$product            = $item->get_product();
		$item_stock_reduced = $item->get_meta( '_reduced_stock', true );

		if ( $item_stock_reduced || ! $product || ! $product->managing_stock() ) {
			continue;
		}

		$qty       = apply_filters( 'woocommerce_order_item_quantity', $item->get_quantity(), $order, $item );
		$item_name = $product->get_formatted_name();
		$new_stock = wc_update_product_stock( $product, $qty, 'decrease' );

		if ( is_wp_error( $new_stock ) ) {
			/* translators: %s item name. */
			$order->add_order_note( sprintf( __( 'Unable to reduce stock for item %s.', 'woocommerce' ), $item_name ) );
			continue;
		}

		$item->add_meta_data( '_reduced_stock', $qty, true );
		$item->save();

		$changes[] = array(
			'product' => $product,
			'from'    => $new_stock + $qty,
			'to'      => $new_stock,
		);
	}

	wc_trigger_stock_change_notifications( $order, $changes );

	do_action( 'woocommerce_reduce_order_stock', $order );
}

/**
 * After stock change events, triggers emails and adds order notes.
 *
 * @since 3.5.0
 * @param WC_Order $order order object.
 * @param array $changes Array of changes.
 */
function wc_trigger_stock_change_notifications( $order, $changes ) {
	if ( empty( $changes ) ) {
		return;
	}

	$order_notes      = array();
	$no_stock_amount  = absint( get_option( 'woocommerce_notify_no_stock_amount', 0 ) );

	foreach ( $changes as $change ) {
		$order_notes[]    = $change['product']->get_formatted_name() . ' ' . $change['from'] . '&rarr;' . $change['to'];
		$low_stock_amount = absint( wc_get_low_stock_amount( wc_get_product( $change['product']->get_id() ) ) );
		if ( $change['to'] <= $no_stock_amount ) {
			do_action( 'woocommerce_no_stock', wc_get_product( $change['product']->get_id() ) );
		} elseif ( $change['to'] <= $low_stock_amount ) {
			do_action( 'woocommerce_low_stock', wc_get_product( $change['product']->get_id() ) );
		}

		if ( $change['to'] < 0 ) {
			do_action(
				'woocommerce_product_on_backorder', array(
					'product'  => wc_get_product( $change['product']->get_id() ),
					'order_id' => $order->get_id(),
					'quantity' => abs( $change['from'] - $change['to'] ),
				)
			);
		}
	}

	$order->add_order_note( __( 'Stock levels reduced:', 'woocommerce' ) . ' ' . implode( ', ', $order_notes ) );
}

/**
 * Increase stock levels for items within an order.
 *
 * @since 3.0.0
 * @param int|WC_Order $order_id Order ID or order instance.
 */
function wc_increase_stock_levels( $order_id ) {
	if ( is_a( $order_id, 'WC_Order' ) ) {
		$order    = $order_id;
		$order_id = $order->get_id();
	} else {
		$order = wc_get_order( $order_id );
	}

	// We need an order, and a store with stock management to continue.
	if ( ! $order || 'yes' !== get_option( 'woocommerce_manage_stock' ) || ! apply_filters( 'woocommerce_can_restore_order_stock', true, $order ) ) {
		return;
	}

	$changes = array();

	// Loop over all items.
	foreach ( $order->get_items() as $item ) {
		if ( ! $item->is_type( 'line_item' ) ) {
			continue;
		}

		// Only reduce stock once for each item.
		$product            = $item->get_product();
		$item_stock_reduced = $item->get_meta( '_reduced_stock', true );

		if ( ! $item_stock_reduced || ! $product || ! $product->managing_stock() ) {
			continue;
		}

		$item_name = $product->get_formatted_name();
		$new_stock = wc_update_product_stock( $product, $item_stock_reduced, 'increase' );

		if ( is_wp_error( $new_stock ) ) {
			/* translators: %s item name. */
			$order->add_order_note( sprintf( __( 'Unable to restore stock for item %s.', 'woocommerce' ), $item_name ) );
			continue;
		}

		$item->delete_meta_data( '_reduced_stock' );
		$item->save();

		$changes[] = $item_name . ' ' . ( $new_stock - $item_stock_reduced ) . '&rarr;' . $new_stock;
	}

	if ( $changes ) {
		$order->add_order_note( __( 'Stock levels increased:', 'woocommerce' ) . ' ' . implode( ', ', $changes ) );
	}

	do_action( 'woocommerce_restore_order_stock', $order );
}

/**
 * See how much stock is being held in pending orders.
 *
 * @since 3.5.0
 * @param WC_Product $product Product to check.
 * @param integer    $exclude_order_id Order ID to exclude.
 * @return int
 */
function wc_get_held_stock_quantity( $product, $exclude_order_id = 0 ) {
	global $wpdb;

	return $wpdb->get_var(
		$wpdb->prepare(
			"
			SELECT SUM( order_item_meta.meta_value ) AS held_qty
			FROM {$wpdb->posts} AS posts
			LEFT JOIN {$wpdb->prefix}woocommerce_order_items as order_items ON posts.ID = order_items.order_id
			LEFT JOIN {$wpdb->prefix}woocommerce_order_itemmeta as order_item_meta ON order_items.order_item_id = order_item_meta.order_item_id
			LEFT JOIN {$wpdb->prefix}woocommerce_order_itemmeta as order_item_meta2 ON order_items.order_item_id = order_item_meta2.order_item_id
			WHERE 	order_item_meta.meta_key    = '_qty'
			AND 	order_item_meta2.meta_key   = %s
			AND 	order_item_meta2.meta_value = %d
			AND 	posts.post_type             IN ( '" . implode( "','", wc_get_order_types() ) . "' )
			AND 	posts.post_status           = 'wc-pending'
			AND		posts.ID                    != %d;",
			'product_variation' === get_post_type( $product->get_stock_managed_by_id() ) ? '_variation_id' : '_product_id',
			$product->get_stock_managed_by_id(),
			$exclude_order_id
		)
	); // WPCS: unprepared SQL ok.
}

/**
 * Return low stock amount to determine if notification needs to be sent
 *
 * @param  WC_Product $product
 * @since  3.5.0
 * @return int
 */
function wc_get_low_stock_amount( WC_Product $product ) {
	if ( $product->is_type( 'variation' ) ) {
		$product = wc_get_product( $product->get_parent_id() );
	}
	$low_stock_amount = $product->get_low_stock_amount();
	if ( '' === $low_stock_amount ) {
		$low_stock_amount = get_option( 'woocommerce_notify_low_stock_amount', 2 );
	}

	return $low_stock_amount;
}
