<?php
/**
 * Test data: counters of sales and coupon uses made by test orders.
 *
 * @package AdminPowerups
 */

namespace SmartWP\AdminPowerups\Modules\TestData;

defined( 'ABSPATH' ) || exit;

/**
 * `_apwc_test_sales` (products) and `_apwc_test_usage` (coupons) tell real sales and uses apart
 * from ours. Changes are gathered during a step and written once per object at its end (each
 * write drops the object's meta cache); outside a step they're written at once.
 *
 * Known drift: a step killed by a real fatal (timeout, memory) skips the `finally` that writes
 * them, so the counts can be lower than the sales and uses our orders made. That errs on the safe
 * side: the product or coupon is then kept as used by real orders.
 *
 * @since 1.0.0
 */
final class Counters {

	/**
	 * Pending changes: post ID => meta key => amount.
	 *
	 * @var array<int, array<string, int>>
	 */
	private static $pending = array();

	/**
	 * Whether changes are being gathered.
	 *
	 * @var bool
	 */
	private static $buffering = false;

	/**
	 * Start gathering changes (a step starts).
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function buffer(): void {
		self::$buffering = true;
	}

	/**
	 * Add to a counter of a test product or coupon (never on other objects).
	 *
	 * @since 1.0.0
	 * @param int    $id  Post ID.
	 * @param string $key Marker::SALES or Marker::USAGE.
	 * @param int    $by  Amount (negative to take off).
	 * @return void
	 */
	public static function add( int $id, string $key, int $by ): void {
		if ( $id <= 0 || 0 === $by ) {
			return;
		}
		self::$pending[ $id ][ $key ] = ( self::$pending[ $id ][ $key ] ?? 0 ) + $by;
		if ( ! self::$buffering ) {
			self::flush();
		}
	}

	/**
	 * Write the gathered changes and stop gathering.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function flush(): void {
		$pending         = self::$pending;
		self::$pending   = array();
		self::$buffering = false;
		foreach ( $pending as $id => $keys ) {
			if ( '' === (string) get_post_meta( $id, Marker::META, true ) ) {
				continue; // Only test objects carry our counters.
			}
			foreach ( $keys as $key => $by ) {
				update_post_meta( $id, $key, max( 0, (int) get_post_meta( $id, $key, true ) + $by ) );
			}
		}
	}

	/**
	 * `woocommerce_recorded_sales`: WooCommerce just recorded (or took back) an order's sales; when
	 * the order is a signed test order, do the same on our count, so staff cancelling a paid test
	 * order doesn't hide a later real sale.
	 *
	 * @since 1.0.0
	 * @param mixed $order_id Order ID.
	 * @return void
	 */
	public static function recorded_sales( $order_id ): void {
		$order = wc_get_order( (int) $order_id );
		if ( ! $order instanceof \WC_Order ) {
			return;
		}
		// Every paid order on the store passes here: read the loaded order's own meta first.
		$batch = (string) $order->get_meta( Marker::META );
		if ( ! Marker::valid_batch( $batch ) || ! Marker::valid_signature( 'order', (int) $order->get_id(), $batch, $order->get_meta( Marker::SIG ) ) ) {
			return;
		}
		$sign = $order->get_data_store()->get_recorded_sales( $order ) ? 1 : -1;
		foreach ( $order->get_items() as $item ) {
			if ( $item instanceof \WC_Order_Item_Product && $item->get_product_id() ) {
				self::add( (int) $item->get_product_id(), Marker::SALES, $sign * (int) $item->get_quantity() );
			}
		}
	}
}