<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class AIEO_Variation_Payload {

	
	const OPTION = 'aieo_variation_payload_enabled';

	
	private static $memo = array();

	
	private static $order = array();

	
	private static $builds = 0;

	
	private static $hits = 0;

	
	private static $invalidations = 0;

	
	private static $enabled = null;

	
	public static function register() {
		add_filter( 'woocommerce_product_class', array( __CLASS__, 'filter_product_class' ), 10, 4 );

		
		
		
		add_action( 'woocommerce_save_product_variation', array( __CLASS__, 'flush_for_variation' ), 10, 1 );
		add_action( 'woocommerce_delete_product_variation', array( __CLASS__, 'flush_for_variation' ), 10, 1 );
		add_action( 'woocommerce_trash_product_variation', array( __CLASS__, 'flush_for_variation' ), 10, 1 );
		add_action( 'woocommerce_update_product', array( __CLASS__, 'flush' ), 10, 1 );
		add_action( 'woocommerce_variation_set_stock', array( __CLASS__, 'flush_for_product_object' ), 10, 1 );
		add_action( 'woocommerce_product_set_stock', array( __CLASS__, 'flush_for_product_object' ), 10, 1 );
	}

	
	public static function is_enabled() {
		if ( null === self::$enabled ) {
			$opt = get_option( self::OPTION, 'yes' );
			self::$enabled = ( 'no' !== $opt );
		}
		
		return (bool) apply_filters( 'aieo_variation_payload_enabled', self::$enabled );
	}

	
	public static function filter_product_class( $classname, $product_type = '', $post_type = '', $product_id = 0 ) {
		if ( 'WC_Product_Variable' !== $classname ) {
			return $classname;
		}
		if ( ! self::is_enabled() ) {
			return $classname;
		}

		
		
		
		if ( ! class_exists( 'AIEO_Product_Variable', false ) ) {
			
			
			
			
			if ( ! class_exists( 'WC_Product_Variable' ) ) {
				return $classname;
			}
			require_once __DIR__ . '/class-aieo-product-variable.php';
		}

		return class_exists( 'AIEO_Product_Variable', false ) ? 'AIEO_Product_Variable' : $classname;
	}

	
	private static function filter_signature() {
		
		$hooks = (array) apply_filters(
			'aieo_variation_payload_signature_hooks',
			array( 'woocommerce_available_variation', 'woocommerce_hide_invisible_variations' )
		);

		$sig = (string) get_option( 'woocommerce_hide_out_of_stock_items', 'no' ) . '|';

		foreach ( $hooks as $hook ) {
			if ( empty( $GLOBALS['wp_filter'][ $hook ] ) ) {
				$sig .= $hook . ':none;';
				continue;
			}
			$registered = $GLOBALS['wp_filter'][ $hook ];
			if ( ! isset( $registered->callbacks ) || ! is_array( $registered->callbacks ) ) {
				continue;
			}
			foreach ( $registered->callbacks as $priority => $callbacks ) {
				
				$sig .= $hook . ':' . $priority . ':' . implode( ',', array_keys( $callbacks ) ) . ';';
			}
		}

		return md5( $sig );
	}

	
	public static function peek( $product_id ) {
		$product_id = (int) $product_id;
		if ( ! isset( self::$memo[ $product_id ] ) ) {
			return null;
		}

		$entry = self::$memo[ $product_id ];
		if ( ! isset( $entry['sig'] ) || $entry['sig'] !== self::filter_signature() ) {
			
			
			self::$invalidations++;
			self::flush( $product_id );
			return null;
		}

		self::$hits++;
		return $entry['payload'];
	}

	
	public static function store( $product_id, array $payload ) {
		$product_id = (int) $product_id;
		if ( $product_id <= 0 ) {
			return;
		}

		self::$builds++;

		
		$max = (int) apply_filters( 'aieo_variation_payload_max_products', 25 );

		if ( ! isset( self::$memo[ $product_id ] ) ) {
			self::$order[] = $product_id;
		}
		self::$memo[ $product_id ] = array(
			'sig'     => self::filter_signature(),
			'payload' => $payload,
		);

		while ( $max > 0 && count( self::$order ) > $max ) {
			$evict = array_shift( self::$order );
			unset( self::$memo[ $evict ] );
		}
	}

	
	public static function flush( $product_id = 0 ) {
		$product_id = (int) $product_id;
		if ( $product_id <= 0 ) {
			self::$memo  = array();
			self::$order = array();
			return;
		}
		unset( self::$memo[ $product_id ] );
		$pos = array_search( $product_id, self::$order, true );
		if ( false !== $pos ) {
			unset( self::$order[ $pos ] );
			self::$order = array_values( self::$order );
		}
	}

	
	public static function flush_for_variation( $variation_id ) {
		$parent = (int) wp_get_post_parent_id( (int) $variation_id );
		if ( $parent > 0 ) {
			self::flush( $parent );
		}
	}

	
	public static function flush_for_product_object( $product ) {
		if ( ! is_object( $product ) || ! method_exists( $product, 'get_id' ) ) {
			self::flush();
			return;
		}
		$id = (int) $product->get_id();
		if ( method_exists( $product, 'get_parent_id' ) ) {
			$parent = (int) $product->get_parent_id();
			if ( $parent > 0 ) {
				self::flush( $parent );
				return;
			}
		}
		self::flush( $id );
	}

	
	public static function stats() {
		return array(
			'builds'        => self::$builds,
			'hits'          => self::$hits,
			'products'      => count( self::$memo ),
			'invalidations' => self::$invalidations,
		);
	}
}