<?php
/**
 * Hooks that mark findings stale on material catalog/settings changes.
 *
 * @package Kayvandra\MarginBeacon
 */

declare(strict_types=1);

namespace Kayvandra\MarginBeacon\Application\Freshness;

use Kayvandra\MarginBeacon\Application\MaterialChange\CouponMaterialHasher;

/**
 * Free V0.9: mark-stale + manual refresh prompt (no Pro auto re-audit).
 */
final class StalenessObserver {

	/**
	 * Previous coupon material hashes keyed by coupon ID (request-scoped).
	 *
	 * @var array<int,string>
	 */
	private $coupon_before = array();

	/**
	 * Previous product price fingerprints.
	 *
	 * @var array<int,string>
	 */
	private $product_before = array();

	/**
	 * @var FreshnessService
	 */
	private $freshness;

	/**
	 * @param FreshnessService|null $freshness Service.
	 */
	public function __construct( $freshness = null ) {
		$this->freshness = $freshness ? $freshness : new FreshnessService();
	}

	/**
	 * @return void
	 */
	public function register() {
		add_action( 'admin_init', array( $this, 'boot_verification_check' ), 5 );

		add_action( 'woocommerce_before_coupon_object_save', array( $this, 'capture_coupon_before' ), 10, 1 );
		add_action( 'woocommerce_coupon_object_updated_props', array( $this, 'on_coupon_updated_props' ), 10, 2 );
		// Fallback for older save paths / admin list edits.
		add_action( 'woocommerce_update_coupon', array( $this, 'on_coupon_id_saved' ), 20, 1 );

		add_action( 'woocommerce_before_product_object_save', array( $this, 'capture_product_before' ), 10, 1 );
		add_action( 'woocommerce_update_product', array( $this, 'on_product_id_saved' ), 20, 1 );
		add_action( 'woocommerce_update_product_variation', array( $this, 'on_product_id_saved' ), 20, 1 );
	}

	/**
	 * @return void
	 */
	public function boot_verification_check() {
		$this->freshness->maybe_mark_needs_verification();
	}

	/**
	 * @param \WC_Coupon $coupon Coupon.
	 * @return void
	 */
	public function capture_coupon_before( $coupon ) {
		if ( ! is_object( $coupon ) || ! method_exists( $coupon, 'get_id' ) ) {
			return;
		}
		$id = (int) $coupon->get_id();
		if ( $id <= 0 ) {
			return;
		}
		$this->coupon_before[ $id ] = CouponMaterialHasher::hash_coupon( $coupon );
	}

	/**
	 * @param \WC_Coupon $coupon Coupon.
	 * @param array      $updated_props Props.
	 * @return void
	 */
	public function on_coupon_updated_props( $coupon, $updated_props ) {
		if ( ! is_object( $coupon ) || ! method_exists( $coupon, 'get_id' ) ) {
			return;
		}
		$id = (int) $coupon->get_id();
		if ( $id <= 0 ) {
			return;
		}
		$after  = CouponMaterialHasher::hash_coupon( $coupon );
		$before = isset( $this->coupon_before[ $id ] ) ? $this->coupon_before[ $id ] : '';
		if ( '' !== $before && hash_equals( $before, $after ) ) {
			return;
		}
		// First save without before snapshot, or material hash changed.
		if ( '' === $before || ! hash_equals( $before, $after ) ) {
			$this->freshness->on_coupon_material_change( $id );
		}
	}

	/**
	 * @param int $coupon_id Coupon ID.
	 * @return void
	 */
	public function on_coupon_id_saved( $coupon_id ) {
		$coupon_id = (int) $coupon_id;
		if ( $coupon_id <= 0 || ! class_exists( '\WC_Coupon' ) ) {
			return;
		}
		// If CRUD path already handled this ID in-request, skip duplicate.
		if ( isset( $this->coupon_before[ $coupon_id ] ) ) {
			return;
		}
		$this->freshness->on_coupon_material_change( $coupon_id );
	}

	/**
	 * @param \WC_Product $product Product.
	 * @return void
	 */
	public function capture_product_before( $product ) {
		if ( ! is_object( $product ) || ! method_exists( $product, 'get_id' ) ) {
			return;
		}
		$id = (int) $product->get_id();
		if ( $id <= 0 ) {
			return;
		}
		$this->product_before[ $id ] = $this->product_price_fingerprint( $product );
	}

	/**
	 * @param int $product_id Product or variation ID.
	 * @return void
	 */
	public function on_product_id_saved( $product_id ) {
		$product_id = (int) $product_id;
		if ( $product_id <= 0 || ! function_exists( 'wc_get_product' ) ) {
			return;
		}
		$product = wc_get_product( $product_id );
		if ( ! $product ) {
			return;
		}
		$after  = $this->product_price_fingerprint( $product );
		$before = isset( $this->product_before[ $product_id ] ) ? $this->product_before[ $product_id ] : '';
		if ( '' !== $before && hash_equals( $before, $after ) ) {
			return;
		}
		$parent = (int) $product->get_parent_id();
		$this->freshness->on_product_material_change( $parent > 0 ? $parent : $product_id, $parent > 0 ? $product_id : 0 );
	}

	/**
	 * Manual COGS meta change (called from ProductCostFields).
	 *
	 * @param int $product_id Product or variation ID.
	 * @return void
	 */
	public function on_manual_cost_change( $product_id ) {
		$product_id = (int) $product_id;
		if ( $product_id <= 0 || ! function_exists( 'wc_get_product' ) ) {
			return;
		}
		$product = wc_get_product( $product_id );
		$parent  = $product ? (int) $product->get_parent_id() : 0;
		$this->freshness->on_product_material_change( $parent > 0 ? $parent : $product_id, $parent > 0 ? $product_id : 0 );
	}

	/**
	 * Price-related fingerprint (material for preflight).
	 *
	 * @param \WC_Product $product Product.
	 * @return string
	 */
	private function product_price_fingerprint( $product ) {
		$payload = array(
			'regular' => (string) $product->get_regular_price(),
			'sale'    => (string) $product->get_sale_price(),
			'price'   => (string) $product->get_price(),
		);
		return hash( 'sha256', (string) wp_json_encode( $payload ) );
	}
}