<?php
/**
 * Granular freshness / staleness for audit findings (FR-090 / FR-005).
 *
 * Order transaction snapshots are never marked stale by catalog changes.
 *
 * @package Kayvandra\MarginBeacon
 */

declare(strict_types=1);

namespace Kayvandra\MarginBeacon\Application\Freshness;

use Kayvandra\MarginBeacon\Infrastructure\Persistence\FindingsRepository;
use Kayvandra\MarginBeacon\Support\Constants;

/**
 * Marks findings stale / needs_verification and exposes dashboard counts.
 */
final class FreshnessService {

	const OPTION_CALC_CONTRACT = 'aksmb_calc_contract_fingerprint';
	const OPTION_SUMMARY       = 'aksmb_freshness_summary';

	/**
	 * @var FindingsRepository
	 */
	private $repo;

	/**
	 * @param FindingsRepository|null $repo Repo.
	 */
	public function __construct( $repo = null ) {
		$this->repo = $repo ? $repo : new FindingsRepository();
	}

	/**
	 * Current calculation contract fingerprint (formula + Woo + adapter).
	 *
	 * @return string
	 */
	public function current_contract_fingerprint() {
		$woo     = defined( 'WC_VERSION' ) ? (string) WC_VERSION : '';
		$payload = array(
			'formula' => defined( 'AKSMB_FORMULA_VERSION' ) ? AKSMB_FORMULA_VERSION : '',
			'plugin'  => defined( 'AKSMB_VERSION' ) ? AKSMB_VERSION : '',
			'woo'     => $woo,
			'adapter' => 'woo_discounts_v1',
		);
		return hash( 'sha256', (string) wp_json_encode( $payload ) );
	}

	/**
	 * On boot: if contract changed, mark all findings Needs verification (AC-015).
	 *
	 * @return bool True when a transition occurred.
	 */
	public function maybe_mark_needs_verification() {
		$current = $this->current_contract_fingerprint();
		$stored  = (string) get_option( self::OPTION_CALC_CONTRACT, '' );

		if ( '' === $stored ) {
			update_option( self::OPTION_CALC_CONTRACT, $current, false );
			$this->refresh_summary_cache();
			return false;
		}

		if ( hash_equals( $stored, $current ) ) {
			return false;
		}

		$this->repo->mark_all_findings_freshness( Freshness::NEEDS_VERIFICATION );
		$this->repo->mark_completed_scans_status( 'needs_verification' );
		update_option( self::OPTION_CALC_CONTRACT, $current, false );
		$this->refresh_summary_cache();
		return true;
	}

	/**
	 * Coupon material edit → that coupon stale; related product findings in same scans partially stale.
	 *
	 * @param int $coupon_id Coupon ID.
	 * @return void
	 */
	public function on_coupon_material_change( $coupon_id ) {
		$coupon_id = (int) $coupon_id;
		if ( $coupon_id <= 0 ) {
			return;
		}
		$scan_ids = $this->repo->mark_entity_freshness( 'coupon', $coupon_id, Freshness::STALE );
		if ( ! empty( $scan_ids ) ) {
			$this->repo->mark_scan_findings_freshness(
				$scan_ids,
				Freshness::PARTIAL_STALE,
				array( 'coupon' => $coupon_id ) // exclude already-stale coupon rows by leaving them; method skips non-fresh.
			);
		}
		$this->refresh_summary_cache();
	}

	/**
	 * Product price / COGS change → product findings stale; sibling coupon findings partial_stale.
	 *
	 * @param int $product_id   Product or variation ID used as entity_id.
	 * @param int $variation_id Optional variation.
	 * @return void
	 */
	public function on_product_material_change( $product_id, $variation_id = 0 ) {
		$product_id   = (int) $product_id;
		$variation_id = (int) $variation_id;
		if ( $product_id <= 0 && $variation_id <= 0 ) {
			return;
		}

		$scan_ids = array();
		if ( $variation_id > 0 ) {
			$scan_ids = array_merge( $scan_ids, $this->repo->mark_entity_freshness( 'variation', $variation_id, Freshness::STALE ) );
			$scan_ids = array_merge( $scan_ids, $this->repo->mark_entity_freshness( 'product', $variation_id, Freshness::STALE ) );
		}
		if ( $product_id > 0 ) {
			$scan_ids = array_merge( $scan_ids, $this->repo->mark_entity_freshness( 'product', $product_id, Freshness::STALE ) );
			$scan_ids = array_merge( $scan_ids, $this->repo->mark_entity_freshness( 'variation', $product_id, Freshness::STALE ) );
		}
		$scan_ids = array_values( array_unique( array_map( 'intval', $scan_ids ) ) );
		if ( ! empty( $scan_ids ) ) {
			$this->repo->mark_scan_findings_freshness( $scan_ids, Freshness::PARTIAL_STALE );
		}
		$this->refresh_summary_cache();
	}

	/**
	 * Global threshold edit → all financial findings stale (FR-090).
	 *
	 * @return void
	 */
	public function on_global_threshold_change() {
		$this->repo->mark_all_findings_freshness( Freshness::STALE, array( Freshness::NEEDS_VERIFICATION ) );
		$this->refresh_summary_cache();
	}

	/**
	 * Dashboard summary counts.
	 *
	 * @return array{fresh:int,partial_stale:int,stale:int,needs_verification:int,coupons_stale:int,products_stale:int,summary_line:string}
	 */
	public function summarize() {
		$cached = get_option( self::OPTION_SUMMARY, null );
		if ( is_array( $cached ) && isset( $cached['summary_line'] ) ) {
			return $cached;
		}
		return $this->refresh_summary_cache();
	}

	/**
	 * Recompute and persist summary.
	 *
	 * @return array
	 */
	public function refresh_summary_cache() {
		$counts   = $this->repo->freshness_counts();
		$entities = $this->repo->stale_entity_counts();

		$partial  = isset( $counts[ Freshness::PARTIAL_STALE ] ) ? (int) $counts[ Freshness::PARTIAL_STALE ] : 0;
		$stale    = isset( $counts[ Freshness::STALE ] ) ? (int) $counts[ Freshness::STALE ] : 0;
		$needs    = isset( $counts[ Freshness::NEEDS_VERIFICATION ] ) ? (int) $counts[ Freshness::NEEDS_VERIFICATION ] : 0;
		$fresh    = isset( $counts[ Freshness::FRESH ] ) ? (int) $counts[ Freshness::FRESH ] : 0;
		$coupons  = isset( $entities['coupon'] ) ? (int) $entities['coupon'] : 0;
		$products = ( isset( $entities['product'] ) ? (int) $entities['product'] : 0 )
			+ ( isset( $entities['variation'] ) ? (int) $entities['variation'] : 0 );

		$line = __( 'All preflight findings are Fresh.', 'marginbeacon' );
		if ( $needs > 0 ) {
			$line = sprintf(
				/* translators: %d: finding count */
				__( 'Needs verification — %d findings require a verification preflight after a calculation contract change.', 'marginbeacon' ),
				$needs
			);
		} elseif ( $partial > 0 || $stale > 0 || $coupons > 0 || $products > 0 ) {
			$line = sprintf(
				/* translators: 1: coupon count 2: product count */
				__( 'Partially stale — %1$d coupons and %2$d products affected. Re-run preflight to refresh.', 'marginbeacon' ),
				$coupons,
				$products
			);
		}

		$summary = array(
			'fresh'              => $fresh,
			'partial_stale'      => $partial,
			'stale'              => $stale,
			'needs_verification' => $needs,
			'coupons_stale'      => $coupons,
			'products_stale'     => $products,
			'summary_line'       => $line,
			'updated_at_gmt'     => gmdate( 'Y-m-d H:i:s' ),
		);
		update_option( self::OPTION_SUMMARY, $summary, false );
		return $summary;
	}
}