<?php
/**
 * Cross-provider result consolidation.
 *
 * @package MediaRightsAudit\External
 */

namespace MediaRightsAudit\External;

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

/**
 * Aggregates external scan results across multiple providers to surface
 * domains that appear in more than one provider's findings (consensus signals).
 *
 * Consensus detection provides stronger copyright-risk signals: a domain
 * independently found by both Google Vision and TinEye is more likely to be
 * a genuine unauthorised copy than one found by a single provider.
 */
class ResultsConsolidator {

	/**
	 * Returns domains confirmed by results from at least $min_providers distinct providers.
	 *
	 * Reads top_domains JSON stored in mra_external_results for the given attachment
	 * and counts how many providers reported each domain. Only domains meeting the
	 * threshold are returned, sorted descending by provider-agreement count.
	 *
	 * @param int $attachment_id WordPress attachment ID.
	 * @param int $min_providers Minimum number of providers that must agree (default: 2).
	 *
	 * @return array<string, int> Domain → agreeing-provider count, sorted descending.
	 */
	public static function get_consensus_domains( int $attachment_id, int $min_providers = 2 ): array {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT provider, top_domains FROM {$wpdb->prefix}mra_external_results WHERE attachment_id = %d",
				$attachment_id
			),
			ARRAY_A
		);

		if ( ! $rows ) {
			return array();
		}

		return self::aggregate_consensus( $rows, $min_providers );
	}

	/**
	 * Computes consensus domains from an array of provider result rows.
	 *
	 * Each row must contain 'provider' (string) and 'top_domains' (JSON string
	 * mapping domain → count). Designed to be called directly in unit tests
	 * by passing mock row data.
	 *
	 * @param array<int, array<string, mixed>> $rows         Provider result rows.
	 * @param int                              $min_providers Minimum provider agreement.
	 *
	 * @return array<string, int> Domain → agreeing-provider count, sorted descending.
	 */
	public static function aggregate_consensus( array $rows, int $min_providers = 2 ): array {
		$domain_to_providers = array();

		foreach ( $rows as $row ) {
			$provider_val = $row['provider'] ?? null;
			$provider     = is_string( $provider_val ) ? $provider_val : '';
			if ( '' === $provider ) {
				continue;
			}

			$domains_val = $row['top_domains'] ?? null;
			$domains_raw = is_string( $domains_val ) ? json_decode( $domains_val, true ) : null;
			$domains     = is_array( $domains_raw ) ? $domains_raw : array();

			foreach ( $domains as $domain => $count ) {
				if ( ! is_string( $domain ) ) {
					continue;
				}
				if ( ! isset( $domain_to_providers[ $domain ] ) ) {
					$domain_to_providers[ $domain ] = array();
				}
				$domain_to_providers[ $domain ][ $provider ] = true;
			}
		}

		$consensus = array();
		foreach ( $domain_to_providers as $domain => $providers_map ) {
			$provider_count = count( $providers_map );
			if ( $provider_count >= $min_providers ) {
				$consensus[ $domain ] = $provider_count;
			}
		}

		arsort( $consensus );
		return $consensus;
	}
}