<?php
/**
 * GA4 report filter builders.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Reports;

use TurtleReport\Profiles\Profile;

defined( 'ABSPATH' ) || exit;

/**
 * Small helpers that build GA4 dimensionFilter expressions.
 */
final class Filters {

	/**
	 * Matches a dimension exactly.
	 *
	 * @param string $field Dimension name.
	 * @param string $value Value.
	 * @return array
	 */
	public static function exact( $field, $value ) {
		return array(
			'filter' => array(
				'fieldName'    => $field,
				'stringFilter' => array(
					'matchType' => 'EXACT',
					'value'     => $value,
				),
			),
		);
	}

	/**
	 * Matches a dimension against a regular expression, ignoring case.
	 *
	 * @param string $field   Dimension name.
	 * @param string $pattern RE2 pattern.
	 * @return array
	 */
	public static function regex( $field, $pattern ) {
		return array(
			'filter' => array(
				'fieldName'    => $field,
				'stringFilter' => array(
					'matchType'     => 'PARTIAL_REGEXP',
					'value'         => $pattern,
					'caseSensitive' => false,
				),
			),
		);
	}

	/**
	 * Matches eventName against a list.
	 *
	 * @param string[] $events Event names.
	 * @return array
	 */
	public static function events( array $events ) {
		return array(
			'filter' => array(
				'fieldName'    => 'eventName',
				'inListFilter' => array( 'values' => array_values( $events ) ),
			),
		);
	}

	/**
	 * Combines filters with AND, skipping nulls.
	 *
	 * @param array ...$filters Filters.
	 * @return array|null
	 */
	public static function all( ...$filters ) {
		$filters = array_values( array_filter( $filters ) );
		if ( ! $filters ) {
			return null;
		}
		return 1 === count( $filters ) ? $filters[0] : array( 'andGroup' => array( 'expressions' => $filters ) );
	}

	/**
	 * Organic Search filter, using the site's chosen channel dimension.
	 *
	 * @param Profile $site Site.
	 * @return array
	 */
	public static function organic( Profile $site ) {
		$field = Profile::BASIS_SESSION === $site->lead_basis ? 'sessionDefaultChannelGroup' : 'firstUserDefaultChannelGroup';
		return self::exact( $field, 'Organic Search' );
	}
}