<?php
/**
 * Groups raw Merchant Center issue rows by product. Pure functions, no WordPress hooks.
 * Returns raw strings; escape at output.
 */

defined( 'ABSPATH' ) || exit;

require_once __DIR__ . '/explanations.php';

/**
 * Split a stored applicable_countries value (comma separated, or a JSON array) into country codes.
 *
 * @return string[]
 */
function feedfixer_split_countries( $value ): array {
	$value = trim( (string) $value );
	if ( '' === $value ) {
		return array();
	}
	if ( '[' === $value[0] ) {
		$decoded = json_decode( $value, true );
		if ( is_array( $decoded ) ) {
			$value = implode( ',', array_filter( $decoded, 'is_scalar' ) );
		}
	}
	$parts = preg_split( '/[\s,;]+/', $value, -1, PREG_SPLIT_NO_EMPTY );
	return array_values( array_unique( $parts ) );
}

/**
 * Group issue rows by product.
 *
 * @param array $rows Rows as arrays or stdClass objects.
 * @return array<int, array{product_id:int, product_name:string, issues:array}>
 */
function feedfixer_group_issues( array $rows ): array {
	$products = array();

	foreach ( $rows as $row ) {
		$row        = (array) $row;
		$product_id = (int) ( $row['product_id'] ?? 0 );
		if ( $product_id <= 0 ) {
			continue;
		}
		if ( ! isset( $products[ $product_id ] ) ) {
			$products[ $product_id ] = array( 'name' => '', 'issues' => array() );
		}
		$p = &$products[ $product_id ];
		if ( '' === $p['name'] ) {
			$p['name'] = trim( (string) ( $row['product'] ?? '' ) );
		}

		$code      = (string) ( $row['code'] ?? '' );
		$severity  = (string) ( $row['severity'] ?? '' );
		$countries = feedfixer_split_countries( $row['applicable_countries'] ?? '' );

		if ( isset( $p['issues'][ $code ] ) ) {
			$p['issues'][ $code ]['countries'] = array_values( array_unique( array_merge( $p['issues'][ $code ]['countries'], $countries ) ) );
			if ( 'error' === $severity ) {
				$p['issues'][ $code ]['severity'] = 'error';
			}
		} else {
			$p['issues'][ $code ] = array(
				'severity'    => $severity,
				'code'        => $code,
				'explanation' => feedfixer_explain_issue( $row ),
				'countries'   => $countries,
			);
		}
		unset( $p );
	}

	$groups = array();
	foreach ( $products as $product_id => $p ) {
		$issues = array_values( $p['issues'] );
		foreach ( $issues as $i => $issue ) {
			$issues[ $i ]['countries'] = implode( ', ', $issue['countries'] );
		}
		// Stable sort (PHP 8): errors first, otherwise keep input order.
		usort( $issues, fn ( $a, $b ) => ( 'error' === $b['severity'] ) <=> ( 'error' === $a['severity'] ) );
		$groups[] = array(
			'product_id'   => $product_id,
			'product_name' => '' !== $p['name'] ? $p['name'] : 'Product #' . $product_id,
			'issues'       => $issues,
		);
	}

	$errors = fn ( array $g ): int => count( array_filter( $g['issues'], fn ( $i ) => 'error' === $i['severity'] ) );
	usort( $groups, fn ( $a, $b ) => array( $errors( $b ), count( $b['issues'] ), $a['product_id'] ) <=> array( $errors( $a ), count( $a['issues'] ), $b['product_id'] ) );

	return $groups;
}

/**
 * Totals for a list of groups.
 *
 * @return array{products:int, issues:int, errors:int}
 */
function feedfixer_issue_counts( array $groups ): array {
	$counts = array( 'products' => count( $groups ), 'issues' => 0, 'errors' => 0 );
	foreach ( $groups as $group ) {
		foreach ( $group['issues'] as $issue ) {
			$counts['issues']++;
			if ( 'error' === $issue['severity'] ) {
				$counts['errors']++;
			}
		}
	}
	return $counts;
}