<?php
/** Read-only product comparison. */
namespace AdParityLite;

defined( 'ABSPATH' ) || exit;

final class Audit {
	/** Decimal syntax only: never silently interpret comma/grouped prices. */
	public static function money( string $value, string $currency = '' ): ?array {
		if ( ! preg_match( '/^(\d{1,12}(?:\.\d{1,6})?)(?:\s+([A-Za-z]{3}))?$/D', trim( $value ), $match ) ) {
			return null;
		}
		$embedded = strtoupper( $match[2] ?? '' );
		$currency = strtoupper( trim( $currency ) );
		if ( '' !== $embedded && '' !== $currency && $embedded !== $currency ) {
			return null;
		}
		$currency = '' !== $embedded ? $embedded : $currency;
		if ( ! preg_match( '/^[A-Z]{3}$/D', $currency ) ) {
			return null;
		}
		return array(
			'amount'   => self::decimal( $match[1] ),
			'currency' => $currency,
		);
	}

	private static function decimal( string $number ): string {
		$parts    = explode( '.', $number, 2 );
		$whole    = ltrim( $parts[0], '0' );
		$fraction = rtrim( $parts[1] ?? '', '0' );
		return ( '' === $whole ? '0' : $whole ) . ( '' !== $fraction ? '.' . $fraction : '' );
	}

	public static function effective_price( array $row, int $now ): ?array {
		$base = self::money( $row['price'], $row['currency'] );
		if ( ! $base || '' === $row['sale_price'] ) {
			return $base;
		}
		$sale = self::money( $row['sale_price'], '' !== $row['currency'] ? $row['currency'] : $base['currency'] );
		if ( ! $sale || $sale['currency'] !== $base['currency'] || (float) $sale['amount'] >= (float) $base['amount'] ) {
			return null;
		}
		if ( '' === $row['sale_price_effective_date'] ) {
			return $sale;
		}
		$dates = explode( '/', $row['sale_price_effective_date'] );
		if ( 2 !== count( $dates ) ) {
			return null;
		}
		$times = array();
		foreach ( $dates as $date ) {
			if ( ! preg_match( '/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}(?::\d{2})?(?:Z|[+-]\d{2}:?\d{2})$/D', $date ) ) {
				return null;
			}
			try {
				$parsed = new \DateTimeImmutable( $date );
				$errors = \DateTimeImmutable::getLastErrors();
				if ( is_array( $errors ) && ( $errors['warning_count'] > 0 || $errors['error_count'] > 0 ) ) {
					return null;
				}
				$times[] = $parsed->getTimestamp();
			} catch ( \Exception $exception ) {
				return null;
			}
		}
		if ( $times[0] >= $times[1] ) {
			return null;
		}
		return $now >= $times[0] && $now < $times[1] ? $sale : $base;
	}

	private static function finding( array &$result, string $code, string $level, string $message, string $fix ): void {
		$result['findings'][] = array(
			'code'    => $code,
			'level'   => $level,
			'message' => $message,
			'fix'     => $fix,
		);
		if ( 'error' === $level || 'checked' === $result['status'] ) {
			$result['status'] = $level;
		}
	}

	public function row( array $row, string $mode, bool $duplicate ): array {
		$result                 = array(
			'id'         => $row['id'],
			'sku'        => $row['sku'],
			'product_id' => 0,
			'status'     => 'checked',
			'findings'   => array(),
			'feed'       => $row,
			'woo'        => array(),
		);
		$price                  = self::effective_price( $row, time() );
		$result['active_price'] = $price;
		if ( '' === $row['id'] ) {
			self::finding( $result, 'feed_id', 'error', __( 'Feed id is empty.', 'adparity-lite' ), __( 'Supply a unique Merchant item id for every row.', 'adparity-lite' ) );
		}
		if ( $duplicate ) {
			self::finding( $result, 'duplicate_id', 'error', __( 'This Merchant item id occurs more than once.', 'adparity-lite' ), __( 'Give each product variation a unique feed id.', 'adparity-lite' ) );
		}
		if ( ! $price ) {
			self::finding( $result, 'feed_price', 'error', __( 'Price, currency or sale date is missing or invalid.', 'adparity-lite' ), __( 'Use 19.90 EUR or a separate currency column. Sale price must be lower; dates need ISO 8601 timezones and start/end.', 'adparity-lite' ) );
		}
		if ( ! in_array( $row['availability'], array( 'in_stock', 'out_of_stock', 'preorder', 'backorder' ), true ) ) {
			self::finding( $result, 'feed_availability', 'error', __( 'Feed availability is missing or invalid.', 'adparity-lite' ), __( 'Use in_stock, out_of_stock, preorder or backorder.', 'adparity-lite' ) );
		}
		$key     = 'sku' === $mode ? ( '' !== $row['sku'] ? $row['sku'] : $row['id'] ) : $row['id'];
		$id      = 'sku' === $mode ? ( '' !== $key ? wc_get_product_id_by_sku( $key ) : 0 ) : ( preg_match( '/^[1-9]\d{0,9}$/D', $key ) ? (int) $key : 0 );
		$product = $id ? wc_get_product( $id ) : false;
		if ( ! $product ) {
			self::finding( $result, 'unmatched', 'error', __( 'No WooCommerce product matches the selected identifier mode.', 'adparity-lite' ), __( 'Choose WooCommerce ID when id contains internal product IDs; otherwise choose SKU and supply sku or use the SKU as id.', 'adparity-lite' ) );
			return $result;
		}
		$result['product_id'] = $product->get_id();
		if ( ! $product->is_type( 'simple' ) ) {
			self::finding( $result, 'unsupported_type', 'review', __( "This product type is outside Lite's simple-product checks.", 'adparity-lite' ), __( 'Review variations and other product types manually. They are not counted as verified by Lite.', 'adparity-lite' ) );
			return $result;
		}
		if ( 'publish' !== $product->get_status() ) {
			self::finding( $result, 'not_public', 'error', __( 'The product is not published.', 'adparity-lite' ), __( 'Remove unpublished items from the feed or publish the intended product.', 'adparity-lite' ) );
			return $result;
		}
		if ( ( '' !== $row['sku'] && $row['sku'] !== $product->get_sku() ) || ( 'sku' === $mode && $key !== $product->get_sku() ) ) {
			self::finding( $result, 'sku', 'error', __( 'The feed SKU disagrees with WooCommerce.', 'adparity-lite' ), __( 'Correct the feed SKU mapping; do not map several variants to the parent SKU.', 'adparity-lite' ) );
		}
		$raw_price     = $product->get_price();
		$display_price = '' === $raw_price ? '' : wc_format_decimal( wc_get_price_to_display( $product ), wc_get_price_decimals() );
		$stock         = $product->is_in_stock() ? ( $product->is_on_backorder( 1 ) ? 'backorder' : 'in_stock' ) : 'out_of_stock';
		$canonical     = $product->get_permalink();
		$result['woo'] = array(
			'sku'          => $product->get_sku(),
			'price'        => $display_price,
			'currency'     => get_woocommerce_currency(),
			'availability' => $stock,
			'url'          => $canonical,
		);
		if ( '' === $display_price ) {
			self::finding( $result, 'woo_price', 'error', __( 'WooCommerce has no price for this product.', 'adparity-lite' ), __( 'Set a product price before advertising it.', 'adparity-lite' ) );
		} elseif ( $price && self::decimal( $display_price ) !== $price['amount'] ) {
			self::finding( $result, 'price', 'error', __( 'The active feed price differs from the store display price.', 'adparity-lite' ), __( 'Refresh the feed and check sale dates and the store tax display setting.', 'adparity-lite' ) );
		}
		if ( $price && $price['currency'] !== $result['woo']['currency'] ) {
			self::finding( $result, 'currency', 'error', __( 'The feed currency differs from the store currency.', 'adparity-lite' ), __( 'Use a feed for the store base currency. Contextual multi-currency feeds are outside this version.', 'adparity-lite' ) );
		}
		if ( $row['availability'] !== $stock ) {
			self::finding( $result, 'availability', 'preorder' === $row['availability'] ? 'review' : 'error', __( 'The feed availability differs from WooCommerce.', 'adparity-lite' ), __( 'Refresh stock values and check backorders. Preorder extensions need manual review.', 'adparity-lite' ) );
		}
		$link_ok = ProductLink::same_origin( $canonical, home_url( '/' ) ) && ProductLink::same_product( $row['link'], $canonical );
		if ( ! $link_ok ) {
			self::finding( $result, 'link', 'error', __( 'The feed link does not select the canonical product.', 'adparity-lite' ), __( 'Use the canonical product URL. Only tracking parameters may differ.', 'adparity-lite' ) );
		}
		return $result;
	}
}