<?php
/**
 * PHP Memory Limit check.
 *
 * @package advanced-analytics
 *
 * @since 4.9.0
 */

declare(strict_types=1);

namespace ADVAN\Checks\Speed;

use ADVAN\Checks\Abstract_Check;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! class_exists( 'ADVAN\Checks\Speed\PHP_Memory_Limit_Check' ) ) {

	/**
	 * Checks if PHP has enough memory allocated.
	 *
	 * @since 4.9.0
	 */
	class PHP_Memory_Limit_Check extends Abstract_Check {

		/**
		 * Check identifier.
		 *
		 * @var string Check identifier.
		 * @since 4.9.0
		 */
		protected static string $id = 'php-memory-limit';

		/**
		 * Check category.
		 *
		 * @var string Check category.
		 * @since 4.9.0
		 */
		protected static string $category = 'speed';

		/**
		 * Check weight (1-10).
		 *
		 * @var int Check weight.
		 * @since 4.9.0
		 */
		protected static int $weight = 5;

		/**
		 * Check title (translatable).
		 *
		 * @return string Check title.
		 *
		 * @since 4.9.0
		 */
		public static function get_title(): string {
			return \__( 'PHP Memory Limit', '0-day-analytics' );
		}

		/**
		 * Check description (translatable).
		 *
		 * @return string Check description.
		 *
		 * @since 4.9.0
		 */
		public static function get_description(): string {
			return \__( 'Checks if PHP has enough memory allocated.', '0-day-analytics' );
		}

		/**
		 * Run the check.
		 *
		 * @return array Check result.
		 *
		 * @since 4.9.0
		 */
		public static function run(): array {
			// Get WordPress memory limit.
			$wp_memory_limit = defined( 'WP_MEMORY_LIMIT' ) ? WP_MEMORY_LIMIT : '40M';

			// Get PHP memory limit.
			$php_memory_limit = ini_get( 'memory_limit' );

			// Convert to bytes.
			$wp_limit_bytes  = static::convert_to_bytes( $wp_memory_limit );
			$php_limit_bytes = static::convert_to_bytes( $php_memory_limit );

			// Use the higher of the two.
			$effective_limit = max( $wp_limit_bytes, $php_limit_bytes );

			$details = array(
				'wp_memory_limit'  => $wp_memory_limit,
				'php_memory_limit' => $php_memory_limit,
				'effective_bytes'  => $effective_limit,
				'effective_mb'     => round( $effective_limit / 1024 / 1024 ),
			);

			$limit_mb = $details['effective_mb'];

			if ( $limit_mb < 64 ) {
				return static::fail(
					'high',
					sprintf(
					/* translators: %d: memory in MB */
						\__( 'Your PHP memory limit is only %d MB. This is very low and may cause errors on your site, especially when using page builders or uploading images.', '0-day-analytics' ),
						$limit_mb
					),
					\__( 'Contact your hosting provider to increase the memory limit to at least 256 MB. You can also try adding define(\'WP_MEMORY_LIMIT\', \'256M\'); to wp-config.php.', '0-day-analytics' ),
					$details
				);
			}

			if ( $limit_mb < 128 ) {
				return static::warning(
					sprintf(
					/* translators: %d: memory in MB */
						\__( 'Your PHP memory limit is %d MB. While this may work for basic sites, you may encounter issues with larger pages or media uploads.', '0-day-analytics' ),
						$limit_mb
					),
					\__( 'Consider increasing to 256 MB for more headroom. Add define(\'WP_MEMORY_LIMIT\', \'256M\'); to wp-config.php or contact your host.', '0-day-analytics' ),
					$details
				);
			}

			if ( $limit_mb < 256 ) {
				return static::info(
					sprintf(
					/* translators: %d: memory in MB */
						\__( 'Your PHP memory limit is %d MB. This is adequate for most sites, though complex sites with page builders may benefit from 256 MB.', '0-day-analytics' ),
						$limit_mb
					),
					$details
				);
			}

			return static::pass(
				sprintf(
				/* translators: %d: memory in MB */
					\__( 'Your PHP memory limit is %d MB, which provides plenty of headroom for WordPress and plugins to operate.', '0-day-analytics' ),
					$limit_mb
				),
				$details
			);
		}

		/**
		 * Convert memory string to bytes.
		 *
		 * @param string $value Memory value string (e.g., '256M').
		 *
		 * @return int Bytes.
		 *
		 * @since 4.9.0
		 *
		 * The memory limit can be specified in php.ini or wp-config.php using shorthand notation (e.g., '256M' for 256 megabytes). This function converts those values into bytes for easier comparison.
		 *
		 * It handles the following cases:
		 * - Unlimited: '-1' is treated as unlimited and returns PHP_INT_MAX.
		 * - Gigabytes (G): Multiplies the number by 1024^3.
		 * - Megabytes (M): Multiplies the number by 1024^2.
		 * - Kilobytes (K): Multiplies the number by 1024.
		 * - Bytes: If no unit is specified, it treats the value as bytes.
		 *
		 * Example usage:
		 * - '256M' => 268435456 bytes
		 * - '1G' => 1073741824 bytes
		 * - '512K' => 524288 bytes
		 * - '-1' => PHP_INT_MAX (unlimited)
		 */
		private static function convert_to_bytes( $value ) {
			$value = trim( $value );

			if ( '-1' === $value ) {
				// Unlimited - return a very high number.
				return PHP_INT_MAX;
			}

			$unit = strtoupper( substr( $value, -1 ) );
			$num  = (int) $value;

			switch ( $unit ) {
				case 'G':
					return $num * 1024 * 1024 * 1024;
				case 'M':
					return $num * 1024 * 1024;
				case 'K':
					return $num * 1024;
				default:
					return $num;
			}
		}
	}
}