<?php
/**
 * Migration Complexity check.
 *
 * @package advanced-analytics
 *
 * @since 4.9.0
 */

declare(strict_types=1);

namespace ADVAN\Checks\Migration;

use ADVAN\Checks\Abstract_Check;

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

if ( ! class_exists( 'ADVAN\Checks\Migration\Migration_Complexity_Check' ) ) {

	/**
	 * Migration Complexity check class.
	 *
	 * @since 4.9.0
	 */
	class Migration_Complexity_Check extends Abstract_Check {

		/**
		 * Check identifier (slug).
		 *
		 * @var string Check identifier (slug).
		 *
		 * @since 4.9.0
		 */
		protected static string $id = 'migration-complexity';

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

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

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

		/**
		 * Check description (translatable).
		 *
		 * @return string Check description.
		 *
		 * @since 4.9.0
		 */
		public static function get_description(): string {
			return __( 'Provides an overall assessment of migration complexity.', '0-day-analytics' );
		}

		/**
		 * Run the check.
		 *
		 * @return array Check result.
		 *
		 * @since 4.9.0
		 */
		public static function run(): array {
			global $wpdb;

			$complexity_score = 0;
			$factors          = array();

			// Factor 1: Database size.
			$db_size    = (int) $wpdb->get_var(
				$wpdb->prepare(
					'SELECT SUM(data_length + index_length)
				FROM information_schema.TABLES
				WHERE table_schema = %s
				AND table_name LIKE %s',
					DB_NAME,
					$wpdb->esc_like( $wpdb->prefix ) . '%'
				)
			);
			$db_size_mb = $db_size / 1024 / 1024;

			if ( $db_size_mb > 1000 ) {
				$complexity_score += 25;
				$factors[]         = __( 'Very large database (over 1GB)', '0-day-analytics' );
			} elseif ( $db_size_mb > 500 ) {
				$complexity_score += 15;
				$factors[]         = __( 'Large database (500MB-1GB)', '0-day-analytics' );
			} elseif ( $db_size_mb > 100 ) {
				$complexity_score += 5;
				$factors[]         = __( 'Medium database size', '0-day-analytics' );
			}

			// Factor 2: Plugin count.
			$plugin_count = count( get_option( 'active_plugins', array() ) );

			if ( $plugin_count > 40 ) {
				$complexity_score += 20;
				$factors[]         = sprintf(
				/* translators: %d: number of plugins */
					__( 'Many active plugins (%d)', '0-day-analytics' ),
					$plugin_count
				);
			} elseif ( $plugin_count > 25 ) {
				$complexity_score += 10;
				$factors[]         = sprintf(
				/* translators: %d: number of plugins */
					__( 'Above average plugin count (%d)', '0-day-analytics' ),
					$plugin_count
				);
			}

			// Factor 3: Custom tables.
			$core_table_count   = 12;
			$total_tables       = (int) $wpdb->get_var(
				$wpdb->prepare(
					'SELECT COUNT(*) FROM information_schema.TABLES
				WHERE table_schema = %s
				AND table_name LIKE %s',
					DB_NAME,
					$wpdb->esc_like( $wpdb->prefix ) . '%'
				)
			);
			$custom_table_count = max( 0, $total_tables - $core_table_count );

			if ( $custom_table_count > 30 ) {
				$complexity_score += 15;
				$factors[]         = sprintf(
				/* translators: %d: number of custom tables */
					__( 'Many custom database tables (%d)', '0-day-analytics' ),
					$custom_table_count
				);
			} elseif ( $custom_table_count > 10 ) {
				$complexity_score += 5;
			}

			// Factor 4: Multisite.
			if ( is_multisite() ) {
				$complexity_score += 30;
				$factors[]         = __( 'Multisite installation', '0-day-analytics' );
			}

			// Factor 5: E-commerce.
			if ( class_exists( 'WooCommerce' ) ) {
				$complexity_score += 15;
				$factors[]         = __( 'WooCommerce store', '0-day-analytics' );
			}

			// Factor 6: Membership/LMS.
			$membership_plugins = array(
				'memberpress/memberpress.php',
				'learnpress/learnpress.php',
				'learndash/learndash.php',
				'pmpro/paid-memberships-pro.php',
			);

			foreach ( $membership_plugins as $plugin ) {
				if ( is_plugin_active( $plugin ) ) {
					$complexity_score += 10;
					$factors[]         = __( 'Membership or LMS site', '0-day-analytics' );
					break;
				}
			}

			// Factor 7: MU-Plugins.
			if ( is_dir( WPMU_PLUGIN_DIR ) ) {
				$mu_files = glob( WPMU_PLUGIN_DIR . '/*.php' );
				if ( ! empty( $mu_files ) ) {
					$complexity_score += 5;
					$factors[]         = __( 'Has must-use plugins', '0-day-analytics' );
				}
			}

			// Determine complexity level.
			$complexity_level = 'simple';
			if ( $complexity_score >= 60 ) {
				$complexity_level = 'complex';
			} elseif ( $complexity_score >= 30 ) {
				$complexity_level = 'moderate';
			}

			$details = array(
				'complexity_score' => $complexity_score,
				'complexity_level' => $complexity_level,
				'factors'          => $factors,
				'database_size_mb' => round( $db_size_mb, 2 ),
				'plugin_count'     => $plugin_count,
				'custom_tables'    => $custom_table_count,
				'is_multisite'     => is_multisite(),
			);

			if ( 'complex' === $complexity_level ) {
				return static::warning(
					sprintf(
					/* translators: %d: complexity score */
						__( 'This site has high migration complexity (score: %d/100). Plan carefully and consider professional migration services for a smooth transition.', '0-day-analytics' ),
						min( 100, $complexity_score )
					),
					! empty( $factors )
					? sprintf(
						/* translators: %s: list of complexity factors */
						__( 'Key factors: %s. Test thoroughly on a staging site before going live.', '0-day-analytics' ),
						implode( ', ', $factors )
					)
					: __( 'Test thoroughly on a staging site before going live.', '0-day-analytics' ),
					$details
				);
			}

			if ( 'moderate' === $complexity_level ) {
				return static::info(
					sprintf(
					/* translators: %d: complexity score */
						__( 'This site has moderate migration complexity (score: %d/100). Standard migration tools should work, but allow extra time for testing.', '0-day-analytics' ),
						$complexity_score
					),
					$details
				);
			}

			return static::pass(
				sprintf(
				/* translators: %d: complexity score */
					__( 'This site has low migration complexity (score: %d/100). A standard migration process should work smoothly.', '0-day-analytics' ),
					$complexity_score
				),
				$details
			);
		}
	}
}