<?php
/**
 * Runtime plugin activation checker.
 *
 * @package ZeroSpamForms
 */

namespace TwoOTwoCode\ZeroSpamForms\Integrations;

defined( 'ABSPATH' ) || exit;

use ReflectionClass;
use ReflectionException;

/**
 * Matches a loaded provider class to the current site or network plugin state.
 */
final class PluginActivationChecker {
	/**
	 * Normalized plugin root.
	 *
	 * @var string
	 */
	private $plugin_root;

	/**
	 * Constructor.
	 *
	 * @param string|null $plugin_root Optional plugin root override for tests.
	 */
	public function __construct( ?string $plugin_root = null ) {
		$root              = null !== $plugin_root ? $plugin_root : ( defined( 'WP_PLUGIN_DIR' ) ? (string) WP_PLUGIN_DIR : '' );
		$this->plugin_root = rtrim( $this->normalize_path( $root ), '/' );
	}

	/**
	 * Whether the plugin that owns a loaded class is currently active.
	 *
	 * @param string $class_name Fully qualified provider class name.
	 */
	public function is_class_owner_active( string $class_name ): bool {
		if ( '' === $this->plugin_root || ! class_exists( $class_name ) ) {
			return false;
		}

		try {
			$reflection  = new ReflectionClass( $class_name );
			$source_file = $reflection->getFileName();
		} catch ( ReflectionException $exception ) {
			unset( $exception );

			return false;
		}

		if ( false === $source_file ) {
			return false;
		}

		$relative_source = $this->get_relative_source_path( $source_file );

		if ( '' === $relative_source ) {
			return false;
		}

		foreach ( $this->get_active_plugin_files() as $plugin_file ) {
			if ( $this->plugin_owns_source( $plugin_file, $relative_source ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Get current site and network active plugin files without persistent caching.
	 *
	 * @return array<int, string>
	 */
	private function get_active_plugin_files(): array {
		$active_plugins  = function_exists( 'get_option' ) ? get_option( 'active_plugins', array() ) : array();
		$network_plugins = function_exists( 'get_site_option' ) ? get_site_option( 'active_sitewide_plugins', array() ) : array();
		$plugin_files    = array();

		if ( is_array( $active_plugins ) ) {
			foreach ( $active_plugins as $plugin_file ) {
				if ( is_string( $plugin_file ) ) {
					$plugin_files[] = $plugin_file;
				}
			}
		}

		if ( is_array( $network_plugins ) ) {
			foreach ( $network_plugins as $plugin_file => $activated_at ) {
				if ( is_string( $plugin_file ) ) {
					$plugin_files[] = $plugin_file;
				} elseif ( is_string( $activated_at ) ) {
					$plugin_files[] = $activated_at;
				}
			}
		}

		return array_values( array_unique( array_map( array( $this, 'normalize_plugin_file' ), $plugin_files ) ) );
	}

	/**
	 * Convert a reflected source file to a path relative to the plugin root.
	 *
	 * @param string $source_file Reflected source file.
	 */
	private function get_relative_source_path( string $source_file ): string {
		$source_file = $this->normalize_path( $source_file );
		$root_prefix = strtolower( $this->plugin_root . '/' );

		if ( 0 !== strpos( strtolower( $source_file ), $root_prefix ) ) {
			return '';
		}

		return ltrim( substr( $source_file, strlen( $root_prefix ) ), '/' );
	}

	/**
	 * Whether an active plugin entry owns a reflected relative source path.
	 *
	 * @param string $plugin_file    Active plugin file.
	 * @param string $relative_source Relative source path.
	 */
	private function plugin_owns_source( string $plugin_file, string $relative_source ): bool {
		if ( '' === $plugin_file || '' === $relative_source ) {
			return false;
		}

		$plugin_file     = strtolower( $plugin_file );
		$relative_source = strtolower( $relative_source );
		$plugin_dir      = dirname( $plugin_file );

		if ( '.' === $plugin_dir ) {
			return $plugin_file === $relative_source;
		}

		return 0 === strpos( $relative_source, rtrim( $plugin_dir, '/' ) . '/' );
	}

	/**
	 * Normalize a plugin option entry.
	 *
	 * @param string $plugin_file Plugin file.
	 */
	private function normalize_plugin_file( string $plugin_file ): string {
		$plugin_file = ltrim( $this->normalize_path( $plugin_file ), '/' );

		if ( '' === $plugin_file || false !== strpos( $plugin_file, '../' ) ) {
			return '';
		}

		return $plugin_file;
	}

	/**
	 * Normalize filesystem separators.
	 *
	 * @param string $path Path.
	 */
	private function normalize_path( string $path ): string {
		return str_replace( '\\', '/', $path );
	}
}