/**
	 * Get Feature Settings Label HTML
	 *
	 * @since 3.1.0
	 * @access private
	 *
	 * @param string $feature_name
	 *
	 * @return int
	 */
	private function get_saved_feature_state( $feature_name ) {
		return get_option( $this->get_feature_option_key( $feature_name ) );
	}

	/**
	 * Get Feature Actual State
	 *
	 * @since 3.1.0
	 * @access private
	 *
	 * @param array $feature
	 *
	 * @return string
	 */
	private function get_feature_actual_state( array $feature ) {
		if ( ! empty( $feature['state'] ) && self::STATE_DEFAULT !== $feature['state'] ) {
			return $feature['state'];
		}

		return $feature['default'];
	}

	/**
	 * On Feature State Change
	 *
	 * @since 3.1.0
	 * @access private
	 *
	 * @param array  $old_feature_data
	 * @param string $new_state
	 * @param string $old_state
	 */
	private function on_feature_state_change( array $old_feature_data, $new_state, $old_state ) {
		$new_feature_data = $this->get_features( $old_feature_data['name'] );
		$this->validate_dependency( $new_feature_data, $new_state );
		$this->features[ $old_feature_data['name'] ]['state'] = $new_state;
		if ( $old_state === $new_state ) {
			return;
		}

		Plugin::$instance->files_manager->clear_cache();
		if ( $new_feature_data['on_state_change'] ) {
			$new_feature_data['on_state_change']( $old_state, $new_state );
		}

		do_action( 'elementor/experiments/feature-state-change/' . $old_feature_data['name'], $old_state, $new_state );
	}

	/**
	 * @throws Exceptions\Dependency_Exception If the feature dependency is not available or not active.
	 */
	private function validate_dependency( array $feature, $new_state ) {
		$rollback = function ( $feature_option_key, $state ) {
			remove_all_actions( 'add_option_' . $feature_option_key );
			remove_all_actions( 'update_option_' . $feature_option_key );

			update_option( $feature_option_key, $state );
		};

		if ( self::STATE_DEFAULT === $new_state ) {
			$new_state = $this->get_feature_actual_state( $feature );
		}

		$feature_option_key = $this->get_feature_option_key( $feature['name'] );

		if ( self::STATE_ACTIVE === $new_state ) {
			if ( empty( $feature['dependencies'] ) ) {
				return;
			}

			// Validate if the current feature dependency is available.
			foreach ( $feature['dependencies'] as $dependency ) {
				$dependency_feature = $this->get_features( $dependency->get_name() );

				if ( ! $dependency_feature ) {
					$rollback( $feature_option_key, self::STATE_INACTIVE );

					throw new Exceptions\Dependency_Exception(
						sprintf(
							'The feature `%s` has a dependency `%s` that is not available.',
							esc_html( $feature['name'] ),
							esc_html( $dependency->get_name() )
						)
					);
				}

				$dependency_state = $this->get_feature_actual_state( $dependency_feature );

				// If dependency is not active.
				if ( self::STATE_INACTIVE === $dependency_state ) {
					$rollback( $feature_option_key, self::STATE_INACTIVE );

					throw new Exceptions\Dependency_Exception(
						sprintf(
							'To turn on `%1$s`, Experiment: `%2$s` activity is required!',
							esc_html( $feature['name'] ),
							esc_html( $dependency_feature['name'] )
						)
					);
				}
			}
		} elseif ( self::STATE_INACTIVE === $new_state ) {
			// Make sure to deactivate a dependant experiment of the current feature when it's deactivated.
			foreach ( $this->get_features() as $current_feature ) {
				if ( empty( $current_feature['dependencies'] ) ) {
					continue;
				}

				$current_feature_state = $this->get_feature_actual_state( $current_feature );

				foreach ( $current_feature['dependencies'] as $dependency ) {
					if ( self::STATE_ACTIVE === $current_feature_state && $feature['name'] === $dependency->get_name() ) {
						update_option( $this->get_feature_option_key( $current_feature['name'] ), static::STATE_INACTIVE );
					}
				}
			}
		}
	}

	private function should_show_hidden() {
		return defined( 'ELEMENTOR_SHOW_HIDDEN_EXPERIMENTS' ) && ELEMENTOR_SHOW_HIDDEN_EXPERIMENTS;
	}

	private function create_dependency_class( $dependency_name, $dependency_args ) {
		if ( class_exists( $dependency_name ) ) {
			return $dependency_name::instance();
		}

		if ( ! empty( $dependency_args ) ) {
			return new Wrap_Core_Dependency( $dependency_args );
		}

		return new Non_Existing_Dependency( $dependency_name );
	}

	/**
	 * The experiments page is a WordPress options page, which means all the experiments are registered via WordPress' register_settings(),
	 * and their states are being sent in the POST request when saving.
	 * The options are being updated in a chronological order based on the POST data.
	 * This behavior interferes with the experiments dependency mechanism because the data that's being sent can be in any order,
	 * while the dependencies mechanism expects it to be in a specific order (dependencies should be activated before their dependents can).
	 * In order to solve this issue, we sort the experiments in the POST data based on their dependencies tree.
	 *
	 * @param array $allowed_options
	 */
	private function sort_allowed_options_by_dependencies( $allowed_options ) {
		if ( ! isset( $allowed_options['elementor'] ) ) {
			return $allowed_options;
		}

		$sorted = Collection::make();
		$visited = Collection::make();

		$sort = function ( $item ) use ( &$sort, $sorted, $visited ) {
			if ( $visited->contains( $item ) ) {
				return;
			}

			$visited->push( $item );

			$feature = $this->get_features( $item );

			if ( ! $feature ) {
				return;
			}

			foreach ( $feature['dependencies'] ?? [] as $dep ) {
				$name = is_string( $dep ) ? $dep : $dep->get_name();

				$sort( $name );
			}

			$sorted->push( $item );
		};

		foreach ( $allowed_options['elementor'] as $option ) {
			$is_experiment_option = strpos( $option, static::OPTION_PREFIX ) === 0;

			if ( ! $is_experiment_option ) {
				continue;
			}

			$sort(
				str_replace( static::OPTION_PREFIX, '', $option )
			);
		}

		$allowed_options['elementor'] = Collection::make( $allowed_options['elementor'] )
			->filter( function ( $option ) {
				return 0 !== strpos( $option, static::OPTION_PREFIX );
			} )
			->merge(
				$sorted->map( function ( $item ) {
					return static::OPTION_PREFIX . $item;
				} )
			)
			->values();

		return $allowed_options;
	}

	public function __construct() {
		$this->init_states();

		$this->init_release_statuses();

		$this->init_features();

		add_action( 'admin_init', function () {
			System_Info::add_report(
				'experiments', [
					'file_name' => __DIR__ . '/experiments-reporter.php',
					'class_name' => __NAMESPACE__ . '\Experiments_Reporter',
				]
			);
		}, 79 /* Before log */ );

		if ( is_admin() ) {
			$page_id = Settings::PAGE_ID;

			add_action( "elementor/admin/after_create_settings/{$page_id}", function( Settings $settings ) {
				$this->register_settings_fields( $settings );
			}, 11 );

			add_filter( 'allowed_options', function ( $allowed_options ) {
				return $this->sort_allowed_options_by_dependencies( $allowed_options );
			}, 11 );
		}

		// Register CLI commands.
		if ( Utils::is_wp_cli() ) {
			\WP_CLI::add_command( 'elementor experiments', WP_CLI::class );
		}
	}

	/**
	 * @param array $experimental_data
	 * @return array
	 *
	 * @throws Exceptions\Dependency_Exception If the feature dependency is not initialized or depends on a hidden experiment.
	 */
	private function initialize_feature_dependencies( array $experimental_data ): array {
		foreach ( $experimental_data['dependencies'] as $key => $dependency ) {
			$feature = $this->get_features( $dependency );

			if ( ! isset( $feature ) ) {
				// since we must validate the state of each dependency, we have to make sure that dependencies are initialized in the correct order, otherwise, error.
				throw new Exceptions\Dependency_Exception(
					sprintf(
						'Feature %s cannot be initialized before dependency feature: %s.',
						esc_html( $experimental_data['name'] ),
						esc_html( $dependency )
					)
				);
			}

			if ( ! empty( $feature[ static::TYPE_HIDDEN ] ) ) {
				throw new Exceptions\Dependency_Exception( 'Depending on a hidden experiment is not allowed.' );
			}

			$experimental_data['dependencies'][ $key ] = $this->create_dependency_class( $dependency, $feature );
			$experimental_data = $this->set_feature_default_state_to_match_dependencies( $feature, $experimental_data );
		}

		return $experimental_data;
	}

	/**
	 * @param array $feature
	 * @param array $experimental_data
	 * @return array
	 *
	 * we must validate the state:
	 * * A user can set a dependant feature to inactive and in upgrade we don't change users settings.
	 * * A developer can set the default state to be invalid (e.g. dependant feature is inactive).
	 * if one of the dependencies is inactive, the main feature should be inactive as well.
	 */
	private function set_feature_default_state_to_match_dependencies( array $feature, array $experimental_data ): array {
		if ( self::STATE_INACTIVE !== $this->get_feature_actual_state( $feature ) ) {
			return $experimental_data;
		}

		if ( self::STATE_ACTIVE === $experimental_data['state'] ) {
			$experimental_data['state'] = self::STATE_INACTIVE;
		} elseif ( self::STATE_DEFAULT === $experimental_data['state'] ) {
			$experimental_data['default'] = self::STATE_INACTIVE;
		}

		return $experimental_data;
	}

	/**
	 * @param array $new_site
	 * @param array $experimental_data
	 * @return array
	 */
	private function set_new_site_default_state( $new_site, array $experimental_data ): array {
		if ( ! $this->install_compare( $new_site['minimum_installation_version'] ) ) {
			return $experimental_data;
		}

		if ( $new_site['always_active'] ) {
			$experimental_data['state'] = self::STATE_ACTIVE;
			$experimental_data['mutable'] = false;
		} elseif ( $new_site['default_active'] ) {
			$experimental_data['default'] = self::STATE_ACTIVE;
		} elseif ( $new_site['default_inactive'] ) {
			$experimental_data['default'] = self::STATE_INACTIVE;
		}

		return $experimental_data;
	}

	/**
	 * @param array $options
	 * @return array
	 */
	private function set_feature_initial_options( array $options ): array {
		$default_experimental_data = [
			'tag' => '', // Deprecated, use 'tags' instead.
			'tags' => [],
			'description' => '',
			'release_status' => self::RELEASE_STATUS_ALPHA,
			'default' => self::STATE_INACTIVE,
			'mutable' => true,
			static::TYPE_HIDDEN => false,
			'new_site' => [
				'always_active' => false,
				'default_active' => false,
				'default_inactive' => false,
				'minimum_installation_version' => null,
			],
			'on_state_change' => null,
			'generator_tag' => false,
			'deprecated' => false,
		];

		$allowed_options = [ 'name', 'title', 'tag', 'tags', 'description', 'release_status', 'default', 'mutable', static::TYPE_HIDDEN, 'new_site', 'on_state_change', 'dependencies', 'generator_tag', 'messages', 'deprecated' ];
		$experimental_data = $this->merge_properties( $default_experimental_data, $options, $allowed_options );

		return $this->unify_feature_tags( $experimental_data );
	}
}