<?php declare(strict_types = 1);
/**
 * Container for data collectors.
 *
 * @package query-monitor
 */

if ( ! class_exists( 'QM_Collectors' ) ) {
/**
 * @implements \IteratorAggregate<string, QM_Collector>
 */
class QM_Collectors implements IteratorAggregate {

	/**
	 * @var array<string, QM_Collector>
	 */
	private $items = array();

	/**
	 * @var boolean
	 */
	private $processed = false;

	/**
	 * @return ArrayIterator<string, QM_Collector>
	 */
	#[\ReturnTypeWillChange]
	public function getIterator() {
		return new ArrayIterator( $this->items );
	}

	/**
	 * @param QM_Collector $collector
	 * @return void
	 */
	public static function add( QM_Collector $collector ) {
		$collectors = self::init();

		$collector->set_up();

		$collectors->items[ $collector->id ] = $collector;
	}

	/**
	 * Fetches a collector instance.
	 *
	 * @param string $id The collector ID.
	 * @return QM_Collector|null The collector object.
	 */
	public static function get( $id ) {
		$collectors = self::init();

		return $collectors->items[ $id ] ?? null;
	}

	/**
	 * @return self
	 */
	public static function init() {
		static $instance;

		if ( ! $instance ) {
			$instance = new QM_Collectors();
			add_action( 'init', array( $instance, 'cease_if_unsupported' ), 0 );
		}

		return $instance;

	}

	/**
	 * Ceases data collection if the current request is not one where QM will output.
	 */
	public function cease_if_unsupported() : void {
		if ( self::request_supported() ) {
			return;
		}

		do_action( 'qm/cease' );
	}

	/**
	 * Determines whether the current request supports data collection.
	 */
	public static function request_supported() : bool {
		// Don't collect during a Customizer preview request:
		if ( function_exists( 'is_customize_preview' ) && is_customize_preview() ) {
			return false;
		}

		// Don't collect during an iframed request, eg. the plugin info modal, an upgrader action, or the Customizer:
		if ( defined( 'IFRAME_REQUEST' ) && IFRAME_REQUEST ) {
			return false;
		}

		// Don't collect inside the Site Editor:
		if ( isset( $_SERVER['SCRIPT_NAME'] ) && '/wp-admin/site-editor.php' === $_SERVER['SCRIPT_NAME'] ) {
			return false;
		}

		// Don't collect on the interim login screen:
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		if ( ! empty( $_GET['interim-login'] ) ) {
			return false;
		}

		// Don't collect in the Elementor preview iframe
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		if ( ! empty( $_GET['elementor-preview'] ) ) {
			return false;
		}

		return true;
	}

	/**
	 * @return void
	 */
	public function process() {
		if ( $this->processed ) {
			return;
		}

		foreach ( $this as $collector ) {
			$collector->tear_down();

			$timer = new QM_Timer();
			$timer->start();

			$collector->process();
			$collector->process_concerns();

			$collector->set_timer( $timer->stop() );
		}

		foreach ( $this as $collector ) {
			$collector->post_process();
		}

		$this->processed = true;
	}

	/**
	 * @return void
	 */
	public static function cease() {
		$collectors = self::init();

		$collectors->processed = true;

		/** @var QM_Collector $collector */
		foreach ( $collectors as $collector ) {
			$collector->tear_down();
			$collector->discard_data();
		}
	}
}
}