<?php
/**
 * Attributes plugin bootstrap (file include) time using the `plugin_loaded` action.
 *
 * @package Bloatwright
 */

namespace Bloatwright\Profiler;

/**
 * Time between consecutive plugin file includes: must-use plugins loaded after the loader, then
 * regular plugins, until plugins_loaded. Network-activated plugins (multisite) and the core setup
 * between the two groups are not charged to anyone: the clock restarts when WordPress reads the
 * active plugins list, right before the first regular plugin loads.
 */
class IncludeTimer {

	/**
	 * Owner resolver.
	 *
	 * @var Owner
	 */
	private $owner;

	/**
	 * Last checkpoint (ns).
	 *
	 * @var float
	 */
	private $last = 0.0;

	/**
	 * Owner => ms.
	 *
	 * @var array<string,float>
	 */
	private $ms = array();

	/**
	 * Between muplugins_loaded and the first regular plugin.
	 *
	 * @var bool
	 */
	private $between = false;

	/**
	 * Constructor.
	 *
	 * @param Owner $owner Owner resolver.
	 */
	public function __construct( Owner $owner ) {
		$this->owner = $owner;
	}

	/**
	 * Start (call before plugins are included).
	 */
	public function start(): void {
		$this->last = (float) hrtime( true );
		add_action( 'plugin_loaded', array( $this, 'on_plugin_loaded' ), -PHP_INT_MAX );
		add_action( 'mu_plugin_loaded', array( $this, 'on_plugin_loaded' ), -PHP_INT_MAX );
		add_action( 'muplugins_loaded', array( $this, 'restart' ), PHP_INT_MAX );
		add_filter( 'pre_option_active_plugins', array( $this, 'restart_on_read' ), PHP_INT_MAX );
		add_filter( 'option_active_plugins', array( $this, 'restart_on_read' ), PHP_INT_MAX );
		add_action( 'plugins_loaded', array( $this, 'stop' ), -PHP_INT_MAX );
	}

	/**
	 * Must-use plugins are done: restart the clock so network-activated plugins and the
	 * muplugins_loaded callbacks are not charged to the first regular plugin.
	 */
	public function restart(): void {
		$this->between = true;
		$this->last    = (float) hrtime( true );
	}

	/**
	 * The active plugins list is read right before regular plugins load: restart the clock again so
	 * the core setup in between is not charged either. Returns the value unchanged.
	 *
	 * @param mixed $value Option value (or pre_option short-circuit value).
	 * @return mixed
	 */
	public function restart_on_read( $value ) {
		if ( $this->between ) {
			$this->last = (float) hrtime( true );
		}
		return $value;
	}

	/**
	 * A plugin main file finished including.
	 *
	 * @param string $file Plugin file.
	 */
	public function on_plugin_loaded( $file ): void {
		$this->between = false;
		$now           = (float) hrtime( true );
		$delta         = ( $now - $this->last ) / 1e6;
		$this->last    = $now;
		$key           = $this->owner->for_file( (string) $file );
		if ( $this->owner->is_self( $key ) ) {
			return;
		}
		$this->ms[ $key ] = ( $this->ms[ $key ] ?? 0.0 ) + $delta;
	}

	/**
	 * Stop listening.
	 */
	public function stop(): void {
		$this->between = false;
		remove_action( 'plugin_loaded', array( $this, 'on_plugin_loaded' ), -PHP_INT_MAX );
		remove_action( 'mu_plugin_loaded', array( $this, 'on_plugin_loaded' ), -PHP_INT_MAX );
		remove_action( 'muplugins_loaded', array( $this, 'restart' ), PHP_INT_MAX );
		remove_filter( 'pre_option_active_plugins', array( $this, 'restart_on_read' ), PHP_INT_MAX );
		remove_filter( 'option_active_plugins', array( $this, 'restart_on_read' ), PHP_INT_MAX );
	}

	/**
	 * Owner => include ms.
	 *
	 * @return array<string,float>
	 */
	public function results(): array {
		$out = array();
		foreach ( $this->ms as $k => $v ) {
			$out[ $k ] = round( $v, 3 );
		}
		return $out;
	}

	/**
	 * Record a manual measurement (tests / synthetic).
	 *
	 * @param string $owner_key Owner.
	 * @param float  $ms Milliseconds.
	 */
	public function add( string $owner_key, float $ms ): void {
		$this->ms[ $owner_key ] = ( $this->ms[ $owner_key ] ?? 0.0 ) + $ms;
	}
}