<?php
/**
 * Plugin bootstrap and module registry.
 *
 * @package PressRoost\AIVE
 */

namespace PressRoost\AIVE;

/**
 * Wires the plugin into WordPress.
 *
 * Core owns two jobs: registering the WordPress hooks that belong to the plugin
 * as a whole - the text domain and the custom cron recurrences - and holding the
 * registry of feature modules whose own hooks it then registers.
 *
 * Modules are injected through register_module() rather than instantiated here,
 * so Core carries no knowledge of the individual modules and this file does not
 * change as the module set grows.
 *
 * @since 1.0.0
 */
final class Core {

	/**
	 * Recurrence slug for the six-hourly schedule.
	 *
	 * @since 1.0.0
	 * @var string
	 */
	public const SCHEDULE_EVERY_6_HOURS = 'aive_every_6_hours';

	/**
	 * Recurrence slug for the daily schedule.
	 *
	 * @since 1.0.0
	 * @var string
	 */
	public const SCHEDULE_DAILY = 'aive_daily';

	/**
	 * Shared instance.
	 *
	 * @since 1.0.0
	 * @var Core|null
	 */
	private static $instance = null;

	/**
	 * Registered feature modules, keyed by module slug.
	 *
	 * @since 1.0.0
	 * @var array<string, ModuleInterface>
	 */
	private $modules = array();

	/**
	 * Whether register_hooks() has already run.
	 *
	 * @since 1.0.0
	 * @var bool
	 */
	private $hooks_registered = false;

	/**
	 * Constructor is private; use instance().
	 *
	 * @since 1.0.0
	 */
	private function __construct() {}

	/**
	 * Returns the shared instance.
	 *
	 * @since 1.0.0
	 *
	 * @return Core Shared instance.
	 */
	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}

		return self::$instance;
	}

	/**
	 * Adds a feature module to the registry.
	 *
	 * Registering the same slug twice replaces the earlier instance, which lets
	 * a test or an add-on substitute a module without duplicating its hooks. A
	 * module added after register_hooks() has run is hooked immediately so that
	 * registration order does not change behaviour.
	 *
	 * @since 1.0.0
	 *
	 * @param ModuleInterface $module Module to register.
	 * @return void
	 */
	public function register_module( ModuleInterface $module ) {
		$this->modules[ $module->slug() ] = $module;

		if ( $this->hooks_registered ) {
			$module->register_hooks();
		}
	}

	/**
	 * Returns the registered modules.
	 *
	 * @since 1.0.0
	 *
	 * @return array<string, ModuleInterface> Modules keyed by slug.
	 */
	public function modules() {
		return $this->modules;
	}

	/**
	 * Returns one registered module by slug.
	 *
	 * @since 1.0.0
	 *
	 * @param string $slug Module slug.
	 * @return ModuleInterface|null Module, or null when not registered.
	 */
	public function module( $slug ) {
		return isset( $this->modules[ $slug ] ) ? $this->modules[ $slug ] : null;
	}

	/**
	 * Registers the plugin's WordPress hooks and those of every module.
	 *
	 * Idempotent: Activator calls it defensively to guarantee the custom cron
	 * recurrences exist before it schedules against them.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function register_hooks() {
		if ( $this->hooks_registered ) {
			return;
		}

		$this->hooks_registered = true;

		add_filter( 'cron_schedules', array( self::class, 'register_cron_schedules' ) ); // phpcs:ignore WordPress.WP.CronInterval.ChangeDetected -- Both added recurrences are 6 hours or longer.
		add_action( 'init', array( $this, 'load_textdomain' ) );
		add_action( 'admin_init', array( Database::class, 'maybe_upgrade' ) );

		foreach ( $this->modules as $module ) {
			$module->register_hooks();
		}
	}

	/**
	 * Adds the plugin's custom cron recurrences.
	 *
	 * `aive_daily` duplicates core's `daily` interval on purpose: owning the
	 * recurrence means a site that filters core's schedules cannot accidentally
	 * unschedule AIVE's cleanup job.
	 *
	 * @since 1.0.0
	 *
	 * @param array<string, array{interval: int, display: string}>|mixed $schedules Registered cron schedules.
	 * @return array<string, array{interval: int, display: string}> Schedules including the plugin's own.
	 */
	public static function register_cron_schedules( $schedules ) {
		if ( ! is_array( $schedules ) ) {
			$schedules = array();
		}

		$schedules[ self::SCHEDULE_EVERY_6_HOURS ] = array(
			'interval' => 6 * HOUR_IN_SECONDS,
			'display'  => __( 'Every 6 hours (SummitCite)', 'summitcite' ),
		);

		$schedules[ self::SCHEDULE_DAILY ] = array(
			'interval' => DAY_IN_SECONDS,
			'display'  => __( 'Once daily (SummitCite)', 'summitcite' ),
		);

		return $schedules;
	}

	/**
	 * Loads the plugin text domain.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function load_textdomain() {
		load_plugin_textdomain(
			'summitcite',
			false,
			dirname( plugin_basename( AIVE_PLUGIN_FILE ) ) . '/languages'
		);
	}
}