<?php
/**
 * Plugin activation routine.
 *
 * @package PressRoost\AIVE
 */

namespace PressRoost\AIVE;

use PressRoost\AIVE\Llms\LlmsCache;
use PressRoost\AIVE\Utils\Helpers;

/**
 * Runs the one-off work a fresh activation needs.
 *
 * Activation must be idempotent: WordPress runs it on every activate, which
 * includes reactivation after an update. Nothing here destroys existing data.
 *
 * @since 1.0.0
 */
final class Activator {

	/**
	 * Cron hook that prunes crawler log rows past their retention window.
	 *
	 * @since 1.0.0
	 * @var string
	 */
	public const CRON_CLEANUP_LOGS = 'aive_cleanup_crawler_logs';

	/**
	 * Cron hook that rescans stale answer-density scores.
	 *
	 * @since 1.0.0
	 * @var string
	 */
	public const CRON_SCAN_DENSITY = 'aive_scan_answer_density';

	/**
	 * Returns the cron events the plugin owns, keyed by hook name.
	 *
	 * @since 1.0.0
	 *
	 * @return array<string, string> Recurrence slug keyed by cron hook name.
	 */
	public static function cron_events() {
		return array(
			self::CRON_CLEANUP_LOGS => Core::SCHEDULE_DAILY,
			self::CRON_SCAN_DENSITY => Core::SCHEDULE_EVERY_6_HOURS,
		);
	}

	/**
	 * Activates the plugin.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public static function activate() {
		Database::create_tables();
		self::set_default_options();
		self::schedule_events();

		/*
		 * Module 4's document is a function of settings, content and ownership,
		 * all of which may have changed while the plugin was inactive. The cache
		 * key already makes a stale entry unreachable; clearing it here means an
		 * activation does not leave unreachable rows behind either.
		 */
		LlmsCache::flush_all();

		/*
		 * Module 4 registers a rewrite rule for /llms.txt. Flushing here means a
		 * freshly activated site serves it without the owner having to re-save
		 * permalinks. This is the expensive-but-correct call that belongs in an
		 * activation hook and nowhere else.
		 */
		flush_rewrite_rules();
	}

	/**
	 * Writes the default settings without discarding an existing configuration.
	 *
	 * On a first activation this seeds every default. On a reactivation it keeps
	 * the stored values and only fills in keys a newer version introduced, so an
	 * upgrade never resets the site owner's choices.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public static function set_default_options() {
		$stored = get_option( Helpers::OPTION_KEY, null );

		if ( ! is_array( $stored ) ) {
			add_option( Helpers::OPTION_KEY, Helpers::default_settings() );

			return;
		}

		$merged = Helpers::merge_settings( $stored );

		if ( $merged !== $stored ) {
			update_option( Helpers::OPTION_KEY, $merged );
		}
	}

	/**
	 * Schedules the plugin's recurring cron events.
	 *
	 * The custom recurrences come from Core's `cron_schedules` filter. That
	 * filter is registered by the main plugin file at include time, which is
	 * what makes it available here: WordPress includes the plugin file during
	 * activate_plugin(), long after plugins_loaded has fired.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public static function schedule_events() {
		// Defensive: guarantees the recurrences exist even if Core was not bootstrapped.
		Core::instance()->register_hooks();

		foreach ( self::cron_events() as $hook => $recurrence ) {
			if ( false !== wp_next_scheduled( $hook ) ) {
				continue;
			}

			$scheduled = wp_schedule_event( time(), $recurrence, $hook );

			if ( false === $scheduled || is_wp_error( $scheduled ) ) {
				Helpers::log(
					'Failed to schedule cron event.',
					array(
						'hook'       => $hook,
						'recurrence' => $recurrence,
					)
				);
			}
		}
	}
}