<?php
/**
 * Lightweight change tracker. Records plugin/theme/core changes so an incident
 * can show "what changed recently" using only Culprit's own logging.
 *
 * Deliberately minimal: a rolling buffer of recent change events kept in a
 * single option. The premium correlation engine builds
 * on this; in the free build it powers the basic recent-change context.
 *
 * @package Culprit
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class Culprit_Changes
 */
class Culprit_Changes {

	const OPTION_KEY = 'culprit_recent_changes';
	const MAX_ENTRIES = 100;

	/**
	 * Register hooks that record changes.
	 */
	public static function init() {
		add_action( 'activated_plugin', array( __CLASS__, 'on_plugin_activated' ), 10, 1 );
		add_action( 'deactivated_plugin', array( __CLASS__, 'on_plugin_deactivated' ), 10, 1 );
		add_action( 'switch_theme', array( __CLASS__, 'on_theme_switched' ), 10, 1 );
		add_action( 'upgrader_process_complete', array( __CLASS__, 'on_upgrade' ), 10, 2 );
	}

	/**
	 * Record a change entry into the rolling buffer.
	 *
	 * @param string $type   Change type (plugin_activated, theme_switched, ...).
	 * @param string $target Human label of what changed.
	 */
	public static function record( $type, $target ) {
		$entries = get_option( self::OPTION_KEY, array() );
		if ( ! is_array( $entries ) ) {
			$entries = array();
		}

		$entries[] = array(
			'type'   => (string) $type,
			'target' => (string) $target,
			'time'   => current_time( 'mysql', true ),
		);

		// Trim to the most recent MAX_ENTRIES.
		if ( count( $entries ) > self::MAX_ENTRIES ) {
			$entries = array_slice( $entries, -self::MAX_ENTRIES );
		}

		update_option( self::OPTION_KEY, $entries, false );
	}

	/**
	 * Return change entries within the last $seconds before $before.
	 *
	 * @param string $before  MySQL UTC datetime anchor.
	 * @param int    $seconds Lookback window in seconds.
	 * @return array
	 */
	public static function changes_before( $before, $seconds = 600 ) {
		$entries = get_option( self::OPTION_KEY, array() );
		if ( ! is_array( $entries ) ) {
			return array();
		}

		$anchor = strtotime( $before . ' UTC' );
		if ( false === $anchor ) {
			return array();
		}

		$out = array();
		foreach ( $entries as $entry ) {
			if ( empty( $entry['time'] ) ) {
				continue;
			}
			$ts = strtotime( $entry['time'] . ' UTC' );
			if ( false === $ts ) {
				continue;
			}
			if ( $ts <= $anchor && $ts >= ( $anchor - $seconds ) ) {
				$out[] = $entry;
			}
		}
		return $out;
	}

	/**
	 * Plugin activated.
	 *
	 * @param string $plugin Plugin basename.
	 */
	public static function on_plugin_activated( $plugin ) {
		self::record( 'plugin_activated', $plugin );
	}

	/**
	 * Plugin deactivated.
	 *
	 * @param string $plugin Plugin basename.
	 */
	public static function on_plugin_deactivated( $plugin ) {
		self::record( 'plugin_deactivated', $plugin );
	}

	/**
	 * Theme switched.
	 *
	 * @param string $new_name New theme name.
	 */
	public static function on_theme_switched( $new_name ) {
		self::record( 'theme_switched', $new_name );
	}

	/**
	 * An update completed (plugin/theme/core).
	 *
	 * @param object $upgrader Upgrader instance (unused).
	 * @param array  $data     Upgrade data.
	 */
	public static function on_upgrade( $upgrader, $data ) {
		unset( $upgrader );
		if ( ! is_array( $data ) ) {
			return;
		}
		$type = isset( $data['type'] ) ? $data['type'] : 'unknown';
		self::record( 'updated_' . $type, isset( $data['action'] ) ? $data['action'] : 'update' );
	}
}