<?php
/**
 * Event log: the data basis for the "green light" and care reports.
 *
 * @package QuietAdmin
 */

namespace QuietAdmin;

defined( 'ABSPATH' ) || exit;

/**
 * Class Event_Log.
 *
 * Writes technical operations (updates, backups, spam blocks,
 * support tickets, impersonations) to a dedicated table. The client only sees
 * the friendly summary of it, never the details.
 *
 * @since 0.1.0
 */
class Event_Log {

	/**
	 * Event type: maintenance/update.
	 *
	 * @var string
	 */
	const TYPE_MAINTENANCE = 'maintenance';

	/**
	 * Event type: security.
	 *
	 * @var string
	 */
	const TYPE_SECURITY = 'security';

	/**
	 * Event type: backup.
	 *
	 * @var string
	 */
	const TYPE_BACKUP = 'backup';

	/**
	 * Event type: support.
	 *
	 * @var string
	 */
	const TYPE_SUPPORT = 'support';

	/**
	 * Event type: agency action (impersonation, Ghost Mode, ...).
	 *
	 * @var string
	 */
	const TYPE_AGENCY = 'agency';

	/**
	 * Table name.
	 *
	 * @since 0.1.0
	 *
	 * @return string
	 */
	public static function table() {
		global $wpdb;

		return $wpdb->prefix . 'quietadmin_events';
	}


	/**
	 * UTC timestamp as MySQL date (for range queries).
	 *
	 * @since 0.1.0
	 *
	 * @param int $timestamp Unix timestamp.
	 * @return string
	 */
	public static function format_utc( $timestamp ) {
		return gmdate( 'Y-m-d H:i:s', (int) $timestamp );
	}

	/**
	 * MySQL date (UTC) X seconds ago.
	 *
	 * @since 0.1.0
	 *
	 * @param int $seconds Seconds into the past.
	 * @return string
	 */
	public static function utc_before( $seconds ) {
		return self::format_utc( time() - absint( $seconds ) );
	}

	/**
	 * Converts a stored UTC date into a Unix timestamp.
	 *
	 * @since 0.1.0
	 *
	 * @param string $mysql_date Date from the table.
	 * @return int
	 */
	public static function to_timestamp( $mysql_date ) {
		$timestamp = mysql2date( 'U', (string) $mysql_date, false );

		return $timestamp ? (int) $timestamp : 0;
	}

	/**
	 * Writes an event.
	 *
	 * @since 0.1.0
	 *
	 * @param string $type  Event type (one of the class constants).
	 * @param string $event Machine-readable key, e.g. 'plugin_updated'.
	 * @param string $title Human-readable description (German).
	 * @param array  $meta  Arbitrary additional data (JSON-encoded).
	 * @return int|false Insert ID.
	 */
	public static function add( $type, $event, $title = '', $meta = array() ) {
		global $wpdb;

		$type  = sanitize_key( (string) $type );
		$event = sanitize_key( (string) $event );

		/**
		 * Filter or suppress the event before saving.
		 *
		 * @since 0.1.0
		 *
		 * @param array|false $log Data, or false to skip.
		 */
		$log = apply_filters(
			'quietadmin_log_event',
			array(
				'event_type' => $type,
				'event'      => $event,
				'title'      => sanitize_text_field( (string) $title ),
				'user_id'    => get_current_user_id(),
				'meta'       => wp_json_encode( $meta ),
				'created_at' => gmdate( 'Y-m-d H:i:s' ), // UTC.
			),
			$type,
			$event,
			$meta
		);

		if ( ! is_array( $log ) ) {
			return false;
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectInsert, WordPress.DB.DirectDatabaseQuery.DirectQuery -- Own log table, no schema caching possible.
		$inserted = $wpdb->insert( self::table(), $log );

		if ( false === $inserted ) {
			return false;
		}

		// Note: Events deliberately no longer reset the "last check" timestamp.
		// A log entry (e.g. a failed login)
		// is not a system check; the timestamp is set exclusively by
		// StatusLights::run_checks().

		return (int) $wpdb->insert_id;
	}

	/**
	 * Entries that refer to a user (author or reference in meta).
	 *
	 * Used by the WordPress privacy tools (export/erasure).
	 *
	 * @since 0.1.2
	 *
	 * @param int $user_id User ID.
	 * @param int $limit   Maximum number.
	 * @param int $offset  Offset.
	 * @return object[]
	 */
	public static function rows_for_user( $user_id, $limit = 50, $offset = 0 ) {
		global $wpdb;

		$user_id = absint( $user_id );

		if ( ! $user_id ) {
			return array();
		}

		$table   = self::table();
		$pattern = '"(' . implode( '|', Privacy::META_USER_KEYS ) . ')":' . $user_id . '([,}])';

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (array) $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
			$wpdb->prepare(
				"SELECT id, event_type, event, title, user_id, meta, created_at FROM {$table} WHERE user_id = %d OR meta REGEXP %s ORDER BY id ASC LIMIT %d OFFSET %d", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$user_id,
				$pattern,
				absint( $limit ),
				absint( $offset )
			)
		);
	}

	/**
	 * Removes the user reference from entries (user ID to 0).
	 *
	 * @since 0.1.2
	 *
	 * @param object[] $rows    Rows from rows_for_user().
	 * @param int      $user_id User ID.
	 * @return int Number of anonymized rows.
	 */
	public static function anonymize_rows( $rows, $user_id ) {
		global $wpdb;

		$user_id = absint( $user_id );
		$done    = 0;

		foreach ( (array) $rows as $row ) {
			$meta = json_decode( (string) $row->meta, true );
			$meta = is_array( $meta ) ? $meta : array();

			foreach ( Privacy::META_USER_KEYS as $key ) {
				if ( isset( $meta[ $key ] ) && (int) $meta[ $key ] === $user_id ) {
					$meta[ $key ] = 0;
				}
			}

			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
			$updated = $wpdb->update(
				self::table(),
				array(
					'user_id' => (int) $row->user_id === $user_id ? 0 : (int) $row->user_id,
					'meta'    => wp_json_encode( $meta ),
				),
				array( 'id' => (int) $row->id ),
				array( '%d', '%s' ),
				array( '%d' )
			);

			if ( false !== $updated ) {
				++$done;
			}
		}

		return $done;
	}

	/**
	 * Time of the last event of a type.
	 *
	 * @since 0.1.1
	 *
	 * @param string $type Event type, empty for all.
	 * @return int Unix timestamp (UTC) or 0.
	 */
	public static function last_event_time( $type = '' ) {
		global $wpdb;

		$table = self::table();

		if ( '' !== $type ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			$created_at = $wpdb->get_var( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
				$wpdb->prepare(
					"SELECT created_at FROM {$table} WHERE event_type = %s ORDER BY created_at DESC, id DESC LIMIT 1", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
					sanitize_key( $type )
				)
			);
		} else {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			$created_at = $wpdb->get_var( "SELECT created_at FROM {$table} ORDER BY created_at DESC, id DESC LIMIT 1" ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
		}

		return $created_at ? self::to_timestamp( $created_at ) : 0;
	}

	/**
	 * Counts events with specific keys in a time range.
	 *
	 * @since 0.1.1
	 *
	 * @param string[] $events Event keys.
	 * @param string   $since  MySQL date (UTC).
	 * @param string   $until  MySQL date (UTC).
	 * @return int
	 */
	public static function count_events( $events, $since = '', $until = '' ) {
		global $wpdb;

		$events = array_values( array_filter( array_map( 'sanitize_key', (array) $events ) ) );

		if ( empty( $events ) ) {
			return 0;
		}

		$table        = self::table();
		$placeholders = implode( ', ', array_fill( 0, count( $events ), '%s' ) );
		$where        = array( "event IN ({$placeholders})" );
		$args         = $events;

		if ( '' !== $since ) {
			$where[] = 'created_at >= %s';
			$args[]  = $since;
		}

		if ( '' !== $until ) {
			$where[] = 'created_at <= %s';
			$args[]  = $until;
		}

		$sql = "SELECT COUNT(*) FROM {$table} WHERE " . implode( ' AND ', $where ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared
		return (int) $wpdb->get_var( $wpdb->prepare( $sql, $args ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
	}

	/**
	 * Events of a time range.
	 *
	 * @since 0.1.0
	 *
	 * @param string $since MySQL date (UTC).
	 * @param string $until MySQL date (UTC).
	 * @param int    $limit Maximum number.
	 * @return object[]
	 */
	public static function get_events( $since, $until, $limit = 500 ) {
		global $wpdb;

		$table = self::table();

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (array) $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
			$wpdb->prepare(
				"SELECT event_type, event, title, user_id, created_at FROM {$table} WHERE created_at >= %s AND created_at <= %s ORDER BY created_at DESC LIMIT %d", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$since,
				$until,
				absint( $limit )
			)
		);
	}

	/**
	 * Counts events of a type in a time range.
	 *
	 * @since 0.1.0
	 *
	 * @param string $type  Event type, empty for all.
	 * @param string $since MySQL date (UTC).
	 * @param string $until MySQL date (UTC).
	 * @return int
	 */
	public static function count( $type = '', $since = '', $until = '' ) {
		global $wpdb;

		$table = self::table();
		$where = array( '1=1' );
		$args  = array();

		if ( '' !== $type ) {
			$where[] = 'event_type = %s';
			$args[]  = sanitize_key( $type );
		}

		if ( '' !== $since ) {
			$where[] = 'created_at >= %s';
			$args[]  = $since;
		}

		if ( '' !== $until ) {
			$where[] = 'created_at <= %s';
			$args[]  = $until;
		}

		$sql = "SELECT COUNT(*) FROM {$table} WHERE " . implode( ' AND ', $where ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared

		if ( ! empty( $args ) ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared
			return (int) $wpdb->get_var( $wpdb->prepare( $sql, $args ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared
		return (int) $wpdb->get_var( $sql ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
	}

	/**
	 * Grouped count by event key.
	 *
	 * @since 0.1.0
	 *
	 * @param string $since MySQL date (UTC).
	 * @param string $until MySQL date (UTC).
	 * @return array<string,int>
	 */
	public static function counts_by_event( $since, $until ) {
		global $wpdb;

		$table = self::table();

		// phpcs:disable WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$rows = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
			$wpdb->prepare(
				"SELECT event, COUNT(*) AS total FROM {$table} WHERE created_at >= %s AND created_at <= %s GROUP BY event ORDER BY total DESC LIMIT 50",
				$since,
				$until
			)
		);
		$counts = array();

		foreach ( (array) $rows as $row ) {
			$counts[ $row->event ] = (int) $row->total;
		}

		// Bulk plugin/theme updates are stored as one row with a component count.
		// Read only those low-volume rows and replace their row totals with the
		// actual number of updated components.
		$weighted_rows = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
			$wpdb->prepare(
				"SELECT event, meta FROM {$table} WHERE event IN (%s, %s) AND created_at >= %s AND created_at <= %s",
				'plugin_updated',
				'theme_updated',
				$since,
				$until
			)
		);
		// phpcs:enable

		foreach ( array( 'plugin_updated', 'theme_updated' ) as $weighted_event ) {
			$counts[ $weighted_event ] = 0;
		}

		foreach ( (array) $weighted_rows as $row ) {
			$event = sanitize_key( (string) $row->event );
			$meta  = json_decode( (string) $row->meta, true );
			$count = is_array( $meta ) && isset( $meta['count'] ) ? max( 1, absint( $meta['count'] ) ) : 1;

			$counts[ $event ] += $count;
		}

		return $counts;
	}

	/**
	 * Delete older events (runs daily via cron).
	 *
	 * @since 0.1.0
	 *
	 * @param int $days Retention period in days.
	 * @return int Number of deleted rows.
	 */
	public static function prune( $days = 180 ) {
		global $wpdb;

		$days   = max( 7, absint( $days ) );
		$table  = self::table();
		$cutoff = self::format_utc( time() - ( $days * DAY_IN_SECONDS ) );

		// phpcs:disable WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$deleted = $wpdb->query( // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from $wpdb->prefix; values are prepared.
			$wpdb->prepare( "DELETE FROM {$table} WHERE created_at < %s", $cutoff )
		);
		// phpcs:enable

		return (int) $deleted;
	}
}