<?php
namespace BavarianRankEngine\Features;

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

class CrawlerLog {
	private const TABLE = 'bre_crawler_log';
	private const CRON  = 'bre_purge_crawler_log';

	public static function install(): void {
		global $wpdb;
		$table   = $wpdb->prefix . self::TABLE;
		$charset = $wpdb->get_charset_collate();

		$sql = "CREATE TABLE IF NOT EXISTS {$table} (
            id          BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            bot_name    VARCHAR(64)     NOT NULL,
            ip_hash     VARCHAR(64)     NOT NULL DEFAULT '',
            url         VARCHAR(512)    NOT NULL DEFAULT '',
            visited_at  DATETIME        NOT NULL,
            PRIMARY KEY (id),
            KEY bot_name (bot_name),
            KEY visited_at (visited_at)
        ) {$charset};";

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		dbDelta( $sql );
	}

	public function register(): void {
		add_action( 'init', array( $this, 'maybe_log' ), 1 );
		add_action( self::CRON, array( $this, 'purge_old' ) );

		if ( ! wp_next_scheduled( self::CRON ) ) {
			wp_schedule_event( time(), 'weekly', self::CRON );
		}
	}

	public function maybe_log(): void {
		$ua = isset( $_SERVER['HTTP_USER_AGENT'] )
			? sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) )
			: '';
		if ( empty( $ua ) ) {
			return;
		}

		$bot = $this->detect_bot( $ua );
		if ( null === $bot ) {
			return;
		}

		global $wpdb;
		$wpdb->insert( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
			$wpdb->prefix . self::TABLE,
			array(
				'bot_name'   => $bot,
				'ip_hash'    => hash( 'sha256', isset( $_SERVER['REMOTE_ADDR'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ) ) : '' ),
				'url'        => mb_substr( isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '', 0, 512 ),
				'visited_at' => current_time( 'mysql' ),
			),
			array( '%s', '%s', '%s', '%s' )
		);
	}

	private function detect_bot( string $ua ): ?string {
		foreach ( array_keys( RobotsTxt::KNOWN_BOTS ) as $bot ) {
			if ( false !== stripos( $ua, $bot ) ) {
				return $bot;
			}
		}
		return null;
	}

	public function purge_old(): void {
		global $wpdb;
		$table = $wpdb->prefix . self::TABLE;
		// phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQL.NotPrepared
		$wpdb->query( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
			"DELETE FROM `{$table}` WHERE visited_at < DATE_SUB(NOW(), INTERVAL 90 DAY)"
		);
		// phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQL.NotPrepared
	}

	public static function get_recent_summary( int $days = 30 ): array {
		global $wpdb;
		if ( ! isset( $wpdb ) ) {
			return array();
		}
		$table = $wpdb->prefix . self::TABLE;
        // phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$sql = "SELECT bot_name, COUNT(*) as visits, MAX(visited_at) as last_seen
                FROM `{$table}`
                WHERE visited_at >= DATE_SUB(NOW(), INTERVAL %d DAY)
                GROUP BY bot_name
                ORDER BY visits DESC";
        // phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		return $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
			$wpdb->prepare( $sql, $days ), // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
			ARRAY_A
		) ?: array();
	}
}