<?php
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Logs AI bot visits into a local table. Nothing leaves the site.
 */
class ATBA_Logger {

	const TABLE = 'atba_visits';

	public function __construct() {
		add_action( 'wp', array( $this, 'maybe_log' ), 1 );
		add_action( 'atba_daily_cleanup', array( $this, 'cleanup' ) );
		if ( ! wp_next_scheduled( 'atba_daily_cleanup' ) ) {
			wp_schedule_event( time(), 'daily', 'atba_daily_cleanup' );
		}
	}

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

		$sql = "CREATE TABLE {$table} (
			id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
			bot VARCHAR(64) NOT NULL,
			url VARCHAR(2048) NOT NULL,
			visited_at DATETIME NOT NULL,
			PRIMARY KEY (id),
			KEY bot (bot),
			KEY visited_at (visited_at)
		) {$charset};";

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

	public function maybe_log() {
		if ( is_admin() || wp_doing_ajax() || wp_doing_cron() ) {
			return;
		}

		$ua  = isset( $_SERVER['HTTP_USER_AGENT'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ) : '';
		$bot = ATBA_Bots::match( $ua );
		if ( ! $bot ) {
			return;
		}

		$uri = isset( $_SERVER['REQUEST_URI'] ) ? esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '/';
		$uri = substr( $uri, 0, 2048 );

		global $wpdb;
		$table = $wpdb->prefix . self::TABLE;

		// Throttle: same bot + same path logged at most once per 10 minutes.
		// Checked against the log table itself (indexed, size-bounded by the
		// retention cron) instead of transients, so unauthenticated requests
		// cannot bloat the options table with unique keys.
		$recent = $wpdb->get_var(
			$wpdb->prepare(
				"SELECT id FROM {$table} WHERE bot = %s AND url = %s AND visited_at > DATE_SUB(NOW(), INTERVAL 10 MINUTE) LIMIT 1", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$bot,
				$uri
			)
		);
		if ( $recent ) {
			return;
		}

		$wpdb->insert(
			$table,
			array(
				'bot'        => $bot,
				'url'        => $uri,
				'visited_at' => current_time( 'mysql' ),
			),
			array( '%s', '%s', '%s' )
		);
	}

	/** Keep the table small: retention configurable, default 90 days. */
	public function cleanup() {
		global $wpdb;
		$days  = (int) apply_filters( 'atba_retention_days', get_option( 'atba_retention', 90 ) );
		$table = $wpdb->prefix . self::TABLE;
		$wpdb->query(
			$wpdb->prepare( "DELETE FROM {$table} WHERE visited_at < DATE_SUB(NOW(), INTERVAL %d DAY)", $days ) // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		);
	}

	/** Summary counts per bot for the last N days. */
	public static function stats( $days = 30 ) {
		global $wpdb;
		$table = $wpdb->prefix . self::TABLE;
		return $wpdb->get_results(
			$wpdb->prepare(
				"SELECT bot, COUNT(*) AS hits, MAX(visited_at) AS last_seen
				 FROM {$table}
				 WHERE visited_at >= DATE_SUB(NOW(), INTERVAL %d DAY)
				 GROUP BY bot ORDER BY hits DESC", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$days
			)
		);
	}

	/** Most crawled URLs for the last N days. */
	public static function top_urls( $days = 30, $limit = 10 ) {
		global $wpdb;
		$table = $wpdb->prefix . self::TABLE;
		return $wpdb->get_results(
			$wpdb->prepare(
				"SELECT url, COUNT(*) AS hits
				 FROM {$table}
				 WHERE visited_at >= DATE_SUB(NOW(), INTERVAL %d DAY)
				 GROUP BY url ORDER BY hits DESC LIMIT %d", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$days,
				$limit
			)
		);
	}
}