<?php

namespace AdPresso\Modules\Tracking;

defined( 'ABSPATH' ) || exit;

/**
 * Stats manager.
 */
class StatsManager {

	private static ?self $instance = null;

	/**
	 * Get singleton.
	 *
	 * @return self
	 */
	public static function get_instance(): self {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Handles a batch of tracking events from the REST API.
	 *
	 * @param array $events Ein Array von Event-Objekten.
	 *
	 * @return bool True bei Erfolg.
	 */
	public function record_batch( array $events ): bool {
		global $wpdb;

		$stats_table      = $wpdb->prefix . 'adpresso_stats';
		$clicks_log_table = $wpdb->prefix . 'adpresso_clicks_log';

		// Group the events, to minimize the number of DB queries
		$grouped_stats = [];

		foreach ( $events as $event ) {
			// Validate the basic data for each event
			$placement_id = absint( $event['placementId'] ?? 0 );
			$group_id     = absint( $event['groupId'] ?? 0 );
			$ad_id        = absint( $event['adId'] ?? 0 );
			$event_type   = sanitize_key( $event['type'] ?? '' );

			if ( ! $ad_id ) {
				continue;
			}

			$key = "{$placement_id}-{$group_id}-{$ad_id}";

			if ( ! isset( $grouped_stats[ $key ] ) ) {
				$grouped_stats[ $key ] = [
					'placement_id'   => $placement_id,
					'group_id'       => $group_id,
					'ad_id'          => $ad_id,
					'impressions'    => 0,
					'impressions_av' => 0,
					'clicks'         => 0,
				];
			}

			// Increment the counter.
			switch ( $event_type ) {
				case 'impression':
					$grouped_stats[ $key ]['impressions']++;
					break;
				case 'impression_av':
					$grouped_stats[ $key ]['impressions_av']++;
					break;
				case 'click':
					$grouped_stats[ $key ]['clicks']++;
					if ( adpresso_fs()->is_premium() ) {
						// Write a detailed click log entry
						$this->log_click_details( $event, $clicks_log_table );
					}
					break;
			}
		}

		if ( empty( $grouped_stats ) ) {
			return true;
		}

		$date_utc  = current_time( 'mysql', true );
		$date_only = substr( $date_utc, 0, 10 );

		$values = [];
		foreach ( $grouped_stats as $stat ) {
			$values[] = $wpdb->prepare(
				'(%s, %d, %d, %d, %d, %d, %d)',
				$date_only,
				$stat['placement_id'],
				$stat['group_id'],
				$stat['ad_id'],
				$stat['impressions'],
				$stat['clicks'],
				$stat['impressions_av']
			);
		}

		$query = "INSERT INTO {$stats_table} (stat_date, placement_id, group_id, ad_id, impressions, clicks, impressions_av)
                  VALUES " . implode( ',', $values ) . "
                  ON DUPLICATE KEY UPDATE
                  impressions = impressions + VALUES(impressions),
                  clicks = clicks + VALUES(clicks),
                  impressions_av = impressions_av + VALUES(impressions_av)";

		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- Bulk insert values are individually prepared above.
		$wpdb->query( $query );

		return true;
	}

	/**
	 * Saves detailed click log entry
	 *
	 * @param array  $event      The clicke vent.
	 * @param string $table_name Name of the log table.
	 */
	private function log_click_details( array $event, string $table_name ): void {
		global $wpdb;

		// Anonymize the IP address before hashing (GDPR-friendly)
		$ip = wp_privacy_anonymize_ip( $_SERVER['REMOTE_ADDR'] ?? '' );

		$wpdb->insert(
			$table_name,
			[
				'timestamp_utc' => current_time( 'mysql', true ),
				'placement_id'  => absint( $event['placementId'] ?? 0 ),
				'group_id'      => absint( $event['groupId'] ?? 0 ),
				'ad_id'         => absint( $event['adId'] ?? 0 ),
				'ip_hash'       => hash( 'sha256', $ip . wp_salt() ),
				'user_agent'    => sanitize_text_field( $_SERVER['HTTP_USER_AGENT'] ?? '' ),
				'target_url'    => esc_url_raw( $event['targetUrl'] ?? '' ),
				'referrer_url'  => esc_url_raw( $_SERVER['HTTP_REFERER'] ?? '' ),
			]
		);
	}
}