<?php
/**
 * Delivers signed events to RootCue. Sending happens in the background (Action Scheduler
 * when WooCommerce provides it, otherwise WP-Cron) so checkout and forms are never slowed down.
 *
 * @package RootCue
 */

defined( 'ABSPATH' ) || exit;

final class RootCue_Client {

	const HOOK        = 'rootcue_deliver_event';
	const MAX_ATTEMPTS = 6;
	const LOG_OPTION  = 'rootcue_delivery_log';

	/** Queue an event for delivery. */
	public static function queue( array $event ): void {
		if ( ! RootCue_Settings::is_configured() ) {
			return;
		}
		self::schedule( $event, 1, 0 );
	}

	private static function schedule( array $event, int $attempt, int $delay ): void {
		$args = array( wp_json_encode( $event ), $attempt );
		if ( function_exists( 'as_schedule_single_action' ) ) {
			as_schedule_single_action( time() + $delay, self::HOOK, $args, 'rootcue' );
		} else {
			wp_schedule_single_event( time() + $delay, self::HOOK, $args );
		}
	}

	/** Background handler. */
	public static function deliver( $event_json, $attempt = 1 ): void {
		$event = json_decode( (string) $event_json, true );
		if ( ! is_array( $event ) ) {
			return;
		}
		$result = self::post( $event );
		if ( $result['ok'] ) {
			self::log( $event, 'delivered', $result['status'] );
			return;
		}
		// 4xx other than 408/429 won't succeed on retry (bad signature, bad data).
		$retryable = 0 === $result['status'] || 408 === $result['status'] || 429 === $result['status'] || $result['status'] >= 500;
		if ( $retryable && $attempt < self::MAX_ATTEMPTS ) {
			self::schedule( $event, $attempt + 1, (int) min( 3600, 30 * ( 2 ** ( $attempt - 1 ) ) ) );
			self::log( $event, 'retrying', $result['status'] );
			return;
		}
		self::log( $event, 'failed', $result['status'] );
	}

	/**
	 * Sends one signed request.
	 *
	 * @return array{ok: bool, status: int, body: string}
	 */
	public static function post( array $event ): array {
		$url    = RootCue_Settings::webhook_url();
		$secret = RootCue_Settings::secret();
		if ( '' === $url || '' === $secret ) {
			return array( 'ok' => false, 'status' => 0, 'body' => 'not configured' );
		}
		$body     = wp_json_encode( $event );
		$response = wp_remote_post(
			$url,
			array(
				'timeout'     => 10,
				'redirection' => 0,
				'headers'     => array(
					'Content-Type'        => 'application/json',
					'X-RootCue-Signature' => RootCue_Payload::sign( $secret, $body, time() ),
					'User-Agent'          => 'RootCue-WordPress/' . ROOTCUE_VERSION,
				),
				'body'        => $body,
			)
		);
		if ( is_wp_error( $response ) ) {
			return array( 'ok' => false, 'status' => 0, 'body' => $response->get_error_message() );
		}
		$status = (int) wp_remote_retrieve_response_code( $response );
		return array( 'ok' => $status >= 200 && $status < 300, 'status' => $status, 'body' => (string) wp_remote_retrieve_body( $response ) );
	}

	/** Keeps the last 25 deliveries — event IDs and types only, never customer details. */
	private static function log( array $event, string $outcome, int $status ): void {
		$log = get_option( self::LOG_OPTION, array() );
		if ( ! is_array( $log ) ) {
			$log = array();
		}
		array_unshift(
			$log,
			array(
				'at'      => time(),
				'type'    => (string) ( $event['type'] ?? '' ),
				'id'      => (string) ( $event['id'] ?? '' ),
				'outcome' => $outcome,
				'status'  => $status,
			)
		);
		update_option( self::LOG_OPTION, array_slice( $log, 0, 25 ), false );
	}
}