<?php

namespace WPMailSMTP\Pro\Emails\Logs\Webhooks\Providers\SparkPost;

use WPMailSMTP\Helpers\Helpers;
use WPMailSMTP\Pro\Emails\Logs\Webhooks\AbstractSubscriber;
use WPMailSMTP\Providers\SparkPost\Mailer;
use WP_Error;
use WPMailSMTP\WP;

/**
 * Class Subscriber.
 *
 * @since 3.3.0
 */
class Subscriber extends AbstractSubscriber {

	/**
	 * Subscription events.
	 *
	 * @since 3.3.0
	 *
	 * @var array
	 */
	const EVENTS = [
		'delivery',
		'bounce',
		'out_of_band',
		'policy_rejection',
		'generation_failure',
		'generation_rejection',
	];

	/**
	 * Create webhook subscription.
	 *
	 * @since 3.3.0
	 *
	 * @return true|WP_Error
	 */
	public function subscribe() {

		$subscription = $this->get_subscription();

		if ( is_wp_error( $subscription ) ) {
			return $subscription;
		}

		// Already subscribed.
		if ( $subscription !== false && empty( array_diff( self::EVENTS, $subscription['events'] ) ) ) {
			return true;
		}

		$events = $subscription !== false ? $subscription['events'] : [];
		$events = array_unique( array_merge( $events, self::EVENTS ) );

		$body = [
			'name'   => esc_html__( 'WP Mail SMTP', 'wp-mail-smtp-pro' ),
			'target' => $this->provider->get_url(),
			'events' => $events,
		];

		// Create subscription.
		$response = $this->request( 'POST', $body );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		return true;
	}

	/**
	 * Remove webhook subscription.
	 *
	 * @since 3.3.0
	 *
	 * @return true|WP_Error
	 */
	public function unsubscribe() {

		$subscription = $this->get_subscription();

		if ( is_wp_error( $subscription ) ) {
			return $subscription;
		}

		// Already unsubscribed.
		if ( $subscription === false ) {
			return true;
		}

		// Delete subscription.
		$response = $this->request( 'DELETE', [], $subscription['id'] );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		return true;
	}

	/**
	 * Check webhook subscription.
	 *
	 * @since 3.3.0
	 *
	 * @return bool|WP_Error
	 */
	public function is_subscribed() {

		$subscription = $this->get_subscription();

		if ( is_wp_error( $subscription ) ) {
			return $subscription;
		}

		// Subscription does not exist.
		if ( $subscription === false ) {
			return false;
		}

		return empty( array_diff( self::EVENTS, $subscription['events'] ) );
	}

	/**
	 * Get subscription if available.
	 *
	 * @since 3.3.0
	 *
	 * @return array|false|WP_Error
	 */
	protected function get_subscription() {

		$response = $this->request();

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		$webhooks = array_filter(
			$response['results'],
			function ( $data ) {
				return $data['target'] === $this->provider->get_url();
			}
		);

		return ! empty( $webhooks ) ? array_values( $webhooks )[0] : false;
	}

	/**
	 * Performs SparkPost webhooks API HTTP request.
	 *
	 * @since 3.3.0
	 *
	 * @param string $method     Request method.
	 * @param array  $params     Request params.
	 * @param array  $webhook_id SparkPost webhooks ID.
	 *
	 * @return mixed|WP_Error
	 */
	protected function request( $method = 'GET', $params = [], $webhook_id = false ) {

		$endpoint = ( $this->provider->get_option( 'region' ) === 'EU' ? Mailer::API_BASE_EU : Mailer::API_BASE_US ) . '/webhooks';

		$args = [
			'method'  => $method,
			'headers' => [
				'Authorization' => $this->provider->get_option( 'api_key' ),
				'Content-Type'  => 'application/json',
			],
		];

		if ( $method === 'GET' ) {
			$endpoint = add_query_arg( $params, $endpoint );
		} else {
			$args['body'] = wp_json_encode( $params );
		}

		if ( $webhook_id !== false ) {
			$endpoint .= '/' . $webhook_id;
		}

		$response = wp_remote_request( $endpoint, $args );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		if ( ! in_array( wp_remote_retrieve_response_code( $response ), [ 200, 204 ], true ) ) {
			return $this->get_response_error( $response );
		}

		return json_decode( wp_remote_retrieve_body( $response ), true );
	}

	/**
	 * Retrieve errors from SparkPost API response.
	 *
	 * @since 3.3.0
	 *
	 * @param array $response Response array.
	 *
	 * @return WP_Error
	 */
	protected function get_response_error( $response ) {

		$body       = json_decode( wp_remote_retrieve_body( $response ) );
		$error_text = [];

		if ( ! empty( $body->errors ) && is_array( $body->errors ) ) {
			foreach ( $body->errors as $error ) {
				if ( ! empty( $error->message ) ) {
					$message     = $error->message;
					$code        = ! empty( $error->code ) ? $error->code : '';
					$description = ! empty( $error->description ) ? $error->description : '';

					$error_text[] = Helpers::format_error_message( $message, $code, $description );
				}
			}
		} else {
			$error_text[] = WP::wp_remote_get_response_error_message( $response );
		}

		return new WP_Error( wp_remote_retrieve_response_code( $response ), implode( WP::EOL, $error_text ) );
	}
}