<?php
/**
 * Talking to the Monthwrap API.
 *
 * Every request carries the site key the agency gave this site. Nothing is sent until a
 * key has been saved on the settings page.
 *
 * @package Monthwrap
 */

defined( 'ABSPATH' ) || exit;

/**
 * Requests to api.monthwrap.com.
 */
class Monthwrap_Api {

	const DEFAULT_URL = 'https://api.monthwrap.com';

	/**
	 * Where the API lives. The MONTHWRAP_API_URL constant or the `monthwrap_api_url`
	 * filter point the plugin at another copy of it, for development.
	 *
	 * @return string Without a trailing slash.
	 */
	public static function base_url() {
		$url = defined( 'MONTHWRAP_API_URL' ) ? MONTHWRAP_API_URL : self::DEFAULT_URL;
		/**
		 * Filters the address of the Monthwrap API.
		 *
		 * @param string $url The API's address.
		 */
		return untrailingslashit( (string) apply_filters( 'monthwrap_api_url', $url ) );
	}

	/**
	 * The saved site key, or an empty string.
	 *
	 * @return string
	 */
	public static function site_key() {
		return (string) get_option( 'monthwrap_site_key', '' );
	}

	/**
	 * Sends a batch of events.
	 *
	 * @param array $events Events as the API expects them.
	 * @return array See request().
	 */
	public static function send_events( array $events ) {
		return self::request(
			'POST',
			'/ingest/events',
			array(
				'plugin_version' => MONTHWRAP_VERSION,
				'events'         => $events,
			)
		);
	}

	/**
	 * Which client and agency a key belongs to.
	 *
	 * @param string|null $key A key to check, or null for the saved one.
	 * @return array See request(). On success, body has client_name and agency_name.
	 */
	public static function whoami( $key = null ) {
		return self::request( 'GET', '/ingest/site', null, $key );
	}

	/**
	 * One request to the API.
	 *
	 * @param string      $method HTTP method.
	 * @param string      $path   Path, starting with a slash.
	 * @param array|null  $body   JSON body, if any.
	 * @param string|null $key    Site key, or null for the saved one.
	 * @return array {
	 *     @type int        $code  HTTP status, or 0 when the API couldn't be reached.
	 *     @type array|null $body  The decoded JSON reply.
	 *     @type string     $error What went wrong, when it couldn't be reached.
	 * }
	 */
	public static function request( $method, $path, $body = null, $key = null ) {
		$args = array(
			'method'     => $method,
			'timeout'    => 15,
			'user-agent' => 'Monthwrap-WordPress/' . MONTHWRAP_VERSION . '; ' . home_url( '/' ),
			'headers'    => array(
				'Authorization' => 'Bearer ' . ( null === $key ? self::site_key() : $key ),
				'Accept'        => 'application/json',
			),
		);
		if ( null !== $body ) {
			$args['headers']['Content-Type'] = 'application/json';
			$args['body']                    = wp_json_encode( $body );
			$args['data_format']             = 'body';
		}

		$response = wp_remote_request( self::base_url() . $path, $args );
		if ( is_wp_error( $response ) ) {
			return array(
				'code'  => 0,
				'body'  => null,
				'error' => $response->get_error_message(),
			);
		}
		$decoded = json_decode( wp_remote_retrieve_body( $response ), true );
		return array(
			'code'  => (int) wp_remote_retrieve_response_code( $response ),
			'body'  => is_array( $decoded ) ? $decoded : null,
			'error' => '',
		);
	}
}