<?php
/**
 * Signed requests to the Eazign service.
 *
 * @package Eazign
 */

defined( 'ABSPATH' ) || exit;

/**
 * HTTP client for the Eazign API (/woo/v1/*).
 *
 * Every request after registration is signed with the site secret:
 * X-Eazign-Signature = hex HMAC-SHA256( secret, time \n METHOD \n path?query \n sha256hex(body) ),
 * see app/lib/woo/site.server.ts in the service.
 */
class Eazign_Client {

	const OPTION = 'eazign_site';

	/**
	 * Stored connection: [ 'id' => site id, 'secret' => site secret, 'connected' => bool ].
	 *
	 * @return array
	 */
	public static function site() {
		$site = get_option( self::OPTION, array() );
		return is_array( $site ) ? $site : array();
	}

	/**
	 * Whether the site is registered with the service.
	 *
	 * @return bool
	 */
	public static function is_registered() {
		$site = self::site();
		return ! empty( $site['id'] ) && ! empty( $site['secret'] );
	}

	/**
	 * Whether the merchant completed the connection.
	 *
	 * @return bool
	 */
	public static function is_connected() {
		$site = self::site();
		return self::is_registered() && ! empty( $site['connected'] );
	}

	/**
	 * Base URL of the service.
	 *
	 * @return string
	 */
	public static function server_url() {
		return untrailingslashit( EAZIGN_SERVER_URL );
	}

	/**
	 * Calls the API.
	 *
	 * @param string     $method  HTTP method.
	 * @param string     $path    Path below /woo/v1/, may contain a query string.
	 * @param array|null $body    JSON body.
	 * @param array      $options signed (bool, default true), timeout (seconds).
	 * @return array|WP_Error Decoded JSON answer.
	 */
	public static function request( $method, $path, $body = null, $options = array() ) {
		$options = wp_parse_args(
			$options,
			array(
				'signed'  => true,
				'timeout' => 30,
			)
		);
		$method  = strtoupper( $method );
		$path    = '/woo/v1/' . ltrim( $path, '/' );
		$payload = null === $body ? '' : wp_json_encode( $body );
		$headers = array( 'Accept' => 'application/json' );
		if ( '' !== $payload ) {
			$headers['Content-Type'] = 'application/json';
		}

		if ( $options['signed'] ) {
			$site = self::site();
			if ( empty( $site['id'] ) || empty( $site['secret'] ) ) {
				return new WP_Error( 'eazign_not_connected', __( 'This shop is not connected to Eazign yet.', 'eazign' ) );
			}
			$time                          = (string) time();
			$headers['X-Eazign-Site']      = $site['id'];
			$headers['X-Eazign-Time']      = $time;
			$headers['X-Eazign-Signature'] = hash_hmac( 'sha256', $time . "\n" . $method . "\n" . $path . "\n" . hash( 'sha256', $payload ), $site['secret'] );
		}

		$response = wp_remote_request(
			self::server_url() . $path,
			array(
				'method'  => $method,
				'headers' => $headers,
				'body'    => '' === $payload ? null : $payload,
				'timeout' => $options['timeout'],
			)
		);
		if ( is_wp_error( $response ) ) {
			return $response;
		}
		$code = wp_remote_retrieve_response_code( $response );
		$data = json_decode( wp_remote_retrieve_body( $response ), true );
		if ( $code >= 400 || ! is_array( $data ) ) {
			$message = is_array( $data ) && ! empty( $data['error'] ) ? $data['error'] : sprintf( /* translators: %d: HTTP status code */ __( 'Eazign service error (HTTP %d)', 'eazign' ), $code );
			return new WP_Error( 'eazign_http_' . $code, $message, array( 'status' => $code ) );
		}
		return $data;
	}

	/**
	 * Shortcuts.
	 *
	 * @param string $path Path below /woo/v1/.
	 * @return array|WP_Error
	 */
	public static function get( $path ) {
		return self::request( 'GET', $path );
	}

	/**
	 * POST shortcut.
	 *
	 * @param string $path    Path below /woo/v1/.
	 * @param array  $body    JSON body.
	 * @param array  $options See request().
	 * @return array|WP_Error
	 */
	public static function post( $path, $body = array(), $options = array() ) {
		return self::request( 'POST', $path, $body, $options );
	}
}