<?php
/**
 * Calls Ojelio's API (/api/v1) from the server.
 *
 * @package Ojelio
 */

namespace Ojelio;

use WP_Error;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Api {

	/**
	 * One call. Answers the decoded body (an empty array for 204), or a WP_Error
	 * whose code is "ojelio_" and the API's error code ("ojelio_unauthorized",
	 * "ojelio_insufficient_credits"...), with the API's message and, in its data,
	 * the HTTP status, the field and Retry-After when there are any. A failure to
	 * reach Ojelio is "ojelio_unreachable".
	 *
	 * @param string $method  GET, POST or DELETE.
	 * @param string $path    Under /api/v1, starting with "/".
	 * @param array  $args    "token" (the connection's), "body" (sent as JSON), "headers", "timeout".
	 * @return array|WP_Error
	 */
	public static function call( $method, $path, array $args = array() ) {
		$headers = array_merge(
			array(
				'Accept'     => 'application/json',
				'User-Agent' => 'Ojelio-WordPress/' . OJELIO_VERSION . '; ' . home_url(),
			),
			isset( $args['headers'] ) ? $args['headers'] : array()
		);
		if ( ! empty( $args['token'] ) ) {
			$headers['Authorization'] = 'Bearer ' . $args['token'];
		}
		$request = array(
			'method'  => $method,
			'headers' => $headers,
			'timeout' => isset( $args['timeout'] ) ? $args['timeout'] : 20,
		);
		if ( array_key_exists( 'body', $args ) ) {
			$request['headers']['Content-Type'] = 'application/json';
			$request['body']                    = wp_json_encode( $args['body'] );
		}

		// Not wp_safe_remote_request(): the address is Ojelio's own, and a test
		// server on this computer (OJELIO_URL) must be reachable.
		$response = wp_remote_request( untrailingslashit( OJELIO_URL ) . '/api/v1' . $path, $request );
		if ( is_wp_error( $response ) ) {
			return new WP_Error(
				'ojelio_unreachable',
				/* translators: %s: the reason the request failed, from WordPress. */
				sprintf( __( 'Could not reach Ojelio: %s', 'ojelio' ), $response->get_error_message() )
			);
		}

		$status = (int) wp_remote_retrieve_response_code( $response );
		$body   = json_decode( wp_remote_retrieve_body( $response ), true );
		if ( $status >= 200 && $status < 300 ) {
			return is_array( $body ) ? $body : array();
		}
		$error = is_array( $body ) && isset( $body['error'] ) && is_array( $body['error'] ) ? $body['error'] : array();
		$code  = isset( $error['code'] ) ? sanitize_key( $error['code'] ) : 'internal';
		$data  = array( 'status' => $status );
		if ( isset( $error['field'] ) ) {
			$data['field'] = $error['field'];
		}
		$retry = wp_remote_retrieve_header( $response, 'retry-after' );
		if ( $retry ) {
			$data['retry_after'] = (int) $retry;
		}
		return new WP_Error(
			'ojelio_' . $code,
			isset( $error['message'] ) ? $error['message'] : __( 'Ojelio answered with an error. Try again in a moment.', 'ojelio' ),
			$data
		);
	}

	/** An address on Ojelio, for links shown to people. */
	public static function app_url( $path = '' ) {
		return untrailingslashit( OJELIO_URL ) . $path;
	}
}