<?php
	
	class ApiRequest {
		
		protected static $baseURL = 'https://www.delijn.be';
		
		protected $apiPath;
		protected $action;
		protected $url;
		
		protected $http_response_header;
		
		public function __toString () {
			return 'ApiRequest[url=' . $this->url . ']';
		}
		
		public function __construct ($apiPath, $action, $method='GET') {
		
			if (!is_string($action)) {
				throw new InvalidArgumentException('$action must be a string');
			}
			$this->apiPath = $apiPath;
			$this->action = $action;
			$this->url = Static::$baseURL.'/'.$apiPath.'/'.$action;
			
			if (preg_match('~//.*//~',$this->url) === 1) {
				throw new InvalidArgumentException('Resulting URL ('.$this->url.') contains a double slash');
			}
			
			if (!is_string($method)) {
				throw new InvalidArgumentException('$method must be a string');
			}
			switch ($method) {
				case 'GET': case 'POST': case 'PUT': case 'DELETE': break;
				throw new InvalidArgumentException('$method must be one of the following: "GET", "POST", "PUT", "DELETE"');
			}
			$this->method = $method;
			
		}
		
		public function exec ($dataToSend=null) {
			
			$opts = array('http' =>
				array(
					'method'  => $this->method
				)
			);
			if (!is_null($dataToSend)) {
				if (is_array($dataToSend)) {
					$opts['http']['content'] = http_build_query($dataToSend);
				} else {
					throw new InvalidArgumentException('$dataToSend must be either NULL or an array');
				}
			}
			
			$context = stream_context_create($opts);
			
			$json = @file_get_contents(
				$this->url, false, $context
			);
			
			// Make the HTTP response header available if they want to get it
			// If there is no network connection, $http_response_header may be undefined
			if (isset($http_response_header)) {
				$this->http_response_header = $http_response_header;
			} else {
				$this->http_response_header = null;
			}
			
			
			$result = json_decode($json, true);
			
			switch (json_last_error()) {
				case JSON_ERROR_NONE:
					return $result;
				break;
				case JSON_ERROR_SYNTAX:
					throw new Exception('Result was not valid JSON: ' . json_last_error_msg());
				break;
				default:
					throw new Exception('Result could not be parsed as JSON: ' . json_last_error_msg());
				break;
			}
			return null;
			
		}
		
		public function getHttpResponseHeader () {
			return $this->http_response_header;
		}
	}
?>