<?php
	// FIXME: this doesn't work on Windows
	// FIXME: doesn't handle arrays
	// FIXME: doesn't handle nested function calls
	// FIXME: no authentication for ApiProvider access is implemented
	// FIXME: doesn't do ApiObjects nor nested ApiProviders right
	/**************************************
	*	This file is meant to help integrate web.d apps
	*	with PHP apps that live on the same domain.
	*
	* 	It's useful for things like single sign on with a web.d core.
	**************************************/

/// This provides (currently) *read-only* access to the web.d session file.
/// It needs access to the session ID cookie, so this has to live on the
/// same domain as your D app, and the D app's cookie should be set to
/// a path permissive enough to be sent here too.
///
/// Note this must also be on the same physical server as web.d (or at
/// least mount the tmp dirs to the same place), since it reads the session
/// data off the local filesystem.
///
/// TIP: you might want to use this to access your ApiProvider methods in D,
/// instead of reading the session alone.
class WebDotDSession {
	/// Access and load the session
	public function __construct($cookieName = "_sess_id") {
		if(isset($_COOKIES[$cookieName])) {
			$token = $_COOKIES[$cookieName];

			$this->sessionId = hash("sha256",
				$_SERVER["REMOTE_ADDR"] . "\r\n" .
				$_SERVER["HTTP_USER_AGENT"] . "\r\n" .
				$token);

			$path = "/tmp/arsd_session_file_" . $this->sessionId;
			if(file_exists($path))
				$this->data =
					json_decode(file_get_contents($path));
		}
	}

	public $sessionId = "";

	/// The data in the session, as a PHP object. Note that any writes
	/// to it will be discarded.
	public $data = null;
}

/// This provides a base for exceptions thrown by D
class WebDotDException extends Exception {}

/**
	If you've used the Javascript generated by web.d, you'll
	find this very familiar; this is a port of that for the
	most part.

	The ApiProvider methods don't make a call directly. Instead,
	they return an object that you can tweak a little, pass
	to other functions, and retreive the data.

	When getting synchronously, D exceptions are translated to PHP
	exceptions, and the return value is returned right here. Use
	the getSync() method to do this.

	NOT IMPLEMENTED IN PHP
	When getting asynchrously, D exceptions are sent to an onError
	delegate, and successes are sent to a handler delegate. Use
	the get() method to do this.
	DONE WITH NOT IMPLEMENTED

	For example:

	// using it anonymously (probably the easiest way)
	$result = $api->getMyData("hello")->getSync(); // it waits for the 
						// D to respond. Fast if
						// local, but can be slow if
						// accessing remote servers.

	// using it with a name
	$call = $api->getMyData("hello");
	// you can change the returned format with a method on the object
	$call->format("html");
	// and now get it
	$result = $call.getSync();

	// you can also chain method calls in one line
	$result = $api->getMyData("hello")->format("html")->getSync();


	You can also change the parameters of the request. You shouldn't
	need this most the time, but sometimes it's useful to have more
	control.

	$call = $api->getMyData("hello");
	// add an additional request param
	$call->setValue("my-request-param", "whatever");
	$call->setMethod("POST"); // override the default HTTP verb for the call

	$call->getSync(); // execute the request


	But, more often than not, you can use the call pretty easily with the
	anonymous one-liner.
*/
class WebDotDMethodCall {
	public function __construct($apiProvider, $method, $url, $params) {
		$this->apiProvider = $apiProvider;
		$this->method = $method;
		$this->url = $url;
		$this->requestedDataFormat = "json";
		$num = 0;
		foreach($params as $arg) {
			$this->urlargs["positional-arg-" . $num] = $arg;
			$num++;
		}
	}

	public function format($dataFormat) {
		$this->requestedDataFormat = $dataFormat;
		return $this;
	}

	public function setMethod($httpMethod) {
		$this->method = $httpMethod;
		return $this;
	}

	public function setValue($name, $value) {
		$this->urlargs[$name] = $value;
		return $this;
	}

	private $apiProvider;
	private $url;
	private $urlargs;
	private $method;
	private $requestedDataFormat;

	public function getSync() {
		$args = "";
		$num = 0;

		$params = $this->urlargs;
		$params["envelopeFormat"] = "json";
		$params["format"] = $this->requestedDataFormat;

		$outputted = false;
		foreach($params as $k => $arg) {
			if($outputted) {
				$args .= "&";
			} else {
				$outputted = true;
			}

			$args .= urlencode($k);
			$args .= "=";
			$args .= urlencode($arg);
		}

		$url = $this->url;

		if($this->method == "GET")
			$url .= "?" . $args;


		$ch = curl_init($url);
		if($this->method == "POST") {
			curl_setopt($ch, CURLOPT_POST,1);
			curl_setopt($ch, CURLOPT_POSTFIELDS, $args);
		}
		curl_setopt($ch, CURLOPT_HEADER,0);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
		$data = curl_exec($ch);

		$resultObj = json_decode($data);

		if($resultObj == null) {
			echo $data;
			throw new WebDotDException("Got null JSON");
		}

		if($resultObj->success) {
			return $resultObj->result;
		} else {
			// FIXME: maybe we can use type for better info?
			$msg = $resultObj->type;
			if(strlen($msg) > 0)
				$msg .= ": ";
			$msg .= $resultObj->errorMessage;
			throw new WebDotDException($msg);
		}

		// assert(0); // not reached
	}
}

/// Base class for accessing web.d ApiProviders.
/// It doesn't do authentication, so you should use a subclass of it.
/// If you are on the same server as the api you are accessing, you can use
/// WebDotDLocalApiProvider, passing it a session object. This works with
/// all web.d classes, since the local authentication is built in.
///
/// Developers: you might use this as a base for your own remote classes,
/// if you are making a web service, adding some authentication or
/// custom branding. See the protected functions for available hooks.
class WebDotDApiProvider {
	private $endpoint;
	// The endpoint is a full URL to the base of your web.d program, with trailing slash.
	// for example: http://mywebsite.com/myapp/
	public function __construct($endpoint) {
		$this->endpoint = $endpoint;
	}

	public function __call($name, $params = null) {
		$url = $this->endpoint . $name;

		return new WebDotDMethodCall($this,
			strpos($name, "get") === 0 ? "GET" : "POST",
			$url,
			$params);
	}
}

/// Provides access to a *local* D ApiProvider. 
class LocalWebDotDProvider extends WebDotDApiProvider {
	/// Takes a WebDotDSession
	public function __construct($session) {

	}
}