<?php
	include "config.php";

	//Get Return from FB
	$code = $_GET["code"];
	$error_reason = $_GET["error_reason"];
	$error = $_GET["error"];
	$error_description = $_GET["error_description"];

	if( $error_reason != "" && $error != "" && $error_description != "" ) {
		echo "<h1>" . $error_reason . "</h1>";
		echo "<p>" . $error_description . "</p>";
		exit();
	}
	else if( $code == "" ) {
		echo "<h1>Unknown Error</h1>";
		echo "<p>Facebook did not properly authenticate you. Please try again.</p>";
		exit();
	}
	else {
		$fb_return_page = $url_app_location."auth.php";

		$fb_auth_page = "https://graph.facebook.com/oauth/access_token?client_id=" . $app_id .
					"&redirect_uri=" . $fb_return_page .
					"&client_secret=" . $app_secret .
					"&code=" . $code;



		$ch = curl_init();
		curl_setopt( $ch, CURLOPT_URL, $fb_auth_page );
		curl_setopt( $ch, CURLOPT_HEADER, 0 );
		curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
		curl_setopt( $ch, CURLOPT_TIMEOUT, 30 );
		$fb_oauth_token = curl_exec( $ch );
		curl_close( $ch );

		parse_str( $fb_oauth_token, $fb_oauth_arr );

		if( ! $fb_oauth_arr["access_token"] ) {
			echo "<h1>Unknown Error</h1>";
			echo "<p>Facebook did not return authentication token. Please try again.</p>";
			exit();
		}

		$access_token = $fb_oauth_arr["access_token"];

		//Post to facebook wall
		$fb_post_page = "https://graph.facebook.com/me/feed?access_token=" . $access_token;
		$message_text = "Appia just updated my status.";
		$fb_message = "message=".$message_text;

		$ch = curl_init();
		curl_setopt( $ch, CURLOPT_URL, $fb_post_page );
		curl_setopt( $ch, CURLOPT_HEADER, 0 );
		curl_setopt( $ch, CURLOPT_POST, true );
		curl_setopt( $ch, CURLOPT_POSTFIELDS, $fb_message );
		curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
		curl_setopt( $ch, CURLOPT_TIMEOUT, 30 );
		$fb_message_return = curl_exec( $ch );
		curl_close( $ch );

		echo "Message Posted to Facebook";
	}
?>