<?php

/**
 * Copyright 2018 Matthias Kesler
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
class MatrixConnection {

    private $hs;
    private $at;

    function __construct($homeserver, $access_token) {
        $this->hs = $homeserver;
        $this->at = $access_token;
    }

    function send($room_id, $message) {
        if (!$this->at) {
            error_log("No access token defined");
            return false;
        }

        $send_message = NULL;
        if (!$message) {
            error_log("no message to send");
            return false;
        } elseif (is_array($message)) {
            $send_message = $message;
        } elseif ($message instanceof MatrixMessage) {
            $send_message = $message->get_object();
        } else {
            error_log("message is of not valid type\n");
            return false;
        }

        $url = "https://" . $this->hs . "/_matrix/client/r0/rooms/"
                . urlencode($room_id) . "/send/m.room.message?access_token=" . $this->at;
        $handle = curl_init($url);
        curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($handle, CURLOPT_TIMEOUT, 60);
        curl_setopt($handle, CURLOPT_POSTFIELDS, json_encode($send_message));
        curl_setopt($handle, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));

        $response = $this->exec_curl_request($handle);
        return isset($response["event_id"]);
    }

    function send_msg($room_id, $message) {
        return $this->send($room_id, array(
                    "msgtype" => "m.notice",
                    "body" => $message
                        )
        );
    }

    function hasUser($username) {
        if (!$username) {
            throw new Exception("no user given to lookup");
        }

        $url = "https://" . $this->hs . "/_matrix/client/r0/profile/@" . $username . ":" . $this->hs;
        $handle = curl_init($url);
        curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($handle, CURLOPT_TIMEOUT, 60);
        curl_setopt($handle, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));

        $res = $this->exec_curl_request($handle);
        return !(isset($res["errcode"]) && $res["errcode"] == "M_UNKNOWN");
    }

    function register($username, $password, $shared_secret) {
        if (!$username) {
            error_log("no username provided");
        }
        if (!$password) {
            error_log("no message to send");
        }

        $mac = hash_hmac('sha1', $username, $shared_secret);

        $data = array(
            "username" => $username,
            "password" => $password,
            "mac" => $mac,
        );
        $url = "https://" . $this->hs . "/_matrix/client/v2_alpha/register";
        $handle = curl_init($url);
        curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($handle, CURLOPT_TIMEOUT, 60);
        curl_setopt($handle, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
        curl_setopt($handle, CURLOPT_POSTFIELDS, json_encode($data));

        try {
            return $this->exec_curl_request($handle);
        } catch (Exception $e) {
            if (strcmp("AUTHENTICATION_FAILED", $e->getMessage()) == 0) {
                throw new Exception("WRONG_REGISTRATION_SHARED_SECRET");
            } else {
                throw $e;
            }
        }
    }

    function exec_curl_request($handle) {
        $response = curl_exec($handle);
        if ($response === false) {
            $errno = curl_errno($handle);
            $error = curl_error($handle);
            error_log("Curl returned error $errno: $error\n");
            curl_close($handle);
            return false;
        }
        $http_code = intval(curl_getinfo($handle, CURLINFO_HTTP_CODE));
        curl_close($handle);

        if ($http_code >= 500) {
            // do not want to DDOS server if something goes wrong
            sleep(10);
            return false;
        } else if ($http_code != 200) {
            $response = json_decode($response, true);
            error_log("Request has failed with error {$response['error']}\n");
            if ($http_code == 401) {
                throw new Exception("AUTHENTICATION_FAILED");
            }
        } else {
            $response = json_decode($response, true);
        }
        return $response;
    }

}

class MatrixMessage {

    private $message;

    function __construct() {
        $this->message = ["msgtype" => "m.notice"];
    }

    function set_type($msgtype) {
        $this->message["msgtype"] = $msgtype;
    }

    function set_format($format) {
        $this->message["format"] = $format;
    }

    function set_body($body) {
        $this->message["body"] = $body;
    }

    function set_formatted_body($fbody, $format = "org.matrix.custom.html") {
        $this->message["formatted_body"] = $fbody;
        $this->message["format"] = $format;
    }

    function get_object() {
        return $this->message;
    }

}

?>