<?php
if (!defined('_GNUBOARD_')) exit; // 개별 페이지 접근 불가

// ActivityPub implementation for GNUBOARD 5
// Go Namhyeon <abuse@catswords.net>
// MIT License
// 2023-04-18 (version 0.1.14-dev)

// References:
//   * https://www.w3.org/TR/activitypub/
//   * https://www.w3.org/TR/activitystreams-core/
//   * https://www.w3.org/TR/activitystreams-vocabulary/
//   * https://github.com/w3c/activitypub/issues/194
//   * https://docs.joinmastodon.org/spec/webfinger/
//   * https://organicdesign.nz/ActivityPub_Code
//   * https://socialhub.activitypub.rocks/t/posting-to-pleroma-inbox/1184
//   * https://github.com/broidHQ/integrations/tree/master/broid-schemas#readme
//   * https://github.com/autogestion/pubgate-telegram
//   * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/

define("ACTIVITYPUB_INSTANCE_ID", md5_file(G5_DATA_PATH . "/dbconfig.php"));
define("ACTIVITYPUB_INSTANCE_VERSION", "0.1.14-dev");
define("ACTIVITYPUB_DEFAULT_SCHEME", "https");    // 외부 통신용 스킴 (SSL 사용이 기본)
define("ACTIVITYPUB_INSECURE_SCHEME", "http");    // 그누보드5 ActivityPub 통신용 스킴 (SSL 사용을 하지 않을 수도 있음을 고려)
define("ACTIVITYPUB_HOST", (empty(G5_DOMAIN) ? $_SERVER['HTTP_HOST'] : G5_DOMAIN));
define("ACTIVITYPUB_URL", (empty(G5_URL) ? ACTIVITYPUB_INSECURE_SCHEME . "://" . ACTIVITYPUB_INSTANCE_ID . ".local" : G5_URL));
define("ACTIVITYPUB_DATA_URL", ACTIVITYPUB_URL . '/' . G5_DATA_DIR);
define("ACTIVITYPUB_G5_BOARDNAME", "apstreams");
define("ACTIVITYPUB_G5_TABLENAME", $g5['write_prefix'] . ACTIVITYPUB_G5_BOARDNAME);
define("ACTIVITYPUB_G5_USERNAME", "apstreams");
define("ACTIVITYPUB_G5_OUTDATED_DAYS", (empty($config['cf_new_del']) ? 30 : $config['cf_new_del']));
define("ACTIVITYPUB_G5_EXPIRED_DAYS", (empty($config['cf_memo_del']) ? 180 : $config['cf_memo_del']));
define("ACTIVITYPUB_ACCESS_TOKEN", "server1.example.org=YOUR_ACCESS_TOKEN; server2.example.org=YOUR_ACCESS_TOKEN;");
define("ACTIVITYPUB_CERTIFICATE_RETRY", 10);    // 최대 인증서 생성 시도 횟수
define("ACTIVITYPUB_CERTIFICATE_DATAFIELD", "mb_9");    // 회원별 인증서(공개키, 개인키)를 저장할 필드 (기본: mb_9)
define("OAUTH2_GRANT_DATAFIELD", "mb_10");    // 회원별 인증 정보를 저장할 필드 (기본: mb_10)
define("DEFAULT_HTML_ENTITY_FLAGS", ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401);
define("NAMESPACE_ACTIVITYSTREAMS", "https://www.w3.org/ns/activitystreams");
define("NAMESPACE_ACTIVITYSTREAMS_PUBLIC", "https://www.w3.org/ns/activitystreams#Public");
define("NAMESPACE_W3ID_SECURITY_V1", "https://w3id.org/security/v1");
define("ACTIVITYPUB_ENABLED_GEOLOCATION", false);   // 위치정보 활성화 (https://lite.ip2location.com/)
define("NAVERCLOUD_ENABLED_GEOLOCATION", false);   // 국내용 위치정보 활성화 (https://www.ncloud.com/product/applicationService/geoLocation)
define("NAVERCLOUD_API_ACCESS_KEY", "");   // 네이버 클라우드 API 키 설정
define("NAVERCLOUD_API_SECRET_KEY", "");   // 네이버 클라우드 API 키 설정
define("OPENWEATHERMAP_ENABLED", false);   // 날씨정보 활성화
define("OPENWEATHERMAP_API_KEY", "");   // 날씨정보 API 키 (https://openweathermap.org/api/one-call-3)
define("KOREAEXIM_ENABLED", false);   // 환율정보 활성화
define("KOREAEXIM_API_KEY", "");   // 환율정보 API 키 (https://www.koreaexim.go.kr/ir/HPHKIR020M01?apino=2&viewtype=C)

$activitypub_loaded_libraries = array();

function activitypub_load_library($name, $callback) {
    global $activitypub_loaded_libraries;
    
    $_ = array(
        "ip2location" => array(
            G5_LIB_PATH . "/IP2Location-PHP-Module/src/Country.php",
            G5_LIB_PATH . "/IP2Location-PHP-Module/src/Database.php",
            G5_LIB_PATH . "/IP2Location-PHP-Module/src/IpTools.php"
        )
    );
    foreach($_[$name] as $f) {
        if (file_exists($f)) include($f);
    }

    array_push($activitypub_loaded_libraries, array(
        "name" => $name,
        "files" => $_[$name],
        "data" => call_user_func($callback)
    ));
}

function activitypub_create_keypair() {
    $keypair = array('', '');

    $privateKeyResource = openssl_pkey_new(array(
        'private_key_bits' => 2048,
        'private_key_type' => OPENSSL_KEYTYPE_RSA
    ));
    
    // Export the private key
    openssl_pkey_export($privateKeyResource, $privateKey);

    // Generate the public key for the private key
    $privateKeyDetailsArray = openssl_pkey_get_details($privateKeyResource);
    $publicKey = $privateKeyDetailsArray['key'];

    // Export keys to variable
    $keypair = array($privateKey, $publicKey);

    // Free the key from memory.
    openssl_free_key($privateKeyResource);

    return $keypair;
}

function activitypub_get_stored_keypair($mb) {
    global $g5;

    $private_key = '';
    $public_key = '';

    // 인증서 생성
    $k = 0;
    while ($k < ACTIVITYPUB_CERTIFICATE_RETRY && (empty($private_key) || empty($public_key))) {
        // 인증서 정보 불러오기
        if ($mb != null && !empty($mb['mb_id'])) {
            $certificate_data = activitypub_parse_stored_data($mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD]);  
            $private_key = activitypub_get_memo($certificate_data['PrivateKeyId']);    // 개인키(Private Key)
            $public_key = activitypub_get_memo($certificate_data['PublicKeyId']);     // 공개키(Public Key)
        }

        // 인증서 정보가 없으면 생성
        if (!$mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD] || empty($private_key) || empty($public_key)) {
            $keypair = activitypub_create_keypair();   // 인증서(공개키, 개인키) 생성
            $private_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[0]);   // 개인키(Private Key)
            $public_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[1]);    // 공개키(Public Key)

            // 회원 정보에 등록
            if ($private_key_id > 0 && $public_key_id > 0) {
                $stored_certificate_data = activitypub_build_stored_data(array(
                    "PrivateKeyId" => $private_key_id,
                    "PublicKeyId" => $public_key_id
                ));
                $sql = " update {$g5['member_table']} set " . ACTIVITYPUB_CERTIFICATE_DATAFIELD . " = '{$stored_certificate_data}' where mb_id = '{$mb['mb_id']}' ";
                sql_query($sql);
            }

            // 회원에게 알림
            $messsge1 = "[시스템] 외부 서버와 통신하기 위한 인증서(개인키, 공개키)가 발급되었습니다. 인증서를 타인과 공유하지 마세요. 인증서는 " . ACTIVITYPUB_G5_EXPIRED_DAYS . "일 후 만료됩니다.";
            $message2 = "[System] The certificate (Private key, Public key) has been issued to communicate with an external server. Do not share it with others. The certificate will expire in " . ACTIVITYPUB_G5_EXPIRED_DAYS . " days.";
            activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $messsge1 . ' ' . $message2);

            // 회원정보 다시 불러오기
            $mb = get_member($mb['mb_id']);

            // 시도 횟수 증가
            $k++;
        }
    }

    return array($private_key, $public_key);
}

function activitypub_get_library_data($name) {
    global $activitypub_loaded_libraries;

    $data = null;

    foreach($activitypub_loaded_libraries as $library) {
        if($library['name'] == $name) {
            $data = $library['data'];
            break;
        }
    }
    
    return $data;
}

function activitypub_json_encode($arr) {
    return json_encode($arr);
}

function activitypub_json_decode($arr) {
    return json_decode($arr, true);
}

function activitypub_parse_stored_data($s) {
    $data = array();

    $terms = array_filter(array_map("trim", explode(";", $s)));
    foreach($terms as $term) {
        list($k, $v) = explode('=', $term);
        $k = html_entity_decode($k, DEFAULT_HTML_ENTITY_FLAGS, 'UTF-8');
        $v = html_entity_decode($v, DEFAULT_HTML_ENTITY_FLAGS, 'UTF-8');
        $data[$k] = $v;
    }

    return $data;
}

function activitypub_build_stored_data($data) {
    $terms = array();
    foreach($data as $k=>$v) {
        $k = htmlentities($k, DEFAULT_HTML_ENTITY_FLAGS, 'UTF-8');
        $v = htmlentities($v, DEFAULT_HTML_ENTITY_FLAGS, 'UTF-8');
        array_push($terms, $k . '=' . $v);
    }
    return implode("; ", $terms);
}

function activitypub_get_url($action, $params = array()) {
    if (count(array_keys($params)) > 0) {
        return ACTIVITYPUB_URL . "/?route=activitypub." . $action . "&" . http_build_query($params);
    } else {
        return ACTIVITYPUB_URL . "/?route=activitypub." . $action;
    }
}

function activitypub_get_icon($mb) {
    global $config;

    $icon_file_url = "";

    if ($config['cf_use_member_icon']) {
        $mb_dir = substr($mb['mb_id'], 0, 2);
        $icon_file = G5_DATA_PATH . '/member/' . $mb_dir . '/' . get_mb_icon_name($mb['mb_id']).'.gif';
        if (file_exists($icon_file)) {
            $icon_filemtile = (defined('G5_USE_MEMBER_IMAGE_FILETIME') && G5_USE_MEMBER_IMAGE_FILETIME) ? '?'.filemtime($icon_file) : '';
            $icon_file_url = ACTIVITYPUB_DATA_URL . '/member/' . $mb_dir . '/' . get_mb_icon_name($mb['mb_id']) . '.gif' . $icon_filemtile;
        }
    }

    if (empty($icon_file_url)) {
        $icon_file_url = "https://www.gravatar.com/avatar/" . md5($mb['mb_email']);
    }

    return $icon_file_url;
}

function activitypub_get_user_interactions() {
    global $g5;

    // 반환할 배열
    $items = array();

    // 최근 활동에서 추출
    $sql = "select * from " . $g5['board_new_table']; 
    $result = sql_query($sql);
    while ($row = sql_fetch_array($result)) {
        $sql2 = "select mb_id from " . ($g5['write_prefix'] . $row['bo_table']) . " where wr_id = '" . $row['wr_id'] . "'";
        $row2 = sql_fetch($sql2);
        if ($row2['mb_id']) {
            array_push($items, array("from" => $row['mb_id'], "to" => $row2['mb_id']));
        }
    }

    // '좋아요'에서 추출
    $sql = "select bo_table, wr_id, mb_id from {$g5['board_good_table']} where bg_flag = 'good'";
    $result = sql_query($sql);
    while ($row = sql_fetch_array($result)) {
        $sql2 = "select mb_id from " . ($g5['write_prefix'] . $row['bo_table']) . " where wr_id = '" . $row['wr_id'] . "'";
        $row2 = sql_fetch($sql2);
        if ($row2['mb_id']) {
            array_push($items, array("from" => $row['mb_id'], "to" => $row2['mb_id']));
        }
    }

    return $items;
}

function activitypub_get_followers($mb) {
    $followers = array();

    if ($mb['mb_id']) {
        $linked_users = activitypub_get_user_interactions();
        foreach($linked_users as $item) {
            if ($item['to'] == $mb['mb_id'] && $item['from'] != $mb['mb_id']) {
                array_push($followers, $item['from']);
            }
        }

        $followers = array_unique($followers);
    }

    return $followers;
}

function activitypub_get_following($mb) {
    $following = array();

    if ($mb['mb_id']) {
        $linked_users = activitypub_get_user_interactions();

        foreach($linked_users as $item) {
            if ($item['from'] == $mb['mb_id'] && $item['to'] != $mb['mb_id']) {
                array_push($following, $item['to']);
            }
        }

        $following = array_unique($following);
    }
    
    return $following;
}

function activitypub_parse_url($url) {
    $ctx = parse_url($url);
    $qstr = $ctx['query'];
    parse_str($qstr, $qctx);
    $ctx['query'] = $qctx;
    return $ctx;
}

function activitypub_add_memo($mb_id, $recv_mb_id, $me_memo) {
    global $g5;
    
    $tmp_row = sql_fetch(" select max(me_id) as max_me_id from {$g5['memo_table']} ");
    $me_id = $tmp_row['max_me_id'] + 1;

    $sql = " insert into {$g5['memo_table']} ( me_recv_mb_id, me_send_mb_id, me_send_datetime, me_memo, me_read_datetime, me_type, me_send_ip ) values ( '{$recv_mb_id}', '{$mb_id}', '" . G5_TIME_YMDHIS . "', '{$me_memo}', '0000-00-00 00:00:00' , 'recv', '{$_SERVER['REMOTE_ADDR']}' ) ";
    sql_query($sql);

    return ($me_id == sql_insert_id() ? $me_id : 0);
}

function activitypub_get_memo($me_id) {
    global $g5;

    $me = sql_fetch(" select me_memo from {$g5['memo_table']} where me_id = '{$me_id}' ");
    return $me['me_memo'];
}

function activitypub_set_liked($good, $bo_table, $wr_id) {
    global $g5;

    // 추천(찬성), 비추천(반대) 카운트 증가
    sql_query(" update {$g5['write_prefix']}{$bo_table} set wr_{$good} = wr_{$good} + 1 where wr_id = '{$wr_id}' ");

    // 내역 생성
    sql_query(" insert {$g5['board_good_table']} set bo_table = '{$bo_table}', wr_id = '{$wr_id}', mb_id = '" . ACTIVITYPUB_G5_USERNAME . "', bg_flag = '{$good}', bg_datetime = '" . G5_TIME_YMDHIS . "' ");
}

function activitypub_build_http_headers($headers) {
    $lines = array();
    foreach($headers as $k=>$v) {
        array_push($lines, $k . ": " . $v);
    }
    return $lines;
}

function activitypub_build_date($dateString='now') {
    // e.g. 18 Dec 2019 10:08:46 GMT
    $dt = ($dateString == "now" ? new DateTime('now', new DateTimeZone('GMT')) : DateTime::createFromFormat('d M Y H:i:s e', $dateString));
    return $dt->format('d M Y H:i:s e');
}

function activitypub_build_digest($body) {
    $digest = hash('sha256', $body, true);
    $digest = base64_encode($digest);
    $digest = 'sha-256=' . $digest;
    return $digest;
}

function activitypub_build_signature($url, $date, $digest, $mb, $method="POST") {
    // get a certificate
    list($private_key, $public_key) = activitypub_get_stored_keypair($mb);
    
    // get host and path from URL
    list($host, $path) = array(parse_url($url, PHP_URL_HOST), parse_url($url, PHP_URL_PATH));

    // build a key id
    $activitypub_user_id = activitypub_get_url("user", array("mb_id" => $mb['mb_id']));
    $keyId = $activitypub_user_id . "#main-key";

    // build a target data to get signature
    $signature = $method . ' ' . $path . "\n" .
        'HOST: ' . $host . "\n" .
        'Date: ' . $date . "\n" .
        'Digest: ' . $digest;

    // create a signature
    openssl_sign($signature, $signature, $privateKey, OPENSSL_ALGO_SHA256);
    $signature = base64_encode($signature);

    // create a signature header
    return 'keyId="' . $keyId . '",headers="(request-target) host date digest",signature="' . $signature . '"';
}

function activitypub_http_get($url, $access_token = '') {
    // build the header
    $headers = array(
        "Date" => activitypub_build_date('now'),
        "Accept" => "application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\""
    );

    // set access token
    if (!empty($access_token)) {
        $headers["Authorization"] = "Bearer " . $access_token;
    }

    // request
    $ch = curl_init();
    curl_setopt_array($ch, array(
        CURLOPT_URL => $url,
        CURLOPT_HTTPHEADER => activitypub_build_http_headers($headers),
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_RETURNTRANSFER => true
    ));
    $response = curl_exec($ch);
    curl_close($ch);

    return activitypub_json_decode($response, true);
}

function activitypub_get_attachments($bo_table, $wr_id) {
    global $g5;

    $attachments = array();

    $sql = "select bf_file, bf_content, bf_type from {$g5['board_file_table']} where bo_table = '$bo_table' and wr_id = '$wr_id'";
    $result = sql_query($sql);
    while ($row = sql_fetch_array($result)) {
        array_push($attachments, array(
            "type" => ($row['bf_type'] > 0 ? "Image" : "File"),
            "content" => $row['bf_content'],
            "url" => G5_DATA_URL . "/file/" . $bo_table . "/" . $row['bf_file']
        ));
    }

    return $attachments;
}

function activitypub_http_post($url, $raw_data, $mb, $access_token = '') {
    // get digest
    $date = activitypub_build_date('now');
    $digest = activitypub_build_digest($raw_data);
    
    // build the headers
    $headers = array(
        "Date" => $date,
        "Digest" => $digest,
        "Content-Type" => "application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"",
    );

    // build the signature
    $signature = activitypub_build_signature($url, $date, $digest, $mb, "POST");
    $headers["Signature"] = $signature;

    // set access token
    if (!empty($access_token)) {
        $headers["Authorization"] = "Bearer " . $access_token;
    }

    // request
    $ch = curl_init();
    curl_setopt_array($ch, array(
        CURLOPT_URL => $url,
        CURLOPT_HTTPHEADER => activitypub_build_http_headers($headers),
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POSTFIELDS => $raw_data,
        CURLOPT_POST => true
    ));
    $response = curl_exec($ch);
    curl_close($ch);

    return activitypub_json_decode($response, true);
}

function navercloud_get_geolocation($ip) {
    $params = array(
        "ip" => $ip,
        "enc" => "utf8",
        "ext" => "t",
        "responseFormatType" => "json"
    );
    $timestamp = floor(microtime(true) * 1000);
    $uri = "/geolocation/v2/geoLocation?" . http_build_query($params);
    $endpoint_url = "https://geolocation.apigw.ntruss.com" . $uri;
    $message = "GET " . $uri . "\n" . $timestamp . "\n" . NAVERCLOUD_API_ACCESS_KEY;
    $sig = base64_encode(hash_hmac("sha256", $message, NAVERCLOUD_API_SECRET_KEY, true));

    $headers = activitypub_build_http_headers(array(
        "x-ncp-apigw-timestamp" => $timestamp,
        "x-ncp-iam-access-key" => NAVERCLOUD_API_ACCESS_KEY,
        "x-ncp-apigw-signature-v2" => $sig
    ));

    $ch = curl_init();
    curl_setopt_array($ch, array(
        CURLOPT_URL => $endpoint_url,
        CURLOPT_HTTPHEADER => $headers,
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_RETURNTRANSFER => true
    ));
    $response = curl_exec($ch);
    curl_close($ch);

    return activitypub_json_decode($response);
}

function openweathermap_get_data($args = array("longitude" => "", "latitude" => "")) {
    $params = array(
        "lat" => $args['latitude'],
        "lon" => $args['longitude'],
        "exclude" => "",
        "appid" => OPENWEATHERMAP_API_KEY
    );
    
    $url = "https://api.openweathermap.org/data/3.0/onecall?" . http_build_query($params);
    $ch = curl_init();
    curl_setopt_array($ch, array(
        CURLOPT_URL => $url,
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_RETURNTRANSFER => true
    ));
    $response = curl_exec($ch);
    curl_close($ch);

    return activitypub_json_decode($response);
}

function koreaexim_get_exchange_data() {
    $data = array();

    $_fval = function($s) {
        return floatval(preg_replace('/\.(?=.*\.)/', '', str_replace(",",".", $s)));
    };

    $params = array(
        "authkey" => KOREAEXIM_API_KEY,
        //"searchdate" => "20180102",
        "data" => "AP01"
    );
    
    $url = "https://www.koreaexim.go.kr/site/program/financial/exchangeJSON?" . http_build_query($params);
    $ch = curl_init();
    curl_setopt_array($ch, array(
        CURLOPT_URL => $url,
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_RETURNTRANSFER => true
    ));
    $response = curl_exec($ch);
    curl_close($ch);

    $items = activitypub_json_decode($response);
    $KRW = array();
    foreach($items as $item) {
        if ($item['result'] === 1) {
            $KRW[$item['cur_unit']] = round(($_fval($item['ttb']) + $_fval($item['tts'])) / 2.0, 2);
        }
    }
    $data['KRW'] = $KRW;

    return $data;
}

function activitypub_publish_content($content, $object_id, $mb, $_added_object = array(), $_added_to = array()) {
    // 위치정보를 사용하는 경우 모듈 로드
    $location_ctx = array();
    if (ACTIVITYPUB_ENABLED_GEOLOCATION) {
        // 위치 정보 확인
        $ip2location_library_data = activitypub_get_library_data("ip2location");

        // 조회해둔 위치 정보가 없다면 새로 조회
        if (!isset($ip2location_library_data['records'])) {
            activitypub_load_library("ip2location", function() {
                $db = new \IP2Location\Database(G5_DATA_PATH . '/IP2LOCATION-LITE-DB11.BIN', \IP2Location\Database::FILE_IO);
                $records = $db->lookup($_SERVER['REMOTE_ADDR'], \IP2Location\Database::ALL);
                return array("db" => $db, "records" => $records);
            });
            $ip2location_library_data = activitypub_get_library_data("ip2location");
        }

        // 위치정보 불러오기
        $records = $ip2location_library_data['records'];

        // 국내 위치 확인
        if (NAVERCLOUD_ENABLED_GEOLOCATION) {
            if ($records['countryCode'] == "KR") {
                // 국내 위치정보 요청
                $response = navercloud_get_geolocation($records['ipAddress']);

                // 정상적으로 반환된 경우
                if ($response['returnCode'] === 0) {
                    $records['cityName'] = implode(", ", array(
                        implode(" ", array(
                            $response['geoLocation']['r1'],
                            $response['geoLocation']['r2'],
                            $response['geoLocation']['r3'],
                            "(" . $response['geoLocation']['net'] . ")"
                        )),
                        $records['cityName']
                    ));
                    $records['longitude'] = $response['geoLocation']['long'];
                    $records['latitude'] = $response['geoLocation']['lat'];
                }
            }
        }

        // 위치정보 전문 작성
        $location_ctx = array(
            "name" => implode(", ", array(
                $records['ipAddress'],
                $records['cityName'],
                $records['regionName'],
                $records['countryName'],
                $records['countryCode'],
                $records['zipCode'],
                $records['timeZone']
            )),
            "type" => "Place",
            "longitude" => $records['longitude'],
            "latitude" => $records['latitude'],
            "units" => "m",
        );

        // 날씨 정보가 활성화되어 있으면
        if (OPENWEATHERMAP_ENABLED) {
            $response = openweathermap_get_data(array(
                "longitude" => $records['longitude'],
                "latitude" => $records['latitude']
            ));

            if (isset($response['current'])) {
                $location_ctx = array_merge($location_ctx, array(
                    "_weather" => $response['current']
                ));
            }
        }

        // 환율 정보가 활성화되어 있으면
        if (KOREAEXIM_ENABLED) {
            if ($records['countryCode'] == "KR") {
                $location_ctx = array_merge($location_ctx, array(
                    "_exchange" => koreaexim_get_exchange_data()
                ));
            }
        }
    }

    // 컨텐츠 파싱
    $terms = activitypub_parse_content($content);

    // 수신자/내용 생성
    $to = array_merge(array(NAMESPACE_ACTIVITYSTREAMS_PUBLIC), $_added_to);
    $content = "";
    foreach($terms as $term_ctx) {
        switch ($term_ctx['type']) {
            case "account":
                // WebFinger 정보 수신
                $account = substr($term_ctx['value'], 1);
                $account_terms = explode('@', $account);
                $account_ctx = array("username" => $account_terms[0], "host" => $account_terms[1]);
                $webfigner_ctx = array("subject" => "");
                if (!empty($account_ctx['host'])) {
                    $counter = 2;    // WebFinger에 연결하는 경우의 수 정의 (=N-1)
                    while ($counter > -1 && $webfigner_ctx['subject'] != ("acct:" . $account)) {
                        switch($counter) {
                            case 0:    // 공통 WebFinger에 연결
                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_DEFAULT_SCHEME . "://" . $account_ctx['host'] . "/.well-known/webfinger?resource=acct:" . $account);
                                break;
                            case 1:    // 실패시, 그누보드5용 WebFinger에 연결
                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_DEFAULT_SCHEME . "://" . $account_ctx['host'] . "/?route=webfinger&resource=acct:" . $account);
                                break;
                            case 2:    // 실패시, 그누보드5용 WebFinger에 연결 + 보안통신 해제
                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_INSECURE_SCHEME . "://" . $account_ctx['host'] . "/?route=webfinger&resource=acct:" . $account);
                                break;
                            default:
                                $counter = -1;
                        }

                        $counter--;   // 시도 횟수 차감
                    }

                    // WebFinger 정보 수신을 못한 경우 아무 작업도 하지 않음
                    if ($counter < 0) break;

                    // 받은 요청으로 처리
                    $webfigner_links = $webfigner_ctx['links'];
                    foreach($webfigner_links as $link) {
                        if ($link['rel'] == "self" && $link['type'] == "application/activity+json") {
                            array_push($to, $link['href']);  // 수신자에 반영
                        }
                    }
                }
                break;

            case "fulltext":
                $content = $term_ctx['value'];
                break;
        }
    }

    // 위치정보가 활성화되어 있으면
    if (ACTIVITYPUB_ENABLED_GEOLOCATION) {
        $object = array_merge($_added_object, array(
            "location" => $location_ctx
        ));
    }

    // 전문 생성
    $object = activitypub_build_note($content, $object_id, $mb, $_added_object);

    // 외부로 보낼 전문 생성
    $data = array(
        "@context" => NAMESPACE_ACTIVITYSTREAMS,
        "type" => "Create",
        "id" => G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME . "#Draft",
        "to" => $to,
        "actor" => $object['attributedTo'],
        "object" => $object
    );

    // 초안(Draft) 작성
    $activity_wr_id = activitypub_update_activity("outbox", $data, $mb, "draft");
    $data['id'] = G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME . "&wr_id=" . $activity_wr_id;

    // 보낼 전문을 인코딩
    $rawdata = activitypub_json_encode($data);

    // 수신자 작업
    foreach($to as $_to) {
        // 공개 네임스페이스인 경우 건너뛰기
        if ($_to == NAMESPACE_ACTIVITYSTREAMS_PUBLIC) continue;

        // 수신자 정보 조회
        $remote_user_ctx = activitypub_http_get($_to);

        // inbox 주소 찾기
        $remote_inbox_url = $remote_user_ctx['inbox'];
        if (empty($remote_inbox_url)) {
            $remote_inbox_url = $remote_user_ctx['endpoints']['sharedInbox'];
        }

        // inbox 주소가 없으면 건너뛰기
        if (empty($remote_inbox_url)) {
            activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "Could not find the inbox of " . $_to);
            continue;
        }

        // 엑세스 토큰(Access Token)이 존재하는 목적지인 경우
        $access_token = '';
        $access_token_data = activitypub_parse_stored_data(ACTIVITYPUB_ACCESS_TOKEN);
        foreach($access_token_data as $k=>$v) {
            if(strpos($_to, "http://" . $k . "/") !== false || strpos($_to, "https://" . $k . "/") !== false) {
                $access_token = $v;
                break;
            }
        }

        // inbox로 데이터 전송
        $response = activitypub_http_post($remote_inbox_url, $rawdata, $mb, $access_token);
    }

    // 발행됨(Published)으로 상태 업데이트
    activitypub_update_activity("outbox", $data, $mb, "published", $activity_wr_id);

    return $data;
}

function activitypub_parse_content($content) {
    $entities = array();

    $pos = -1;
    $get_next_position = function ($pos) use ($content) {
        try {
            return min(array_filter(array(
                strpos($content, '@', $pos + 1),
                strpos($content, '#', $pos + 1),
                strpos($content, 'http://', $pos + 1),
                strpos($content, 'https://', $pos + 1)
            ), "is_numeric"));
        } catch (ValueError $e) {
            return false;
        }
    };

    $pos = $get_next_position($pos);
    while ($pos !== false) {
        $end = strpos($content, ' ', $pos + 1);

        $expr = "";
        if ($end !== false) {
            $expr = substr($content, $pos, $end - $pos);
        } else {
            $expr = substr($content, $pos);
        }

        // EXAMPLE: @username@server1.example.org
        if (substr($expr, 0, 1) == '@' && strpos(substr($expr, 1), '@') !== false) {
            array_push($entities, array("type" => "account", "value" => $expr));
        } else if (substr($expr, 0, 1) == '#') {
            array_push($entities, array("type" => "hashtag", "value" => $expr));
        } else if (substr($expr, 0, 4) == 'http') {
            array_push($entities, array("type" => "url", "value" => $expr));
        }

        $pos = $get_next_position($pos);
    }
    
    // 전체 텍스트 추가
    array_push($entities, array("type" => "fulltext", "value" => $content));
    
    return $entities;
}

function activitypub_update_activity($inbox = "inbox", $data, $mb = array("mb_id" => ACTIVITYPUB_G5_USERNAME), $status = "draft", $wr_id = 0) {
    global $g5;
    
    // 게시판 테이블이름
    $write_table = ACTIVITYPUB_G5_TABLENAME;

    // Activity 초안(Draft)이 없는 경우
    if (!($wr_id > 0)) {
        // 기본 파라미터
        $to = $data['to'];
        $object = $data['object'];
        $content = $object['content'];

        // 공개 설정이 없는 경우 비밀글로 설정
        $wr_option = '';
        if (!in_array(NAMESPACE_ACTIVITYSTREAMS_PUBLIC, $to))
            $wr_option = 'secret';

        // 게시글로 등록
        $wr_num = get_next_num($write_table);
        $wr_reply = '';
        $ca_name = $inbox;    // Inbox/Outbox
        $wr_subject = mb_substr($content, 0, 50);
        $wr_seo_title = $content;
        $wr_content = $content . "\r\n\r\n[외부에서 전송된 글입니다.]";
        $wr_link1 = $data['actor'];
        $wr_link2 = '';
        $wr_homepage = $data['actor'];
        $wr_6 = $data['type'];    // Type of Activity

        // 수신자 확인
        $receivers = array();
        foreach($to as $_to) {
            // 수신자 주소(URL) 처리
            $url_ctx = activitypub_parse_url($_to);
            $host = $url_ctx['host'];
            $query = $url_ctx['query'];

            // 특정 회원이 지목되어 있다면 수신자 추가
            if ($host == ACTIVITYPUB_HOST && !empty($query['mb_id'])) {
                array_push($receivers, $query['mb_id']);
            }
        }
        $wr_7 = implode(',', $receivers);

        // 상태 작업
        //  * 주어진 임무를 진행하기 전이라면: draft
        //  * 일을 저지른 뒤라면: published
        $wr_8 = $status;

        // 게시글로 등록
        $sql = "
            insert into $write_table
                set wr_num = '$wr_num',
                    wr_reply = '$wr_reply',
                    wr_comment = 0,
                    ca_name = '$ca_name',
                    wr_option = '$wr_option',
                    wr_subject = '$wr_subject',
                    wr_content = '$wr_content',
                    wr_seo_title = '$wr_seo_title',
                    wr_link1 = '$wr_link1',
                    wr_link2 = '$wr_link2',
                    wr_link1_hit = 0,
                    wr_link2_hit = 0,
                    wr_hit = 0,
                    wr_good = 0,
                    wr_nogood = 0,
                    mb_id = '{$mb['mb_id']}',
                    wr_password = '',
                    wr_name = '{$mb['mb_nick']}',
                    wr_email = '',
                    wr_homepage = '$wr_homepage',
                    wr_datetime = '" . G5_TIME_YMDHIS . "',
                    wr_last = '" . G5_TIME_YMDHIS . "',
                    wr_ip = '{$_SERVER['REMOTE_ADDR']}',
                    wr_1 = '',
                    wr_2 = '',
                    wr_3 = '',
                    wr_4 = '',
                    wr_5 = '',
                    wr_6 = '$wr_6',
                    wr_7 = '$wr_7',
                    wr_8 = '$wr_8',
                    wr_9 = '',
                    wr_10 = ''
        ";
        sql_query($sql);
        $wr_id = sql_insert_id();
    }

    // Activity를 발행됨(published)으로 상태를 업데이트하는 경우
    if ($status == "published") {
        // 저장 전 데이터 처리
        $now_utc_tz = str_replace('+00:00', 'Z', gmdate('c'));
        $data['published'] = $now_utc_tz;
        $data['updated'] = $now_utc_tz;

        // 요청 전문은 파일로 저장
        $raw_context = activitypub_json_encode($data);
        $filename = md5($raw_context) . ".json";
        $filepath = G5_DATA_PATH . "/file/" . ACTIVITYPUB_G5_BOARDNAME . "/" . $filename;
        $result = file_put_contents($filepath, $raw_context);
        if ($result !== false) {
            $bf_source = $filename;
            $bf_file = $filename;
            $bf_content = "application/activity+json";
            $bf_filesize = strlen($raw_context);
            $sql = " insert into {$g5['board_file_table']}
                        set bo_table = '" . ACTIVITYPUB_G5_BOARDNAME . "',
                             wr_id = '{$wr_id}',
                             bf_no = 0,
                             bf_source = '{$bf_source}',
                             bf_file = '{$bf_file}',
                             bf_content = '{$bf_content}',
                             bf_fileurl = '',
                             bf_thumburl = '',
                             bf_storage = '',
                             bf_download = 0,
                             bf_filesize = '{$bf_filesize}',
                             bf_width = 0,
                             bf_height = 0,
                             bf_type = 0,
                             bf_datetime = '" . G5_TIME_YMDHIS . "' ";
            sql_query($sql);

            $sql = "update $write_table set wr_file = 1 where wr_id = '{$wr_id}'";
            sql_query($sql);
        }

        // 상태 업데이트
        $sql = "update $write_table set wr_8 = 'published' where wr_id = '$wr_id'";
        sql_query($sql);
    }

    return $wr_id;
}

function activitypub_get_objects($mb, $inbox = "inbox") {
    global $g5;

    $items = array();

    // 정보 불러오기
    $sql = "";
    if(!$mb['mb_id']) {
        $sql = "select wr_id from " . ACTIVITYPUB_G5_TABLENAME . "
            where ca_name = '$inbox'
                and DATE(wr_datetime) BETWEEN CURDATE() - INTERVAL " . ACTIVITYPUB_G5_OUTDATED_DAYS . " DAY AND CURDATE()
        ";
    } else {
        $sql = "select wr_id from " . ACTIVITYPUB_G5_TABLENAME . "
            where ca_name = '$inbox'
                and FIND_IN_SET('$mb_id', wr_7) > 0
                and DATE(wr_datetime) BETWEEN CURDATE() - INTERVAL " . ACTIVITYPUB_G5_OUTDATED_DAYS . " DAY AND CURDATE()
        ";
    }
    $result = sql_query($sql);

    // 정보 조회 후 처리
    while ($row = sql_fetch_array($result)) {
        $sql2 = "select * from {$g5['board_file_table']}
            where bo_table = '" . ACTIVITYPUB_G5_BOARDNAME . "' and wr_id = '{$row['wr_id']}' and bf_content = 'application/activity+json'";
        $result2 = sql_query($sql2);
        while ($row2 = sql_fetch_array($result2)) {
            $filename = $row2['bf_file'];
            $filepath = G5_DATA_PATH . "/file/" . ACTIVITYPUB_G5_BOARDNAME . "/" . $filename;
            if(file_exists($filepath)) {
                array_push($items, activitypub_json_decode(file_get_contents($filepath))['object']);
            }
        }
    }

    // 전문 만들기
    return activitypub_build_collection($items);
}

// Object type: Note
function activitypub_build_note($content, $object_id, $mb, $_added_object = array()) {
    return array_merge(array(
        "type" => "Note",
        "generator" => "G5.ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (GNUBOARD " . G5_GNUBOARD_VER . "; " . ACTIVITYPUB_INSTANCE_ID . ")",
        "id" => $object_id,
        "attributedTo" => activitypub_get_url("user", array("mb_id" => $mb['mb_id'])),
        "content" => $content,
        "icon" => activitypub_get_icon($mb)
    ), $_added_object);
}

// Object type: Collection
function activitypub_build_collection($items, $summary = '') {
    return array(
        "@context" => NAMESPACE_ACTIVITYSTREAMS,
        "generator" => "G5.ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (GNUBOARD " . G5_GNUBOARD_VER . "; " . ACTIVITYPUB_INSTANCE_ID . ")",
        "summary" => $summary,
        "type" => "Collection",
        "totalItems" => count($items),
        "items" => $items,
        "updated" => str_replace('+00:00', 'Z', gmdate('c'))
    );
}

class _GNUBOARD_ActivityPub {
    public static function open() {
        header("Content-Type: application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"");
    }

    public static function webfinger() {
        $params = array(
            "resource" => $_GET['resource']
        );

        if (empty($params['resource'])) {
            return activitypub_json_encode(array("message" => "Resource could not be empty"));
        }
        
        $resource = $params['resource'];
        $resource_type = '';
        $resource_value = '';
        $pos = strpos($resource, ':');
        if ($pos !== false) {
            $resource_type = substr($resource, 0, $pos);
            $resource_value = substr($resource, $pos + 1);
        }
        
        switch($resource_type) {
            case "acct":
                // 값 분리
                list($username, $host) = explode('@', $resource_value);

                // 호스트가 일치하지 않는 경우
                if ($host != ACTIVITYPUB_HOST) {
                    return activitypub_json_encode(array("message" => "Invalid host"));
                }
                

                // 회원 정보 확인
                $mb = get_member($username);
                if (empty($mb['mb_id'])) {
                    return activitypub_json_encode(array("message" => "Not registered user"));
                }

                // 응답 본문 생성
                $context = array(
                    "subject" => $params['resource'],
                    "aliases" => array(
                        activitypub_get_url("user", array("mb_id" => $mb['mb_id']))
                    ),
                    "links" => array(
                        array(
                            "rel" => "http://webfinger.net/rel/profile-page",
                            "type" => "text/html",
                            "href" => G5_BBS_URL . "/profile.php?mb_id=" . $mb['mb_id']
                        ),
                        array(
                            "rel" => "self",
                            "type" => "application/activity+json",
                            "href" => activitypub_get_url("user", array("mb_id" => $mb['mb_id']))
                        ),
                        /*
                        array(
                            "rel" => "http://ostatus.org/schema/1.0/subscribe",
                            "href" => activitypub_get_url("ostatus", array("mb_id" => $mb['mb_id'], "uri" => "{uri}"))
                        )
                        */
                    )
                );

                // 응답 본문 출력
                return activitypub_json_encode($context);

                break;

            case "http":
            case "https":
                return activitypub_json_encode(array("message" => "Not implemented"));
                break;

            default:
                return activitypub_json_encode(array("message" => "Not supported resource type"));
                break;
        }
    }

    public static function user() {
        $mb = get_member($_GET['mb_id']);

        if (!$mb['mb_id']) {
            return activitypub_json_encode(array("message" => "Could not find the user"));
        }

        // 인증서 정보 불러오기
        list($private_key, $public_key) = activitypub_get_stored_keypair($mb);

        // 본문 생성
        $activitypub_user_id = activitypub_get_url("user", array("mb_id" => $mb['mb_id']));
        $context = array(
            "@context" => array(NAMESPACE_ACTIVITYSTREAMS, NAMESPACE_W3ID_SECURITY_V1, array("@language" => "ko")),
            "type" => "Person",
            "id" => $activitypub_user_id,
            "name" => $mb['mb_name'],
            "preferredUsername" => $mb['mb_nick'],
            "summary" => $mb['mb_profile'],
            "inbox" => activitypub_get_url("inbox", array("mb_id" => $mb['mb_id'])),
            "outbox" => activitypub_get_url("outbox", array("mb_id" => $mb['mb_id'])),
            "followers" => activitypub_get_url("followers", array("mb_id" => $mb['mb_id'])),
            "following" => activitypub_get_url("following", array("mb_id" => $mb['mb_id'])),
            "liked" => activitypub_get_url("liked", array("mb_id" => $mb['mb_id'])),
            "icon" => array(
                activitypub_get_icon($mb)
            ),
            "endpoints" => array(
                "sharedInbox" => activitypub_get_url("inbox")
            ),
            "publicKey" => array(
                "id" => $activitypub_user_id . "#main-key",
                "owner" => $activitypub_user_id,
                "publicKeyPem" => $public_key
            )
        );

        return activitypub_json_encode($context);
    }

    public static function inbox() {
        // HTTP 요청 유형에 따라 작업
        switch ($_SERVER['REQUEST_METHOD']) {
            case "POST":
                // 개인에게 보낸 메시지는 쪽지에 저장
                // 공개(Public) 설정한 메시지는 ACTIVITYPUB_G5_TABLENAME에 저장
                $data = activitypub_json_decode(file_get_contents("php://input"), true);

                if (empty($data['@context'])) {
                    return activitypub_json_encode(array("message" => "This is a broken context"));
                }
                
                if ($data['@context'] != NAMESPACE_ACTIVITYSTREAMS) {
                    return activitypub_json_encode(array("message" => "This is not an ActivityStreams request"));
                }
                
                // 컨텐츠 변수 정의
                $content = '';

                // 컨텐츠 처리
                if (!empty($data['type'])) {
                    // 정보 불러오기 
                    $mb = get_member(ACTIVITYPUB_G5_USERNAME);

                    // 수신자 확인
                    $to = $data['to'];

                    // 원글 정보 확인
                    $object = $data['object'];

                    // 타입 별 해야될 일 지정
                    switch ($data['type']) {
                        case "Create":
                            // 스트링 및 오브젝트 타입을 모두 호환하도록 설정
                            if (is_string($object))
                                $object = array("id" => $object);

                            // 컨텐츠가 비어있는 경우
                            if (empty($object['content']))
                                $object['content'] = "[NO CONTENT]";

                            // 수신된 내용 등록
                            $activity_wr_id = activitypub_update_activity("inbox", $data, $mb, "published");

                            // 컨텐츠 설정
                            $bo = get_board_db(ACTIVITYPUB_G5_BOARDNAME, true);
                            $content = sprintf("%s\r\n\r\n[외부에서 전송된 글입니다. 자세한 내용은 %s#%s 글을 확인하세요.]", $object['content'], $bo['bo_subject'], $activity_wr_id);

                            // 답글인지 확인
                            if (!empty($object['inReplyTo'])) {
                                // 답글 정보 확인
                                $query = activitypub_parse_url($object['inReplyTo'])['query'];

                                // 특정 글이 지목되어 있을 때 -> 댓글로 작성
                                if (!empty($query['bo_table']) && !empty($query['wr_id'])) {
                                    $wr_id = $query['wr_id'];
                                    $write_table = $g5['write_prefix'] . $query['bo_table'];
                                    $wr = get_write($write_table, $wr_id);

                                    // 글이 존재하는 경우
                                    if (!empty($wr['wr_id'])) {
                                        $mb = get_member(ACTIVITYPUB_G5_USERNAME);
                                        $wr_homepage = $data['actor'];

                                        $sql = "
                                            insert into $write_table
                                                set ca_name = '{$wr['ca_name']}',
                                                     wr_option = '',
                                                     wr_num = '{$wr['wr_num']}',
                                                     wr_reply = '',
                                                     wr_parent = '{$wr['wr_id']}',
                                                     wr_is_comment = 1,
                                                     wr_comment = '',
                                                     wr_comment_reply = '',
                                                     wr_subject = '',
                                                     wr_content = '$content',
                                                     mb_id = '{$mb['mb_id']}',
                                                     wr_password = '',
                                                     wr_name = '{$mb['mb_nick']}',
                                                     wr_email = '',
                                                     wr_homepage = '$wr_homepage',
                                                     wr_datetime = '" . G5_TIME_YMDHIS . "',
                                                     wr_last = '',
                                                     wr_ip = '{$_SERVER['REMOTE_ADDR']}',
                                                     wr_1 = '',
                                                     wr_2 = '',
                                                     wr_3 = '',
                                                     wr_4 = '',
                                                     wr_5 = '',
                                                     wr_6 = '',
                                                     wr_7 = '',
                                                     wr_8 = '',
                                                     wr_9 = '',
                                                     wr_10 = ''
                                        ";
                                        sql_query($sql);
                                    }

                                    // 원글이 삭제된 경우
                                    else {
                                        return activitypub_json_encode(array("message" => "Could not find the original message"));
                                    }
                                }
                            }
                            break;

                        case "Like":
                            // 스트링 및 오브젝트 타입을 모두 호환하도록 설정
                            if (is_string($object))
                                $object = array("id" => $object);

                            // object 처리
                            $url_ctx = activitypub_parse_url($object['id']);
                            $host = $url_ctx['host'];
                            $query = $url_ctx['query'];

                            // 원글을 특정한 경우
                            if ($host == ACTIVITYPUB_HOST && !empty($query['bo_table']) && !empty($query['wr_id'])) {
                                $wr_id = $query['wr_id'];
                                $write_table = G5_TABLE_PREFIX . $query['bo_table'];
                                $wr = get_write($write_table, $wr_id);
                                $bo = get_board_db(ACTIVITYPUB_G5_BOARDNAME, true);

                                // 원글이 존재하는 경우
                                if (!empty($wr['wr_id'])) {
                                    activitypub_set_liked("good", $query['bo_table'], $wr['wr_id']);
                                }

                                // 원글이 삭제된 경우
                                else {
                                    return activitypub_json_encode(array("message" => "Could not find the original message"));
                                }
                            }
                            
                            // 특정하지 않은 경우
                            else {
                                return activitypub_json_encode(array("message" => "Could not specify the original message"));
                            }

                            // 보낼 내용 설정
                            $content = sprintf(
                                "아래 사용자가 %s #%s 글을 추천하였습니다.\r\n\r\n%s",
                                $bo['bo_subject'],
                                $wr['wr_id'],
                                $data['actor']
                            );

                            break;

                        case "Dislike":
                            // 스트링 및 오브젝트 타입을 모두 호환하도록 설정
                            if (is_string($object))
                                $object = array("id" => $object);

                            // object 처리
                            $url_ctx = activitypub_parse_url($object['id']);
                            $host = $url_ctx['host'];
                            $query = $url_ctx['query'];

                            // 원글을 특정한 경우
                            if ($host == ACTIVITYPUB_HOST && !empty($query['bo_table']) && !empty($query['wr_id'])) {
                                $wr_id = $query['wr_id'];
                                $write_table = G5_TABLE_PREFIX . $query['bo_table'];
                                $wr = get_write($write_table, $wr_id);
                                $bo = get_board_db(ACTIVITYPUB_G5_BOARDNAME, true);

                                // 원글이 존재하는 경우
                                if (!empty($wr['wr_id'])) {
                                    activitypub_set_liked("nogood", $query['bo_table'], $wr['wr_id']);
                                }

                                // 원글이 삭제된 경우
                                else {
                                    return activitypub_json_encode(array("message" => "Could not find the original message"));
                                }
                            }

                            // 특정하지 않은 경우
                            else {
                                return activitypub_json_encode(array("message" => "Could not specify the original message"));
                            }
                            
                            // 보낼 내용 설정
                            $content = sprintf(
                                "아래 사용자가 %s #%s 글을 비추천하였습니다.\r\n\r\n%s",
                                $bo['bo_subject'],
                                $wr['wr_id'],
                                $data['actor']
                            );

                            break;

                        default:
                            return activitypub_json_encode(array("message" => "This is not implemented type"));
                    }

                    // 받을사람(수신자) 처리
                    foreach($to as $_to) {
                        // 수신자 주소(URL) 처리
                        $url_ctx = activitypub_parse_url($_to);
                        $host = $url_ctx['host'];
                        $query = $url_ctx['query'];

                        // 특정 회원이 지목되어 있다면 쪽지를 보냄
                        if ($host == ACTIVITYPUB_HOST && !empty($query['mb_id'])) {
                            switch ($query['route']) {
                                case "activitypub.user":
                                    activitypub_add_memo($mb['mb_id'], $query['mb_id'], $content);
                                    break;

                                case "activitypub.followers":
                                    $followers = activitypub_get_followers($mb);
                                    foreach($followers as $_mb_id) {
                                        activitypub_add_memo($mb['mb_id'], $_mb_id, $content);
                                    }
                                    break;

                                case "activitypub.following":
                                    $following = activitypub_get_following($mb);
                                    foreach($following as $_mb_id) {
                                        activitypub_add_memo($mb['mb_id'], $_mb_id, $content);
                                    }
                                    break;
                            }
                        }
                    }
                }

                else {
                    return activitypub_json_encode(array("message" => "Type could not be an empty"));
                }

                return activitypub_json_encode(array("message" => "Success"));

            case "GET":
                $mb = get_member($_GET['mb_id']);
                return activitypub_json_encode(activitypub_get_objects($mb, "inbox"));

            default:
                return activitypub_json_encode(array("message" => "Not supported method"));
        }
    }

    public static function outbox() {
        // HTTP 요청 유형에 따라 작업
        switch ($_SERVER['REQUEST_METHOD']) {
            // 규격 문서에서 POST/Outbox에 해당하는 작업은 그누5에선 훅(Hook)으로 작업
            case "POST":
                return activitypub_json_encode(array(
                    "message" => "Disallowed method. Please go to " . G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME
                ));

            // 가장 최근의 활동을 가져옴
            case "GET":
                $mb = get_member($_GET['mb_id']);
                return activitypub_json_encode(activitypub_get_objects($mb, "outbox"));
        }
    }

    public static function followers() {
        $mb = get_member($_GET['mb_id']);
        return activitypub_json_encode(activitypub_build_collection(activitypub_get_followers($mb), "{$mb['mb_name']}'s followers"));
    }
    
    public static function following() {
        $mb = get_member($_GET['mb_id']);
        return activitypub_json_encode(activitypub_build_collection(activitypub_get_following($mb), "{$mb['mb_name']}'s following"));
    }

    public static function liked() {
        return self::inbox();
    }
    
    public static function shares() {
        global $g5;

        $items = array();  // 항목을 담을 배열

        /* // TODO: Remove (Security Reason)
        // 게시판인 경우
        if (array_key_exists("bo_table", $_GET)) {
            $bo = get_board_db($_GET['bo_table'], true);

            if (!empty($bo['bo_table'])) {
                switch($bo['bo_table']) {
                    case ACTIVITYPUB_G5_BOARDNAME:
                        return self::inbox();   // 액티비티를 저장하는 테이블인 경우 inbox와 동일하게 취급

                    default:
                        

                        // 조회할 페이지 수 불러오기
                        $page = intval($_GET['page']);
                        if ($page < 1) {
                            $page = 1;
                        }

                        // 페이지 당 표시할 게시물 수 불러오기
                        $page_rows = 0;
                        if (!empty($bo['bo_mobile_page_rows'])) {
                            $page_rows = intval($bo['bo_mobile_page_rows']);
                        } else if (!empty($bo['bo_page_rows'])) {
                            $page_rows = intval($bo['bo_page_rows']);
                        }

                        // 페이지 당 표시할 게시물 수가 1보다 작으면 기본값(15)로 설정
                        if ($pages_rows < 1) {
                            $page_rows = 15;
                        }

                        // SQL 작성
                        $write_table = $g5['write_prefix'] . $bo['bo_table'];
                        $offset = ($page - 1) * $page_rows;
                        $sql = "select wr_id, mb_id, wr_content, wr_datetime from {$write_table} where FIND_IN_SET('secret', wr_option) = 0 order by wr_datetime desc limit {$offset}, {$page_rows} ";

                        // SQL 실행
                        $result = sql_query($sql);
                        while ($row = sql_fetch_array($result)) {
                            $object_id = G5_BBS_URL . "/board.php?bo_table={$bo['bo_table']}&wr_id={$row['wr_id']}";
                            $mb = get_member($row['mb_id']);
                            $content = $row['wr_content'];
                            array_push($items, activitypub_build_note($content, $object_id, $mb));
                        }
                }
            }
        }
        */

        // 최근 활동에서 추출
        $sql = "select * from " . $g5['board_new_table']; 
        $result = sql_query($sql);
        while ($row = sql_fetch_array($result)) {
            $write_table = $g5['write_prefix'] . $row['bo_table'];
            $sql2 = "select wr_id, mb_id, wr_content, wr_datetime from {$write_table} where wr_id = '{$row['wr_id']}' and FIND_IN_SET('secret', wr_option) = 0 ";
            $row2 = sql_fetch($sql2);
            if ($row2['wr_id']) {
                $object_id = G5_BBS_URL . "/board.php?bo_table={$row['bo_table']}&wr_id={$row2['wr_id']}";
                $mb = get_member($row2['mb_id']);
                $content = $row2['wr_content'];
                array_push($items, activitypub_build_note($content, $object_id, $mb));
            }
        }

        // 결과 반환
        return activitypub_json_encode(activitypub_build_collection($items, "Latest shares"));
    }

    public static function authorize() {
        $grant_type = $_GET['grant_type'];

        switch ($grant_type) {
            case "authorization_code":
                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
                break;

            case "password":
                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
                break;

            case "client_credentials":
                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
                break;
        }
    }

    public static function close() {
        exit();
    }
}

// 훅(Hook) 등록
function _activitypub_memo_form_update_after($member_list, $str_nick_list, $redirect_url, $me_memo) {
    global $member;

    // 'apstreams' 계정이 있는지 확인
    if (!in_array(ACTIVITYPUB_G5_USERNAME, $member_list['id'])) return;

    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
    $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));

    // 글 전송하기
    if (!empty($mb['mb_id'])) {
        // 글 전송하기
        $data = activitypub_publish_content(
            $me_memo,
            activitypub_get_url("user", array("mb_id" => $mb['mb_id'])),
            $mb
        );
    }
}

function _activitypub_write_update_after($board, $wr_id, $w, $qstr, $redirect_url) {
    global $g5, $member;

    // 본문 가져오기
    $sql = "select wr_id, wr_content from {$g5['write_prefix']}{$board['bo_table']} where wr_id = '{$wr_id}'";
    $row = sql_fetch($sql);
    if (empty($row['wr_id'])) return;
    
    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
    $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));

    // 추가할 오브젝트 속성
    $_added_object = array();

    // 파일 첨부여부 확인
    $attachments = activitypub_get_attachments($board['bo_table'], $wr_id);
    if (count($attachments)) {
        $_added_object['attachment'] = $attachments;    // ActivityPub 표준 용어는 'attachment'
    }

    // 글 전송하기
    if (!empty($mb['mb_id'])) {
        $data = activitypub_publish_content(
            $row['wr_content'],
            G5_BBS_URL . "/board.php?bo_table={$board['bo_table']}&wr_id={$row['wr_id']}",
            $mb,
            $_added_object
        );
    }
}

function _activitypub_comment_update_after($board, $wr_id, $w, $qstr, $redirect_url, $comment_id, $reply_array) {
    global $g5, $member;

    // 본문(댓글) 가져오기
    $sql = "select wr_id, wr_content from {$g5['write_prefix']}{$board['bo_table']} where wr_id = '{$wr_id}'";
    $row = sql_fetch($sql);
    if (empty($row['wr_id'])) return;
    
    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
    $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));

    // 추가할 오브젝트 속성
    $_added_object = array(
        "inReplyTo" => G5_BBS_URL . "/board.php?bo_table={$board['bo_table']}&wr_id={$row['wr_id']}"
    );

    // 파일 첨부여부 확인
    $attachments = activitypub_get_attachments($board['bo_table'], $wr_id);
    if (count($attachments)) {
        $_added_object['attachment'] = $attachments;    // ActivityPub 표준 용어는 'attachment'
    }

    // 글 전송하기
    if (!empty($mb['mb_id'])) {
        $data = activitypub_publish_content(
            $row['wr_content'],
            G5_BBS_URL . "/board.php?bo_table={$board['bo_table']}&wr_id={$row['wr_parent']}&c_id=" . $comment_id,
            $mb,
            $_added_object
        );
    }
}

add_event("write_update_after", "_activitypub_write_update_after", 0, 5);
add_event("comment_update_after", "_activitypub_comment_update_after", 0, 7);
add_event("memo_form_update_after", "_activitypub_memo_form_update_after", 0, 4);

// 확장 라이브러리 가져오기 (*.activitypub.lib.php)
$tmp = dir(G5_LIB_PATH);
while ($entry = $tmp->read()) {
    if (preg_match("/(\.activitypub\.lib\.php)$/i", $entry))
        include(G5_LIB_PATH . "/" . $entry);
}

// 모든 준비가 완료되고 작업 시작
$route = array_key_exists("route", $_GET) ? $_GET['route'] : "";

switch ($route) {
    // 일부 소프트웨어는 통신을 하기 위해 아래와 같이 설정을 해야할 수 있습니다. (선택사항)
    // .htaccess에 추가
    //
    //     <IfModule mod_rewrite.c>
    //         RewriteEngine on
    //         RewriteRule ^\.well-known/webfinger /?route=webfinger [QSA,L]
    //     </IfModule>
    //
    // 참고: https://wordpress.org/support/topic/htaccess-conflict/
    //
    case "webfinger":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::webfinger();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.user":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::user();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.inbox":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::inbox();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.outbox":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::outbox();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.followers":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::followers();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.following":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::following();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.liked":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::liked();
        _GNUBOARD_ActivityPub::close();
        break;
        
    case "activitypub.shares":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::shares();
        _GNUBOARD_ActivityPub::close();
        break;
        
    case "oauth2.authorize":  // TODO
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::authorize();
        _GNUBOARD_ActivityPub::close();
        break;
}