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

// ActivityPub implementation for GNUBOARD 5
// Go Namhyeon <gnh1201@gmail.com>

// References:
//   * https://www.w3.org/TR/activitypub/

define("ACTIVITYPUB_INSTANCE_ID", md5_file(G5_DATA_PATH . "/dbconfig.php"));
define("ACTIVITYPUB_URL", (empty(G5_URL) ? "http://" . ACTIVITYPUB_INSTANCE_ID . ".local" : G5_URL));
define("ACTIVITYPUB_DATA_URL", ACTIVITYPUB_URL . '/' . G5_DATA_DIR);
define("ACTIVITYPUB_G5_TABLENAME", G5_TABLE_PREFIX . "apstreams");
define("ACTIVITYPUB_G5_USERNAME", "apstreams");
define("NAMESPACE_ACTIVITYSTREAMS", "https://www.w3.org/ns/activitystreams");
define("NAMESPACE_ACTIVITYSTREAMS_PUBLIC", "https://www.w3.org/ns/activitystreams#Public");

function activitypub_get_url($action, $params) {
    return ACTIVITYPUB_URL . "/?route=activitypub." . $action . "&" . http_build_query($params);
}

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

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_recent_items() {
    global $g5;
    
    $items = array();
    $sql = "select * from " . $g5['board_new_table']; 
    $result = sql_query($sql);
    while ($row = sql_fetch_array($result)) {
        $sql2 = "select * from " . ($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']) {
        $recent_items = activitypub_get_recent_items();
        foreach($recent_items 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']) {
        $recent_items = activitypub_get_recent_items();
        
        foreach($recent_items 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) {
    $ctx = parse_url($object['id']);
    $qstr = $ctx['query'];
    parse_str($qstr, $qctx);
    $ctx['query'] = $qctx;
    return $ctx;
}

function activitypub_add_memo($mb_id, $recv_mb_id, $me_memo) {
    $tmp_row = sql_fetch(" select max(me_id) as max_me_id from {$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());
}

class _GNUBOARD_ActivityPub {
    public static function open() {
        header("Content-Type: application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"");
    }
    
    public static function whois() {
        $mb = get_member($_GET['mb_id']);

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

        $context = array(
            "@context" => array(ACTIVITYPUB_CONTEXT_URL, array("@language" => "ko")),
            "type" => "Person",
            "id" => activitypub_get_url("whois", array("mb_id" => $mb['mb_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)
            )
        );

        return activitypub_json_encode($context);
    }

    public static function streams() {
        $params = array(
            "bo_table" => $_GET['bo_table'],
            "wr_id" => $_GET['wr_id']
        );

        if (!empty($params['bo_table']) && !empty($params['wr_id'])) {
            $query_string = http_build_query(array(
                "bo_table" => $params['bo_table'],
                "wr_id" => $params['wr_id']
            ));

            $link = G5_BBS_URL . "/board.php?" . $query_string;
            header("Location: " . $link);
        } else {
            return activitypub_json_encode(array("message" => "Could not find the stream"));
        }
    }

    public static function inbox() {
        // 개인에게 보낸 메시지는 쪽지
        // 공개(Public) 설정한 메시지는 ACTIVITYPUB_STREAMS_TABLENAME 에 저장
        
        $data = 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"));
        }
        
        switch ($data['type']) {
            case "Create":
                // 멤버정보 처리
                $mb_id = activitypub_parse_url($data['actor'])['query']['mb_id'];
                if (empty($mb_id)) {
                    return activitypub_json_encode(array("message" => "This is not a valid actor"));
                }
                $mb = get_member($mb_id);

                // 내용 처리
                $object = $data['object'];
                if (empty($object)) {
                    return activitypub_json_encode(array("message" => "Content is empty"));
                }
                $content = $object['content'];

                // 받을사람 처리
                foreach($to as $_to) {
                    $query = activitypub_parse_url($_to)['query'];

                    // 공개 게시물일 때
                    if ($_to == NAMESPACE_ACTIVITYSTREAMS_PUBLIC) {
                        $mb = get_member(ACTIVITYPUB_G5_USERNAME);

                        $write_table = ACTIVITYPUB_G5_TABLENAME;
                        $wr_num = get_next_num($write_table);
                        $wr_reply = '';
                        $ca_name = 'ActivityStreams';
                        $wr_subject = mb_substr($content, 0, 45);
                        $wr_content = $content;
                        $wr_link1 = $data['actor'];
                        $wr_homepage = $data['actor'];

                        $sql = "
                            insert into $write_table
                                set wr_num = '$wr_num',
                                    wr_reply = '$wr_reply',
                                    wr_comment = 0,
                                    ca_name = '$ca_name',
                                    wr_option = '',
                                    wr_subject = '$wr_subject',
                                    wr_content = '$wr_content',
                                    wr_seo_title = '$wr_seo_title',
                                    wr_link1 = '$wr_link1',
                                    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_name']}',
                                    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_7 = '',
                                    wr_8 = '',
                                    wr_9 = '',
                                    wr_10 = ''
                        ";
                        sql_query($sql);

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

                    // 특정 회원이 지목되어 있을 때 -> 메모로 작성
                    else if (!empty($query['mb_id'])) {
                        switch ($query['route']) {
                            case "activitypub.whois":
                                activitypub_add_memo($query['mb_id'], $content);
                                break;

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

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

                    // 특정 글이 지목되어 있을 때 -> 댓글로 작성
                    else if (!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);

                        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 = '{$mb['mb_name']}',
                                         wr_email = '',
                                         wr_homepage = '$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);
                        }
                    }
                }
                break;

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

    public static function outbox() {
        // TODO
    }

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

    public static function liked() {
        return array(
            "message" => "Not implemented"
        );
    }
    
    public static function close() {
        exit();
    }
}

$route = $_GET['route'];

switch ($route) {
    case "activitypub.whois":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::whois();
        _GNUBOARD_ActivityPub::close();
        break;

    case "activitypub.streams":
        _GNUBOARD_ActivityPub::open();
        echo _GNUBOARD_ActivityPub::streams();
        _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;
}