/**
 * This file is part of Haketilo.
 *
 * Function: Storage through messages (server side).
 *
 * Copyright (C) 2021 Wojtek Kosior
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute forms of that code without the copy of the GNU
 * GPL normally required by section 4, provided you include this
 * license notice and, in case of non-source distribution, a URL
 * through which recipients can access the Corresponding Source.
 * If you modify file(s) with this exception, you may extend this
 * exception to your version of the file(s), but you are not
 * obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * As a special exception to the GPL, any HTML file which merely
 * makes function calls to this code, and for that purpose
 * includes it by reference shall be deemed a separate work for
 * copyright law purposes. If you modify this code, you may extend
 * this exception to your version of the code, but you are not
 * obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * I, Wojtek Kosior, thereby promise not to sue for violation of this file's
 * license. Although I request that you do not make use this code in a
 * proprietary program, I am not going to enforce this in court.
 */

/*
 * IMPORTS_START
 * IMPORT listen_for_connection
 * IMPORT get_storage
 * IMPORT list_prefixes
 * IMPORT CONNECTION_TYPE
 * IMPORTS_END
 */

var storage;

async function handle_remote_call(port, message)
{
    let [call_id, func, args] = message;

    try {
	let result = await Promise.resolve(storage[func](...args));
	port.postMessage({call_id, result});
    } catch (error) {
	error = error + '';
	port.postMessage({call_id, error});
    }
}

function remove_storage_listener(cb)
{
    storage.remove_change_listener(cb);
}

function new_connection(port)
{
    console.log("new remote storage connection!");

    const message = {};
    for (const prefix of list_prefixes)
	message[prefix] = storage.get_all(prefix);

    port.postMessage(message);

    let handle_change = change => port.postMessage(change);

    storage.add_change_listener(handle_change);

    port.onMessage.addListener(m => handle_remote_call(port, m));
    port.onDisconnect.addListener(() =>
				  remove_storage_listener(handle_change));
}

async function start_storage_server()
{
    storage = await get_storage();

    listen_for_connection(CONNECTION_TYPE.REMOTE_STORAGE, new_connection);
}

/*
 * EXPORTS_START
 * EXPORT start_storage_server
 * EXPORTS_END
 */