/**
 * This file is part of Haketilo.
 *
 * Function: Showing and error/info/confirmation dialog.
 *
 * Copyright (C) 2022 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 of this code in a
 * proprietary program, I am not going to enforce this in court.
 */

#FROM html/DOM_helpers.js IMPORT clone_template
#FROM common/lock.js IMPORT make_lock, lock, try_lock, unlock

function make(on_dialog_show, on_dialog_hide)
{
    const dialog_context = clone_template("dialog");
    Object.assign(dialog_context, {
	on_dialog_show,
	on_dialog_hide,
	shown: false,
	queue: 0,
	lock: make_lock(),
	callback: null
    });

    for (const [id, val] of [["yes", true], ["no", false], ["ok", undefined]]) {
	const but = dialog_context[`${id}_but`];
	but.haketilo_dialog_result = val;
	but.addEventListener("click", e => close_dialog(dialog_context, e));
    }

    return dialog_context;
}
#EXPORT make

function close_dialog(dialog_context, event)
{
    if (event && event.target.parentElement.classList.contains("hide"))
	return;

    const result = event ? event.target.haketilo_dialog_result : undefined;

    if (dialog_context.queue > 0)
	dialog_context.callback(result);
}
#EXPORT  close_dialog  AS close

async function show_dialog(dialog_context, shown_buts_id, msg)
{
    dialog_context.queue++;

    if (!dialog_context.shown) {
	dialog_context.shown = true;
	dialog_context.on_dialog_show();
    }

    /*
     * We want the dialog to be ready for calling close() right after
     * show_dialog() gets called. For this, we want locking to happen
     * synchronously if possible. If impossible (lock taken), this means dialog
     * is already open, hence it's also ready for close()'ing.
     */
    if (!try_lock(dialog_context.lock))
	await lock(dialog_context.lock);

    [...dialog_context.msg.childNodes].forEach(n => n.remove());
    dialog_context.msg.append(...msg);
    for (const buts_id of ["ask_buts", "conf_buts"]) {
	const action = buts_id === shown_buts_id ? "remove" : "add";
	dialog_context[buts_id].classList[action]("hide");
    }

    const result = await new Promise(cb => dialog_context.callback = cb);

    if (--dialog_context.queue == 0) {
	dialog_context.shown = false;
	dialog_context.on_dialog_hide();
    }

    unlock(dialog_context.lock);

    return result;
}

const error = (ctx, ...msg) => show_dialog(ctx, "conf_buts", msg);
#EXPORT error

/* info() and error() are the same for now, we might later change that. */
const info = error;
#EXPORT info

const ask = (ctx, ...msg) => show_dialog(ctx, "ask_buts", msg);
#EXPORT ask

const loader = (ctx, ...msg) => show_dialog(ctx, null, msg);
#EXPORT loader