{#
SPDX-License-Identifier: GPL-3.0-or-later

Haketilo popup display script.

This file is part of Hydrilla&Haketilo.

Copyright (C) 2021,2022 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.
#}

(function(){
    document.currentScript.remove();

    /*
     * To slightly decrease the chance of accidental popup breakage we snapshot
     * methods that other code might redefine.
     */
    function get_setter(obj, name) {
        return Object.getOwnPropertyDescriptor(obj, name).set;
    }

    const ElementPrototype = [0, 0, 0]
          .reduce(n => Object.getPrototypeOf(n), document.documentElement);

    const prepend_fun  = ElementPrototype.prepend;
    const setattr_fun  = ElementPrototype.setAttribute;
    const remove_fun   = ElementPrototype.remove;
    const setinner_fun = get_setter(ElementPrototype, "innerHTML");
    const open_fun     = window.open;

    const shortcut        = "HKT";
    const nonce           = atob("{{nonce_b64}}");
    const popup_style     = "{{popup_style}}";
    const popup_html      = atob("{{popup_page_b64}}");
    const popup_container = document.createElement("div");
    const popup_frame     = document.createElement("iframe");

    function make_style(styles_obj) {
        return Object.entries(styles_obj)
            .map(([key, val]) => `${key}: ${val} !important`)
            .join(';');
    }

    const frame_style = make_style({
        "position":         "absolute",
        "left":             "50%",
        "top":              "50%",
        "transform":        "translate(-50%, -50%)",
        "display":          "block",
        "visibility":       "visible",
        "min-width":        "initial",
        "width":            "600px",
        "max-width":        "calc(100vw - 20px)",
        "min-height":       "initial",
        "height":           "700px",
        "max-height":       "calc(100vh - 20px)",
        "background-color": "#fff",
        "opacity":          "100%",
        "margin":           0,
        "padding":          0,
        "border":           "none",
        "border-radius":    "5px"
    });

    const container_style = make_style({
        "position":         "fixed",
        "left":             "0",
        "top":              "0",
        "transform":        "initial",
        "z-index":          2147483647,
        "display":          "block",
        "visibility":       "visible",
        "min-width":        "100vw",
        "max-width":        "100vw",
        "min-height":       "100vh",
        "max-height":       "100vh",
        "background-color": "#0008",
        "opacity":          "100%",
        "margin":           0,
        "padding":          0,
        "border":           "none",
        "border-radius":    0
    });

    const popup_blob_opts = {type: "text/html;charset=UTF-8"};
    const popup_blob = new Blob([popup_html], popup_blob_opts);
    const popup_url = URL.createObjectURL(popup_blob);

    function show_popup_dialog() {
        setattr_fun.call(popup_frame, "srcdoc", popup_html);
        setattr_fun.call(popup_frame, "nonce", nonce);
        setattr_fun.call(popup_frame, "style", frame_style);

        setattr_fun.call(popup_container, "style", container_style);
        setinner_fun.call(popup_container, "");
        prepend_fun.call(popup_container, popup_frame);

        prepend_fun.call(document.body, popup_container);
    }

    let popup_newtab_wanted = false;

    function show_popup_newtab() {
        /*
         * We cannot open popup directly here because browsers block window
         * creation attempts from "keypress" event handlers. Instead, we set a
         * flag to have "click" event handler open the popup.
         */
        popup_newtab_wanted = true;
        console.info(`You typed "${shortcut}". Please click anywhere on the page to show Haketilo page information.`);
    }

    function show_popup() {
        if (popup_style === "T") {
            show_popup_newtab();
        } else {
            /* popup_syle === "D" */
            show_popup_dialog();
        }
    }

    function hide_popup_dialog() {
        remove_fun.call(popup_container);
    }

    let letters_matched = 0;

    function matches_previous(letter) {
        return letters_matched > 0 && letter === shortcut[letters_matched - 1];
    }

    function match_letter(letter) {
        if (letter !== shortcut[letters_matched] && !matches_previous(letter))
            letters_matched = 0;

        if (letter === shortcut[letters_matched]) {
            if (++letters_matched === shortcut.length) {
                letters_matched = 0;
                return true;
            }
        }

        return false;
    }

    function consume_keypress(event) {
        if (!event.isTrusted)
            return;

        if (match_letter(event.key))
            show_popup();
    }

    function cancel_event(event) {
        event.stopImmediatePropagation();
        event.stopPropagation();
        event.preventDefault();
    }

    function consume_click(event) {
        if (!event.isTrusted)
            return;

        if (popup_style === "T") {
            if (popup_newtab_wanted) {
                popup_newtab_wanted = false;
                cancel_event(event);
                window.open(
                    popup_url,
                    "_blank",
                    "popup,width=600px,height=700px"
                );
            }
        } else {
            /* popup_syle === "D" */
            if (event.target === popup_container) {
                hide_popup_dialog();
                cancel_event(event);
            }
        }
    }

    document.addEventListener("keypress", consume_keypress, {capture: true});
    document.addEventListener("click",    consume_click,    {capture: true});
})();