Arrow keys will scroll pages and figures, and numbers for total sections/topics/pages are inserted
// ==UserScript==
// @name Arrow keys for NetAcad
// @namespace https://static-course-assets.s3.amazonaws.com/
// @version 0.10
// @description Arrow keys will scroll pages and figures, and numbers for total sections/topics/pages are inserted
// @author TakingItCasual
// @match https://static-course-assets.s3.amazonaws.com/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
function get_active_button_i(button_list){
for(let i=0; i < button_list.length; i++){
if(button_list[i].classList.contains("active")) return i;
}
return -1; // Shouldn't be reached
}
function prev_figure(fig_buttons, active_button_i){
if(active_button_i == 0) return false;
fig_buttons[active_button_i-1].click()
return true;
}
function next_figure(fig_buttons, active_button_i){
if(active_button_i == fig_buttons.length-1) return false;
fig_buttons[active_button_i+1].click()
return true;
}
function scroll_figure(figs, scroll_func){
if(figs.length == 0) return false;
let fig_buttons = [];
figs.forEach(function(fig){
fig_buttons.push(fig.getElementsByTagName("button")[0]);
});
let active_button_i = get_active_button_i(fig_buttons);
return scroll_func(fig_buttons, active_button_i);
}
document.onkeydown = function(e){
// If, for example, the search overlay is active, disable arrow keys
if(document.getElementsByClassName("overlay active").length > 0) return;
let menu_bar = window.top.document.getElementById("page-slide-buttons");
let figs = [...menu_bar.getElementsByTagName("li")];
if(e.keyCode == 37){
if(!scroll_figure(figs, prev_figure)){
window.top.document.getElementById("page-menu-previous-button").click();
}
}else if(e.keyCode == 39){
if(!scroll_figure(figs, next_figure)){
window.top.document.getElementById("page-menu-next-button").click();
}
}
};
let _maps = [
["map-sections", "2"],
["map-topics", "3"],
["map-pages", "4"],
]
for(const _map of _maps){
let _part_map = window.top.document.getElementById(_map[0]);
let _part_max = _part_map.getElementsByTagName("li").length;
if(_part_max > 0){ // This script is run 3 times, the first of which the counts are zero
if(_map[0] == "map-sections") _part_max--; // Section numbering seems to always start from 0
const _header = window.top.document.querySelector("div#page-header");
let _part_text = _header.querySelector('li[aria-level="' + _map[1] + '"] span.breadcrumbs-header');
let tmp_txt = _part_text.innerHTML;
if(tmp_txt.indexOf("/") == -1){ // To prevent the 3rd run from repeating this
let last_dot = tmp_txt.lastIndexOf(".") + 1;
_part_text.innerHTML = tmp_txt.slice(0, last_dot) + "(" + tmp_txt.slice(last_dot) + "/" + _part_max + ")";
}
}
}
})();