// ==UserScript==
// @name         GrimRipper
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  BW Canvas Ripper
// @author       XXXXXXXXXIII
// @match        https://viewer.bookwalker.jp/*
// @license      MIT
// @downloadURL none
// ==/UserScript==

// TODO: First page may not download properly
(function() {
    'use strict';
    console.log("Hello There");
    var saved = false;
    var page = -1;
    
    setInterval(() => {
        try {
            if (page < 1) page = getPageNum();
            if (page != getPageNum()) saved = false;
            if (page < 1 || saved) return;
            if (isLoading()) return;
            console.log("rippin' page " + getPageNum());
            let canvas = getActiveCanvas();
            canvas.style.width = '1125';
            canvas.style.height = '1600';
            saveCanvas(canvas, page);
            saved = true;
            page = getPageNum();
            NFBR.a6G.Initializer.Z4p.menu.options.a6l.moveToNext(); // USER: Auto page flip, comment out if not needed
        } catch (e) {
            console.log("Not Ready");
            saved = false;
        }
    }, 3000); // USER: Time interval
})();

function saveCanvas(canvas, page) {
    //let image = canvas.toDataURL("image/jpeg", 1.0); // Very Slow, highly not recommended.
    canvas.toBlob((blob) => {
      var image = URL.createObjectURL(blob);
      var a = document.createElement('a');
      a.href = image;
      document.body.appendChild(a);
      a.download = page + ".png";
      a.click();
    }, "image/png", 1.0);
}

function isLoading() {
    if (document.getElementById('viewport0').style.visibility == 'visible') {
        return document.getElementById('viewport0').getElementsByClassName("loading")[0].style.visibility == 'visible';
    } else {
        return document.getElementById('viewport1').getElementsByClassName("loading")[0].style.visibility == 'visible';
    }
}

function getActiveCanvas() {
    if (document.getElementById('viewport0').style.visibility == 'visible') {
        return document.getElementById('viewport0').getElementsByTagName("CANVAS")[0];
    } else {
        return document.getElementById('viewport1').getElementsByTagName("CANVAS")[0];
    }
}

function getPageNum() {
    var pageNum = document.getElementById('pageSliderCounter').innerHTML;
    return Number(pageNum.replace(/\/.*/i, ""));
}