// ==UserScript==
// @name         EBJ ripper
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Rips from EBJ kind of automatically, only runs with FF w/ GM don't try it on anything else god fucking damnit
// @author       (You)
// @run-at       document-start
// @include      https://br.ebookjapan.jp/br/reader/viewer/view.html*
// @require      https://raw.githubusercontent.com/eligrey/FileSaver.js/master/FileSaver.js
// @require      https://ajax.googleapis.com/ajax/libs/jquery/1.12.3/jquery.min.js
// @grant		 none
// ==/UserScript==

(function() {
    'use strict';
    //snatch toBlob() before the sneaky japs remove it
    var f = HTMLCanvasElement.prototype.toBlob;
	//Keep track of which page we're at at so we don't save dupes
    var page=0;
	$(document).ready(function(){
		var observer = new MutationObserver(function(mutations) {
			mutations.forEach(function(mutation) {
			   if (mutation.attributeName === "class"){
				setTimeout(500);
				// Check to see if actually want to run the script
				if(!confirm("Try and dump pages?")) return false;
				observer.disconnect();
				main();
			   }
			});
		});
		observer.observe(document.body,{
			attributes: true
		});
    });
    function main(){
        //Extract the cover page before inserting the observer
        var allCanvas = document.getElementsByTagName("canvas");
        extract(5, allCanvas);
        //Create observer
        var observer = new MutationObserver(function(mutations) {
            //Gather all the canvas that fired the observer and send to extract
            var i;
            var canvasE = [];
            for(i = 0;i<mutations.length;i++){
                canvasE[i] = mutations[i].target;
            }
            extract(3, canvasE);
        });
        var observerConfig = {
            attributes: true,
            subtree: true,
            Filter:['page']
        };
        var targetNode = document.getElementById("inner");
        observer.observe(targetNode, observerConfig);
    }

    function extract(t, canvas){
        //Check if canvas is 'current', if yes save to disk. If canvas were extracted flip pages after t seconds
        var i;
        var extracted;
        for(i = 0;i<canvas.length;i++){
            if(canvas[i].getAttribute("class")=="current"&&canvas[i].getAttribute("page")==page){
                save(page+1, canvas[i]);
                extracted = true;
                page++;
            }
        }
        if(extracted===true){
            window.setTimeout(flipPages, t*1000);
        }
    }

    function flipPages(){
        //Simulate a click to the controller element, this function is called on a timed delay to ensure the next pages are preloaded
        var elem = document.getElementById("controller");
        triggerMouseEvent(elem, "mousedown");
        triggerMouseEvent(elem, "mouseup");
    }

    function save(n, c){
        //Saves with a filename consisting of the book's title and the page + 1 (it starts from 0)
        var e = document.createElement('canvas');
        e=c;
        e.toBlob=f;
        e.toBlob(function(blob) {
            var filename = getFilename(n);
            saveAs(blob, filename);
            console.log("saved as "+filename);
        });
    }

    function getFilename(n){
        //Returns a filename in the Book title_000.png format
        var title = document.title;
        return title + "_" + prefix(3, n.toString()) + ".png";
    }

    function prefix(n, s){
        //Returns the page number with 3 digits for sorting purposes.
        var i = 0;
        var strPrefix="";
        for(i=0;i<n-s.length;i++){
            strPrefix+="0";
        }
        s = strPrefix+s;
        return s;
    }

    function triggerMouseEvent(node, eventType){
        //This is an internal function for mouse click events, fuck using jQuery for this.
        var clickEvent = document.createEvent ('MouseEvents');
        clickEvent.initEvent (eventType, true, true);
        node.dispatchEvent (clickEvent);
    }

})();