// ==UserScript==
// @name         Hide Images
// @namespace    http://tampermonkey.net/
// @version      0.5.6
// @description  Hide dumb frogposters
// @author       ECHibiki-/qa/
// @match http://boards.4chan.org/*
// @match https://boards.4chan.org/*
// @include https://boards.4chan.org/*
// @include http://boards.4chan.org/*
// @run-at document-start
// @grant none
// @downloadURL none
// ==/UserScript==

/**
Hold Control and Shift to hide images, but keep threads open.
Doesn't interfere with 4chanx and you can still see images it if you mouse over them.
Hidden images reapear in 48 hours.
*/

var localStoreThreads;
var bowser;
var finished = false;

//is storage possible
function storageAvailable(type) {
    try {
        var storage = window[type],
            x = '__storage_test__';
        storage.setItem(x, x);
        storage.removeItem(x);
        return true;
    }
    catch(e) {
        return e instanceof DOMException && (
            // everything except Firefox
            e.code === 22 ||
            // Firefox
            e.code === 1014 ||
            // test name field too, because code might not be present
            // everything except Firefox
            e.name === 'QuotaExceededError' ||
            // Firefox
            e.name === 'NS_ERROR_DOM_QUOTA_REACHED') &&
            // acknowledge QuotaExceededError only if there's something already stored
            storage.length !== 0;
    }
}

//What Browser
function detectBrowser() { 
    if((navigator.userAgent.indexOf("Opera") || navigator.userAgent.indexOf('OPR')) != -1 ) 
    {
        console.log("Opera");
        return 0;
    }
    else if(navigator.userAgent.indexOf("Chrome") != -1 )
    {
        console.log("Chrome");
        return 1;
    }
    else if(navigator.userAgent.indexOf("Safari") != -1)
    {
        console.log("Safari");
        return 2;
    }
    else if(navigator.userAgent.indexOf("Firefox") != -1 ) 
    {
        console.log("FireFox");
        return 3;
    }
    else if((navigator.userAgent.indexOf("MSIE") != -1 ) || (!!document.documentMode == true )) //IF IE > 10
    {
        console.log("IE");
        return 4;
    }  
    else 
    {
        console.log("Other");
        return -1;
    }
}

//hide image onclick listener
function hideImage(event){
    var hideIndex = this.src.indexOf(".HIDDEN");
    if((event.ctrlKey && event.shiftKey) && hideIndex == -1){
        event.preventDefault();
        event.stopPropagation();
        if (storageAvailable('localStorage')) {
            if(this.id.charAt(0) == "p") this.id =  "f" + this.id.substr(1);
            localStorage.setItem(this.id, Date.now());
        }
        else {
            console.log("No Storage");
        }
        this.src = this.src + ".HIDDEN" +  "?" + Date.now();
        return false;
    }
    else if(event.ctrlKey && event.shiftKey){
        event.preventDefault();
        event.stopPropagation();
        if (storageAvailable('localStorage')) {
            if(this.id.charAt(0) == "p") this.id =  "f" + this.id.substr(1);
            localStorage.removeItem(this.id);
        }
        else {
            console.log("No Storage");
        }
        this.src = this.src.substring(0, hideIndex);
        return false;
    }
    return true;
}

//functions to find properties by regex
function getPropertyByRegex(obj,propName) {
    var re = new RegExp("^" + propName + "(\\[\\d*\\])?$"),
        key;
    var rtnArray = [];
    for (key in obj)
        if (re.test(key))
            rtnArray.push(key);
    return rtnArray;
}

//retrieve from memory the hidden iamges
function retrieveStates(){
    var i = 0,
        oJson = {},
        sKey;
    while( i < window.localStorage.length) {
        i++;
        sKey = window.localStorage.key(i);
        oJson[sKey] = window.localStorage.getItem(sKey);
    }
    localStoreThreads = getPropertyByRegex(oJson,"f[0-9]*IMG");
    localStoreThreads.forEach(function callback(elem){
        if(Date.now() - oJson[elem] > 172800000)
            localStorage.removeItem(elem);
        var node = document.getElementById(""+elem);
        if(node !== null && node.src.indexOf(".HIDDEN") == -1){
            node.src = node.src + ".HIDDEN" +  "?" + Date.now(); 
        }
        if((node = document.getElementById("p"+elem.substring(1))) !== null && node.src.indexOf(".HIDDEN") == -1){
            node.src = node.src + ".HIDDEN" +  "?" + Date.now();           
        }
        else if((node = document.getElementById("thread-"+elem.substring(1))) !== null && node.src.indexOf(".HIDDEN") == -1){
            node.src = node.src + ".HIDDEN" +  "?" + Date.now(); 
        }
    });
}

//initial onload setup
function ImageListener(){
    var start = document;
    var itterator = document.createTreeWalker(start, NodeFilter.SHOW_ELEMENTS, NodeFilter.SHOW_ELEMENTS);
    var node = "";
    var i = 0;
    while((node = itterator.nextNode())){
        var tag = node.tagName;
        if(tag  === "img" || tag  === "IMG"){
            if(node.getAttribute("data-md5") !== null || node.className.indexOf("thumb") != -1){
                finished = true;
                node.id = node.parentNode.parentNode.id + "IMG";
                node.addEventListener("click", hideImage, {passive:false, capture:false, once:false});
            }
        }
    }
    var delForm = document.getElementById("delform");
    if(delForm !== null){
        observeDynamicMutation(delForm.firstChild);
    }
    else{
        observeDynamicMutation(start);
    }
    retrieveStates();
    finished = true;
}

//detect page changes
function observeDynamicMutation(){
    var node = document;
    var observer = new MutationObserver(function callBack(mutations){
        //var later = Date.now();
        if(finished) var start = document.getElementById("delform").firstChild;
        else var start = document;
        var itterator = document.createTreeWalker(start, NodeFilter.SHOW_ELEMENTS, NodeFilter.SHOW_ELEMENTS);
        var node = "";
        var i = 0;
        while((node = itterator.nextNode())){
            var tag = node.tagName;
            if(tag  === "img" || tag  === "IMG"){
                if(node.getAttribute("data-md5") !== null || node.className.indexOf("thumb") != -1){
                    finished = true;
                    node.id = node.parentNode.parentNode.id + "IMG";
                    node.addEventListener("click", hideImage, {passive:false, capture:false, once:false});
                }
            }
        }
        retrieveStates();
        //console.log(Date.now() - later);
    });
    var config = {subtree: true, childList:true};
    observer.observe(node, config);
}

if (window.top != window.self)  //-- Don't run on frames or iframes
    return;

browser = detectBrowser();
ImageListener();
console.log("Script loaded: Hide Images");