// ==UserScript==
// @name        Ecchi captcha
// @namespace   Violentmonkey Scripts
// @match       https://iichan.hk/*
// @match       http://iichan.hk/*
// @grant       none
// @version     1.0
// @author      -
// @description 01/04/2022, 20:12:48
// ==/UserScript==

// user-defined variables, put your favorite tags here
var tags = ["solo","1girl","panties"];
var showExplicit = false;
var thumbnailSize = 200;
var postsPerPage = 100;

var randomPage = Math.floor(Math.random()*1000); // random page
var url = "https://danbooru.donmai.us/posts.json?page="+randomPage+"&limit="+postsPerPage+"&only=id,large_file_url,image_width,image_height&tags=";

var posts;
var captcha = document.getElementById("captcha").parentElement;

function getPosts(){
  url += tags.join("+");
  if (!showExplicit) url+="&rating=sq";

  var request = new XMLHttpRequest();
        request.onreadystatechange = function(e)
        {
            if (request.readyState == 4)
            {
        posts = JSON.parse(request.responseText).filter(p=>p.large_file_url != null);
        var img = posts[Math.floor(Math.random()*posts.length)];
        updateCaptcha(img); // random image on the page
        captcha.addEventListener('click', getRandomImage, false);
            }
        }
   request.open('GET', url, true);
     request.setRequestHeader('Accept', 'text/plain');
     request.send(null);
}

function updateCaptcha(image){
  var ratio = image.image_width/image.image_height;
  var thumbWidth, thumbHeight;
  if (ratio > 1) { // horizontal image
    thumbWidth = thumbnailSize+"px";
    thumbHeight = Math.floor(thumbnailSize/ratio)+"px";
  }
  else{
    thumbHeight = thumbnailSize+"px";
    thumbWidth = Math.floor(thumbnailSize*ratio)+"px";
  }
  var img = new Image();
  img.onload = function() {
    captcha.setAttribute("style", "display: block; width:"+thumbWidth+";height:"+thumbHeight+"; background-size: "+thumbWidth+" "+thumbHeight+";background-image: url('"+img.src+"');");
  }
  img.src = image.large_file_url;
  if (img.complete) img.onload();
}

function getRandomImage(){
  captcha.style.opacity = "0.5";
  updateCaptcha(posts[Math.floor(Math.random()*posts.length)]);
  captcha.style.opacity = "1";
}

window.addEventListener('load', getPosts, false);