// ==UserScript==
// @name         nh_load_all
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://nhentai.net/g/*
// @grant        none
// ==/UserScript==

(function() {
  'use strict';

  let buttonElement, imageQueue, continueOnError;
  let imageSources = [];
  let imageHeight = '100vh';
  let imageWidth = '50%';
  let title = document.title;
  let container = document.getElementById('thumbnail-container');
  let gallerythumbs = document.getElementsByClassName('gallerythumb');
  let pattern = /.*galleries\/([\d\/]+).*\.(.*)$/;
  let replacement = "https://i.nhentai.net/galleries/$1.$2";
  let numProcesses = 1;

  window.reloadImage = function(imageElement) {
    let reloadCount = imageElement.getAttribute('data-reload-count');
    let dataSource = imageElement.getAttribute('data-source');
    let currentTime = (new Date()).getTime();

    if (reloadCount < 3) {
      imageElement.src = `${dataSource}?t=${currentTime}`;
      imageElement.setAttribute('data-reload-count', reloadCount + 1);
      console.log(`${reloadCount}: reloading img ${dataSource}`);
    } else {
      console.log(`max retry of ${reloadCount} reached - ${dataSource}`);
      if (typeof continueOnError === 'undefined') {
        continueOnError = confirm('Unable to load image. Proceed with next images?');
      }
      if (continueOnError) {
        processQueue();
      }
    }
  };

  for (let gallerythumb of gallerythumbs) {
    let imageElement = gallerythumb.getElementsByTagName('img')[0];
    let dataSource = imageElement.getAttribute('data-src');
    let imageSource = dataSource.replace(pattern, replacement);
    imageSources.push(imageSource);
  }
  document.title = `[INC - ${imageSources.length}] ${title}`;
  container.innerHTML = '';

  // insert one image a time
  imageQueue = [...imageSources];
  window.processQueue = function() {
    let numRemainingImages = imageQueue.length;
    if (numRemainingImages === 0) {
      console.log('no more images left');
      document.title = `[COMPLETE] ${title}`;
      return;
    }
    let imageSource = imageQueue.shift();
    let imageElement = document.createElement("img");
    imageElement.src = imageSource;
    imageElement.setAttribute('data-reload-count', 0);
    imageElement.setAttribute('data-source', imageElement.src);
    imageElement.setAttribute('onerror', 'reloadImage(this)');
    imageElement.setAttribute('onload', 'processQueue()');
    imageElement.style.background = `transparent url('https://thinkfuture.com/wp-content/uploads/2013/10/loadingSpinner.gif') center no-repeat;`;
    imageElement.style['max-width'] = imageWidth;
    imageElement.style['max-height'] = imageHeight;
    container.appendChild(imageElement);
    // notify progress
    console.log(`image added: ${imageElement.src}`);
    document.title = `[INC - ${numRemainingImages}] ${title}`;
  };
  // start queue
  for (var i = 0; i < numProcesses; i++) {
    processQueue();
  }

  // add button to update height
  buttonElement = document.createElement('button');
  buttonElement.className = 'btn btn-primary btn-custom';
  buttonElement.innerText = '200vh';
  buttonElement.style = `position: fixed; top: 2em; right: 2em;`;

  buttonElement.addEventListener('click', function() {
    if (imageHeight === '200vh') {
      imageHeight = '100vh';
      imageWidth = '50%';
      this.innerText = '200vh';
    } else {
      imageHeight = '200vh';
      imageWidth = '100%';
      this.innerText = '100vh';
    }

    let imgs = document.querySelectorAll('#thumbnail-container img');
    for (let img of imgs) {
      if (img) {
        img.style['max-width'] = imageWidth;
        img.style['max-height'] = imageHeight;
      }
    }
    console.log(`settings cssText to ${imgs[0].style.cssText}`);
  });
  document.body.append(buttonElement);

  // pagedown on right
  document.addEventListener('keydown', function(e) {
    let height = window.innerHeight;

    switch(e.keyCode) {
    case 37: // left
      window.scrollBy(0, -height);
      break;
    case 39: // right
      window.scrollBy(0, height);
      break;
    default: return; // exit this handler for other keys
    }
    e.preventDefault(); // prevent the default action (scroll / move caret)
  });

})();