// ==UserScript==
// @name         RED Cover Inspector
// @namespace    https://greasyfork.org/users/321857-anakunda
// @version      1.002
// @description  Adds simple cover sticker if needs updating for unsupported host / big size / small resolution
// @author       Anakunda
// @copyright    2020, Anakunda (https://greasyfork.org/users/321857-anakunda)
// @license      GPL-3.0-or-later
// @match        https://redacted.ch/torrents.php?id=*
// @connect      *
// @grant        GM_xmlhttpRequest
// @grant        GM_getValue
// @grant        GM_setValue
// @downloadURL none
// ==/UserScript==

function getRemoteFileSize(url) {
  return new Promise(function(resolve, reject) {
	var imageSize, abort = GM_xmlhttpRequest({
	  method: 'GET', url: url, responseType: 'arraybuffer',
	  onreadystatechange: function(response) {
		if (imageSize || response.readyState < XMLHttpRequest.HEADERS_RECEIVED
			|| !/^(?:Content-Length):\s*(\d+)\b/im.test(response.responseHeaders)) return;
		if (!(imageSize = parseInt(RegExp.$1))) return;
		resolve(imageSize);
		abort.abort();
	  },
	  onload: function(response) { // fail-safe
		if (imageSize) return;
		if (response.status >= 200 && response.status < 400) resolve(response.responseText.length /*response.response.byteLength*/);
			else reject('image not accessible');
	  },
	  onerror: response => { reject('image not accessible') },
	  ontimeout: response => { reject('image not accessible') },
	});
  });
}

function formattedSize(size) {
  return size < 1024**1 ? Math.round(size) + ' B'
	: size < 1024**2 ? (Math.round(size * 10 / 2**10) / 10) + ' KiB'
	: size < 1024**3 ? (Math.round(size * 100 / 2**20) / 100) + ' MiB'
	: size < 1024**4 ? (Math.round(size * 100 / 2**30) / 100) + ' GiB'
	: size < 1024**5 ? (Math.round(size * 100 / 2**40) / 100) + ' TiB'
	: (Math.round(size * 100 / 2**50) / 100) + ' PiB';
}

var acceptableCoverSize = GM_getValue('acceptable_cover_size');
if (!(acceptableCoverSize > 0)) GM_setValue('acceptable_cover_size', acceptableCoverSize = 2048);
var acceptableCoverResolution = GM_getValue('acceptable_cover_resolution');
if (!(acceptableCoverResolution > 0)) GM_setValue('acceptable_cover_resolution', acceptableCoverResolution = 200);

document.querySelectorAll('div#covers p > img').forEach(function(img) {
  if (img.src.startsWith(document.location.origin) && img.src.endsWith('/noartwork/music.png')) return;
  getRemoteFileSize(img.src).catch(function(reason) {
	console.warn('Failed to get remote image size (' + img.src + '):', reason);
	return undefined;
  }).then(function(size) {
	const span = (content, isOK = false) => (isOK ? '<span>' : '<span style="color: yellow;">') + content + '</span>',
		  isProxied = img.src.startsWith(document.location.origin + '/image.php?'),
		  isPreferredHost = img.src.startsWith('https://ptpimg.me'),
		  isInvalid = isProxied && size < 2 * 2**10 && img.naturalWidth == 400 && img.naturalHeight == 100,
		  isSizeOK = !(size > acceptableCoverSize * 2**10),
		  isResolutionOK = Math.min(img.naturalWidth, img.naturalHeight) >= acceptableCoverResolution;
	if (isPreferredHost && isSizeOK && isResolutionOK) return;
	let div = document.createElement('div');
	div.style = 'color: white; border: 1px solid whitesmoke; background-color: #ae2300; ' +
	  'position: relative; font: 700 8pt "Segoe UI"; padding: 1px 5px;';
	if (!isInvalid) {
	  div.style.float = 'right';
	  div.style.right = '5px';
	  div.style.bottom = '25px';
	  div.innerHTML = span(formattedSize(size), isSizeOK) + ' / ' +
		span(img.naturalWidth + '×' + img.naturalHeight, isResolutionOK);
	  if (isProxied) div.innerHTML = span('PROXY') + ' / ' + div.innerHTML;
		  else if (!isPreferredHost) div.innerHTML = span('XTRN') + ' / ' + div.innerHTML;
	} else {
	  div.style.bottom = '3px';
	  div.innerHTML = span('INVALID');
	}
	img.insertAdjacentElement('afterend', div);
	if (isInvalid) img.remove();
  });
});