// this doesn't properly deal with eg, .gov.uk .co.ck etc
function parseDomain(host){
  var chunks = host.split(".")
  if (chunks.length == 1) return chunks[0]
  else return chunks[chunks.length - 2]
}

function escapeHtml(txt) {
    if (!txt) { return ""; }
    // txt = annoyingCaps(txt)
    return $("<span>").text(txt).html()
}


URLRegex = /((\b(http\:\/\/|https\:\/\/|ftp\:\/\/)|(www\.))+(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?)/gi;
PicRegex = /\.(jpg|jpeg|png|gif|bmp|svg|webp|fid)$/i;
VideoRegex = /\.(mp4|webm|mov|m4v|gifv)$/i;
RecipRegex = /(^|\s)@\w+/g;
TopicRegex = /(^|\s)#\w+/g;

function splitTrailingPunctuation(url) {
  if (!url) return { "url": url, "suffix": "" };
  // Common punctuation that follows pasted links in chat.
  var match = url.match(/[)\]\}\.,!\?;:'"]+$/);
  if (!match) return { "url": url, "suffix": "" };
  return { "url": url.slice(0, -match[0].length), "suffix": match[0] };
}

function imgurIdFromUri(uri) {
  var host = (uri.host || "").toLowerCase();
  if (!host || !host.match(/(^|\.)imgur\.com$/i)) return null;
  if (!uri.file) return null;

  var fileLower = uri.file.toLowerCase();
  if (PicRegex.test(fileLower) || VideoRegex.test(fileLower)) return null;

  if (!uri.file.match(/^[A-Za-z0-9]+$/)) return null;
  return uri.file;
}

function imgurCandidateUrls(id) {
  var base = "https://i.imgur.com/" + id;
  return [base + ".jpg", base + ".png", base + ".gif", base + ".jpeg"];
}

function imgurHotlinkFallback(img) {
  try {
    var candidates = (img.getAttribute("data-imgur-candidates") || "").split("|");
    if (!candidates.length || !candidates[0]) return;

    var idx = parseInt(img.getAttribute("data-imgur-idx") || "0", 10);
    var next = idx + 1;
    if (next >= candidates.length) {
      var link = img.parentNode;
      if (link && link.tagName == "A") {
        var href = link.getAttribute("href") || "";
        while (link.firstChild) link.removeChild(link.firstChild);
        link.appendChild(document.createTextNode(href));
      }
      return;
    }

    img.setAttribute("data-imgur-idx", "" + next);
    img.src = candidates[next];
  } catch (e) {}
}


function getImagesAsArray(text) {
  var imgs = []
  var urls = text.match(URLRegex)
  if (urls === null) return imgs
  for (var i = 0; i<urls.length; i++){
    var split = splitTrailingPunctuation(urls[i]);
    var normalized = normalizeUrl(split.url);
    var uri = parseUri(normalized);

    // Try to turn common "page" links into direct image URLs (best-effort).
    var imgurId = imgurIdFromUri(uri);
    var candidate = imgurId ? imgurCandidateUrls(imgurId)[0] : normalized;

    var urlWithoutParams = candidate.replace(/[?#].*$/i, "");
    if (PicRegex.test(urlWithoutParams)) imgs.push(candidate)
  }
  return imgs
}

function topicReplace(text) {
    text = $.trim(text).toLowerCase();
    var topicLabel = text.substring(1);
    return ' <a target="_blank" href="'+ RootDomain + 't/' + topicLabel + '">' + text + '</a> ';
}

function recipientReplace(atText, recips) {
    recips = recips || [];

    var space = '';    
    if (atText[0] == ' ') {
        atText = atText.slice(1);
        space = ' ';
    }
    
    var nick = atText.slice(1).toLowerCase();
    var matchedRecip;
    for (var i = 0; i < recips.length; i++) {
        if (recips[i].toLowerCase() == nick) {
            matchedRecip = recips[i];
            break;
        }
    }
    
    if (matchedRecip) {
        return space + '<a target="_blank" href="' + RootDomain + matchedRecip + '">@' + matchedRecip + '</a>';
    } else {
        return space + atText;
    }
}

function linkify(text, recips) {
    LastMsgContainsImage = false;
    var recipWrapper = function(text) { return recipientReplace(text, recips); };
    return text
        .replace(URLRegex, linkReplace)
        .replace(RecipRegex, recipWrapper)
        .replace(TopicRegex, topicReplace);
}

// use this in escapeHtml to turn everyone's text lIkE tHiS
function annoyingCaps(text){
  var chunks = text.split(" ")
  for(var i=0; i<chunks.length; i++){
    var chunk = chunks[i]
    if (!chunk.length || chunk.substr(0,4) == 'http') continue;
    var letters=chunk.split("")
    for(var j = 0; j<letters.length; j++){
      if (j % 2) letters[j] = letters[j].toUpperCase()
      else letters[j] = letters[j].toLowerCase()
    }
    chunks[i] = letters.join("")
  } 
  return chunks.join(" ")
}


function imgClickHandler() {
	// Ugly hack. Don't open new links in chat, only in logs.
	// Ugly hack mkII: ensure middle-click opens images in new tab
	// c.f. http://code.google.com/p/chromium/issues/detail?id=255
	if ($.browser.webkit && event.button != 0) {
		event.stopPropagation();
	} else {
		return $('#chatrap').length == 0;
	}
}

// durty hack to use a global to check this... but otherwise i'd have to rewrite the String.replace function? :/
var LastMsgContainsImage = false
function linkReplace(url) {
    var split = splitTrailingPunctuation(url);
    var hrefUrl = normalizeUrl(split.url);
    var uri = parseUri(hrefUrl);

    // Best-effort support for Imgur page links (e.g. https://imgur.com/<id>).
    var imgurId = imgurIdFromUri(uri);
    if (imgurId) {
      LastMsgContainsImage = true;
      var candidates = imgurCandidateUrls(imgurId);
      var first = candidates[0];
      return "<a target=\"_blank\" href=\"" + hrefUrl + "\" class=\"img-wrapper\" onclick=\"return imgClickHandler()\">"
             + "<img src=\"" + first + "\" class=\"unbound imgur-hotlink\" data-imgur-idx=\"0\" data-imgur-candidates=\"" + candidates.join("|") + "\" onerror=\"imgurHotlinkFallback(this)\">"
             + "</a>" + split.suffix;
    }

    linkUrl = hrefUrl;

    var type = getUriType(uri)
    
    if (type == 'image') {
      LastMsgContainsImage = true;
      return "<a target=\"_blank\" href=\"" + linkUrl + "\" class=\"img-wrapper\" onclick=\"return imgClickHandler()\"><img src=\"" + linkUrl + "\" class=\"unbound\"></a>" + split.suffix;
    } else if (type == 'video') {
      LastMsgContainsImage = true;
      var videoUrl = linkUrl.replace(/\.gifv([?#].*)?$/i, ".mp4$1");
      return "<a target=\"_blank\" href=\"" + linkUrl + "\" class=\"video-wrapper\" onclick=\"return imgClickHandler()\"><video src=\"" + videoUrl + "\" autoplay loop muted controls playsinline></video></a>" + split.suffix;
    } else if (type == 'youtube') {
      Youtube.startAnimation();
      return "<a target=\"_blank\" class=\"youtube\" href=\"" + linkUrl + "\">" +
             "<img class=\"youtube-thumb\" width=\"130\" height=\"97\" src=\"" + Youtube.nextThumbUrl(uri.queryKey.v) + "\">" +
             "<img class=\"youtube-controls\" src=\"/static/img/youtube.controls.png\"></a>" + split.suffix;
    } else if (type == 'midi') {
      return '<embed src="' + linkUrl + '" autostart="false" loop="false" volume="80" width="150" height="20" style="vertical-align:bottom"> <a href="' + linkUrl + '">' + uri.file + '</a>' + split.suffix;
    } else if (type == 'wav') {
      return '<audio src="' + linkUrl + '" controls volume="80" width="150" height="20" style="vertical-align:bottom"></audio> <a href="' + linkUrl + '">' + uri.file + '</a>' + split.suffix;
    } else
        return "<a target=\"_blank\" href=\"" + linkUrl + "\">" + split.url + "</a>" + split.suffix;
    
}


function getUriType(uri){
  if (PicRegex.test(uri.file.toLowerCase()))
    return "image";

  if (VideoRegex.test(uri.file.toLowerCase()))
    return "video";
  
  var domain = parseDomain(uri.host)
  
  if (domain == "gstatic" && uri.path == "/images" && 'q' in uri.queryKey)
    return "image"; 
  
 // actual image url = uri.queryKey['q'].split(":").slice(2).join(":") but often the original image is broken...


  if (domain == "youtube" && ('v' in uri.queryKey || uri.anchor.indexOf('v') != -1))
    return "youtube";
  
  if (uri.path.substr(-4) == ".mid" || uri.path.substr(-5) == ".midi")
    return "midi"

  if (uri.path.substr(-4) == ".wav")
    return "wav"

  
  return "link";
}

function linkifyWithoutImage(text) {
    LastMsgContainsImage = false
    return text.replace(URLRegex, linkReplaceWithoutImage);
}

function linkReplaceWithoutImage(url){
    var urlWithoutParams = url.replace(/\?.*$/i, "");
    linkUrl = normalizeUrl(url);

    return "<a target='_blank' href='" + linkUrl + "'>" + url + "</a>"
}