/**
 * This code is mostly from the old Etherpad. Please help us to comment this code. 
 * This helps other people to understand this code better and helps them to improve it.
 * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
 */

// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.domline
// %APPJET%: import("etherpad.admin.plugins");
/**
 * Copyright 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// requires: top
// requires: plugins
// requires: undefined

var Security = require('./security');
var hooks = require('./pluginfw/hooks');
var _ = require('./underscore');
var lineAttributeMarker = require('./linestylefilter').lineAttributeMarker;
var noop = function(){};


var domline = {};

domline.addToLineClass = function(lineClass, cls)
{
  // an "empty span" at any point can be used to add classes to
  // the line, using line:className.  otherwise, we ignore
  // the span.
  cls.replace(/\S+/g, function(c)
  {
    if (c.indexOf("line:") == 0)
    {
      // add class to line
      lineClass = (lineClass ? lineClass + ' ' : '') + c.substring(5);
    }
  });
  return lineClass;
}

// if "document" is falsy we don't create a DOM node, just
// an object with innerHTML and className
domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
{
  var result = {
    node: null,
    appendSpan: noop,
    prepareForAdd: noop,
    notifyAdded: noop,
    clearSpans: noop,
    finishUpdate: noop,
    lineMarker: 0
  };

  var document = optDocument;

  if (document)
  {
    result.node = document.createElement("div");
  }
  else
  {
    result.node = {
      innerHTML: '',
      className: ''
    };
  }

  var html = [];
  var preHtml = '',
  postHtml = '';
  var curHTML = null;

  function processSpaces(s)
  {
    return domline.processSpaces(s, doesWrap);
  }

  var perTextNodeProcess = (doesWrap ? _.identity : processSpaces);
  var perHtmlLineProcess = (doesWrap ? processSpaces : _.identity);
  var lineClass = 'ace-line';

  result.appendSpan = function(txt, cls)
  {

    var processedMarker = false;
    // Handle lineAttributeMarker, if present
    if (cls.indexOf(lineAttributeMarker) >= 0)
    {
      var listType = /(?:^| )list:(\S+)/.exec(cls);
      var start = /(?:^| )start:(\S+)/.exec(cls);

      _.map(hooks.callAll("aceDomLinePreProcessLineAttributes", {
        domline: domline,
        cls: cls
      }), function(modifier)
      {
        preHtml += modifier.preHtml;
        postHtml += modifier.postHtml;
        processedMarker |= modifier.processedMarker;
      });

      if (listType)
      {
        listType = listType[1];
        if (listType)
        {
          if(listType.indexOf("number") < 0)
          {
            preHtml += '<ul class="list-' + Security.escapeHTMLAttribute(listType) + '"><li>';
            postHtml = '</li></ul>' + postHtml;
          }
          else
          {
            if(start){ // is it a start of a list with more than one item in?
              if(start[1] == 1){ // if its the first one at this level?
                lineClass = lineClass + " " + "list-start-" + listType; // Add start class to DIV node
              }
              preHtml += '<ol start='+start[1]+' class="list-' + Security.escapeHTMLAttribute(listType) + '"><li>';
            }else{
              preHtml += '<ol class="list-' + Security.escapeHTMLAttribute(listType) + '"><li>'; // Handles pasted contents into existing lists
            }
            postHtml += '</li></ol>';
          }
        } 
        processedMarker = true;
      }
      _.map(hooks.callAll("aceDomLineProcessLineAttributes", {
        domline: domline,
        cls: cls
      }), function(modifier)
      {
        preHtml += modifier.preHtml;
        postHtml += modifier.postHtml;
        processedMarker |= modifier.processedMarker;
      });
      if( processedMarker ){
        result.lineMarker += txt.length;
        return; // don't append any text
      } 
    }
    var href = null;
    var simpleTags = null;
    if (cls.indexOf('url') >= 0)
    {
      cls = cls.replace(/(^| )url:(\S+)/g, function(x0, space, url)
      {
        href = url;
        return space + "url";
      });
    }
    if (cls.indexOf('tag') >= 0)
    {
      cls = cls.replace(/(^| )tag:(\S+)/g, function(x0, space, tag)
      {
        if (!simpleTags) simpleTags = [];
        simpleTags.push(tag.toLowerCase());
        return space + tag;
      });
    }

    var extraOpenTags = "";
    var extraCloseTags = "";

    _.map(hooks.callAll("aceCreateDomLine", {
      domline: domline,
      cls: cls
    }), function(modifier)
    {
      cls = modifier.cls;
      extraOpenTags = extraOpenTags + modifier.extraOpenTags;
      extraCloseTags = modifier.extraCloseTags + extraCloseTags;
    });

    if ((!txt) && cls)
    {
      lineClass = domline.addToLineClass(lineClass, cls);
    }
    else if (txt)
    {
      if (href)
      {
        urn_schemes = new RegExp("^(about|geo|mailto|tel):");
        if(!~href.indexOf("://") && !urn_schemes.test(href)) // if the url doesn't include a protocol prefix, assume http
        {
          href = "http://"+href;
        }
        extraOpenTags = extraOpenTags + '<a href="' + Security.escapeHTMLAttribute(href) + '">';
        extraCloseTags = '</a>' + extraCloseTags;
      }
      if (simpleTags)
      {
        simpleTags.sort();
        extraOpenTags = extraOpenTags + '<' + simpleTags.join('><') + '>';
        simpleTags.reverse();
        extraCloseTags = '</' + simpleTags.join('></') + '>' + extraCloseTags;
      }
      html.push('<span class="', Security.escapeHTMLAttribute(cls || ''), '">', extraOpenTags, perTextNodeProcess(Security.escapeHTML(txt)), extraCloseTags, '</span>');
    }
  };
  result.clearSpans = function()
  {
    html = [];
    lineClass = ''; // non-null to cause update
    result.lineMarker = 0;
  };

  function writeHTML()
  {
    var newHTML = perHtmlLineProcess(html.join(''));
    if (!newHTML)
    {
      if ((!document) || (!optBrowser))
      {
        newHTML += '&nbsp;';
      }
      else if (!optBrowser.msie)
      {
        newHTML += '<br/>';
      }
    }
    if (nonEmpty)
    {
      newHTML = (preHtml || '') + newHTML + (postHtml || '');
    }
    html = preHtml = postHtml = ''; // free memory
    if (newHTML !== curHTML)
    {
      curHTML = newHTML;
      result.node.innerHTML = curHTML;
    }
    if (lineClass !== null) result.node.className = lineClass;

    hooks.callAll("acePostWriteDomLineHTML", {
      node: result.node
    });
  }
  result.prepareForAdd = writeHTML;
  result.finishUpdate = writeHTML;
  result.getInnerHTML = function()
  {
    return curHTML || '';
  };
  return result;
};

domline.processSpaces = function(s, doesWrap)
{
  if (s.indexOf("<") < 0 && !doesWrap)
  {
    // short-cut
    return s.replace(/ /g, '&nbsp;');
  }
  var parts = [];
  s.replace(/<[^>]*>?| |[^ <]+/g, function(m)
  {
    parts.push(m);
  });
  if (doesWrap)
  {
    var endOfLine = true;
    var beforeSpace = false;
    // last space in a run is normal, others are nbsp,
    // end of line is nbsp
    for (var i = parts.length - 1; i >= 0; i--)
    {
      var p = parts[i];
      if (p == " ")
      {
        if (endOfLine || beforeSpace) parts[i] = '&nbsp;';
        endOfLine = false;
        beforeSpace = true;
      }
      else if (p.charAt(0) != "<")
      {
        endOfLine = false;
        beforeSpace = false;
      }
    }
    // beginning of line is nbsp
    for (var i = 0; i < parts.length; i++)
    {
      var p = parts[i];
      if (p == " ")
      {
        parts[i] = '&nbsp;';
        break;
      }
      else if (p.charAt(0) != "<")
      {
        break;
      }
    }
  }
  else
  {
    for (var i = 0; i < parts.length; i++)
    {
      var p = parts[i];
      if (p == " ")
      {
        parts[i] = '&nbsp;';
      }
    }
  }
  return parts.join('');
};

exports.domline = domline;