/* -*- Mode: Javascript; indent-tabs-mode:nil; js-indent-level: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */

/*************************************************************
 *
 *  MathJax/extensions/mml-preview.js
 *  
 *  Implements a fast preview using the NativeMML output jax
 *  and then a slower update using whatever output jax the user
 *  has selected.  The MathML is styled for those browsers that
 *  don't support MathML natively.
 *  
 *  ---------------------------------------------------------------------
 *  
 *  Copyright (c) 2014-2018 The MathJax Consortium
 * 
 *  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.
 */

(function (HUB,HTML) {

  var MMLpreview = MathJax.Extension["mml-preview"] = {
    version: "2.7.5",

    //
    //  Configuration for the chunking of the main output
    //  after the previews have been created
    //
    config: HUB.CombineConfig("mml-preview",{
      EqnChunk: 5, EqnChunkFactor: 1, EqnChunkDelay: 15000
    }),
    
    //
    //  Styles used for browsers that don't have native MathML support
    //
    styles: {
      "math": {
        "font-family": "Times, 'Times New Roman', serif",
        "display": "inline",
        "text-indent": "0",
        "white-space": "nowrap"
      },
      "math[display='block']": {
        "display": "block",
        "text-indent": "0",
        "text-align": "center",
        "margin": "1em 0"
      },
//      "math *[mathbackground]": {
//        "display": "inline-block!important",
//        "background-color": "attr(mathbackground)"
//      },
//      "math *[mathcolor]": {
//        "color": "attr(mathcolor)"
//      },

      "mi": {"font-style": "italic"},
      "mo": {"margin": "0 .15em"},
      "mphantom": {"visibility": "hidden", "display":"inline-block"},
//      "mspace": {
//        "display": "inline-block!important",
//        "width": "attr(width)",
//        "height": "attr(height)"
//      },
      
      "mfrac": {
        "display": "inline-table!important",
        "vertical-align": "middle",
        "border-collapse": "collapse",
        "margin": "0 .125em"
      },
      "mfrac > *": {
        "display": "table-row!important"
      },
      "mfrac:not([linethickness='0']) > *:first-child": {
        "border-bottom": "thin solid"
      },
      
      "msqrt, mroot": {
        "display":"-webkit-inline-flex!important",
        "display ":"inline-flex!important",
        "margin-left": ".6em",
        "vertical-align": "middle",
        "border-top": "solid thin",
        "margin-top": "1px"
      },
      "msqrt:before, mroot:before": {
        "margin-left": "-.6em",
        "content": '"\u221A"'
      },
      "mroot > *:nth-child(2)": {
        "margin-top": "-.5em",
        "margin-right": ".25em",
        "margin-left": "-.75em",
        "font-size": "80%", "line-height": 1,
        "-webkit-order": -1, "order": -1
      },

      "msubsup > *:nth-child(2), msub > *:nth-child(2)": {
        "font-size": "80%", "line-height": 1,
        "vertical-align": "sub"
      },
      "msubsup > *:nth-child(3), msup > *:nth-child(2)": {
        "font-size": "80%", "line-height": 1,
        "vertical-align": "super"
      },
      
      "munderover, munder, mover": {
        "display":"-webkit-inline-flex!important",
        "-webkit-flex-direction": "column",
        "display ":"inline-flex!important",
        "flex-direction": "column"
      },
      "munderover > *:nth-child(2), munder > *:nth-child(2)": {
        "font-size": "80%", "line-height": 1
      },
      "munderover > *:nth-child(3), mover > *:nth-child(2)": {
        "-webkit-order": -1, "order": -1,
        "font-size": "80%", "line-height": 1
      },
      "mover": {"vertical-align": "text-bottom"},
      "munder": {"vertical-align": "text-top"},
      "munderover": {"vertical-align": "middle"},
      
      "mtable": {
        "display": "inline-table!important",
        "vertical-align": "middle",
        "border-collapse": "collapse"
      },
      "mtr, mlabeledtr": {
        "display": "table-row!important"
      },
      "mtd": {
        "display": "table-cell!important",
        "padding-left": "1em",
        "padding-top": ".5em"
      },
      "mtr > *:first-child": {"padding-left": 0},
      "mtable > mtr:first-child > *": {"padding-top": 0},
      "mlabeledtr > *:first-child": {"display":"none"},
      
      "semantics > *": {"display":"none!important"},
      "semantics > *:first-child": {"display":"inline"}
    },
    
    //
    //  Ajust the chunking of the output jax
    //
    Config: function () {
      HUB.Config({
        "HTML-CSS": this.config,
        "SVG": this.config
      });
    },

    //
    //  Insert a preview span, if there isn't one already,
    //  and call the NativeMML output jax to create the preview
    //
    Preview: function (data) {
      var preview = data.script.previousSibling;
      if (!preview || preview.className !== HUB.config.preRemoveClass) {
        preview = HTML.Element("span",{className:HUB.config.preRemoveClass});
        data.script.parentNode.insertBefore(preview,data.script);
      }
      preview.innerHTML = "";
      try {data.math.root.toNativeMML(preview)} catch (e) {}
      return data;
    },

    //
    //  Hook into the inut jax postFilter to create the previews as
    //  the input jax are processed.
    //
    Register: function (name) {
      HUB.Register.StartupHook(name+" Jax Require",function () {
        var jax = MathJax.InputJax[name];
        var delay = HUB.config.delayJaxRegistration;
        HUB.config.delayJaxRegistration = true;
        HUB.Register.StartupHook(name+" Jax Ready",function () {HUB.config.delayJaxRegistration = delay});
        jax.require.push(
          "[MathJax]/jax/output/NativeMML/config.js",
          "[MathJax]/jax/output/NativeMML/jax.js"
        );
        jax.postfilterHooks.Add(["Preview",MathJax.Extension["mml-preview"]]);
      });
    }
  }

  //
  //  Hook into each input jax
  //
  MMLpreview.Register("TeX");
  MMLpreview.Register("MathML");
  MMLpreview.Register("AsciiMath");
  
  HUB.Register.StartupHook("End Config",["Config",MMLpreview]);
  
  HUB.Register.StartupHook("onLoad",function () {
    var test = HTML.addElement(document.body,"div",{
      style: {
        visibility:"hidden", position:"absolute", left:0, top:0,
        height:"auto", width:"auto", "font-family":"serif", "line-height":"normal",
        display:"block!important"
      }
    });
    test.innerHTML = "<math><mfrac><mi>xx</mi><mi>yy</mi></mfrac></math>";
    if (test.offsetHeight < test.offsetWidth) {MathJax.Ajax.Styles(MMLpreview.styles)}
  });

})(MathJax.Hub,MathJax.HTML);

MathJax.Ajax.loadComplete("[MathJax]/extensions/mml-preview.js");