/*
 *    Copyright [2015] [wisemapping]
 *
 *   Licensed under WiseMapping Public License, Version 1.0 (the "License").
 *   It is basically the Apache License, Version 2.0 (the "License") plus the
 *   "powered by wisemapping" text requirement on every single page;
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the license at
 *
 *       http://www.wisemapping.org/license
 *
 *   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.
 */

/**
 * Cross-browser implementation of creating an XML document object.
 */
export const createDocument = function () {
  var doc = null;
  if ($defined(window.ActiveXObject)) {
    //http://blogs.msdn.com/b/xmlteam/archive/2006/10/23/using-the-right-version-of-msxml-in-internet-explorer.aspx
    var progIDs = ['Msxml2.DOMDocument.6.0', 'Msxml2.DOMDocument.3.0'];
    for (var i = 0; i < progIDs.length; i++) {
      try {
        doc = new ActiveXObject(progIDs[i]);
        break;
      } catch (ex) {}
    }
  } else if (window.document.implementation && window.document.implementation.createDocument) {
    doc = window.document.implementation.createDocument('', '', null);
  }
  $assert(doc, 'Parser could not be instantiated');

  return doc;
};

/*
 Function: $defined
 Returns true if the passed in value/object is defined, that means is not null or undefined.

 Arguments:
 obj - object to inspect
 */

export const $defined = function (obj) {
  return obj != undefined;
};

export const $assert = function (assert, message) {
  if (!$defined(assert) || !assert) {
    logStackTrace();
    console.log(message);
    throw new Error(message);
  }
};

export const sign = function (value) {
  return value >= 0 ? 1 : -1;
};

export function logStackTrace(exception) {
  if (!$defined(exception)) {
    try {
      throw Error('Unexpected Exception');
    } catch (e) {
      exception = e;
    }
  }
  var result = '';
  if (exception.stack) {
    //Firefox  and Chrome...
    result = exception.stack;
  } else if (window.opera && exception.message) {
    //Opera
    result = exception.message;
  } else {
    //IE and Safari
    result = exception.sourceURL + ': ' + exception.line + '\n\n';

    var currentFunction = arguments.callee.caller;
    while (currentFunction) {
      var fn = currentFunction.toString();
      result = result + '\n' + fn;
      currentFunction = currentFunction.caller;
    }
  }
  window.errorStack = result;
  return result;
}