/*
Embedded SVG-edit API

General usage:
- Have an iframe somewhere pointing to a version of svg-edit > r1000
- Initialize the magic with:
const svgCanvas = new EmbeddedSVGEdit(window.frames.svgedit);
- Pass functions in this format:
svgCanvas.setSvgString('string')
- Or if a callback is needed:
svgCanvas.setSvgString('string')(function(data, error){
  if (error){
  // There was an error
  } else{
  // Handle data
  }
})

Everything is done with the same API as the real svg-edit,
and all documentation is unchanged.

However, this file depends on the postMessage API which
can only support JSON-serializable arguments and
return values, so, for example, arguments whose value is
'undefined', a function, a non-finite number, or a built-in
object like Date(), RegExp(), etc. will most likely not behave
as expected. In such a case one may need to host
the SVG editor on the same domain and reference the
JavaScript methods on the frame itself.

The only other difference is
when handling returns: the callback notation is used instead.

const blah = new EmbeddedSVGEdit(window.frames.svgedit);
blah.clearSelection('woot', 'blah', 1337, [1, 2, 3, 4, 5, 'moo'], -42, {a: 'tree',b:6, c: 9})(function(){console.log('GET DATA',arguments)})
*/

let cbid = 0;

function getCallbackSetter (d) {
  return function () {
    const t = this, // New callback
      args = [].slice.call(arguments),
      cbid = t.send(d, args, function () {}); // The callback (currently it's nothing, but will be set later)

    return function (newcallback) {
      t.callbacks[cbid] = newcallback; // Set callback
    };
  };
}

/*
* Having this separate from messageListener allows us to
* avoid using JSON parsing (and its limitations) in the case
* of same domain control
*/
function addCallback (t, data) {
  const result = data.result || data.error,
    cbid = data.id;
  if (t.callbacks[cbid]) {
    if (data.result) {
      t.callbacks[cbid](result);
    } else {
      t.callbacks[cbid](result, 'error');
    }
  }
}

function messageListener (e) {
  // We accept and post strings as opposed to objects for the sake of IE9 support; this
  //   will most likely be changed in the future
  if (typeof e.data !== 'string') {
    return;
  }
  const {allowedOrigins} = this,
    data = e.data && JSON.parse(e.data);
  if (!data || typeof data !== 'object' || data.namespace !== 'svg-edit' ||
    e.source !== this.frame.contentWindow ||
    (!allowedOrigins.includes('*') && !allowedOrigins.includes(e.origin))
  ) {
    return;
  }
  addCallback(this, data);
}

function getMessageListener (t) {
  return function (e) {
    messageListener.call(t, e);
  };
}

/**
* @param {HTMLIFrameElement} frame
* @param {array} [allowedOrigins=[]] Array of origins from which incoming
*   messages will be allowed when same origin is not used; defaults to none.
*   If supplied, it should probably be the same as svgEditor's allowedOrigins
*/
export default class EmbeddedSVGEdit {
  constructor (frame, allowedOrigins) {
    this.allowedOrigins = allowedOrigins || [];
    // Initialize communication
    this.frame = frame;
    this.callbacks = {};
    // List of functions extracted with this:
    // Run in firebug on http://svg-edit.googlecode.com/svn/trunk/docs/files/svgcanvas-js.html

    // for (const i=0,q=[],f = document.querySelectorAll('div.CFunction h3.CTitle a'); i < f.length; i++) { q.push(f[i].name); }; q
    // const functions = ['clearSelection', 'addToSelection', 'removeFromSelection', 'open', 'save', 'getSvgString', 'setSvgString',
    // 'createLayer', 'deleteCurrentLayer', 'setCurrentLayer', 'renameCurrentLayer', 'setCurrentLayerPosition', 'setLayerVisibility',
    // 'moveSelectedToLayer', 'clear'];

    // Newer, well, it extracts things that aren't documented as well. All functions accessible through the normal thingy can now be accessed though the API
    // const {svgCanvas} = frame.contentWindow;
    // const l = [];
    // for (const i in svgCanvas) { if (typeof svgCanvas[i] === 'function') { l.push(i);} };
    // alert("['" + l.join("', '") + "']");
    // Run in svgedit itself
    const functions = [
      'clearSvgContentElement', 'setIdPrefix', 'getCurrentDrawing', 'addSvgElementFromJson', 'getTransformList', 'matrixMultiply', 'hasMatrixTransform', 'transformListToTransform', 'convertToNum', 'findDefs', 'getUrlFromAttr', 'getHref', 'setHref', 'getBBox', 'getRotationAngle', 'getElem', 'getRefElem', 'assignAttributes', 'cleanupElement', 'remapElement', 'recalculateDimensions', 'sanitizeSvg', 'runExtensions', 'addExtension', 'round', 'getIntersectionList', 'getStrokedBBox', 'getVisibleElements', 'getVisibleElementsAndBBoxes', 'groupSvgElem', 'getId', 'getNextId', 'call', 'bind', 'prepareSvg', 'setRotationAngle', 'recalculateAllSelectedDimensions', 'clearSelection', 'addToSelection', 'selectOnly', 'removeFromSelection', 'selectAllInCurrentLayer', 'getMouseTarget', 'removeUnusedDefElems', 'svgCanvasToString', 'svgToString', 'embedImage', 'setGoodImage', 'open', 'save', 'rasterExport', 'exportPDF', 'getSvgString', 'randomizeIds', 'uniquifyElems', 'setUseData', 'convertGradients', 'convertToGroup', 'setSvgString', 'importSvgString', 'identifyLayers', 'createLayer', 'cloneLayer', 'deleteCurrentLayer', 'setCurrentLayer', 'renameCurrentLayer', 'setCurrentLayerPosition', 'setLayerVisibility', 'moveSelectedToLayer', 'mergeLayer', 'mergeAllLayers', 'leaveContext', 'setContext', 'clear', 'linkControlPoints', 'getContentElem', 'getRootElem', 'getSelectedElems', 'getResolution', 'getZoom', 'getVersion', 'setUiStrings', 'setConfig', 'getTitle', 'setGroupTitle', 'getDocumentTitle', 'setDocumentTitle', 'getEditorNS', 'setResolution', 'getOffset', 'setBBoxZoom', 'setZoom', 'getMode', 'setMode', 'getColor', 'setColor', 'setGradient', 'setPaint', 'setStrokePaint', 'setFillPaint', 'getStrokeWidth', 'setStrokeWidth', 'setStrokeAttr', 'getStyle', 'getOpacity', 'setOpacity', 'getFillOpacity', 'getStrokeOpacity', 'setPaintOpacity', 'getPaintOpacity', 'getBlur', 'setBlurNoUndo', 'setBlurOffsets', 'setBlur', 'getBold', 'setBold', 'getItalic', 'setItalic', 'getFontFamily', 'setFontFamily', 'setFontColor', 'getFontColor', 'getFontSize', 'setFontSize', 'getText', 'setTextContent', 'setImageURL', 'setLinkURL', 'setRectRadius', 'makeHyperlink', 'removeHyperlink', 'setSegType', 'convertToPath', 'changeSelectedAttribute', 'deleteSelectedElements', 'cutSelectedElements', 'copySelectedElements', 'pasteElements', 'groupSelectedElements', 'pushGroupProperties', 'ungroupSelectedElement', 'moveToTopSelectedElement', 'moveToBottomSelectedElement', 'moveUpDownSelected', 'moveSelectedElements', 'cloneSelectedElements', 'alignSelectedElements', 'updateCanvas', 'setBackground', 'cycleElement', 'getPrivateMethods', 'zoomChanged', 'ready', 'getUIStrings'
    ];

    // TODO: rewrite the following, it's pretty scary.
    for (let i = 0; i < functions.length; i++) {
      this[functions[i]] = getCallbackSetter(functions[i]);
    }

    // Older IE may need a polyfill for addEventListener, but so it would for SVG
    window.addEventListener('message', getMessageListener(this), false);
  }

  send (name, args, callback) {
    const t = this;
    cbid++;

    this.callbacks[cbid] = callback;
    setTimeout((function (cbid) {
      return function () { // Delay for the callback to be set in case its synchronous
        /*
        * Todo: Handle non-JSON arguments and return values (undefined,
        *   nonfinite numbers, functions, and built-in objects like Date,
        *   RegExp), etc.? Allow promises instead of callbacks? Review
        *   SVG-Edit functions for whether JSON-able parameters can be
        *   made compatile with all API functionality
        */
        // We accept and post strings for the sake of IE9 support
        if (window.location.origin === t.frame.contentWindow.location.origin) {
          // Although we do not really need this API if we are working same
          //  domain, it could allow us to write in a way that would work
          //  cross-domain as well, assuming we stick to the argument limitations
          //  of the current JSON-based communication API (e.g., not passing
          //  callbacks). We might be able to address these shortcomings; see
          //  the todo elsewhere in this file.
          const message = {id: cbid},
            {svgCanvas} = t.frame.contentWindow;
          try {
            message.result = svgCanvas[name].apply(svgCanvas, args);
          } catch (err) {
            message.error = err.message;
          }
          addCallback(t, message);
        } else { // Requires the ext-xdomain-messaging.js extension
          t.frame.contentWindow.postMessage(JSON.stringify({namespace: 'svgCanvas', id: cbid, name, args}), '*');
        }
      };
    }(cbid)), 0);

    return cbid;
  }
}