/**
 * @license
 * Visual Blocks Editor
 *
 * Copyright 2011 Google Inc.
 * https://developers.google.com/blockly/
 *
 * 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.
 */

/**
 * @fileoverview Functions for injecting Blockly into a web page.
 * @author fraser@google.com (Neil Fraser)
 */
'use strict';

goog.provide('Blockly.inject');

goog.require('Blockly.Css');
goog.require('Blockly.Options');
goog.require('Blockly.WorkspaceSvg');
goog.require('goog.dom');
goog.require('goog.ui.Component');
goog.require('goog.userAgent');


/**
 * Inject a Blockly editor into the specified container element (usually a div).
 * @param {!Element|string} container Containing element, or its ID,
 *     or a CSS selector.
 * @param {Object=} opt_options Optional dictionary of options.
 * @return {!Blockly.Workspace} Newly created main workspace.
 */
Blockly.inject = function(container, opt_options) {
  if (goog.isString(container)) {
    container = document.getElementById(container) ||
        document.querySelector(container);
  }
  // Verify that the container is in document.
  if (!goog.dom.contains(document, container)) {
    throw 'Error: container is not in current document.';
  }
  var options = new Blockly.Options(opt_options || {});
  var subContainer = goog.dom.createDom('div', 'injectionDiv');
  container.appendChild(subContainer);
  var svg = Blockly.createDom_(subContainer, options);
  var workspace = Blockly.createMainWorkspace_(svg, options);
  Blockly.init_(workspace);
  workspace.markFocused();
  Blockly.bindEventWithChecks_(svg, 'focus', workspace, workspace.markFocused);
  Blockly.svgResize(workspace);
  return workspace;
};

/**
 * Create the SVG image.
 * @param {!Element} container Containing element.
 * @param {!Blockly.Options} options Dictionary of options.
 * @return {!Element} Newly created SVG image.
 * @private
 */
Blockly.createDom_ = function(container, options) {
  // Sadly browsers (Chrome vs Firefox) are currently inconsistent in laying
  // out content in RTL mode.  Therefore Blockly forces the use of LTR,
  // then manually positions content in RTL as needed.
  container.setAttribute('dir', 'LTR');
  // Closure can be trusted to create HTML widgets with the proper direction.
  goog.ui.Component.setDefaultRightToLeft(options.RTL);

  // Load CSS.
  Blockly.Css.inject(options.hasCss, options.pathToMedia);

  // Build the SVG DOM.
  /*
  <svg
    xmlns="http://www.w3.org/2000/svg"
    xmlns:html="http://www.w3.org/1999/xhtml"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    version="1.1"
    class="blocklySvg">
    ...
  </svg>
  */
  var svg = Blockly.createSvgElement('svg', {
    'xmlns': 'http://www.w3.org/2000/svg',
    'xmlns:html': 'http://www.w3.org/1999/xhtml',
    'xmlns:xlink': 'http://www.w3.org/1999/xlink',
    'version': '1.1',
    'class': 'blocklySvg'
  }, container);
  /*
  <defs>
    ... filters go here ...
  </defs>
  */
  var defs = Blockly.createSvgElement('defs', {}, svg);
  // Each filter/pattern needs a unique ID for the case of multiple Blockly
  // instances on a page.  Browser behaviour becomes undefined otherwise.
  // https://neil.fraser.name/news/2015/11/01/
  var rnd = String(Math.random()).substring(2);
  /*
    <filter id="blocklyEmbossFilter837493">
      <feGaussianBlur in="SourceAlpha" stdDeviation="1" result="blur" />
      <feSpecularLighting in="blur" surfaceScale="1" specularConstant="0.5"
                          specularExponent="10" lighting-color="white"
                          result="specOut">
        <fePointLight x="-5000" y="-10000" z="20000" />
      </feSpecularLighting>
      <feComposite in="specOut" in2="SourceAlpha" operator="in"
                   result="specOut" />
      <feComposite in="SourceGraphic" in2="specOut" operator="arithmetic"
                   k1="0" k2="1" k3="1" k4="0" />
    </filter>
  */
  var embossFilter = Blockly.createSvgElement('filter',
      {'id': 'blocklyEmbossFilter' + rnd}, defs);
  Blockly.createSvgElement('feGaussianBlur',
      {'in': 'SourceAlpha', 'stdDeviation': 1, 'result': 'blur'}, embossFilter);
  var feSpecularLighting = Blockly.createSvgElement('feSpecularLighting',
      {'in': 'blur', 'surfaceScale': 1, 'specularConstant': 0.5,
       'specularExponent': 10, 'lighting-color': 'white', 'result': 'specOut'},
      embossFilter);
  Blockly.createSvgElement('fePointLight',
      {'x': -5000, 'y': -10000, 'z': 20000}, feSpecularLighting);
  Blockly.createSvgElement('feComposite',
      {'in': 'specOut', 'in2': 'SourceAlpha', 'operator': 'in',
       'result': 'specOut'}, embossFilter);
  Blockly.createSvgElement('feComposite',
      {'in': 'SourceGraphic', 'in2': 'specOut', 'operator': 'arithmetic',
       'k1': 0, 'k2': 1, 'k3': 1, 'k4': 0}, embossFilter);
  options.embossFilterId = embossFilter.id;
  /*
    <pattern id="blocklyDisabledPattern837493" patternUnits="userSpaceOnUse"
             width="10" height="10">
      <rect width="10" height="10" fill="#aaa" />
      <path d="M 0 0 L 10 10 M 10 0 L 0 10" stroke="#cc0" />
    </pattern>
  */
  var disabledPattern = Blockly.createSvgElement('pattern',
      {'id': 'blocklyDisabledPattern' + rnd,
       'patternUnits': 'userSpaceOnUse',
       'width': 10, 'height': 10}, defs);
  Blockly.createSvgElement('rect',
      {'width': 10, 'height': 10, 'fill': '#aaa'}, disabledPattern);
  Blockly.createSvgElement('path',
      {'d': 'M 0 0 L 10 10 M 10 0 L 0 10', 'stroke': '#cc0'}, disabledPattern);
  options.disabledPatternId = disabledPattern.id;
  /*
    <pattern id="blocklyGridPattern837493" patternUnits="userSpaceOnUse">
      <rect stroke="#888" />
      <rect stroke="#888" />
    </pattern>
  */
  var gridPattern = Blockly.createSvgElement('pattern',
      {'id': 'blocklyGridPattern' + rnd,
       'patternUnits': 'userSpaceOnUse'}, defs);
  if (options.gridOptions['length'] > 0 && options.gridOptions['spacing'] > 0) {
    Blockly.createSvgElement('line',
        {'stroke': options.gridOptions['colour']},
        gridPattern);
    if (options.gridOptions['length'] > 1) {
      Blockly.createSvgElement('line',
          {'stroke': options.gridOptions['colour']},
          gridPattern);
    }
    // x1, y1, x1, x2 properties will be set later in updateGridPattern_.
  }
  options.gridPattern = gridPattern;
  return svg;
};

/**
 * Create a main workspace and add it to the SVG.
 * @param {!Element} svg SVG element with pattern defined.
 * @param {!Blockly.Options} options Dictionary of options.
 * @return {!Blockly.Workspace} Newly created main workspace.
 * @private
 */
Blockly.createMainWorkspace_ = function(svg, options) {
  options.parentWorkspace = null;
  var mainWorkspace = new Blockly.WorkspaceSvg(options);
  mainWorkspace.scale = options.zoomOptions.startScale;
  svg.appendChild(mainWorkspace.createDom('blocklyMainBackground'));
  // A null translation will also apply the correct initial scale.
  mainWorkspace.translate(0, 0);
  mainWorkspace.markFocused();

  if (!options.readOnly && !options.hasScrollbars) {
    var workspaceChanged = function() {
      if (Blockly.dragMode_ == Blockly.DRAG_NONE) {
        var metrics = mainWorkspace.getMetrics();
        var edgeLeft = metrics.viewLeft + metrics.absoluteLeft;
        var edgeTop = metrics.viewTop + metrics.absoluteTop;
        if (metrics.contentTop < edgeTop ||
            metrics.contentTop + metrics.contentHeight >
            metrics.viewHeight + edgeTop ||
            metrics.contentLeft <
                (options.RTL ? metrics.viewLeft : edgeLeft) ||
            metrics.contentLeft + metrics.contentWidth > (options.RTL ?
                metrics.viewWidth : metrics.viewWidth + edgeLeft)) {
          // One or more blocks may be out of bounds.  Bump them back in.
          var MARGIN = 25;
          var blocks = mainWorkspace.getTopBlocks(false);
          for (var b = 0, block; block = blocks[b]; b++) {
            var blockXY = block.getRelativeToSurfaceXY();
            var blockHW = block.getHeightWidth();
            // Bump any block that's above the top back inside.
            var overflowTop = edgeTop + MARGIN - blockHW.height - blockXY.y;
            if (overflowTop > 0) {
              block.moveBy(0, overflowTop);
            }
            // Bump any block that's below the bottom back inside.
            var overflowBottom =
                edgeTop + metrics.viewHeight - MARGIN - blockXY.y;
            if (overflowBottom < 0) {
              block.moveBy(0, overflowBottom);
            }
            // Bump any block that's off the left back inside.
            var overflowLeft = MARGIN + edgeLeft -
                blockXY.x - (options.RTL ? 0 : blockHW.width);
            if (overflowLeft > 0) {
              block.moveBy(overflowLeft, 0);
            }
            // Bump any block that's off the right back inside.
            var overflowRight = edgeLeft + metrics.viewWidth - MARGIN -
                blockXY.x + (options.RTL ? blockHW.width : 0);
            if (overflowRight < 0) {
              block.moveBy(overflowRight, 0);
            }
          }
        }
      }
    };
    mainWorkspace.addChangeListener(workspaceChanged);
  }
  // The SVG is now fully assembled.
  Blockly.svgResize(mainWorkspace);
  Blockly.WidgetDiv.createDom();
  Blockly.Tooltip.createDom();
  return mainWorkspace;
};

/**
 * Initialize Blockly with various handlers.
 * @param {!Blockly.Workspace} mainWorkspace Newly created main workspace.
 * @private
 */
Blockly.init_ = function(mainWorkspace) {
  var options = mainWorkspace.options;
  var svg = mainWorkspace.getParentSvg();

  // Supress the browser's context menu.
  Blockly.bindEventWithChecks_(svg, 'contextmenu', null,
      function(e) {
        if (!Blockly.isTargetInput_(e)) {
          e.preventDefault();
        }
      });

  var workspaceResizeHandler = Blockly.bindEventWithChecks_(window, 'resize',
      null,
      function() {
        Blockly.hideChaff(true);
        Blockly.svgResize(mainWorkspace);
      });
  mainWorkspace.setResizeHandlerWrapper(workspaceResizeHandler);

  Blockly.inject.bindDocumentEvents_();

  if (options.languageTree) {
    if (mainWorkspace.toolbox_) {
      mainWorkspace.toolbox_.init(mainWorkspace);
    } else if (mainWorkspace.flyout_) {
      // Build a fixed flyout with the root blocks.
      mainWorkspace.flyout_.init(mainWorkspace);
      mainWorkspace.flyout_.show(options.languageTree.childNodes);
      mainWorkspace.flyout_.scrollToStart();
      // Translate the workspace sideways to avoid the fixed flyout.
      mainWorkspace.scrollX = mainWorkspace.flyout_.width_;
      if (options.toolboxPosition == Blockly.TOOLBOX_AT_RIGHT) {
        mainWorkspace.scrollX *= -1;
      }
      mainWorkspace.translate(mainWorkspace.scrollX, 0);
    }
  }

  if (options.hasScrollbars) {
    mainWorkspace.scrollbar = new Blockly.ScrollbarPair(mainWorkspace);
    mainWorkspace.scrollbar.resize();
  }

  // Load the sounds.
  if (options.hasSounds) {
    Blockly.inject.loadSounds_(options.pathToMedia, mainWorkspace);
  }
};

/**
 * Bind document events, but only once.  Destroying and reinjecting Blockly
 * should not bind again.
 * Bind events for scrolling the workspace.
 * Most of these events should be bound to the SVG's surface.
 * However, 'mouseup' has to be on the whole document so that a block dragged
 * out of bounds and released will know that it has been released.
 * Also, 'keydown' has to be on the whole document since the browser doesn't
 * understand a concept of focus on the SVG image.
 * @private
 */
Blockly.inject.bindDocumentEvents_ = function() {
  if (!Blockly.documentEventsBound_) {
    Blockly.bindEventWithChecks_(document, 'keydown', null, Blockly.onKeyDown_);
    Blockly.bindEventWithChecks_(document, 'touchend', null, Blockly.longStop_);
    Blockly.bindEventWithChecks_(document, 'touchcancel', null,
        Blockly.longStop_);
    // Don't use bindEvent_ for document's mouseup since that would create a
    // corresponding touch handler that would squeltch the ability to interact
    // with non-Blockly elements.
    document.addEventListener('mouseup', Blockly.onMouseUp_, false);
    // Some iPad versions don't fire resize after portrait to landscape change.
    if (goog.userAgent.IPAD) {
      Blockly.bindEventWithChecks_(window, 'orientationchange', document,
          function() {
            // TODO(#397): Fix for multiple blockly workspaces.
            Blockly.svgResize(Blockly.getMainWorkspace());
          });
    }
  }
  Blockly.documentEventsBound_ = true;
};

/**
 * Load sounds for the given workspace.
 * @param {string} pathToMedia The path to the media directory.
 * @param {!Blockly.Workspace} workspace The workspace to load sounds for.
 * @private
 */
Blockly.inject.loadSounds_ = function(pathToMedia, workspace) {
  workspace.loadAudio_(
      [pathToMedia + 'click.mp3',
       pathToMedia + 'click.wav',
       pathToMedia + 'click.ogg'], 'click');
  workspace.loadAudio_(
      [pathToMedia + 'disconnect.wav',
       pathToMedia + 'disconnect.mp3',
       pathToMedia + 'disconnect.ogg'], 'disconnect');
  workspace.loadAudio_(
      [pathToMedia + 'delete.mp3',
       pathToMedia + 'delete.ogg',
       pathToMedia + 'delete.wav'], 'delete');

  // Bind temporary hooks that preload the sounds.
  var soundBinds = [];
  var unbindSounds = function() {
    while (soundBinds.length) {
      Blockly.unbindEvent_(soundBinds.pop());
    }
    workspace.preloadAudio_();
  };

  // These are bound on mouse/touch events with Blockly.bindEventWithChecks_, so
  // they restrict the touch identifier that will be recognized.  But this is
  // really something that happens on a click, not a drag, so that's not
  // necessary.

  // Android ignores any sound not loaded as a result of a user action.
  soundBinds.push(
      Blockly.bindEventWithChecks_(document, 'mousemove', null, unbindSounds,
          true));
  soundBinds.push(
      Blockly.bindEventWithChecks_(document, 'touchstart', null, unbindSounds,
          true));
};

/**
 * Modify the block tree on the existing toolbox.
 * @param {Node|string} tree DOM tree of blocks, or text representation of same.
 */
Blockly.updateToolbox = function(tree) {
  console.warn('Deprecated call to Blockly.updateToolbox, ' +
               'use workspace.updateToolbox instead.');
  Blockly.getMainWorkspace().updateToolbox(tree);
};