/**
 * @license
 * Copyright 2019 Google LLC
 *
 * 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 Methods for graphically rendering a cursor as SVG.
 * @author samelh@microsoft.com (Sam El-Husseini)
 */
'use strict';


goog.provide('Blockly.blockRendering.CursorSvg');

goog.require('Blockly.ASTNode');


/**
 * Class for a cursor.
 * @param {!Blockly.WorkspaceSvg} workspace The workspace the cursor belongs to.
 * @param {!Blockly.blockRendering.ConstantProvider} constants The constants for
 *     the renderer.
  * @param {boolean=} opt_marker True if the cursor is a marker. A marker is used
 *     to save a location and is an immovable cursor. False or undefined if the
 *     cursor is not a marker.
 * @constructor
 */
Blockly.blockRendering.CursorSvg = function(workspace, constants, opt_marker) {
  /**
   * The workspace the cursor belongs to.
   * @type {!Blockly.WorkspaceSvg}
   * @private
   */
  this.workspace_ = workspace;

  /**
   * True if the cursor should be drawn as a marker, false otherwise.
   * A marker is drawn as a solid blue line, while the cursor is drawns as a
   * flashing red one.
   * @type {boolean}
   * @private
   */
  this.isMarker_ = !!opt_marker;

  /**
   * The workspace, field, or block that the cursor SVG element should be
   * attached to.
   * @type {Blockly.WorkspaceSvg|Blockly.Field|Blockly.BlockSvg}
   * @private
   */
  this.parent_ = null;

  /**
   * The constants necessary to draw the cursor.
   * @type {Blockly.blockRendering.ConstantProvider}
   * @protected
   */
  this.constants_ = constants;

  /**
   * The current SVG element for the cursor.
   * @type {Element}
   */
  this.currentCursorSvg = null;
};

/**
 * The name of the CSS class for a cursor.
 * @const {string}
 */
Blockly.blockRendering.CursorSvg.CURSOR_CLASS = 'blocklyCursor';

/**
 * The name of the CSS class for a marker.
 * @const {string}
 */
Blockly.blockRendering.CursorSvg.MARKER_CLASS = 'blocklyMarker';

/**
 * What we multiply the height by to get the height of the cursor.
 * Only used for the block and block connections.
 * @type {number}
 * @const
 */
Blockly.blockRendering.CursorSvg.HEIGHT_MULTIPLIER = 3 / 4;

/**
 * Return the root node of the SVG or null if none exists.
 * @return {SVGElement} The root SVG node.
 */
Blockly.blockRendering.CursorSvg.prototype.getSvgRoot = function() {
  return this.svgGroup_;
};

/**
 * True if the cursor should be drawn as a marker, false otherwise.
 * A marker is drawn as a solid blue line, while the cursor is drawns as a
 * flashing red one.
 * @return {boolean} The root SVG node.
 */
Blockly.blockRendering.CursorSvg.prototype.isMarker = function() {
  return this.isMarker_;
};

/**
 * Create the DOM element for the cursor.
 * @return {!SVGElement} The cursor controls SVG group.
 * @package
 */
Blockly.blockRendering.CursorSvg.prototype.createDom = function() {
  var className = this.isMarker() ?
      Blockly.blockRendering.CursorSvg.MARKER_CLASS :
      Blockly.blockRendering.CursorSvg.CURSOR_CLASS;

  this.svgGroup_ =
      Blockly.utils.dom.createSvgElement('g', {
        'class': className
      }, null);

  this.createDomInternal_();
  return this.svgGroup_;
};

/**
 * Attaches the SVG root of the cursor to the SVG group of the parent.
 * @param {!Blockly.WorkspaceSvg|!Blockly.Field|!Blockly.BlockSvg} newParent
 *    The workspace, field, or block that the cursor SVG element should be
 *    attached to.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.setParent_ = function(newParent) {
  if (this.isMarker_) {
    if (this.parent_) {
      this.parent_.setMarkerSvg(null);
    }
    newParent.setMarkerSvg(this.getSvgRoot());
  } else {
    if (this.parent_) {
      this.parent_.setCursorSvg(null);
    }
    newParent.setCursorSvg(this.getSvgRoot());
  }
  this.parent_ = newParent;
};

/**************************
 * Display
 **************************/

/**
 * Show the cursor as a combination of the previous connection and block,
 * the output connection and block, or just the block.
 * @param {Blockly.BlockSvg} block The block the cursor is currently on.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithBlockPrevOutput_ = function(block) {
  if (!block) {
    return;
  }
  var width = block.width;
  var height = block.height;
  var cursorHeight = height * Blockly.blockRendering.CursorSvg.HEIGHT_MULTIPLIER;
  var cursorOffset = this.constants_.CURSOR_BLOCK_PADDING;

  if (block.previousConnection) {
    this.positionPrevious_(width, cursorOffset, cursorHeight);
  } else if (block.outputConnection) {
    this.positionOutput_(width, height);
  } else {
    this.positionBlock_(width, cursorOffset, cursorHeight);
  }

  this.setParent_(block);
  this.showCurrent_();
};

/**
 * Show the visual representation of a workspace coordinate.
 * This is a horizontal line.
 * @param {!Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithCoordinates_ = function(curNode) {
  var wsCoordinate = curNode.getWsCoordinate();
  var x = wsCoordinate.x;
  var y = wsCoordinate.y;

  if (this.workspace_.RTL) {
    x -= this.constants_.CURSOR_WS_WIDTH;
  }

  this.positionLine_(x, y, this.constants_.CURSOR_WS_WIDTH);
  this.setParent_(this.workspace_);
  this.showCurrent_();
};

/**
 * Show the visual representation of a field.
 * This is a box around the field.
 * @param {!Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithField_ = function(curNode) {
  var field = /** @type {Blockly.Field} */ (curNode.getLocation());
  var width = field.getSize().width;
  var height = field.getSize().height;

  this.positionRect_(0, 0, width, height);
  this.setParent_(field);
  this.showCurrent_();
};

/**
 * Show the visual representation of an input.
 * This is a puzzle piece.
 * @param {!Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithInput_ = function(curNode) {
  var connection = /** @type {Blockly.Connection} */
      (curNode.getLocation());
  var sourceBlock = /** @type {!Blockly.BlockSvg} */ (connection.getSourceBlock());

  this.positionInput_(connection);
  this.setParent_(sourceBlock);
  this.showCurrent_();
};


/**
 * Show the visual representation of a next connection.
 * This is a horizontal line.
 * @param {!Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithNext_ = function(curNode) {
  var connection = curNode.getLocation();
  var targetBlock = /** @type {Blockly.BlockSvg} */ (connection.getSourceBlock());
  var x = 0;
  var y = connection.getOffsetInBlock().y;
  var width = targetBlock.getHeightWidth().width;
  if (this.workspace_.RTL) {
    x = -width;
  }
  this.positionLine_(x, y, width);
  this.setParent_(targetBlock);
  this.showCurrent_();
};

/**
 * Show the visual representation of a stack.
 * This is a box with extra padding around the entire stack of blocks.
 * @param {!Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showWithStack_ = function(curNode) {
  var block = /** @type {Blockly.BlockSvg} */ (curNode.getLocation());

  // Gets the height and width of entire stack.
  var heightWidth = block.getHeightWidth();

  // Add padding so that being on a stack looks different than being on a block.
  var width = heightWidth.width + this.constants_.CURSOR_STACK_PADDING;
  var height = heightWidth.height + this.constants_.CURSOR_STACK_PADDING;

  // Shift the rectangle slightly to upper left so padding is equal on all sides.
  var xPadding = -this.constants_.CURSOR_STACK_PADDING / 2;
  var yPadding = -this.constants_.CURSOR_STACK_PADDING / 2;

  var x = xPadding;
  var y = yPadding;

  if (this.workspace_.RTL) {
    x = -(width + xPadding);
  }
  this.positionRect_(x, y, width, height);
  this.setParent_(block);
  this.showCurrent_();
};

/**
 * Show the current cursor.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showCurrent_ = function() {
  this.hide();
  this.currentCursorSvg.style.display = '';
};

/**************************
 * Position
 **************************/

/**
 * Position the cursor for a block.
 * Displays an outline of the top half of a rectangle around a block.
 * @param {number} width The width of the block.
 * @param {number} cursorOffset The extra padding for around the block.
 * @param {number} cursorHeight The height of the cursor.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.positionBlock_ = function(
    width, cursorOffset, cursorHeight) {
  var cursorPath = Blockly.utils.svgPaths.moveBy(-cursorOffset, cursorHeight) +
      Blockly.utils.svgPaths.lineOnAxis('V', -cursorOffset) +
      Blockly.utils.svgPaths.lineOnAxis('H', width + cursorOffset * 2) +
      Blockly.utils.svgPaths.lineOnAxis('V', cursorHeight);
  this.cursorBlock_.setAttribute('d', cursorPath);
  if (this.workspace_.RTL) {
    this.flipRtl_(this.cursorBlock_);
  }
  this.currentCursorSvg = this.cursorBlock_;
};

/**
 * Position the cursor for an input connection.
 * Displays a filled in puzzle piece.
 * @param {!Blockly.Connection} connection The connection to position cursor around.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.positionInput_ = function(connection) {
  var x = connection.getOffsetInBlock().x;
  var y = connection.getOffsetInBlock().y;

  var path = Blockly.utils.svgPaths.moveTo(0, 0) +
      this.constants_.PUZZLE_TAB.pathDown;

  this.cursorInput_.setAttribute('d', path);
  this.cursorInput_.setAttribute('transform',
      'translate(' + x + ',' + y + ')' + (this.workspace_.RTL ? ' scale(-1 1)' : ''));
  this.currentCursorSvg = this.cursorInput_;
};

/**
 * Move and show the cursor at the specified coordinate in workspace units.
 * Displays a horizontal line.
 * @param {number} x The new x, in workspace units.
 * @param {number} y The new y, in workspace units.
 * @param {number} width The new width, in workspace units.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.positionLine_ = function(x, y, width) {
  this.cursorSvgLine_.setAttribute('x', x);
  this.cursorSvgLine_.setAttribute('y', y);
  this.cursorSvgLine_.setAttribute('width', width);
  this.currentCursorSvg = this.cursorSvgLine_;
};

/**
 * Position the cursor for an output connection.
 * Displays a puzzle outline and the top and bottom path.
 * @param {number} width The width of the block.
 * @param {number} height The height of the block.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.positionOutput_ = function(width, height) {
  var cursorPath = Blockly.utils.svgPaths.moveBy(width, 0) +
    Blockly.utils.svgPaths.lineOnAxis('h', -(width - this.constants_.PUZZLE_TAB.width)) +
    Blockly.utils.svgPaths.lineOnAxis('v', this.constants_.TAB_OFFSET_FROM_TOP) +
    this.constants_.PUZZLE_TAB.pathDown +
    Blockly.utils.svgPaths.lineOnAxis('V', height) +
    Blockly.utils.svgPaths.lineOnAxis('H', width);
  this.cursorBlock_.setAttribute('d', cursorPath);
  if (this.workspace_.RTL) {
    this.flipRtl_(this.cursorBlock_);
  }
  this.currentCursorSvg = this.cursorBlock_;
};

/**
 * Position the cursor for a previous connection.
 * Displays a half rectangle with a notch in the top to represent the previous
 * connection.
 * @param {number} width The width of the block.
 * @param {number} cursorOffset The offset of the cursor from around the block.
 * @param {number} cursorHeight The height of the cursor.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.positionPrevious_ = function(
    width, cursorOffset, cursorHeight) {
  var cursorPath = Blockly.utils.svgPaths.moveBy(-cursorOffset, cursorHeight) +
      Blockly.utils.svgPaths.lineOnAxis('V', -cursorOffset) +
      Blockly.utils.svgPaths.lineOnAxis('H', this.constants_.NOTCH_OFFSET_LEFT) +
      this.constants_.NOTCH.pathLeft +
      Blockly.utils.svgPaths.lineOnAxis('H', width + cursorOffset * 2) +
      Blockly.utils.svgPaths.lineOnAxis('V', cursorHeight);
  this.cursorBlock_.setAttribute('d', cursorPath);
  if (this.workspace_.RTL) {
    this.flipRtl_(this.cursorBlock_);
  }
  this.currentCursorSvg = this.cursorBlock_;
};

/**
 * Move and show the cursor at the specified coordinate in workspace units.
 * Displays a filled in rectangle.
 * @param {number} x The new x, in workspace units.
 * @param {number} y The new y, in workspace units.
 * @param {number} width The new width, in workspace units.
 * @param {number} height The new height, in workspace units.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.positionRect_ = function(x, y, width, height) {
  this.cursorSvgRect_.setAttribute('x', x);
  this.cursorSvgRect_.setAttribute('y', y);
  this.cursorSvgRect_.setAttribute('width', width);
  this.cursorSvgRect_.setAttribute('height', height);
  this.currentCursorSvg = this.cursorSvgRect_;
};

/**
 * Flip the SVG paths in RTL.
 * @param {!SVGElement} cursor The cursor that we want to flip.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.flipRtl_ = function(cursor) {
  cursor.setAttribute('transform', 'scale(-1 1)');
};

/**
 * Hide the cursor.
 * @package
 */
Blockly.blockRendering.CursorSvg.prototype.hide = function() {
  this.cursorSvgLine_.style.display = 'none';
  this.cursorSvgRect_.style.display = 'none';
  this.cursorInput_.style.display = 'none';
  this.cursorBlock_.style.display = 'none';
};

/**
 * Update the cursor.
 * @param {Blockly.ASTNode} oldNode The previous node the cursor was on or null.
 * @param {Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @package
 */
Blockly.blockRendering.CursorSvg.prototype.draw = function(oldNode, curNode) {
  if (!curNode) {
    this.hide();
    return;
  }

  this.showAtLocation_(curNode);

  this.fireCursorEvent_(oldNode, curNode);

  // Ensures the cursor will be visible immediately after the move.
  var animate = this.currentCursorSvg.childNodes[0];
  if (animate !== undefined) {
    animate.beginElement && animate.beginElement();
  }
};


/**
 * Update the cursor's visible state based on the type of curNode..
 * @param {Blockly.ASTNode} curNode The node that we want to draw the cursor for.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.showAtLocation_ = function(curNode) {
  if (curNode.getType() == Blockly.ASTNode.types.BLOCK) {
    var block = /** @type {Blockly.BlockSvg} */ (curNode.getLocation());
    this.showWithBlockPrevOutput_(block);
  } else if (curNode.getType() == Blockly.ASTNode.types.OUTPUT) {
    var outputBlock = /** @type {Blockly.BlockSvg} */ (curNode.getLocation().getSourceBlock());
    this.showWithBlockPrevOutput_(outputBlock);
  } else if (curNode.getLocation().type == Blockly.INPUT_VALUE) {
    this.showWithInput_(curNode);
  } else if (curNode.getLocation().type == Blockly.NEXT_STATEMENT) {
    this.showWithNext_(curNode);
  } else if (curNode.getType() == Blockly.ASTNode.types.PREVIOUS) {
    var previousBlock = /** @type {Blockly.BlockSvg} */ (curNode.getLocation().getSourceBlock());
    this.showWithBlockPrevOutput_(previousBlock);
  } else if (curNode.getType() == Blockly.ASTNode.types.FIELD) {
    this.showWithField_(curNode);
  } else if (curNode.getType() == Blockly.ASTNode.types.WORKSPACE) {
    this.showWithCoordinates_(curNode);
  } else if (curNode.getType() == Blockly.ASTNode.types.STACK) {
    this.showWithStack_(curNode);
  }
};

/**
 * Fire event for the cursor or marker.
 * @param {Blockly.ASTNode} oldNode The old node the cursor used to be on.
 * @param {!Blockly.ASTNode} curNode The new node the cursor is currently on.
 * @private
 */
Blockly.blockRendering.CursorSvg.prototype.fireCursorEvent_ = function(oldNode, curNode) {
  var curBlock = curNode.getSourceBlock();
  var eventType = this.isMarker_ ? 'markedNode' : 'cursorMove';
  var event = new Blockly.Events.Ui(curBlock, eventType, oldNode, curNode);
  if (curNode.getType() == Blockly.ASTNode.types.WORKSPACE) {
    event.workspaceId = curNode.getLocation().id;
  }
  Blockly.Events.fire(event);
};

/**
 * Get the properties to make a cursor blink.
 * @return {!Object} The object holding attributes to make the cursor blink.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.getBlinkProperties_ = function() {
  return {
    'attributeType': 'XML',
    'attributeName': 'fill',
    'dur': '1s',
    'values': this.constants_.CURSOR_COLOUR + ';transparent;transparent;',
    'repeatCount': 'indefinite'
  };
};


/**
 * Create the cursor SVG.
 * @return {Element} The SVG node created.
 * @protected
 */
Blockly.blockRendering.CursorSvg.prototype.createDomInternal_ = function() {
  /* This markup will be generated and added to the .svgGroup_:
  <g>
    <rect width="100" height="5">
      <animate attributeType="XML" attributeName="fill" dur="1s"
        values="transparent;transparent;#fff;transparent" repeatCount="indefinite" />
    </rect>
  </g>
  */

  var colour = this.isMarker_ ? this.constants_.MARKER_COLOUR :
      this.constants_.CURSOR_COLOUR;
  this.cursorSvg_ = Blockly.utils.dom.createSvgElement('g',
      {
        'width': this.constants_.CURSOR_WS_WIDTH,
        'height': this.constants_.WS_CURSOR_HEIGHT
      }, this.svgGroup_);

  // A horizontal line used to represent a workspace coordinate or next connection.
  this.cursorSvgLine_ = Blockly.utils.dom.createSvgElement('rect',
      {
        'fill': colour,
        'width': this.constants_.CURSOR_WS_WIDTH,
        'height': this.constants_.WS_CURSOR_HEIGHT,
        'style': 'display: none'
      },
      this.cursorSvg_);

  // A filled in rectangle used to represent a stack.
  this.cursorSvgRect_ = Blockly.utils.dom.createSvgElement('rect',
      {
        'class': 'blocklyVerticalCursor',
        'rx': 10, 'ry': 10,
        'style': 'display: none',
        'stroke': colour
      },
      this.cursorSvg_);

  // A filled in puzzle piece used to represent an input value.
  this.cursorInput_ = Blockly.utils.dom.createSvgElement('path',
      {
        'transform': '',
        'style': 'display: none',
        'fill': colour
      },
      this.cursorSvg_);

  // A path used to represent a previous connection and a block, an output
  // connection and a block, or a block.
  this.cursorBlock_ = Blockly.utils.dom.createSvgElement('path',
      {
        'transform': '',
        'style': 'display: none',
        'fill': 'none',
        'stroke': colour,
        'stroke-width': this.constants_.CURSOR_STROKE_WIDTH
      },
      this.cursorSvg_);

  // Markers and stack cursors don't blink.
  if (!this.isMarker_) {
    var blinkProperties = this.getBlinkProperties_();
    Blockly.utils.dom.createSvgElement('animate', this.getBlinkProperties_(),
        this.cursorSvgLine_);
    Blockly.utils.dom.createSvgElement('animate', blinkProperties,
        this.cursorInput_);
    blinkProperties['attributeName'] = 'stroke';
    Blockly.utils.dom.createSvgElement('animate', blinkProperties,
        this.cursorBlock_);
  }

  return this.cursorSvg_;
};

/**
 * Dispose of this cursor.
 * @package
 */
Blockly.blockRendering.CursorSvg.prototype.dispose = function() {
  if (this.svgGroup_) {
    Blockly.utils.dom.removeNode(this.svgGroup_);
  }
};