/**
 * @license
 * Copyright 2018 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Class for comment move event.
 */
'use strict';

/**
 * Class for comment move event.
 * @class
 */
goog.module('Blockly.Events.CommentMove');

const CommentBase = goog.require('Blockly.Events.CommentBase');
const Coordinate = goog.require('Blockly.utils.Coordinate');
/* eslint-disable-next-line no-unused-vars */
const WorkspaceComment = goog.requireType('Blockly.WorkspaceComment');
const eventUtils = goog.require('Blockly.Events.utils');
const object = goog.require('Blockly.utils.object');
const registry = goog.require('Blockly.registry');


/**
 * Class for a comment move event.  Created before the move.
 * @param {!WorkspaceComment=} opt_comment The comment that is being
 *     moved.  Undefined for a blank event.
 * @extends {CommentBase}
 * @constructor
 * @alias Blockly.Events.CommentMove
 */
const CommentMove = function(opt_comment) {
  CommentMove.superClass_.constructor.call(this, opt_comment);
  if (!opt_comment) {
    return;  // Blank event to be populated by fromJson.
  }

  /**
   * The comment that is being moved.  Will be cleared after recording the new
   * location.
   * @type {WorkspaceComment}
   */
  this.comment_ = opt_comment;

  /**
   * The location before the move, in workspace coordinates.
   * @type {!Coordinate}
   */
  this.oldCoordinate_ = opt_comment.getXY();

  /**
   * The location after the move, in workspace coordinates.
   * @type {Coordinate}
   */
  this.newCoordinate_ = null;
};
object.inherits(CommentMove, CommentBase);

/**
 * Record the comment's new location.  Called after the move.  Can only be
 * called once.
 */
CommentMove.prototype.recordNew = function() {
  if (!this.comment_) {
    throw Error(
        'Tried to record the new position of a comment on the ' +
        'same event twice.');
  }
  this.newCoordinate_ = this.comment_.getXY();
  this.comment_ = null;
};

/**
 * Type of this event.
 * @type {string}
 */
CommentMove.prototype.type = eventUtils.COMMENT_MOVE;

/**
 * Override the location before the move.  Use this if you don't create the
 * event until the end of the move, but you know the original location.
 * @param {!Coordinate} xy The location before the move,
 *     in workspace coordinates.
 */
CommentMove.prototype.setOldCoordinate = function(xy) {
  this.oldCoordinate_ = xy;
};

/**
 * Encode the event as JSON.
 * @return {!Object} JSON representation.
 */
// TODO (#1266): "Full" and "minimal" serialization.
CommentMove.prototype.toJson = function() {
  const json = CommentMove.superClass_.toJson.call(this);
  if (this.oldCoordinate_) {
    json['oldCoordinate'] = Math.round(this.oldCoordinate_.x) + ',' +
        Math.round(this.oldCoordinate_.y);
  }
  if (this.newCoordinate_) {
    json['newCoordinate'] = Math.round(this.newCoordinate_.x) + ',' +
        Math.round(this.newCoordinate_.y);
  }
  return json;
};

/**
 * Decode the JSON event.
 * @param {!Object} json JSON representation.
 */
CommentMove.prototype.fromJson = function(json) {
  CommentMove.superClass_.fromJson.call(this, json);

  if (json['oldCoordinate']) {
    const xy = json['oldCoordinate'].split(',');
    this.oldCoordinate_ = new Coordinate(Number(xy[0]), Number(xy[1]));
  }
  if (json['newCoordinate']) {
    const xy = json['newCoordinate'].split(',');
    this.newCoordinate_ = new Coordinate(Number(xy[0]), Number(xy[1]));
  }
};

/**
 * Does this event record any change of state?
 * @return {boolean} False if something changed.
 */
CommentMove.prototype.isNull = function() {
  return Coordinate.equals(this.oldCoordinate_, this.newCoordinate_);
};

/**
 * Run a move event.
 * @param {boolean} forward True if run forward, false if run backward (undo).
 */
CommentMove.prototype.run = function(forward) {
  const workspace = this.getEventWorkspace_();
  const comment = workspace.getCommentById(this.commentId);
  if (!comment) {
    console.warn('Can\'t move non-existent comment: ' + this.commentId);
    return;
  }

  const target = forward ? this.newCoordinate_ : this.oldCoordinate_;
  // TODO: Check if the comment is being dragged, and give up if so.
  const current = comment.getXY();
  comment.moveBy(target.x - current.x, target.y - current.y);
};

registry.register(registry.Type.EVENT, eventUtils.COMMENT_MOVE, CommentMove);

exports = CommentMove;