/**
 * @license
 * Copyright 2021 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Calculates and reports flyout workspace metrics.
 */
'use strict';

/**
 * Calculates and reports flyout workspace metrics.
 * @class
 */
goog.module('Blockly.FlyoutMetricsManager');

/* eslint-disable-next-line no-unused-vars */
const {IFlyout} = goog.requireType('Blockly.IFlyout');
const {MetricsManager} = goog.require('Blockly.MetricsManager');
/* eslint-disable-next-line no-unused-vars */
const {WorkspaceSvg} = goog.requireType('Blockly.WorkspaceSvg');


/**
 * Calculates metrics for a flyout's workspace.
 * The metrics are mainly used to size scrollbars for the flyout.
 * @extends {MetricsManager}
 * @alias Blockly.FlyoutMetricsManager
 */
class FlyoutMetricsManager extends MetricsManager {
  /**
   * @param {!WorkspaceSvg} workspace The flyout's workspace.
   * @param {!IFlyout} flyout The flyout.
   */
  constructor(workspace, flyout) {
    super(workspace);

    /**
     * The flyout that owns the workspace to calculate metrics for.
     * @type {!IFlyout}
     * @protected
     */
    this.flyout_ = flyout;
  }

  /**
   * Gets the bounding box of the blocks on the flyout's workspace.
   * This is in workspace coordinates.
   * @return {!SVGRect|{height: number, y: number, width: number, x: number}}
   *     The bounding box of the blocks on the workspace.
   * @private
   */
  getBoundingBox_() {
    let blockBoundingBox;
    try {
      blockBoundingBox = this.workspace_.getCanvas().getBBox();
    } catch (e) {
      // Firefox has trouble with hidden elements (Bug 528969).
      // 2021 Update: It looks like this was fixed around Firefox 77 released in
      // 2020.
      blockBoundingBox = {height: 0, y: 0, width: 0, x: 0};
    }
    return blockBoundingBox;
  }

  /**
   * @override
   */
  getContentMetrics(opt_getWorkspaceCoordinates) {
    // The bounding box is in workspace coordinates.
    const blockBoundingBox = this.getBoundingBox_();
    const scale = opt_getWorkspaceCoordinates ? 1 : this.workspace_.scale;

    return {
      height: blockBoundingBox.height * scale,
      width: blockBoundingBox.width * scale,
      top: blockBoundingBox.y * scale,
      left: blockBoundingBox.x * scale,
    };
  }

  /**
   * @override
   */
  getScrollMetrics(
      opt_getWorkspaceCoordinates, opt_viewMetrics, opt_contentMetrics) {
    const contentMetrics = opt_contentMetrics || this.getContentMetrics();
    const margin = this.flyout_.MARGIN * this.workspace_.scale;
    const scale = opt_getWorkspaceCoordinates ? this.workspace_.scale : 1;

    // The left padding isn't just the margin. Some blocks are also offset by
    // tabWidth so that value and statement blocks line up.
    // The contentMetrics.left value is equivalent to the variable left padding.
    const leftPadding = contentMetrics.left;

    return {
      height: (contentMetrics.height + 2 * margin) / scale,
      width: (contentMetrics.width + leftPadding + margin) / scale,
      top: 0,
      left: 0,
    };
  }
}

exports.FlyoutMetricsManager = FlyoutMetricsManager;