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

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

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

const registry = goog.require('Blockly.registry');
const toolboxUtils = goog.require('Blockly.utils.toolbox');
/* eslint-disable-next-line no-unused-vars */
const {IFlyout} = goog.requireType('Blockly.IFlyout');
/* eslint-disable-next-line no-unused-vars */
const {IMetricsManager} = goog.require('Blockly.IMetricsManager');
/* eslint-disable-next-line no-unused-vars */
const {IToolbox} = goog.requireType('Blockly.IToolbox');
/* eslint-disable-next-line no-unused-vars */
const {Metrics} = goog.requireType('Blockly.utils.Metrics');
const {Size} = goog.require('Blockly.utils.Size');
/* eslint-disable-next-line no-unused-vars */
const {WorkspaceSvg} = goog.requireType('Blockly.WorkspaceSvg');


/**
 * The manager for all workspace metrics calculations.
 * @param {!WorkspaceSvg} workspace The workspace to calculate metrics
 *     for.
 * @implements {IMetricsManager}
 * @constructor
 * @alias Blockly.MetricsManager
 */
const MetricsManager = function(workspace) {
  /**
   * The workspace to calculate metrics for.
   * @type {!WorkspaceSvg}
   * @protected
   */
  this.workspace_ = workspace;
};

/**
 * Describes the width, height and location of the toolbox on the main
 * workspace.
 * @typedef {{
 *            width: number,
 *            height: number,
 *            position: !toolboxUtils.Position
 *          }}
 */
MetricsManager.ToolboxMetrics;
/**
 * Describes where the viewport starts in relation to the workspace SVG.
 * @typedef {{
 *            left: number,
 *            top: number
 *          }}
 */
MetricsManager.AbsoluteMetrics;
/**
 * All the measurements needed to describe the size and location of a container.
 * @typedef {{
 *            height: number,
 *            width: number,
 *            top: number,
 *            left: number
 *          }}
 */
MetricsManager.ContainerRegion;
/**
 * Describes fixed edges of the workspace.
 * @typedef {{
 *            top: (number|undefined),
 *            bottom: (number|undefined),
 *            left: (number|undefined),
 *            right: (number|undefined)
 *          }}
 */
MetricsManager.FixedEdges;
/**
 * Common metrics used for UI elements.
 * @typedef {{
 *            viewMetrics: !MetricsManager.ContainerRegion,
 *            absoluteMetrics: !MetricsManager.AbsoluteMetrics,
 *            toolboxMetrics: !MetricsManager.ToolboxMetrics
 *          }}
 */
MetricsManager.UiMetrics;
/**
 * Gets the dimensions of the given workspace component, in pixel coordinates.
 * @param {?IToolbox|?IFlyout} elem The element to get the
 *     dimensions of, or null.  It should be a toolbox or flyout, and should
 *     implement getWidth() and getHeight().
 * @return {!Size} An object containing width and height
 *     attributes, which will both be zero if elem did not exist.
 * @protected
 */
MetricsManager.prototype.getDimensionsPx_ = function(elem) {
  let width = 0;
  let height = 0;
  if (elem) {
    width = elem.getWidth();
    height = elem.getHeight();
  }
  return new Size(width, height);
};

/**
 * Gets the width and the height of the flyout on the workspace in pixel
 * coordinates. Returns 0 for the width and height if the workspace has a
 * category toolbox instead of a simple toolbox.
 * @param {boolean=} opt_own Whether to only return the workspace's own flyout.
 * @return {!MetricsManager.ToolboxMetrics} The width and height of the
 *     flyout.
 * @public
 */
MetricsManager.prototype.getFlyoutMetrics = function(opt_own) {
  const flyoutDimensions =
      this.getDimensionsPx_(this.workspace_.getFlyout(opt_own));
  return {
    width: flyoutDimensions.width,
    height: flyoutDimensions.height,
    position: this.workspace_.toolboxPosition,
  };
};

/**
 * Gets the width, height and position of the toolbox on the workspace in pixel
 * coordinates. Returns 0 for the width and height if the workspace has a simple
 * toolbox instead of a category toolbox. To get the width and height of a
 * simple toolbox @see {@link getFlyoutMetrics}.
 * @return {!MetricsManager.ToolboxMetrics} The object with the width,
 *     height and position of the toolbox.
 * @public
 */
MetricsManager.prototype.getToolboxMetrics = function() {
  const toolboxDimensions = this.getDimensionsPx_(this.workspace_.getToolbox());

  return {
    width: toolboxDimensions.width,
    height: toolboxDimensions.height,
    position: this.workspace_.toolboxPosition,
  };
};

/**
 * Gets the width and height of the workspace's parent SVG element in pixel
 * coordinates. This area includes the toolbox and the visible workspace area.
 * @return {!Size} The width and height of the workspace's parent
 *     SVG element.
 * @public
 */
MetricsManager.prototype.getSvgMetrics = function() {
  return this.workspace_.getCachedParentSvgSize();
};

/**
 * Gets the absolute left and absolute top in pixel coordinates.
 * This is where the visible workspace starts in relation to the SVG container.
 * @return {!MetricsManager.AbsoluteMetrics} The absolute metrics for
 *     the workspace.
 * @public
 */
MetricsManager.prototype.getAbsoluteMetrics = function() {
  let absoluteLeft = 0;
  const toolboxMetrics = this.getToolboxMetrics();
  const flyoutMetrics = this.getFlyoutMetrics(true);
  const doesToolboxExist = !!this.workspace_.getToolbox();
  const doesFlyoutExist = !!this.workspace_.getFlyout(true);
  const toolboxPosition =
      doesToolboxExist ? toolboxMetrics.position : flyoutMetrics.position;

  const atLeft = toolboxPosition === toolboxUtils.Position.LEFT;
  const atTop = toolboxPosition === toolboxUtils.Position.TOP;
  if (doesToolboxExist && atLeft) {
    absoluteLeft = toolboxMetrics.width;
  } else if (doesFlyoutExist && atLeft) {
    absoluteLeft = flyoutMetrics.width;
  }
  let absoluteTop = 0;
  if (doesToolboxExist && atTop) {
    absoluteTop = toolboxMetrics.height;
  } else if (doesFlyoutExist && atTop) {
    absoluteTop = flyoutMetrics.height;
  }

  return {
    top: absoluteTop,
    left: absoluteLeft,
  };
};

/**
 * Gets the metrics for the visible workspace in either pixel or workspace
 * coordinates. The visible workspace does not include the toolbox or flyout.
 * @param {boolean=} opt_getWorkspaceCoordinates True to get the view metrics in
 *     workspace coordinates, false to get them in pixel coordinates.
 * @return {!MetricsManager.ContainerRegion} The width, height, top and
 *     left of the viewport in either workspace coordinates or pixel
 *     coordinates.
 * @public
 */
MetricsManager.prototype.getViewMetrics = function(
    opt_getWorkspaceCoordinates) {
  const scale = opt_getWorkspaceCoordinates ? this.workspace_.scale : 1;
  const svgMetrics = this.getSvgMetrics();
  const toolboxMetrics = this.getToolboxMetrics();
  const flyoutMetrics = this.getFlyoutMetrics(true);
  const doesToolboxExist = !!this.workspace_.getToolbox();
  const toolboxPosition =
      doesToolboxExist ? toolboxMetrics.position : flyoutMetrics.position;

  if (this.workspace_.getToolbox()) {
    if (toolboxPosition === toolboxUtils.Position.TOP ||
        toolboxPosition === toolboxUtils.Position.BOTTOM) {
      svgMetrics.height -= toolboxMetrics.height;
    } else if (
        toolboxPosition === toolboxUtils.Position.LEFT ||
        toolboxPosition === toolboxUtils.Position.RIGHT) {
      svgMetrics.width -= toolboxMetrics.width;
    }
  } else if (this.workspace_.getFlyout(true)) {
    if (toolboxPosition === toolboxUtils.Position.TOP ||
        toolboxPosition === toolboxUtils.Position.BOTTOM) {
      svgMetrics.height -= flyoutMetrics.height;
    } else if (
        toolboxPosition === toolboxUtils.Position.LEFT ||
        toolboxPosition === toolboxUtils.Position.RIGHT) {
      svgMetrics.width -= flyoutMetrics.width;
    }
  }
  return {
    height: svgMetrics.height / scale,
    width: svgMetrics.width / scale,
    top: -this.workspace_.scrollY / scale,
    left: -this.workspace_.scrollX / scale,
  };
};

/**
 * Gets content metrics in either pixel or workspace coordinates.
 * The content area is a rectangle around all the top bounded elements on the
 * workspace (workspace comments and blocks).
 * @param {boolean=} opt_getWorkspaceCoordinates True to get the content metrics
 *     in workspace coordinates, false to get them in pixel coordinates.
 * @return {!MetricsManager.ContainerRegion} The
 *     metrics for the content container.
 * @public
 */
MetricsManager.prototype.getContentMetrics = function(
    opt_getWorkspaceCoordinates) {
  const scale = opt_getWorkspaceCoordinates ? 1 : this.workspace_.scale;

  // Block bounding box is in workspace coordinates.
  const blockBox = this.workspace_.getBlocksBoundingBox();

  return {
    height: (blockBox.bottom - blockBox.top) * scale,
    width: (blockBox.right - blockBox.left) * scale,
    top: blockBox.top * scale,
    left: blockBox.left * scale,
  };
};

/**
 * Returns whether the scroll area has fixed edges.
 * @return {boolean} Whether the scroll area has fixed edges.
 * @package
 */
MetricsManager.prototype.hasFixedEdges = function() {
  // This exists for optimization of bump logic.
  return !this.workspace_.isMovableHorizontally() ||
      !this.workspace_.isMovableVertically();
};

/**
 * Computes the fixed edges of the scroll area.
 * @param {!MetricsManager.ContainerRegion=} opt_viewMetrics The view
 *     metrics if they have been previously computed. Passing in null may cause
 *     the view metrics to be computed again, if it is needed.
 * @return {!MetricsManager.FixedEdges} The fixed edges of the scroll
 *     area.
 * @protected
 */
MetricsManager.prototype.getComputedFixedEdges_ = function(opt_viewMetrics) {
  if (!this.hasFixedEdges()) {
    // Return early if there are no edges.
    return {};
  }

  const hScrollEnabled = this.workspace_.isMovableHorizontally();
  const vScrollEnabled = this.workspace_.isMovableVertically();

  const viewMetrics = opt_viewMetrics || this.getViewMetrics(false);

  const edges = {};
  if (!vScrollEnabled) {
    edges.top = viewMetrics.top;
    edges.bottom = viewMetrics.top + viewMetrics.height;
  }
  if (!hScrollEnabled) {
    edges.left = viewMetrics.left;
    edges.right = viewMetrics.left + viewMetrics.width;
  }
  return edges;
};

/**
 * Returns the content area with added padding.
 * @param {!MetricsManager.ContainerRegion} viewMetrics The view
 *     metrics.
 * @param {!MetricsManager.ContainerRegion} contentMetrics The content
 *     metrics.
 * @return {{top: number, bottom: number, left: number, right: number}} The
 *     padded content area.
 * @protected
 */
MetricsManager.prototype.getPaddedContent_ = function(
    viewMetrics, contentMetrics) {
  const contentBottom = contentMetrics.top + contentMetrics.height;
  const contentRight = contentMetrics.left + contentMetrics.width;

  const viewWidth = viewMetrics.width;
  const viewHeight = viewMetrics.height;
  const halfWidth = viewWidth / 2;
  const halfHeight = viewHeight / 2;

  // Add a padding around the content that is at least half a screen wide.
  // Ensure padding is wide enough that blocks can scroll over entire screen.
  const top =
      Math.min(contentMetrics.top - halfHeight, contentBottom - viewHeight);
  const left =
      Math.min(contentMetrics.left - halfWidth, contentRight - viewWidth);
  const bottom =
      Math.max(contentBottom + halfHeight, contentMetrics.top + viewHeight);
  const right =
      Math.max(contentRight + halfWidth, contentMetrics.left + viewWidth);

  return {top: top, bottom: bottom, left: left, right: right};
};

/**
 * Returns the metrics for the scroll area of the workspace.
 * @param {boolean=} opt_getWorkspaceCoordinates True to get the scroll metrics
 *     in workspace coordinates, false to get them in pixel coordinates.
 * @param {!MetricsManager.ContainerRegion=} opt_viewMetrics The view
 *     metrics if they have been previously computed. Passing in null may cause
 *     the view metrics to be computed again, if it is needed.
 * @param {!MetricsManager.ContainerRegion=} opt_contentMetrics The
 *     content metrics if they have been previously computed. Passing in null
 *     may cause the content metrics to be computed again, if it is needed.
 * @return {!MetricsManager.ContainerRegion} The metrics for the scroll
 *    container.
 */
MetricsManager.prototype.getScrollMetrics = function(
    opt_getWorkspaceCoordinates, opt_viewMetrics, opt_contentMetrics) {
  const scale = opt_getWorkspaceCoordinates ? this.workspace_.scale : 1;
  const viewMetrics = opt_viewMetrics || this.getViewMetrics(false);
  const contentMetrics = opt_contentMetrics || this.getContentMetrics();
  const fixedEdges = this.getComputedFixedEdges_(viewMetrics);

  // Add padding around content.
  const paddedContent = this.getPaddedContent_(viewMetrics, contentMetrics);

  // Use combination of fixed bounds and padded content to make scroll area.
  const top = fixedEdges.top !== undefined ? fixedEdges.top : paddedContent.top;
  const left =
      fixedEdges.left !== undefined ? fixedEdges.left : paddedContent.left;
  const bottom = fixedEdges.bottom !== undefined ? fixedEdges.bottom :
                                                   paddedContent.bottom;
  const right =
      fixedEdges.right !== undefined ? fixedEdges.right : paddedContent.right;

  return {
    top: top / scale,
    left: left / scale,
    width: (right - left) / scale,
    height: (bottom - top) / scale,
  };
};

/**
 * Returns common metrics used by UI elements.
 * @return {!MetricsManager.UiMetrics} The UI metrics.
 */
MetricsManager.prototype.getUiMetrics = function() {
  return {
    viewMetrics: this.getViewMetrics(),
    absoluteMetrics: this.getAbsoluteMetrics(),
    toolboxMetrics: this.getToolboxMetrics(),
  };
};

/**
 * Returns an object with all the metrics required to size scrollbars for a
 * top level workspace.  The following properties are computed:
 * Coordinate system: pixel coordinates, -left, -up, +right, +down
 * .viewHeight: Height of the visible portion of the workspace.
 * .viewWidth: Width of the visible portion of the workspace.
 * .contentHeight: Height of the content.
 * .contentWidth: Width of the content.
 * .scrollHeight: Height of the scroll area.
 * .scrollWidth: Width of the scroll area.
 * .svgHeight: Height of the Blockly div (the view + the toolbox,
 *    simple or otherwise),
 * .svgWidth: Width of the Blockly div (the view + the toolbox,
 *    simple or otherwise),
 * .viewTop: Top-edge of the visible portion of the workspace, relative to
 *     the workspace origin.
 * .viewLeft: Left-edge of the visible portion of the workspace, relative to
 *     the workspace origin.
 * .contentTop: Top-edge of the content, relative to the workspace origin.
 * .contentLeft: Left-edge of the content relative to the workspace origin.
 * .scrollTop: Top-edge of the scroll area, relative to the workspace origin.
 * .scrollLeft: Left-edge of the scroll area relative to the workspace origin.
 * .absoluteTop: Top-edge of the visible portion of the workspace, relative
 *     to the blocklyDiv.
 * .absoluteLeft: Left-edge of the visible portion of the workspace, relative
 *     to the blocklyDiv.
 * .toolboxWidth: Width of the toolbox, if it exists.  Otherwise zero.
 * .toolboxHeight: Height of the toolbox, if it exists.  Otherwise zero.
 * .flyoutWidth: Width of the flyout if it is always open.  Otherwise zero.
 * .flyoutHeight: Height of the flyout if it is always open.  Otherwise zero.
 * .toolboxPosition: Top, bottom, left or right. Use TOOLBOX_AT constants to
 *     compare.
 * @return {!Metrics} Contains size and position metrics of a top
 *     level workspace.
 * @public
 */
MetricsManager.prototype.getMetrics = function() {
  const toolboxMetrics = this.getToolboxMetrics();
  const flyoutMetrics = this.getFlyoutMetrics(true);
  const svgMetrics = this.getSvgMetrics();
  const absoluteMetrics = this.getAbsoluteMetrics();
  const viewMetrics = this.getViewMetrics();
  const contentMetrics = this.getContentMetrics();
  const scrollMetrics =
      this.getScrollMetrics(false, viewMetrics, contentMetrics);

  return {
    contentHeight: contentMetrics.height,
    contentWidth: contentMetrics.width,
    contentTop: contentMetrics.top,
    contentLeft: contentMetrics.left,

    scrollHeight: scrollMetrics.height,
    scrollWidth: scrollMetrics.width,
    scrollTop: scrollMetrics.top,
    scrollLeft: scrollMetrics.left,

    viewHeight: viewMetrics.height,
    viewWidth: viewMetrics.width,
    viewTop: viewMetrics.top,
    viewLeft: viewMetrics.left,

    absoluteTop: absoluteMetrics.top,
    absoluteLeft: absoluteMetrics.left,

    svgHeight: svgMetrics.height,
    svgWidth: svgMetrics.width,

    toolboxWidth: toolboxMetrics.width,
    toolboxHeight: toolboxMetrics.height,
    toolboxPosition: toolboxMetrics.position,

    flyoutWidth: flyoutMetrics.width,
    flyoutHeight: flyoutMetrics.height,
  };
};

registry.register(
    registry.Type.METRICS_MANAGER, registry.DEFAULT, MetricsManager);

exports.MetricsManager = MetricsManager;