/*
*  Copyright (C) 1998-2023 by Northwoods Software Corporation. All Rights Reserved.
*/

/*
* This is an extension and not part of the main GoJS library.
* Note that the API for this class may change with any version, even point releases.
* If you intend to use an extension in production, you should copy the code to your own source directory.
* Extensions can be found in the GoJS kit under the extensions or extensionsJSM folders.
* See the Extensions intro page (https://gojs.net/latest/intro/extensions.html) for more information.
*/

import * as go from '../release/go.js';

/**
 * This class implements an inspector for GoJS model data objects.
 * The constructor takes three arguments:
 *   - `divid` ***string*** a string referencing the HTML ID of the to-be inspector's div
 *   - `diagram` ***Diagram*** a reference to a GoJS Diagram
 *   - `options` ***Object*** an optional JS Object describing options for the inspector
 *
 * Options:
 *   - `inspectSelection` ***boolean*** see {@link #inspectSelection}
 *   - `includesOwnProperties` ***boolean*** see {@link #includesOwnProperties}
 *   - `properties` ***Object*** see {@link #properties}
 *   - `propertyModified` ***function(propertyName, newValue, inspector)*** see {@link #propertyModified}
 *   - `multipleSelection` ***boolean*** see {@link #multipleSelection}
 *   - `showUnionProperties` ***boolean*** see {@link #showUnionProperties}
 *   - `showLimit` ***number*** see {@link #showLimit}
 *
 * Options for properties:
 *   - `show` ***boolean | function*** a boolean value to show or hide the property from the inspector, or a predicate function to show conditionally.
 *   - `readOnly` ***boolean | function*** whether or not the property is read-only
 *   - `type` ***string*** a string describing the data type. Supported values: "string|number|boolean|color|arrayofnumber|point|rect|size|spot|margin|select|date|datetime-local|time"
 *   - `defaultValue` ***any*** a default value for the property. Defaults to the empty string.
 *   - `choices` ***Array | function*** when type === "select", the Array of choices to use or a function that returns the Array of choices.
 *
 * Example usage of Inspector:
 * ```js
 * var inspector = new Inspector("myInspector", myDiagram,
 *   {
 *     includesOwnProperties: false,
 *     properties: {
 *       "key": { show: Inspector.showIfPresent, readOnly: true },
 *       "comments": { show: Inspector.showIfNode  },
 *       "LinkComments": { show: Inspector.showIfLink },
 *       "chosen": { show: Inspector.showIfNode, type: "checkbox" },
 *       "state": { show: Inspector.showIfNode, type: "select", choices: ["Stopped", "Parked", "Moving"] }
 *     }
 *   });
 * ```
 *
 * This is the basic HTML Structure that the Inspector creates within the given DIV element:
 * ```html
 * <div id="divid" class="inspector">
 *   <tr>
 *     <td>propertyName</td>
 *     <td><input value=propertyValue /></td>
 *   </tr>
 *   ...
 * </div>
 * ```
 *
 * If you want to experiment with this extension, try the <a href="../../extensionsJSM/DataInspector.html">Data Inspector</a> sample.
 * @category Extension
 */
export class Inspector {
  private _div: HTMLDivElement;
  private _diagram: go.Diagram;
  private _inspectedObject: go.ObjectData | null = null;
  // Inspector options defaults:
  private _inspectSelection: boolean = true;
  private _includesOwnProperties: boolean = true;
  private _properties: { [index: string]: any } = {};
  private _propertyModified: ((a: string, b: string, c: Inspector) => void) | null = null;
  private _multipleSelection: boolean = false;
  private _showUnionProperties: boolean = false;
  private _showLimit: number = 0;

  // Private variables used to keep track of internal state
  private inspectedProperties: { [index: string]: any } = {};
  private multipleProperties: { [index: string]: any } = {};
  private tabIndex: number;
  // Functions used to keep the Inspector up-to-date
  private inspectOnModelChanged: ((e: go.ChangedEvent) => void);
  private inspectOnSelectionChanged: ((e: go.DiagramEvent) => void);

  /**
   * Constructs an Inspector and sets up properties based on the options provided.
   * Also sets up change listeners on the Diagram so the Inspector stays up-to-date.
   * @param {string} divid a string referencing the HTML ID of the to-be Inspector's div
   * @param {Diagram} diagram a reference to a GoJS Diagram
   * @param {Object=} options an optional JS Object describing options for the inspector
   */
  constructor(divid: string, diagram: go.Diagram, options?: { [index: string]: any }) {
    const mainDiv = document.getElementById(divid) as HTMLDivElement;
    mainDiv.className = 'inspector';
    mainDiv.innerHTML = '';
    this._div = mainDiv;
    this._diagram = diagram;
    this.tabIndex = 0;
    // Set properties based on options
    if (options !== undefined) {
      if (options.inspectSelection !== undefined) this._inspectSelection = options.inspectSelection;
      if (options.includesOwnProperties !== undefined) this._includesOwnProperties = options.includesOwnProperties;
      if (options.properties !== undefined) this._properties = options.properties;
      if (options.propertyModified !== undefined) this._propertyModified = options.propertyModified;
      if (options.multipleSelection !== undefined) this._multipleSelection = options.multipleSelection;
      if (options.showUnionProperties !== undefined) this._showUnionProperties = options.showUnionProperties;
      if (options.showLimit !== undefined) this._showLimit = options.showLimit;
    }
    // Prepare change listeners
    const self = this;
    this.inspectOnModelChanged = (e: go.ChangedEvent) => {
      if (e.isTransactionFinished) self.inspectObject();
    };
    this.inspectOnSelectionChanged = (e: go.DiagramEvent) => { self.inspectObject(); };
    this._diagram.addModelChangedListener(this.inspectOnModelChanged);
    if (this._inspectSelection) {
      this._diagram.addDiagramListener('ChangedSelection', this.inspectOnSelectionChanged);
    }
  }

  /**
   * This read-only property returns the HTMLElement containing the Inspector.
   */
  get div(): HTMLDivElement { return this._div; }

  /**
   * Gets or sets the {@link Diagram} associated with this Inspector.
   */
  get diagram(): go.Diagram { return this._diagram; }
  set diagram(val: go.Diagram) {
    if (val !== this._diagram) {
      // First, unassociate change listeners with current inspected diagram
      this._diagram.removeModelChangedListener(this.inspectOnModelChanged);
      this._diagram.removeDiagramListener('ChangedSelection', this.inspectOnSelectionChanged);
      // Now set the diagram and add the necessary change listeners
      this._diagram = val;
      this._diagram.addModelChangedListener(this.inspectOnModelChanged);
      if (this._inspectSelection) {
        this._diagram.addDiagramListener('ChangedSelection', this.inspectOnSelectionChanged);
        this.inspectObject();
      } else {
        this.inspectObject(null);
      }
    }
  }

  /**
   * This read-only property returns the object currently being inspected.
   *
   * To set the inspected object, call {@link #inspectObject}.
   */
  get inspectedObject(): go.ObjectData | null { return this._inspectedObject; }

  /**
   * Gets or sets whether the Inspector automatically inspects the associated Diagram's selection.
   * When set to false, the Inspector won't show anything until {@link #inspectObject} is called.
   *
   * The default value is true.
   */
  get inspectSelection(): boolean { return this._inspectSelection; }
  set inspectSelection(val: boolean) {
    if (val !== this._inspectSelection) {
      this._inspectSelection = val;
      if (this._inspectSelection) {
        this._diagram.addDiagramListener('ChangedSelection', this.inspectOnSelectionChanged);
        this.inspectObject();
      } else {
        this._diagram.removeDiagramListener('ChangedSelection', this.inspectOnSelectionChanged);
        this.inspectObject(null);
      }
    }
  }

  /**
   * Gets or sets whether the Inspector includes all properties currently on the inspected object.
   *
   * The default value is true.
   */
  get includesOwnProperties(): boolean { return this._includesOwnProperties; }
  set includesOwnProperties(val: boolean) {
    if (val !== this._includesOwnProperties) {
      this._includesOwnProperties = val;
      this.inspectObject();
    }
  }

  /**
   * Gets or sets the properties that the Inspector will inspect, maybe setting options for those properties.
   * The object should contain string: Object pairs represnting propertyName: propertyOptions.
   * Can be used to include or exclude additional properties.
   *
   * The default value is an empty object.
   */
  get properties(): go.ObjectData { return this._properties; }
  set properties(val: go.ObjectData) {
    if (val !== this._properties) {
      this._properties = val;
      this.inspectObject();
    }
  }

  /**
   * Gets or sets the function to be called when a property is modified by the Inspector.
   * The first paremeter will be the property name, the second will be the new value, and the third will be a reference to this Inspector.
   *
   * The default value is null, meaning nothing will be done.
   */
  get propertyModified(): ((a: string, b: string, c: Inspector) => void) | null { return this._propertyModified; }
  set propertyModified(val: ((a: string, b: string, c: Inspector) => void) | null) {
    if (val !== this._propertyModified) {
      this._propertyModified = val;
    }
  }

  /**
   * Gets or sets whether the Inspector displays properties for multiple selected objects or just the first.
   *
   * The default value is false, meaning only the first item in the {@link Diagram#selection} is inspected.
   */
  get multipleSelection(): boolean { return this._multipleSelection; }
  set multipleSelection(val: boolean) {
    if (val !== this._multipleSelection) {
      this._multipleSelection = val;
      this.inspectObject();
    }
  }

  /**
   * Gets or sets whether the Inspector displays the union or intersection of properties for multiple selected objects.
   *
   * The default value is false, meaning the intersection of properties is inspected.
   */
  get showUnionProperties(): boolean { return this._showUnionProperties; }
  set showUnionProperties(val: boolean) {
    if (val !== this._showUnionProperties) {
      this._showUnionProperties = val;
      this.inspectObject();
    }
  }

  /**
   * Gets or sets how many objects will be displayed when {@link #multipleSelection} is true.
   *
   * The default value is 0, meaning all selected objects will be displayed for a given property.
   */
  get showLimit(): number { return this._showLimit; }
  set showLimit(val: number) {
    if (val !== this._showLimit) {
      this._showLimit = val;
      this.inspectObject();
    }
  }

  /**
   * This predicate function can be used as a value for the `show` option for properties.
   * When used, the property will only be shown when inspecting a {@link Node}.
   * @param {Part} part the Part being inspected
   * @return {boolean}
   */
  public static showIfNode(part: go.Part): boolean { return part instanceof go.Node; }

  /**
   * This predicate function can be used as a value for the `show` option for properties.
   * When used, the property will only be shown when inspecting a {@link Link}.
   * @param {Part} part the Part being inspected
   * @return {boolean}
   */
  public static showIfLink(part: go.Part): boolean { return part instanceof go.Link; }

  /**
   * This predicate function can be used as a value for the `show` option for properties.
   * When used, the property will only be shown when inspecting a {@link Group}.
   * @param {Part} part the Part being inspected
   * @return {boolean}
   */
  public static showIfGroup(part: go.Part): boolean { return part instanceof go.Group; }

  /**
   * This predicate function can be used as a value for the `show` option for properties.
   * When used, the property will only be shown if present.
   * Useful for properties such as `key`, which will be shown on Nodes and Groups, but normally not on Links
   * @param {Part|null} part the Part being inspected
   * @param {string} propname the property to check presence of
   * @return {boolean}
   */
  public static showIfPresent(data: go.Part | null, propname: string): boolean {
    if (data instanceof go.Part) data = data.data;
    return typeof data === 'object' && (data as any)[propname] !== undefined;
  }

  /**
   * Update the HTML state of this Inspector with the given object.
   *
   * If passed an object, the Inspector will inspect that object.
   * If passed null, this will do nothing.
   * If no parameter is supplied, the {@link #inspectedObject} will be set based on the value of {@link #inspectSelection}.
   * @param {Object=} object an optional argument, used when {@link #inspectSelection} is false to
   *   set {@link #inspectedObject} and show and edit that object's properties.
   */
  public inspectObject(object?: go.ObjectData | null): void {
    let inspectedObject: go.ObjectData | null = null;
    let inspectedObjects: go.Set<go.ObjectData> | null = null;
    if (object === null) return;
    if (object === undefined) {
      if (this._inspectSelection) {
        if (this._multipleSelection) { // gets the selection if multiple selection is true
          inspectedObjects = this._diagram.selection;
          this._inspectedObject = inspectedObjects.first();
        } else { // otherwise grab the first object
          inspectedObject = this._diagram.selection.first();
        }
      } else { // if there is a single inspected object
        inspectedObject = this._inspectedObject;
      }
    } else { // if object was passed in as a parameter
      inspectedObject = object;
    }
    if (!inspectedObjects && inspectedObject) {
      inspectedObjects = new go.Set<go.ObjectData>();
      inspectedObjects.add(inspectedObject);
    }
    if (!inspectedObjects || inspectedObjects.count < 1) { // if nothing is selected
      this.updateAllHTML();
      return;
    }

    if (inspectedObjects) {
      const mainDiv = this._div;
      mainDiv.innerHTML = '';
      const shared: go.Map<string, any> = new go.Map<string, any>(); // for properties that the nodes have in common
      const properties: go.Map<string, any> = new go.Map<string, any>(); // for adding properties
      const all: go.Map<string, any> = new go.Map<string, any>(); // used later to prevent changing properties when unneeded
      const it = inspectedObjects.iterator;
      let nodecount = 2;
      // Build table:
      const table = document.createElement('table');
      const tbody = document.createElement('tbody');
      this.inspectedProperties = {};
      this.tabIndex = 0;
      const declaredProperties = this._properties;
      it.next();
      inspectedObject = it.value;
      this._inspectedObject = inspectedObject;
      let data = (inspectedObject instanceof go.Part) ? inspectedObject.data : inspectedObject;
      if (data) { // initial pass to set shared and all
        // Go through all the properties passed in to the inspector and add them to the map, if appropriate:
        for (const name in declaredProperties) {
          const desc = declaredProperties[name];
          if (!this.canShowProperty(name, desc, inspectedObject)) continue;
          const val = this.findValue(name, desc, data);
          if (val === '' && this._properties[name] && this._properties[name].type === 'checkbox') {
            shared.add(name, false);
            all.add(name, false);
          } else {
            shared.add(name, val);
            all.add(name, val);
          }
        }
        // Go through all the properties on the model data and add them to the map, if appropriate:
        if (this._includesOwnProperties) {
          for (const k in data) {
            if (k === '__gohashid') continue; // skip internal GoJS hash property
            if (this.inspectedProperties[k]) continue; // already exists
            if (declaredProperties[k] && !this.canShowProperty(k, declaredProperties[k], inspectedObject)) continue;
            shared.add(k, data[k]);
            all.add(k, data[k]);
          }
        }
      }
      while (it.next() && (this._showLimit < 1 || nodecount <= this._showLimit)) { // grabs all the properties from the other selected objects
        properties.clear();
        inspectedObject = it.value;
        if (inspectedObject) {
          // use either the Part.data or the object itself (for model.modelData)
          data = (inspectedObject instanceof go.Part) ? inspectedObject.data : inspectedObject;
          if (data) {
            // Go through all the properties passed in to the inspector and add them to properties to add, if appropriate:
            for (const name in declaredProperties) {
              const desc = declaredProperties[name];
              if (!this.canShowProperty(name, desc, inspectedObject)) continue;
              const val = this.findValue(name, desc, data);
              if (val === '' && this._properties[name] && this._properties[name].type === 'checkbox') {
                properties.add(name, false);
              } else {
                properties.add(name, val);
              }
            }
            // Go through all the properties on the model data and add them to properties to add, if appropriate:
            if (this._includesOwnProperties) {
              for (const k in data) {
                if (k === '__gohashid') continue; // skip internal GoJS hash property
                if (this.inspectedProperties[k]) continue; // already exists
                if (declaredProperties[k] && !this.canShowProperty(k, declaredProperties[k], inspectedObject)) continue;
                properties.add(k, data[k]);
              }
            }
          }
        }
        if (!this._showUnionProperties) {
          // Cleans up shared map with properties that aren't shared between the selected objects
          // Also adds properties to the add and shared maps if applicable
          const addIt = shared.iterator;
          const toRemove: Array<string> = [];
          while (addIt.next()) {
            if (properties.has(addIt.key)) {
              let newVal = all.get(addIt.key) + '|' + properties.get(addIt.key);
              all.set(addIt.key, newVal);
              if ((declaredProperties[addIt.key] && declaredProperties[addIt.key].type !== 'color'
                  && declaredProperties[addIt.key].type !== 'checkbox' && declaredProperties[addIt.key].type !== 'select')
                  || !declaredProperties[addIt.key]) { // for non-string properties i.e color
                newVal = shared.get(addIt.key) + '|' + properties.get(addIt.key);
                shared.set(addIt.key, newVal);
              }
            } else { // toRemove array since addIt is still iterating
              toRemove.push(addIt.key);
            }
          }
          for (let i = 0; i < toRemove.length; i++) { // removes anything that doesn't showUnionProperties
            shared.remove(toRemove[i]);
            all.remove(toRemove[i]);
          }
        } else {
          // Adds missing properties to all with the correct amount of seperators
          let addIt = properties.iterator;
          while (addIt.next()) {
            if (all.has(addIt.key)) {
              if ((declaredProperties[addIt.key] && declaredProperties[addIt.key].type !== 'color'
                  && declaredProperties[addIt.key].type !== 'checkbox' && declaredProperties[addIt.key].type !== 'select')
                  || !declaredProperties[addIt.key]) { // for non-string properties i.e color
                const newVal = all.get(addIt.key) + '|' + properties.get(addIt.key);
                all.set(addIt.key, newVal);
              }
            } else {
              let newVal = '';
              for (let i = 0; i < nodecount - 1; i++) newVal += '|';
              newVal += properties.get(addIt.key);
              all.set(addIt.key, newVal);
            }
          }
          // Adds bars in case properties is not in all
          addIt = all.iterator;
          while (addIt.next()) {
            if (!properties.has(addIt.key)) {
              if ((declaredProperties[addIt.key] && declaredProperties[addIt.key].type !== 'color'
                  && declaredProperties[addIt.key].type !== 'checkbox' && declaredProperties[addIt.key].type !== 'select')
                  || !declaredProperties[addIt.key]) { // for non-string properties i.e color
                const newVal = all.get(addIt.key) + '|';
                all.set(addIt.key, newVal);
              }
            }
          }
        }
        nodecount++;
      }
      // builds the table property rows and sets multipleProperties to help with updateall
      let mapIt;
      if (!this._showUnionProperties) mapIt = shared.iterator;
      else mapIt = all.iterator;
      while (mapIt.next()) {
        tbody.appendChild(this.buildPropertyRow(mapIt.key, mapIt.value)); // shows the properties that are allowed
      }
      table.appendChild(tbody);
      mainDiv.appendChild(table);
      const allIt = all.iterator;
      while (allIt.next()) {
        this.multipleProperties[allIt.key] = allIt.value; // used for updateall to know which properties to change
      }
    }
  }

  /**
   * This predicate should be false if the given property should not be shown.
   * Normally it only checks the value of "show" on the property descriptor.
   *
   * The default value is true.
   * @param {string} propertyName the property name
   * @param {Object} propertyDesc the property descriptor
   * @param {Object} inspectedObject the data object
   * @return {boolean} whether a particular property should be shown in this Inspector
   */
  public canShowProperty(propertyName: string, propertyDesc: go.ObjectData, inspectedObject: go.ObjectData): boolean {
    const prop = propertyDesc as any;
    if (prop.show === false) return false;
    // if "show" is a predicate, make sure it passes or do not show this property
    if (typeof prop.show === 'function') return prop.show(inspectedObject, propertyName);
    return true;
  }

  /**
   * This predicate should be false if the given property should not be editable by the user.
   * Normally it only checks the value of "readOnly" on the property descriptor.
   *
   * The default value is true.
   * @param {string} propertyName the property name
   * @param {Object} propertyDesc the property descriptor
   * @param {Object} inspectedObject the data object
   * @return {boolean} whether a particular property should be shown in this Inspector
   */
  public canEditProperty(propertyName: string, propertyDesc: go.ObjectData, inspectedObject: go.ObjectData | null): boolean {
    if (this._diagram.isReadOnly || this._diagram.isModelReadOnly) return false;
    if (inspectedObject === null) return false;
    // assume property values that are functions of Objects cannot be edited
    const data = (inspectedObject instanceof go.Part) ? inspectedObject.data : inspectedObject;
    const valtype = typeof data[propertyName];
    if (valtype === 'function') return false;
    if (propertyDesc) {
      const prop = propertyDesc as any;
      if (prop.readOnly === true) return false;
      // if "readOnly" is a predicate, make sure it passes or do not show this property
      if (typeof prop.readOnly === 'function') return !prop.readOnly(inspectedObject, propertyName);
    }
    return true;
  }

  /**
   * @ignore
   * @param propName
   * @param propDesc
   * @param data
   */
  private findValue(propName: string, propDesc: any, data: any): any {
    let val = '';
    if (propDesc && propDesc.defaultValue !== undefined) val = propDesc.defaultValue;
    if (data[propName] !== undefined) val = data[propName];
    if (val === undefined) return '';
    return val;
  }

  /**
   * This sets `inspectedProperties[propertyName]` and creates the HTML table row for a given property:
   * ```html
   * <tr>
   *   <td>propertyName</td>
   *   <td><input value=propertyValue /></td>
   * </tr>
   * ```
   *
   * This method can be customized to change how an Inspector row is rendered.
   * @param {string} propertyName the property name
   * @param {*} propertyValue the property value
   * @return {HTMLTableRowElement} the table row
   */
  public buildPropertyRow(propertyName: string, propertyValue: any): HTMLTableRowElement {
    const tr = document.createElement('tr');

    const td1 = document.createElement('td');
    let displayName;
    if (this._properties[propertyName] && this._properties[propertyName].name !== undefined) { // name changes the dispaly name shown on inspector
      displayName = this._properties[propertyName].name;
    } else {
      displayName = propertyName;
    }
    td1.textContent = displayName;

    tr.appendChild(td1);

    const td2 = document.createElement('td');
    const decProp = this._properties[propertyName];
    let input: HTMLInputElement | HTMLSelectElement  | null = null;
    const self = this;
    function updateall() {
      if (self._diagram.selection.count === 1 || !self.multipleSelection) {
        self.updateAllProperties();
      } else {
        self.updateAllObjectsProperties();
      }
    }

    if (decProp && decProp.type === 'select') {
      const inputs = input = document.createElement('select') as HTMLSelectElement;
      this.updateSelect(decProp, inputs, propertyName, propertyValue);
      inputs.addEventListener('change', updateall);
    } else {
      const inputi = input = document.createElement('input') as HTMLInputElement;
      if (inputi && inputi.setPointerCapture) {
        inputi.addEventListener("pointerdown", e => inputi.setPointerCapture(e.pointerId));
      }
      inputi.value = this.convertToString(propertyValue);
      if (decProp) {
        const t = decProp.type;
        if (t !== 'string' && t !== 'number' && t !== 'boolean' &&
          t !== 'arrayofnumber' && t !== 'point' && t !== 'size' &&
          t !== 'rect' && t !== 'spot' && t !== 'margin') {
          inputi.setAttribute('type', decProp.type);
        }
        if (decProp.type === 'color') {
          if (inputi.type === 'color') {
            inputi.value = this.convertToColor(propertyValue);
            // input.addEventListener('input', updateall); // removed with multi select
            inputi.addEventListener('change', updateall);
          }
        } if (decProp.type === 'checkbox') {
          inputi.checked = !!propertyValue;
          inputi.addEventListener('change', updateall);
        }
      }
      if (inputi.type !== 'color') inputi.addEventListener('blur', updateall);
    }

    if (input) {
      input.tabIndex = this.tabIndex++;
      input.disabled = !this.canEditProperty(propertyName, decProp, this._inspectedObject);
      td2.appendChild(input);
    }
    tr.appendChild(td2);

    this.inspectedProperties[propertyName] = input;
    return tr;
  }

  /**
   * @hidden @ignore
   * HTML5 color input will only take hex,
   * so let HTML5 canvas convert the color into hex format.
   * This converts "rgb(255, 0, 0)" into "#FF0000", etc.
   */
  public convertToColor(propertyValue: string): string {
    const ctx: CanvasRenderingContext2D | null = document.createElement('canvas').getContext('2d');
    if (ctx === null) return '#000000';
    ctx.fillStyle = propertyValue;
    return ctx.fillStyle;
  }

  /**
   * @hidden @ignore
   */
  public convertToArrayOfNumber(propertyValue: string): Array<number> | null {
    if (propertyValue === 'null') return null;
    const split = propertyValue.split(' ');
    const arr: Array<number> = [];
    for (let i = 0; i < split.length; i++) {
      const str = split[i];
      if (!str) continue;
      arr.push(parseFloat(str));
    }
    return arr;
  }

  /**
   * @hidden @ignore
   */
  public convertToString(x: any): string {
    if (x === undefined) return 'undefined';
    if (x === null) return 'null';
    if (x instanceof go.Point) return go.Point.stringify(x);
    if (x instanceof go.Size) return go.Size.stringify(x);
    if (x instanceof go.Rect) return go.Rect.stringify(x);
    if (x instanceof go.Spot) return go.Spot.stringify(x);
    if (x instanceof go.Margin) return go.Margin.stringify(x);
    if (x instanceof go.List) return this.convertToString(x.toArray());
    if (Array.isArray(x)) {
      let str = '';
      for (let i = 0; i < x.length; i++) {
        if (i > 0) str += ' ';
        const v = x[i];
        str += this.convertToString(v);
      }
      return str;
    }
    return x.toString();
  }

  /**
   * @hidden @ignore
   * Update all of the HTML in this Inspector.
   */
  public updateAllHTML(): void {
    const inspectedProps = this.inspectedProperties;
    const isPart = this._inspectedObject instanceof go.Part;
    const data = isPart ? (this._inspectedObject as any).data : this._inspectedObject;
    if (!data) {  // clear out all of the fields
      for (const name in inspectedProps) {
        const input = inspectedProps[name];
        if (input instanceof HTMLSelectElement) {
          input.innerHTML = '';
        } else if (input.type === 'color') {
          input.value = '#000000';
        } else if (input.type === 'checkbox') {
          input.checked = false;
        } else {
          input.value = '';
        }
      }
    } else {
      for (const name in inspectedProps) {
        const input = inspectedProps[name];
        const propertyValue = data[name];
        if (input instanceof HTMLSelectElement) {
          const decProp = this._properties[name];
          this.updateSelect(decProp, input, name, propertyValue);
        } else if (input.type === 'color') {
          input.value = this.convertToColor(propertyValue);
        } else if (input.type === 'checkbox') {
          input.checked = !!propertyValue;
        } else {
          input.value = this.convertToString(propertyValue);
        }
      }
    }
  }

  /**
   * @hidden @ignore
   * Update an HTMLSelectElement with an appropriate list of choices, given the propertyName
   */
  public updateSelect(decProp: any, select: HTMLSelectElement, propertyName: string, propertyValue: any): void {
    select.innerHTML = '';  // clear out anything that was there
    let choices = decProp.choices;
    if (typeof choices === 'function') choices = choices(this._inspectedObject, propertyName);
    if (!Array.isArray(choices)) choices = [];
    decProp.choicesArray = choices;  // remember list of actual choice values (not strings)
    for (let i = 0; i < choices.length; i++) {
      const choice = choices[i];
      const opt = document.createElement('option');
      opt.text = this.convertToString(choice);
      select.add(opt);
    }
    select.value = this.convertToString(propertyValue);
  }

  private parseValue(decProp: any, value: any, input: any, oldval: any) {
    // If it's a boolean, or if its previous value was boolean,
    // parse the value to be a boolean and then update the input.value to match
    let type = '';
    if (decProp !== undefined && decProp.type !== undefined) {
      type = decProp.type;
    }
    if (type === '') {
      if (typeof oldval === 'boolean') type = 'boolean'; // infer boolean
      else if (typeof oldval === 'number') type = 'number';
      else if (oldval instanceof go.Point) type = 'point';
      else if (oldval instanceof go.Size) type = 'size';
      else if (oldval instanceof go.Rect) type = 'rect';
      else if (oldval instanceof go.Spot) type = 'spot';
      else if (oldval instanceof go.Margin) type = 'margin';
    }

    // convert to specific type, if needed
    switch (type) {
      case 'boolean': value = !(value === false || value === 'false' || value === '0'); break;
      case 'number': value = parseFloat(value); break;
      case 'arrayofnumber': value = this.convertToArrayOfNumber(value); break;
      case 'point': value = go.Point.parse(value); break;
      case 'size': value = go.Size.parse(value); break;
      case 'rect': value = go.Rect.parse(value); break;
      case 'spot': value = go.Spot.parse(value); break;
      case 'margin': value = go.Margin.parse(value); break;
      case 'checkbox': value = input.checked; break;
      case 'select': value = decProp.choicesArray[input.selectedIndex]; break;
    }

    return value;
  }

  /**
   * @hidden @ignore
   * Update all of the data properties of all the objects in {@link #inspectedObjects} according to the
   * current values held in the HTML input elements.
   */
  private updateAllObjectsProperties() {
    const inspectedProps = this.inspectedProperties;
    const diagram = this._diagram;
    diagram.startTransaction('set all properties');
    for (const name in inspectedProps) {
      const input = inspectedProps[name];
      let value = input.value;
      const arr1: Array<string> = value.split('|');
      let arr2: Array<string> = [];
      if (this.multipleProperties[name]) {
        // don't split if it is union and its checkbox type
        if (this._properties[name] && this._properties[name].type === 'checkbox' && this._showUnionProperties) {
          arr2.push(this.multipleProperties[name]);
        } else if (this._properties[name]) {
          arr2 = this.multipleProperties[name].toString().split('|');
        }
      }
      const it = diagram.selection.iterator;
      let change = false;
      if (this._properties[name] && this._properties[name].type === 'checkbox') change = true; // always change checkbox
      if (arr1.length < arr2.length // i.e Alpha|Beta -> Alpha procs the change
          && (!this._properties[name] // from and to links
          || !(this._properties[name] // do not change color checkbox and choices due to them always having less
          && (this._properties[name].type === 'color' || this._properties[name].type === 'checkbox' || this._properties[name].type === 'choices')))) {
            change = true;
      } else { // standard detection in change in properties
        for (let j = 0; j < arr1.length && j < arr2.length; j++) {
          if (!(arr1[j] === arr2[j])
              && !(this._properties[name] && this._properties[name].type === 'color' && arr1[j].toLowerCase() === arr2[j].toLowerCase())) {
            change = true;
          }
        }
      }
      if (change) { // only change properties it needs to change instead all of them
        for (let i = 0; i < diagram.selection.count; i++) {
          it.next();
          const isPart = it.value instanceof go.Part;
          const data = isPart ? it.value.data : it.value;

          if (data) { // ignores the selected node if there is no data
            if (i < arr1.length) value = arr1[i];
            else value = arr1[0];

            // don't update "readOnly" data properties
            const decProp = this._properties[name];
            if (!this.canEditProperty(name, decProp, it.value)) continue;

            const oldval = data[name];
            value = this.parseValue(decProp, value, input, oldval);

            // in case parsed to be different, such as in the case of boolean values,
            // the value shown should match the actual value
            input.value = value;

            // modify the data object in an undo-able fashion
            diagram.model.setDataProperty(data, name, value);

            // notify any listener
            if (this.propertyModified !== null) this.propertyModified(name, value, this);
          }
        }
      }
    }
    diagram.commitTransaction('set all properties');
  }

  /**
   * @hidden @ignore
   * Update all of the data properties of {@link #inspectedObject} according to the
   * current values held in the HTML input elements.
   */
  private updateAllProperties() {
    const inspectedProps = this.inspectedProperties;
    const diagram = this._diagram;
    const isPart = this.inspectedObject instanceof go.Part;
    const data = isPart ? (this.inspectedObject as any).data : this.inspectedObject;
    if (!data) return;  // must not try to update data when there's no data!

    diagram.startTransaction('set all properties');
    for (const name in inspectedProps) {
      const input = inspectedProps[name];
      let value = input.value;

      // don't update "readOnly" data properties
      const decProp = this._properties[name];
      if (!this.canEditProperty(name, decProp, this.inspectedObject)) continue;

      const oldval = data[name];
      value = this.parseValue(decProp, value, input, oldval);

      // in case parsed to be different, such as in the case of boolean values,
      // the value shown should match the actual value
      input.value = value;

      // modify the data object in an undo-able fashion
      diagram.model.setDataProperty(data, name, value);

      // notify any listener
      if (this.propertyModified !== null) this.propertyModified(name, value, this);
    }
    diagram.commitTransaction('set all properties');
  }
}