// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
/*-----------------------------------------------------------------------------
| Copyright (c) 2014-2017, PhosphorJS Contributors
|
| Distributed under the terms of the BSD 3-Clause License.
|
| The full license is in the file LICENSE, distributed with this software.
|----------------------------------------------------------------------------*/
import { IDisposable } from '@lumino/disposable';

import { ISignal, Signal } from '@lumino/signaling';

import { VirtualElement } from '@lumino/virtualdom';

/**
 * An object which holds data related to an object's title.
 *
 * #### Notes
 * A title object is intended to hold the data necessary to display a
 * header for a particular object. A common example is the `TabPanel`,
 * which uses the widget title to populate the tab for a child widget.
 *
 * It is the responsibility of the owner to call the title disposal.
 */
export class Title<T> implements IDisposable {
  /**
   * Construct a new title.
   *
   * @param options - The options for initializing the title.
   */
  constructor(options: Title.IOptions<T>) {
    this.owner = options.owner;
    if (options.label !== undefined) {
      this._label = options.label;
    }
    if (options.mnemonic !== undefined) {
      this._mnemonic = options.mnemonic;
    }
    if (options.icon !== undefined) {
      this._icon = options.icon;
    }

    if (options.iconClass !== undefined) {
      this._iconClass = options.iconClass;
    }
    if (options.iconLabel !== undefined) {
      this._iconLabel = options.iconLabel;
    }
    if (options.caption !== undefined) {
      this._caption = options.caption;
    }
    if (options.className !== undefined) {
      this._className = options.className;
    }
    if (options.closable !== undefined) {
      this._closable = options.closable;
    }
    this._dataset = options.dataset || {};
  }

  /**
   * A signal emitted when the state of the title changes.
   */
  get changed(): ISignal<this, void> {
    return this._changed;
  }

  /**
   * The object which owns the title.
   */
  readonly owner: T;

  /**
   * Get the label for the title.
   *
   * #### Notes
   * The default value is an empty string.
   */
  get label(): string {
    return this._label;
  }

  /**
   * Set the label for the title.
   */
  set label(value: string) {
    if (this._label === value) {
      return;
    }
    this._label = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the mnemonic index for the title.
   *
   * #### Notes
   * The default value is `-1`.
   */
  get mnemonic(): number {
    return this._mnemonic;
  }

  /**
   * Set the mnemonic index for the title.
   */
  set mnemonic(value: number) {
    if (this._mnemonic === value) {
      return;
    }
    this._mnemonic = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the icon renderer for the title.
   *
   * #### Notes
   * The default value is undefined.
   */
  get icon(): VirtualElement.IRenderer | undefined {
    return this._icon;
  }

  /**
   * Set the icon renderer for the title.
   *
   * #### Notes
   * A renderer is an object that supplies a render and unrender function.
   */
  set icon(value: VirtualElement.IRenderer | undefined) {
    if (this._icon === value) {
      return;
    }
    this._icon = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the icon class name for the title.
   *
   * #### Notes
   * The default value is an empty string.
   */
  get iconClass(): string {
    return this._iconClass;
  }

  /**
   * Set the icon class name for the title.
   *
   * #### Notes
   * Multiple class names can be separated with whitespace.
   */
  set iconClass(value: string) {
    if (this._iconClass === value) {
      return;
    }
    this._iconClass = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the icon label for the title.
   *
   * #### Notes
   * The default value is an empty string.
   */
  get iconLabel(): string {
    return this._iconLabel;
  }

  /**
   * Set the icon label for the title.
   *
   * #### Notes
   * Multiple class names can be separated with whitespace.
   */
  set iconLabel(value: string) {
    if (this._iconLabel === value) {
      return;
    }
    this._iconLabel = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the caption for the title.
   *
   * #### Notes
   * The default value is an empty string.
   */
  get caption(): string {
    return this._caption;
  }

  /**
   * Set the caption for the title.
   */
  set caption(value: string) {
    if (this._caption === value) {
      return;
    }
    this._caption = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the extra class name for the title.
   *
   * #### Notes
   * The default value is an empty string.
   */
  get className(): string {
    return this._className;
  }

  /**
   * Set the extra class name for the title.
   *
   * #### Notes
   * Multiple class names can be separated with whitespace.
   */
  set className(value: string) {
    if (this._className === value) {
      return;
    }
    this._className = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the closable state for the title.
   *
   * #### Notes
   * The default value is `false`.
   */
  get closable(): boolean {
    return this._closable;
  }

  /**
   * Set the closable state for the title.
   *
   * #### Notes
   * This controls the presence of a close icon when applicable.
   */
  set closable(value: boolean) {
    if (this._closable === value) {
      return;
    }
    this._closable = value;
    this._changed.emit(undefined);
  }

  /**
   * Get the dataset for the title.
   *
   * #### Notes
   * The default value is an empty dataset.
   */
  get dataset(): Title.Dataset {
    return this._dataset;
  }

  /**
   * Set the dataset for the title.
   *
   * #### Notes
   * This controls the data attributes when applicable.
   */
  set dataset(value: Title.Dataset) {
    if (this._dataset === value) {
      return;
    }
    this._dataset = value;
    this._changed.emit(undefined);
  }

  /**
   * Test whether the title has been disposed.
   */
  get isDisposed(): boolean {
    return this._isDisposed;
  }

  /**
   * Dispose of the resources held by the title.
   *
   * #### Notes
   * It is the responsibility of the owner to call the title disposal.
   */
  dispose(): void {
    if (this.isDisposed) {
      return;
    }
    this._isDisposed = true;

    Signal.clearData(this);
  }

  private _label = '';
  private _caption = '';
  private _mnemonic = -1;
  private _icon: VirtualElement.IRenderer | undefined = undefined;
  private _iconClass = '';
  private _iconLabel = '';
  private _className = '';
  private _closable = false;
  private _dataset: Title.Dataset;
  private _changed = new Signal<this, void>(this);
  private _isDisposed = false;
}

/**
 * The namespace for the `Title` class statics.
 */
export namespace Title {
  /**
   * A type alias for a simple immutable string dataset.
   */
  export type Dataset = { readonly [key: string]: string };

  /**
   * An options object for initializing a title.
   */
  export interface IOptions<T> {
    /**
     * The object which owns the title.
     */
    owner: T;

    /**
     * The label for the title.
     */
    label?: string;

    /**
     * The mnemonic index for the title.
     */
    mnemonic?: number;

    /**
     * The icon renderer for the title.
     */
    icon?: VirtualElement.IRenderer;

    /**
     * The icon class name for the title.
     */
    iconClass?: string;

    /**
     * The icon label for the title.
     */
    iconLabel?: string;

    /**
     * The caption for the title.
     */
    caption?: string;

    /**
     * The extra class name for the title.
     */
    className?: string;

    /**
     * The closable state for the title.
     */
    closable?: boolean;

    /**
     * The dataset for the title.
     */
    dataset?: Dataset;
  }
}