// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.

import {
  Kernel
} from '@jupyterlab/services';

import {
  each
} from 'phosphor/lib/algorithm/iteration';

import {
  DisposableSet
} from 'phosphor/lib/core/disposable';

import {
  CommandRegistry
} from 'phosphor/lib/ui/commandregistry';

import {
  Keymap
} from 'phosphor/lib/ui/keymap';

import {
  Menu
} from 'phosphor/lib/ui/menu';

import {
  Widget
} from 'phosphor/lib/ui/widget';

import {
  showDialog
} from '../dialog';

import {
  DocumentManager
} from '../docmanager';

import {
  createFromDialog
} from './dialogs';

import {
  FileBrowserModel
} from './model';

import * as utils
  from './utils';


/**
 * The class name added to a file buttons widget.
 */
const FILE_BUTTONS_CLASS = 'jp-FileButtons';

/**
 * The class name added to a button node.
 */
const BUTTON_CLASS = 'jp-FileButtons-button';

/**
 * The class name added to a button content node.
 */
const CONTENT_CLASS = 'jp-FileButtons-buttonContent';

/**
 * The class name added to a button icon node.
 */
const ICON_CLASS = 'jp-FileButtons-buttonIcon';

/**
 * The class name added to the create button.
 */
const CREATE_CLASS = 'jp-id-create';

/**
 * The class name added to the add button.
 */
const MATERIAL_CREATE = 'jp-AddIcon';

/**
 * The class name added to the upload button.
 */
const MATERIAL_UPLOAD = 'jp-UploadIcon';

/**
 * The class name added to the refresh button.
 */
const MATERIAL_REFRESH = 'jp-RefreshIcon';

/**
 * The class name added to the down caret.
 */
const MATERIAL_DOWNCARET = 'jp-DownCaretIcon';

/**
 * The class name added to a material icon button.
 */
const MATERIAL_CLASS = 'jp-MaterialIcon';

/**
 * The class name added to the upload button.
 */
const UPLOAD_CLASS = 'jp-id-upload';

/**
 * The class name added to the refresh button.
 */
const REFRESH_CLASS = 'jp-id-refresh';

/**
 * The class name added to an active create button.
 */
const ACTIVE_CLASS = 'jp-mod-active';

/**
 * The class name added to a dropdown icon.
 */
const DROPDOWN_CLASS = 'jp-FileButtons-dropdownIcon';


/**
 * A widget which hosts the file browser buttons.
 */
export
class FileButtons extends Widget {
  /**
   * Construct a new file browser buttons widget.
   */
  constructor(options: FileButtons.IOptions) {
    super();
    this.addClass(FILE_BUTTONS_CLASS);
    this._model = options.model;

    this._buttons.create.onmousedown = this._onCreateButtonPressed;
    this._buttons.upload.onclick = this._onUploadButtonClicked;
    this._buttons.refresh.onclick = this._onRefreshButtonClicked;
    this._input.onchange = this._onInputChanged;

    let node = this.node;
    node.appendChild(this._buttons.create);
    node.appendChild(this._buttons.upload);
    node.appendChild(this._buttons.refresh);

    this._commands = options.commands;
    this._keymap = options.keymap;
    this._manager = options.manager;
  }

  /**
   * Dispose of the resources held by the widget.
   */
  dispose(): void {
    this._buttons = null;
    this._commands = null;
    this._input = null;
    this._keymap = null;
    this._manager = null;
    this._model = null;
    super.dispose();
  }

  /**
   * Get the model used by the widget.
   */
  get model(): FileBrowserModel {
    return this._model;
  }

  /**
   * Get the document manager used by the widget.
   */
  get manager(): DocumentManager {
    return this._manager;
  }

  /**
   * Get the create button node.
   */
  get createNode(): HTMLButtonElement {
    return this._buttons.create;
  }

  /**
   * Get the upload button node.
   */
  get uploadNode(): HTMLButtonElement {
    return this._buttons.upload;
  }

  /**
   * Get the refresh button node.
   */
  get refreshNode(): HTMLButtonElement {
    return this._buttons.refresh;
  }

  /**
   * Create a file from a creator.
   *
   * @param creatorName - The name of the file creator.
   *
   * @returns A promise that resolves with the created widget.
   */
  createFrom(creatorName: string): Promise<Widget> {
    return createFromDialog(this.model, this.manager, creatorName);
  }

  /**
   * Open a file by path.
   *
   * @param path - The path of the file.
   *
   * @param widgetName - The name of the widget factory to use.
   *
   * @param kernel - The kernel model to use.
   *
   * @return The widget for the path.
   */
  open(path: string, widgetName='default', kernel?: Kernel.IModel): Widget {
    let widget = this._manager.openOrReveal(path, widgetName, kernel);
    return widget;
  }

  /**
   * Create a new file by path.
   *
   * @param path - The path of the file.
   *
   * @param widgetName - The name of the widget factory to use.
   *
   * @param kernel - The kernel model to use.
   *
   * @return The widget for the path.
   */
  createNew(path: string, widgetName='default', kernel?: Kernel.IModel): Widget {
    return this._manager.createNew(path, widgetName, kernel);
  }

  /**
   * The 'mousedown' handler for the create button.
   */
  private _onCreateButtonPressed = (event: MouseEvent) => {
    // Do nothing if nothing if it's not a left press.
    if (event.button !== 0) {
      return;
    }

    // Do nothing if the create button is already active.
    let button = this._buttons.create;
    if (button.classList.contains(ACTIVE_CLASS)) {
      return;
    }

    // Create a new dropdown menu and snap the button geometry.
    let commands = this._commands;
    let keymap = this._keymap;
    let dropdown = Private.createDropdownMenu(this, commands, keymap);
    let rect = button.getBoundingClientRect();

    // Mark the button as active.
    button.classList.add(ACTIVE_CLASS);

    // Setup the `aboutToClose` signal handler. The menu is disposed on an
    // animation frame to allow a mouse press event which closed the
    // menu to run its course. This keeps the button from re-opening.
    dropdown.aboutToClose.connect(() => {
      requestAnimationFrame(() => { dropdown.dispose(); });
    });

    // Setup the `disposed` signal handler. This restores the button
    // to the non-active state and allows a new menu to be opened.
    dropdown.disposed.connect(() => {
      button.classList.remove(ACTIVE_CLASS);
    });

    // Popup the menu aligned with the bottom of the create button.
    dropdown.open(rect.left, rect.bottom, { forceX: false, forceY: false });
  };


  /**
   * The 'click' handler for the upload button.
   */
  private _onUploadButtonClicked = (event: MouseEvent) => {
    if (event.button !== 0) {
      return;
    }
    this._input.click();
  };

  /**
   * The 'click' handler for the refresh button.
   */
  private _onRefreshButtonClicked = (event: MouseEvent) => {
    if (event.button !== 0) {
      return;
    }
    // Force a refresh of the current directory.
    this._model.cd('.');
  };

  /**
   * The 'change' handler for the input field.
   */
  private _onInputChanged = () => {
    let files = Array.prototype.slice.call(this._input.files);
    Private.uploadFiles(this, files as File[]);
  };

  private _buttons = Private.createButtons();
  private _commands: CommandRegistry = null;
  private _input = Private.createUploadInput();
  private _keymap: Keymap = null;
  private _manager: DocumentManager = null;
  private _model: FileBrowserModel;
}


/**
 * The namespace for the `FileButtons` class statics.
 */
export
namespace FileButtons {
  /**
   * An options object for initializing a file buttons widget.
   */
  export
  interface IOptions {
    /**
     * The command registry for use with the file buttons.
     */
    commands: CommandRegistry;

    /**
     * The keymap for use with the file buttons.
     */
    keymap: Keymap;

    /**
     * A file browser model instance.
     */
    model: FileBrowserModel;

    /**
     * A document manager instance.
     */
    manager: DocumentManager;
  }
}


/**
 * The namespace for the `FileButtons` private data.
 */
namespace Private {
  /**
   * The ID counter prefix for new commands.
   *
   * #### Notes
   * Even though the commands are disposed when the dropdown menu is disposed,
   * in order to guarantee there are no race conditions with other `FileButtons`
   * instances, each set of commands is prefixed.
   */
  let id = 0;

  /**
   * An object which holds the button nodes for a file buttons widget.
   */
  export
  interface IButtonGroup {
    create: HTMLButtonElement;
    upload: HTMLButtonElement;
    refresh: HTMLButtonElement;
  }

  /**
   * Create the button group for a file buttons widget.
   */
  export
  function createButtons(): IButtonGroup {
    let create = document.createElement('button');
    let upload = document.createElement('button');
    let refresh = document.createElement('button');

    let createContent = document.createElement('span');
    let uploadContent = document.createElement('span');
    let refreshContent = document.createElement('span');

    let createIcon = document.createElement('span');
    let uploadIcon = document.createElement('span');
    let refreshIcon = document.createElement('span');
    let dropdownIcon = document.createElement('span');

    create.type = 'button';
    upload.type = 'button';
    refresh.type = 'button';

    create.title = 'Create New...';
    upload.title = 'Upload File(s)';
    refresh.title = 'Refresh File List';

    create.className = `${BUTTON_CLASS} ${CREATE_CLASS}`;
    upload.className = `${BUTTON_CLASS} ${UPLOAD_CLASS}`;
    refresh.className = `${BUTTON_CLASS} ${REFRESH_CLASS}`;

    createContent.className = CONTENT_CLASS;
    uploadContent.className = CONTENT_CLASS;
    refreshContent.className = CONTENT_CLASS;

    // TODO make these icons configurable.
    createIcon.className = ICON_CLASS + ' ' + MATERIAL_CLASS + ' ' + MATERIAL_CREATE;
    uploadIcon.className = ICON_CLASS + ' ' + MATERIAL_CLASS + ' ' + MATERIAL_UPLOAD;
    refreshIcon.className = ICON_CLASS + ' ' + MATERIAL_CLASS + ' ' + MATERIAL_REFRESH;
    dropdownIcon.className = DROPDOWN_CLASS + ' ' + MATERIAL_CLASS + ' ' + MATERIAL_DOWNCARET;

    createContent.appendChild(createIcon);
    createContent.appendChild(dropdownIcon);
    uploadContent.appendChild(uploadIcon);
    refreshContent.appendChild(refreshIcon);

    create.appendChild(createContent);
    upload.appendChild(uploadContent);
    refresh.appendChild(refreshContent);

    return { create, upload, refresh };
  }

  /**
   * Create the upload input node for a file buttons widget.
   */
  export
  function createUploadInput(): HTMLInputElement {
    let input = document.createElement('input');
    input.type = 'file';
    input.multiple = true;
    return input;
  }

  /**
   * Create a new folder.
   */
  export
  function createNewFolder(widget: FileButtons): void {
    widget.model.newUntitled({ type: 'directory' }).catch(error => {
      utils.showErrorMessage('New Folder Error', error);
    });
  }

  /**
   * Create a new dropdown menu for the create new button.
   */
  export
  function createDropdownMenu(widget: FileButtons, commands: CommandRegistry, keymap: Keymap): Menu {
    let menu = new Menu({ commands, keymap });
    let prefix = `file-buttons-${++id}`;
    let disposables = new DisposableSet();
    let registry = widget.manager.registry;
    let command: string;

    // Remove all the commands associated with this menu upon disposal.
    menu.disposed.connect(() => disposables.dispose());

    command = `${prefix}:new-text-folder`;
    disposables.add(commands.addCommand(command, {
      execute: () => { createNewFolder(widget); },
      label: 'Folder'
    }));
    menu.addItem({ command });

    each(registry.creators(), creator => {
      command = `${prefix}:new-${creator.name}`;
      disposables.add(commands.addCommand(command, {
        execute: () => {
          widget.createFrom(creator.name);
        },
        label: creator.name
      }));
      menu.addItem({ command });
    });
    return menu;
  }

  /**
   * Upload an array of files to the server.
   */
  export
  function uploadFiles(widget: FileButtons, files: File[]): void {
    let pending = files.map(file => uploadFile(widget, file));
    Promise.all(pending).catch(error => {
      utils.showErrorMessage('Upload Error', error);
    });
  }

  /**
   * Upload a file to the server.
   */
  function uploadFile(widget: FileButtons, file: File): Promise<any> {
    return widget.model.upload(file).catch(error => {
      let exists = error.message.indexOf('already exists') !== -1;
      if (exists) {
        return uploadFileOverride(widget, file);
      }
      throw error;
    });
  }

  /**
   * Upload a file to the server checking for override.
   */
  function uploadFileOverride(widget: FileButtons, file: File): Promise<any> {
    let options = {
      title: 'Overwrite File?',
      body: `"${file.name}" already exists, overwrite?`
    };
    return showDialog(options).then(button => {
      if (widget.isDisposed || button.text !== 'Ok') {
        return;
      }
      return widget.model.upload(file, true);
    });
  }
}