/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { isNonEmptyArray } from '../../../../vs/base/common/arrays';
import { DisposableStore } from '../../../../vs/base/common/lifecycle';
import { ICodeEditor } from '../../../../vs/editor/browser/editorBrowser';
import { ISelectedSuggestion, SuggestWidget } from './suggestWidget';
import { CharacterSet } from '../../../../vs/editor/common/core/characterClassifier';
import { EditorOption } from '../../../../vs/editor/common/config/editorOptions';

export class CommitCharacterController {
  private readonly _disposables = new DisposableStore();

  private _active?: {
    readonly acceptCharacters: CharacterSet;
    readonly item: ISelectedSuggestion;
  };

  constructor(
    editor: ICodeEditor,
    widget: SuggestWidget,
    accept: (selected: ISelectedSuggestion) => any
  ) {
    this._disposables.add(
      widget.onDidShow(() => this._onItem(widget.getFocusedItem()))
    );
    this._disposables.add(widget.onDidFocus(this._onItem, this));
    this._disposables.add(widget.onDidHide(this.reset, this));

    this._disposables.add(
      editor.onWillType((text) => {
        if (this._active && !widget.isFrozen()) {
          const ch = text.charCodeAt(text.length - 1);
          if (
            this._active.acceptCharacters.has(ch) &&
            editor.getOption(EditorOption.acceptSuggestionOnCommitCharacter)
          ) {
            accept(this._active.item);
          }
        }
      })
    );
  }

  private _onItem(selected: ISelectedSuggestion | undefined): void {
    if (
      !selected ||
      !isNonEmptyArray(selected.item.completion.commitCharacters)
    ) {
      // no item or no commit characters
      this.reset();
      return;
    }

    if (this._active && this._active.item.item === selected.item) {
      // still the same item
      return;
    }

    // keep item and its commit characters
    const acceptCharacters = new CharacterSet();
    for (const ch of selected.item.completion.commitCharacters) {
      if (ch.length > 0) {
        acceptCharacters.add(ch.charCodeAt(0));
      }
    }
    this._active = { acceptCharacters, item: selected };
  }

  reset(): void {
    this._active = undefined;
  }

  dispose() {
    this._disposables.dispose();
  }
}