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

import {
  IDisposable,
  DisposableStore,
} from '../../../../vs/base/common/lifecycle';
import { ICodeEditor } from '../../../../vs/editor/browser/editorBrowser';
import { SuggestModel } from '../../../../vs/editor/contrib/suggest/suggestModel';

export class OvertypingCapturer implements IDisposable {
  private static readonly _maxSelectionLength = 51200;
  private readonly _disposables = new DisposableStore();

  private _lastOvertyped: { value: string; multiline: boolean }[] = [];
  private _empty: boolean = true;

  constructor(editor: ICodeEditor, suggestModel: SuggestModel) {
    this._disposables.add(
      editor.onWillType(() => {
        if (!this._empty) {
          return;
        }
        if (!editor.hasModel()) {
          return;
        }

        const selections = editor.getSelections();
        const selectionsLength = selections.length;

        // Check if it will overtype any selections
        let willOvertype = false;
        for (let i = 0; i < selectionsLength; i++) {
          if (!selections[i].isEmpty()) {
            willOvertype = true;
            break;
          }
        }
        if (!willOvertype) {
          return;
        }

        this._lastOvertyped = [];
        const model = editor.getModel();
        for (let i = 0; i < selectionsLength; i++) {
          const selection = selections[i];
          // Check for overtyping capturer restrictions
          if (
            model.getValueLengthInRange(selection) >
            OvertypingCapturer._maxSelectionLength
          ) {
            return;
          }
          this._lastOvertyped[i] = {
            value: model.getValueInRange(selection),
            multiline: selection.startLineNumber !== selection.endLineNumber,
          };
        }
        this._empty = false;
      })
    );

    this._disposables.add(
      suggestModel.onDidCancel((e) => {
        if (!this._empty && !e.retrigger) {
          this._empty = true;
        }
      })
    );
  }

  getLastOvertypedInfo(
    idx: number
  ): { value: string; multiline: boolean } | undefined {
    if (!this._empty && idx >= 0 && idx < this._lastOvertyped.length) {
      return this._lastOvertyped[idx];
    }
    return undefined;
  }

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