// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

import {

CancellationToken,

FormattingOptions,

OnTypeFormattingEditProvider,

Position,

TextDocument,

TextEdit

} from 'vscode';

import { LineFormatter } from '../formatters/lineFormatter';

import { TokenizerMode, TokenType } from '../language/types';

import { getDocumentTokens } from '../providers/providerUtilities';

export class OnEnterFormatter implements OnTypeFormattingEditProvider {

private readonly formatter = new LineFormatter();

public provideOnTypeFormattingEdits(

document: TextDocument,

position: Position,

_ch: string,

_options: FormattingOptions,

_cancellationToken: CancellationToken

): TextEdit[] {

if (position.line === 0) {

return [];

}

// Check case when the entire line belongs to a comment or string

const prevLine = document.lineAt(position.line - 1);

const tokens = getDocumentTokens(document, position, TokenizerMode.CommentsAndStrings);

const lineStartTokenIndex = tokens.getItemContaining(document.offsetAt(prevLine.range.start));

const lineEndTokenIndex = tokens.getItemContaining(document.offsetAt(prevLine.range.end));

if (lineStartTokenIndex >= 0 && lineStartTokenIndex === lineEndTokenIndex) {

const token = tokens.getItemAt(lineStartTokenIndex);

if (token.type === TokenType.Semicolon || token.type === TokenType.String) {

return [];

}

}

const formatted = this.formatter.formatLine(document, prevLine.lineNumber);

if (formatted === prevLine.text) {

return [];

}

return [new TextEdit(prevLine.range, formatted)];

}

}