/*---------------------------------------------------------------------------------------------

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

* Licensed under the MIT License. See License.txt in the project root for license information.

*--------------------------------------------------------------------------------------------*/

'use strict';

import * as fs from 'fs';

import * as crypto from 'crypto';

import * as stream from 'stream';

import { TPromise } from 'vs/base/common/winjs.base';

import { once } from 'vs/base/common/functional';

export function checksum(path: string, sha1hash: string): TPromise<void> {

const promise = new TPromise<string>((c, e) => {

const input = fs.createReadStream(path);

const hash = crypto.createHash('sha1');

const hashStream = hash as any as stream.PassThrough;

input.pipe(hashStream);

const done = once((err?: Error, result?: string) => {

input.removeAllListeners();

hashStream.removeAllListeners();

if (err) {

e(err);

} else {

c(result);

}

});

input.once('error', done);

input.once('end', done);

hashStream.once('error', done);

hashStream.once('data', (data: Buffer) => done(null, data.toString('hex')));

});

return promise.then(hash => {

if (hash !== sha1hash) {

return TPromise.wrapError<void>(new Error('Hash mismatch'));

}

return TPromise.as(null);

});

}