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

// Licensed under the MIT License.

'use strict';

import { nbformat } from '@jupyterlab/coreutils/lib/nbformat';

export function concatMultilineString(str : nbformat.MultilineString) : string {

if (Array.isArray(str)) {

let result = '';

for (let i = 0; i < str.length; i += 1) {

const s = str[i];

if (i < str.length - 1 && !s.endsWith('\n')) {

result = result.concat(`${s}\n`);

} else {

result = result.concat(s);

}

}

return result.trim();

}

return str.toString().trim();

}

export function formatStreamText(str: string) : string {

// Go through the string, looking for \r's that are not followed by \n. This is

// a special case that means replace the string before. This is necessary to

// get an html display of this string to behave correctly.

// Note: According to this:

// https://jsperf.com/javascript-concat-vs-join/2.

// Concat is way faster than array join for building up a string.

let result = '';

let previousLinePos = 0;

for (let i = 0; i < str.length; i += 1) {

if (str[i] === '\r') {

// See if this is a line feed. If so, leave alone. This is goofy windows \r\n

if (i < str.length - 1 && str[i + 1] === '\n') {

// This line is legit, output it and convert to '\n' only.

result += str.substr(previousLinePos, (i - previousLinePos));

result += '\n';

previousLinePos = i + 2;

i += 1;

} else {

// This line should replace the previous one. Skip our \r

previousLinePos = i + 1;

}

} else if (str[i] === '\n') {

// This line is legit, output it. (Single linefeed)

result += str.substr(previousLinePos, (i - previousLinePos) + 1);

previousLinePos = i + 1;

}

}

result += str.substr(previousLinePos, str.length - previousLinePos);

return result;

}