enigma-bbs/core/word_wrap.js

/* jslint node: true */
'use strict';

const renderStringLength	= require('./string_util.js').renderStringLength;

//	deps
const assert				= require('assert');
const _						= require('lodash');

exports.wordWrapText	= wordWrapText;

const SPACE_CHARS		= [
	' ', '\f', '\n', '\r', '\v',
	'​\u00a0', '\u1680', '​\u180e', '\u2000​', '\u2001', '\u2002', '​\u2003', '\u2004',
	'\u2005', '\u2006​', '\u2007', '\u2008​', '\u2009', '\u200a​', '\u2028', '\u2029​',
	'\u202f', '\u205f​', '\u3000',
];

const REGEXP_WORD_WRAP = new RegExp(`\t|[${SPACE_CHARS.join('')}]`, 'g');

function wordWrapText(text, options) {
	assert(_.isObject(options));
	assert(_.isNumber(options.width));

	options.tabHandling	= options.tabHandling || 'expand';
	options.tabWidth	= options.tabWidth || 4;
	options.tabChar		= options.tabChar || ' ';

	//const REGEXP_GOBBLE = new RegExp(`.{0,${options.width}}`, 'g');
	//
	//	For a given word, match 0->options.width chars -- alwasy include a full trailing ESC
	//	sequence if present!
	//
	//	:TODO: Need to create ansi.getMatchRegex or something - this is used all over
	const REGEXP_GOBBLE = new RegExp(`.{0,${options.width}}\\x1b\\[[\\?=;0-9]*[ABCDEFGHJKLMSTfhlmnprsu]|.{0,${options.width}}`, 'g');

	let m;
	let word;
	let c;
	let renderLen;
	let i			= 0;
	let wordStart	= 0;
	let result		= { wrapped : [ '' ], renderLen : [ 0 ] };

	function expandTab(column) {
		const remainWidth = options.tabWidth - (column % options.tabWidth);
		return new Array(remainWidth).join(options.tabChar);
	}

	function appendWord() {
		word.match(REGEXP_GOBBLE).forEach( w => {
			renderLen = renderStringLength(w);

			if(result.renderLen[i] + renderLen > options.width) {
				if(0 === i) {
					result.firstWrapRange = { start : wordStart, end : wordStart + w.length };
				}

				result.wrapped[++i]	= w;
				result.renderLen[i]	= renderLen;
			} else {
				result.wrapped[i] 	+= w;
				result.renderLen[i] = (result.renderLen[i] || 0) + renderLen;
			}
		});
	}

	//
	//	Some of the way we word wrap is modeled after Sublime Test 3:
	//
	//	*	Sublime Text 3 for example considers spaces after a word
	//		part of said word. For example, "word    " would be wraped
	//		in it's entirity.
	//
	//	*	Tabs in Sublime Text 3 are also treated as a word, so, e.g.
	//		"\t" may resolve to "      " and must fit within the space.
	//
	//	*	If a word is ultimately too long to fit, break it up until it does.
	//
	while(null !== (m = REGEXP_WORD_WRAP.exec(text))) {
		word = text.substring(wordStart, REGEXP_WORD_WRAP.lastIndex - 1);

		c = m[0].charAt(0);
		if(SPACE_CHARS.indexOf(c) > -1) {
			word += m[0];
		} else if('\t' === c) {
			if('expand' === options.tabHandling) {
				//	Good info here: http://c-for-dummies.com/blog/?p=424
				word += expandTab(result.wrapped[i].length + word.length) + options.tabChar;
			} else {
				word += m[0];
			}
		}

		appendWord();
		wordStart = REGEXP_WORD_WRAP.lastIndex + m[0].length - 1;
	}

	word = text.substring(wordStart);
	appendWord();

	return result;
}