import LipsumPreset from './LipsumPreset';
import LipsumPresetDefault from './LipsumPresetDefault';

export function generate(preset = new LipsumPresetDefault()): string {
	var result = "";
	var isFirstWord = true;
	var wordsRemaining = getRandomWordCount(preset);
	var fullStopWait = getRandomFullStopWait(preset);
	var commaWait = getRandomCommaWait(preset);
	var hyphenWait = getRandomHyphenWait(preset);
	var enDashWait = getRandomEnDashWait(preset);
	var capitalStartWait = getRandomCapitalStartWait(preset);
	var space = "";
	var spaceWait = 0;
	var word = "";
	var lastWord = "";
	
	while (true) {
		if (!isFirstWord) {
			space = " ";
			if (spaceWait < 1 && lastWord.length >= 4) {
				if (fullStopWait < 1 && wordsRemaining >= preset.fullStopAfterMin) {
					space = ". ";
					fullStopWait = getRandomFullStopWait(preset);
					capitalStartWait = 0;
					spaceWait = 2;
				} else if (commaWait < 1 && wordsRemaining >= preset.commaAfterMin) {
					if (getRandomIsSemicolon(preset)) {
						space = "; ";
					} else if (getRandomIsColon(preset)) {
						space = ": ";
					} else {
						space = ", ";
					}
					spaceWait = 2;
					commaWait = getRandomCommaWait(preset);
				} else if (hyphenWait < 1) {
					space = "-";
					hyphenWait = getRandomHyphenWait(preset);
					capitalStartWait = Math.max(1, capitalStartWait);
					wordsRemaining++;
					spaceWait = 1;
				} else if (enDashWait < 1) {
					space = " – ";
					enDashWait = getRandomEnDashWait(preset);
					spaceWait = 2;
				}
			}
			result += space;
		}
		
		word = getRandomWord(preset, lastWord);
		lastWord = word;
		
		if (preset.capitalStart && isFirstWord || capitalStartWait < 1) {
			word = capitalizeFirstLetter(word);
			capitalStartWait = getRandomCapitalStartWait(preset);
		}
		if (getRandomIsHighlighted(preset)) {
			word = preset.highlightBefore + word + preset.highlightAfter;
		}
		
		result += word;
		
		wordsRemaining--;
		spaceWait--;
		fullStopWait--;
		commaWait--;
		hyphenWait--;
		enDashWait--;
		capitalStartWait--;
		
		isFirstWord = false;
		if (wordsRemaining < 1) {
			break;
		}
	}
	
	if (preset.fullStopAtEnd) {
		result += ".";
	}
	
	return result;
}

function getRandomBetweenInclusive(min: number, max: number): number {
	var diff = max - min + 1;
	var result = Math.floor(min + Math.random() * diff);
	if (isNaN(result)) result = Infinity;
	return result;
}

function getRandomCommaWait(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.commaAfterMin, preset.commaAfterMax);
}

function getRandomFullStopWait(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.fullStopAfterMin, preset.fullStopAfterMax);
}

function getRandomHyphenWait(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.hyphenAfterMin, preset.hyphenAfterMax);
}

function getRandomEnDashWait(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.enDashAfterMin, preset.enDashAfterMax);
}

function getRandomWordCount(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.wordCountMin, preset.wordCountMax);
}

function getRandomIsSemicolon(preset: LipsumPreset): boolean {
	return Math.random() < preset.semicolonChance;
}

function getRandomIsColon(preset: LipsumPreset): boolean {
	return Math.random() < preset.colonChance;
}

function getRandomCapitalStartWait(preset: LipsumPreset): number {
	return getRandomBetweenInclusive(preset.capitalStartAfterMin, preset.capitalStartAfterMax);
}

function getRandomIsHighlighted(preset: LipsumPreset): boolean {
	return Math.random() < preset.highlightChance;
}

function capitalizeFirstLetter(src: string): string {
	return src.slice(0, 1).toUpperCase() + src.slice(1);
}

function getRandomWord(preset: LipsumPreset, notThisWord: string): string {
	var word = "";
	do {
		word = preset.words[getRandomBetweenInclusive(0, preset.words.length - 1)];
	} while (word == notThisWord);
	return word;
}

export default {
	generate
}