/* Userscript to highlight sentences by readability */



// Set score colors for css if they have not been defined

var readabilityScoreColors = readabilityScoreColors || 

	'rgb(255,96,96)', 

	'rgb(255,128,128)', 

	'rgb(255,192,128)', 

	'rgb(255,224,128)', 

	'rgb(255,255,128)', 

	'rgb(214,255,128)', 

	'rgb(171,255,128)', 

	'rgb(128,255,128)', 

	'rgb(128,255,171)', 

	'rgb(128,255,214)',];





// Goes through all the p-elements and splits their content into span-elements. Each span corresponds to a sentence.

function divideParagraphsIntoSentences(){

	let paragraphs = document.querySelectorAll('.mw-parser-output > p');

	

	// Periods are the main guide for where sentences start and end.

	// However, not all periods mark sentences, like in different forms of abbreviations.

	// Placeholders are used for exceptions.

	let periodPlaceholder = 'PERIOD_PLACEHOLDER';

	let exceptionString = '...; Mr.; Mrs.; Dr.; Jr.; Sr.; Prof.; St.; Ave.; Corp.; Inc.; Ltd.; Co.; Gov.; Capt.; Sgt.; et al.; vs.; e.t.a.; .A.; .B.; .C.; .D.; .E.; .F.; .G.; .H.; .I.; .J.; .K.; .L.; .M.; .N.; .O.; .P.; .Q.; .R.; .S.; .T.; .U.; .V.; .W.; .X.; .Y.; .Z.;  A.;  B.;  C.;  D.;  E.;  F.;  G.;  H.;  I.;  J.;  K.;  L.;  M.;  N.;  O.;  P.;  Q.;  R.;  S.;  T.;  U.;  V.;  W.;  X.;  Y.;  Z.; .a.; .b.; .c.; .d.; .e.; .f.; .g.; .h.; .i.; .j.; .k.; .l.; .m.; .n.; .o.; .p.; .q.; .r.; .s.; .t.; .u.; .v.; .w.; .x.; .y.; .z.; .a; .b; .c; .d; .e; .f; .g; .h; .i; .j; .k; .l; .m; .n; .o; .p; .q; .r; .s; .t; .u; .v; .w; .x; .y; .z; 0.0; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; 1.0; 1.1; 1.2; 1.3; 1.4; 1.5; 1.6; 1.7; 1.8; 1.9; 2.0; 2.1; 2.2; 2.3; 2.4; 2.5; 2.6; 2.7; 2.8; 2.9; 3.0; 3.1; 3.2; 3.3; 3.4; 3.5; 3.6; 3.7; 3.8; 3.9; 4.0; 4.1; 4.2; 4.3; 4.4; 4.5; 4.6; 4.7; 4.8; 4.9; 5.0; 5.1; 5.2; 5.3; 5.4; 5.5; 5.6; 5.7; 5.8; 5.9; 6.0; 6.1; 6.2; 6.3; 6.4; 6.5; 6.6; 6.7; 6.8; 6.9; 7.0; 7.1; 7.2; 7.3; 7.4; 7.5; 7.6; 7.7; 7.8; 7.9; 8.0; 8.1; 8.2; 8.3; 8.4; 8.5; 8.6; 8.7; 8.8; 8.9; 9.0; 9.1; 9.2; 9.3; 9.4; 9.5; 9.6; 9.7; 9.8; 9.9. .0; .1; .2; .3; .4; .5; .6; .7; .8; .9;';

	let exceptionStringSeparator = '; ';

	let periodExceptions = exceptionString.split(exceptionStringSeparator);

	let periodExceptionPlaceholders = exceptionString.split('.').join(periodPlaceholder).split(exceptionStringSeparator);

	

	for(let paragraph of paragraphs){

		let textContent = paragraph.textContent.split('\r').join('').split('\n').join('').trim();

		

		// exclude very short paragraphs

		if(textContent.length > 20){

			divideIntoSentences(paragraph, periodExceptions, periodExceptionPlaceholders);

		}

	}



	// remove very short sentences

	let sentenceElements = document.getElementsByClassName('sentence');

	for(let sentenceElement of sentenceElements){

		let sentenceText = getSentenceText(sentenceElement);

		if(sentenceText.trim().length < 10){

			sentenceElement.classList.remove('sentence');

		}

	}



	// Split the content of a p-element into span-elements. Each span corresponds to a sentence.

	function divideIntoSentences(paragraph, periodExceptions, periodExceptionPlaceholders){

		// Loop through all the nodes inside the p-element.

		// Span-open-tags and close-tags are placed through code.

		let innerHTML = getSpanStartTag();

		let currentChild = paragraph.firstChild;

		while(currentChild){

			// if it is a text node, modify it

			if(currentChild.nodeType === Node.TEXT_NODE){

				innerHTML += adjustTextNodes(currentChild.nodeValue, periodExceptions, periodExceptionPlaceholders);

			}

			

			// if its an element, add outerHTML

			else if(currentChild.nodeType === Node.ELEMENT_NODE){

				innerHTML += currentChild.outerHTML;

			}

			

			// otherwise add nodeValue

			else{

				innerHTML += currentChild.nodeValue;

			}

			

			currentChild = currentChild.nextSibling;

		}



		innerHTML += '</span>';

		

		paragraph.innerHTML = innerHTML;



		// utility function to get the code for the opening span tag

		function getSpanStartTag(){

			return `<span class="sentence">`;

		}

		

		// utility function to get the code for span tags in the middle (closing + opening)

		function getSpanEndAndStart(punctuation){

			return punctuation + '</span>' + getSpanStartTag();

		}

		

		// utility function to modify text nodes

		// they contain the punctuation relevant for sentences

		function adjustTextNodes(text, periodExceptions, periodExceptionPlaceholders){

			// use placeholders to remove all periods that do not mark sentences

			text = insertPlaceholders(text, periodExceptions, periodExceptionPlaceholders);

			

			// split using the remaining punctuation

			text = text.split('.').join(getSpanEndAndStart('.'))

					.split('!').join(getSpanEndAndStart('!'))

					.split('?').join(getSpanEndAndStart('?'));

					

			

			// use placeholders to return all periods that do not mark sentences

			text = removePlaceholders(text, periodExceptions, periodExceptionPlaceholders);

			

			return text;

			

			function insertPlaceholders(text, periodExceptions, periodExceptionPlaceholders){

				let modifiedText = text;

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

					modifiedText = modifiedText.split(periodExceptionsi]).join(periodExceptionPlaceholdersi]);

				}

				return modifiedText;

			}

			

			function removePlaceholders(text, periodExceptions, periodExceptionPlaceholders){

				let modifiedText = text;

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

					modifiedText = modifiedText.split(periodExceptionPlaceholdersi]).join(periodExceptionsi]);

				}

				return modifiedText;

			}

		}

	}

}



// Function to rate the readability of sentences and give them their class accordingly.

function rateSentences(){

	

	// class names for different scores

	const scoreClasses = 

		'score-10-0', 

		'score-20-10', 

		'score-30-20', 

		'score-40-30', 

		'score-50-40', 

		'score-60-50', 

		'score-70-60', 

		'score-80-70', 

		'score-90-80', 

		'score-100-90'];

		

	// Loop through all sentences, add their score class and their title attribute.

	let sentenceElements = document.body.getElementsByClassName('sentence');

	for(let sentenceElement of sentenceElements){

		let sentenceText = getSentenceText(sentenceElement);

		let score = getSentenceScore(sentenceText);

		if(!isNaN(score)){

			sentenceElement.title = `Score: ${score.toFixed(2)}`;

			sentenceElement.dataset.sentenceText = sentenceText;

			sentenceElement.dataset.score = score;

			sentenceElement.classList.add(getScoreClass(score, scoreClasses));

		}

		else{

			sentenceElement.classList.remove('sentence');

		}

	}



	// Add the style sheet to color the score classes.

	addScoreStyleSheet(scoreClasses, readabilityScoreColors);



	function getScoreClass(score, scoreClasses){

		let index = Math.floor(score / 10);

		if(index < 0){

			index = 0;

		}

		if(index > 9){

			index = 9;

		}

		return scoreClassesindex];

	}



	function addScoreStyleSheet(scoreClasses, readabilityScoreColors){

		const style = document.createElement('style');

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

			style.innerHTML += `.${scoreClassesi} {background-color: ${readabilityScoreColorsi}; } `;

		}

		document.head.appendChild(style);

	}

}



// Creates an overview at the top of the page

// This overview shows the readability of the whole article and other information

function createOverview(){

	// Readability depends on the number of syllables, words, and sentences

	let totalSyllableCount = 0;

	let totalPolySyllableCount = 0;

	let totalWordCount = 0;

	const sentenceElements = document.getElementsByClassName('sentence');

	let totalSentenceCount = sentenceElements.length;

	const sentenceLengthArray = [];

	for(let sentenceElement of sentenceElements){

		let sentenceText = getSentenceText(sentenceElement);

		let words = getWords(sentenceText);

		totalWordCount += words.length;

		sentenceLengthArray.push(words.length);

		for(let word of words){

			let syllableCount = getSyllableCount(word);

			totalSyllableCount += syllableCount;

			if(syllableCount >= 3){

				totalPolySyllableCount++;

			}

		}

	}

	

	let totalReadability = getFleschKincaidReadability(totalSyllableCount, totalWordCount, totalSentenceCount);

	let totalGradeLevel = getFleschKincaidGradeLevel(totalSyllableCount, totalWordCount, totalSentenceCount);

	let totalSmogGradeLevel = getSmogGradeLevel(totalPolySyllableCount, totalSentenceCount);

	

	const mainDiv = document.getElementById('mw-content-text');

	const overviewDiv = document.createElement('div');

	mainDiv.insertBefore(overviewDiv, mainDiv.firstChild);

	const headline = document.createElement('h2');

	overviewDiv.appendChild(headline);

	headline.innerHTML = 'Readability overview';

	const tableDiv = document.createElement('div');

	overviewDiv.appendChild(tableDiv);

	tableDiv.style.display = 'flex';

	insertOverviewTable(tableDiv);

	insertKeyTable(tableDiv);

	//overviewDiv.appendChild(document.createElement('br'));

	insertSentenceTable(overviewDiv);

	

	function insertOverviewTable(parent){

		const overviewTable = document.createElement('table');

		parent.appendChild(overviewTable);

		overviewTable.classList.add('wikitable');

		overviewTable.style.marginRight = '20px';

		

		/*const overviewCaption = document.createElement('caption');

		overviewTable.appendChild(overviewCaption);

		overviewCaption.innerHTML = 'Readability overview';*/

		

		const overviewTableBody = document.createElement('tbody');

		overviewTable.appendChild(overviewTableBody);

		addRow(overviewTableBody, 'Readability (<a href="/info/en/?search=Flesch%E2%80%93Kincaid_readability_tests">Flesch</a>)', totalReadability.toFixed(2));

		addRow(overviewTableBody, 'Grade level (<a href="/info/en/?search=Flesch%E2%80%93Kincaid_readability_tests">Flesch</a>)', totalGradeLevel.toFixed(2));

		addRow(overviewTableBody, 'Grade level (<a href="/info/en/?search=SMOG">SMOG</a>)', totalSmogGradeLevel.toFixed(2));

		addRow(overviewTableBody, 'Sentences', totalSentenceCount);

		addRow(overviewTableBody, 'Words', totalWordCount);

		addRow(overviewTableBody, 'Syllables', totalSyllableCount);

		addRow(overviewTableBody, 'Average sentence length', (totalWordCount/totalSentenceCount).toFixed(2));

		addRow(overviewTableBody, 'Standard deviation<br>of sentence length', (getStandardDeviation(sentenceLengthArray)).toFixed(2));

		

		function getStandardDeviation(numbers){

			const sum = numbers.reduce(function(sum, number){return sum + number;});

			const mean = sum / numbers.length;

			const varianceSum = numbers.reduce(function(sum, number){console.log(Math.pow(number - mean, 2)); return sum + Math.pow(number - mean, 2);}, 0);

			const variance = varianceSum/numbers.length;

			const standardDeviation = Math.sqrt(variance);

			return standardDeviation;

		}

	}

	

	// Key for the coloring

	function insertKeyTable(parent){

		const keyTable = document.createElement('table');

		parent.appendChild(keyTable);

		keyTable.classList.add('wikitable');

		keyTable.innerHTML = `<thead>

		<tr>

			<th>Score</th>

			<th>School level</th>

		</tr>

	</thead>

	<tbody>

		<tr class="score-100-90">

			<td>100–90</td>

			<td>5th grade</td>

		</tr>

		<tr class="score-90-80">

			<td>90–80</td>

			<td>6th grade</td>

		</tr>

		<tr class="score-80-70">

			<td>80–70</td>

			<td>7th grade</td>

		</tr>

		<tr class="score-70-60">

			<td>70–60</td>

			<td>8th & 9th grade</td>

		</tr>

		<tr class="score-60-50">

			<td>60–50</td>

			<td>10th to 12th grade</td>

		</tr>

		<tr class="score-50-40">

			<td>50–40</td>

			<td>College</td>

		</tr>

		<tr class="score-40-30">

			<td>40–30</td>

			<td>College</td>

		</tr>

		<tr class="score-30-20">

			<td>30–20</td>

			<td>College graduate</td>

		</tr>

		<tr class="score-20-10">

			<td>20–10</td>

			<td>College graduate</td>

		</tr>

		<tr class="score-10-0">

			<td>10–0</td>

			<td>College graduate</td>

		</tr>

	</tbody>`;

	}

	

	

	// sentence table to display all sentences ordered by lowest score

	function insertSentenceTable(parent){

		// button to show/hide the table

		const sentenceTableButton = document.createElement('button');

		parent.append(sentenceTableButton);

		sentenceTableButton.innerHTML = 'Show sentences ordered by lowest score';

		sentenceTableButton.style.fontSize = "24px";

		

		// the table itself

		const sentenceTable = document.createElement('table');

		parent.appendChild(sentenceTable);

		sentenceTable.classList.add('wikitable');

		sentenceTable.style.display = 'none';

		

		const sentenceCaption = document.createElement('caption');

		sentenceTable.appendChild(sentenceCaption);

		sentenceCaption.innerHTML = 'Sentences ordered by lowest score';

		

		const sentenceTableBody = document.createElement('tbody');

		sentenceTable.appendChild(sentenceTableBody);



		// matrix to store the table values

		const sentenceMatrix = [];

		for(let sentenceElement of sentenceElements){

			let sentenceText = sentenceElement.dataset.sentenceText;

			let score = parseFloat(sentenceElement.dataset.score);

			sentenceMatrix.push([sentenceText, score]);

		}

		

		// sort by lowest score

		sentenceMatrix.sort(function(a, b){

			return a1 - b1];

		});

		

		// loop through the matrix and add one row per index

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

			let sentenceText = sentenceMatrixi][0];

			let score = sentenceMatrixi][1];

			addRow(sentenceTableBody, sentenceText, score.toFixed(2));

		}

		

		// show/hide function of the button

		sentenceTableButton.onclick = function(){

			if(sentenceTableButton.innerHTML.includes('Show')){

				sentenceTable.style.display = '';

				sentenceTableButton.innerHTML = sentenceTableButton.innerHTML.split('Show').join('Hide');

			}

			else{

				sentenceTable.style.display = 'none';

				sentenceTableButton.innerHTML = sentenceTableButton.innerHTML.split('Hide').join('Show');

			}

		};

	}

	

	// utility function to add rows to a table

	function addRow(tableBody, name, value){

		let row = document.createElement('tr');

		

		let nameCell = document.createElement('td');

		nameCell.innerHTML = name;

		row.appendChild(nameCell);

		

		let valueCell = document.createElement('td');

		valueCell.innerHTML = value;

		row.appendChild(valueCell);

		

		tableBody.appendChild(row);

	}

}



// Utility function to extract the text from a sentence element

function getSentenceText(sentenceElement){

	// hide references and certain templates

	let refs = sentenceElement.querySelectorAll('.reference, .Inline-Template');

	for(let ref of refs){

		ref.style.display = 'none';

	}

	

	// the innerText attribute ignores hidden elements

	let sentenceText = sentenceElement.innerText;

	

	// show them again

	for(let ref of refs){

		ref.style.display = '';

	}

	

	// formatting

	if(sentenceText0 == '"'){

		sentenceText = sentenceText.substring(1);

	}

	sentenceText = sentenceText.trim();

	

	return sentenceText;

}



// utility function to get the readability score of a sentence

function getSentenceScore(sentenceText){

	let syllableCount = 0;

	

	let words = getWords(sentenceText);

	for(let word of words){

		syllableCount += getSyllableCount(word);

	}

	

	let wordCount = words.length;

	let score = getFleschKincaidReadability(syllableCount, wordCount, 1);

	

	return score;

}



// utility function: this is the main metric

function getFleschKincaidReadability(syllableCount, wordCount, sentenceCount){

	let wordsPerSentence = wordCount / sentenceCount;

	let syllablesPerWord = syllableCount / wordCount;

	let score = 206.835 - (1.015 * wordsPerSentence) - (84.6 * syllablesPerWord);

	return score;

}



// utility function: this shows the grade level and is used for the overview

function getFleschKincaidGradeLevel(syllableCount, wordCount, sentenceCount){

	let wordsPerSentence = wordCount / sentenceCount;

	let syllablesPerWord = syllableCount / wordCount;

	let score = (0.39 * wordsPerSentence) + (11.8 * syllablesPerWord) - 15.59;

	return score;

}



// utility function: get SMOG readability for the overview

function getSmogGradeLevel(polySyllableCount, sentenceCount){

	let smogGradeLevel = 1.0430 * Math.sqrt(polySyllableCount * 30 / sentenceCount) + 3.1291;

	return smogGradeLevel;

}



// utility function to extract words from a sentence

function getWords(sentenceText){

	let punctuation = '.?!,;:"()[]{}--./&*#$%@+-=<>|~^\\' + "'";

	for(let character of punctuation){

		sentenceText = sentenceText.split(character).join('');

	}

	

	sentenceText = sentenceText.trim();

	sentenceText = fullReplace(sentenceText, '  ', ' ');

	

	let words = sentenceText.split(' ');

	words = words.filter(function(word) {

		return word.length > 0;

	});

	

	return words;

}



// utility function to count the syllables of a word

function getSyllableCount(word){

	word = word.toLowerCase();

	

	if (word.endsWith('e')) {

		word = word.slice(0, -1);

	}

	word = word.split('e').join('a')

		.split('i').join('a')

		.split('o').join('a')

		.split('u').join('a')

		.split('y').join('a')

		.split('e').join('a');

		

	word = fullReplace(word, 'aa', 'a');

	

	let syllableCount = word.split('a').length - 1;

	if(syllableCount < 1){

		syllableCount = 1;

	}

	

	return syllableCount;

}



// utility function to iteratively replace a string until no more occurrences are found

function fullReplace(string, oldSubstring, newSubstring){

	let newString = string;

	while(newString.includes(oldSubstring)){

		newString = newString.split(oldSubstring).join(newSubstring);

	}

	return newString;

}



// anonymous main function

(function(){

	// restrict script to mainspace, userspace, wikipedia, help, and draftspace

	const namespaceNumber = mw.config.get('wgNamespaceNumber');

	const allowedNamespaces = 0, 2, 4, 12, 118];

	if (allowedNamespaces.indexOf(namespaceNumber) != -1) {

		// add a link to the toolbox

		$.when(mw.loader.using('mediawiki.util'), $.ready).then(function (){

			var portletlink = mw.util.addPortletLink('p-tb', '#', 'Readability');

			

			// run the main function when the link is clicked

			portletlink.onclick = function(e) {

				e.preventDefault();

				divideParagraphsIntoSentences();

				rateSentences();

				createOverview();

			};

		});

	}

})();