'use strict';

let xSize = 1;
let ySize = 1;
let minesToPlace = 1;
let totalSpaces = xSize * ySize;
let goingRight = false;
let errorFlags = {
	rows: false,
	columns: false,
	mines: false,
};

function setupMinefield() {
	let mineField = new Array(ySize);
	
	for (let i = 0; i < ySize; i++){
		mineField[i] = new Array(xSize);
	}

	for (let i = 0; i < ySize; i++){
		for (let j = 0; j < xSize; j++){
			mineField[i][j] = 0;
		}
	}
	
	return mineField;
}

function getRandomInt(max) {
  return Math.floor(Math.random() * Math.floor(max));
}

function fillWithMines(mineField){
	let locationsSet = new Set();
	while (locationsSet.size < minesToPlace){
		locationsSet.add(getRandomInt(totalSpaces-1));
	}
	for (let mineLocation of locationsSet){
		let yField = Math.floor(mineLocation / xSize);
		let xField = mineLocation % xSize;
		//alert("location=" + mineLocation + ", yField=" + yField + ", xField=" + xField);
		mineField[yField][xField] = "B";
	}
}

function updateAllSweeperValues(mineField){
	for (let i = 0; i < ySize; i++){
		for (let j = 0; j < xSize; j++){
			if (mineField[i][j] != "B"){
				updateSweeperValue(mineField,i,j);
			}
		}
	}
}

function updateSweeperValue(mineField,yPos,xPos){
	let xMax = xSize - 1;
	let yMax = ySize - 1;
	if (yPos == 0 && xPos == 0){
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
	}
	else if (yPos == 0 && xPos == xMax){
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
	}
	else if (yPos == yMax && xPos == 0){
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
	}
	else if (yPos == yMax && xPos == xMax){
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
	}
	else if (yPos == 0){
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
	}
	else if (yPos == yMax){
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
	}
	else if (xPos == 0){
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
	}
	else if (xPos == xMax){
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
	}
	else{
		if (mineField[yPos+1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos+1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos-1][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos][xPos-1] == "B") mineField[yPos][xPos]++;
		if (mineField[yPos+1][xPos-1] == "B") mineField[yPos][xPos]++;
	}
}

function convertToDiscordEmoji(input){
	switch (input){
		case 0:
			return ":zero:";
		case 1:
			return ":one:";
		case 2:
			return ":two:";
		case 3:
			return ":three:";
		case 4:
			return ":four:";
		case 5:
			return ":five:";
		case 6:
			return ":six:";
		case 7:
			return ":seven:";
		case 8:
			return ":eight:";
		case "B":
			return ":bomb:";
		default:
			return ":poop:";
	}
}

function getDiscordTextForm(mineField){
	let mineFieldString = "Total mines: " + minesToPlace + "\n";
	for (let i = 0; i < ySize; i++){
		for (let j = 0; j < xSize; j++){
			mineFieldString += ("||" + convertToDiscordEmoji(mineField[i][j]) + "|| ");
		}
		mineFieldString += "\n";
	}
	return mineFieldString;
}

function changeHeader(){
	let image = document.querySelector("#header");
	let imageNumber = image.src.slice(-5,-4);
	let newImage = "images/header-";
	if (imageNumber == 1 || imageNumber == 3){
		newImage = newImage + "2.png";
		goingRight = !goingRight;
	}
	else if (imageNumber == 2 && goingRight){
		newImage += "3.png";
	}
	else if (imageNumber == 2 && !goingRight){
		newImage += "1.png";
	}
	image.setAttribute("src", newImage);
}

function generateAndDisplay(){
	let input = document.querySelector("#rowsInput").value;
	if (!verifyDimension(input)){
		//alert("ERROR: Rows value should be from 1 to 30, inclusive");
		return;
	}
	ySize = input;
	input = document.querySelector("#columnsInput").value;
	if (!verifyDimension(input)){
		//alert("ERROR: Columns value should be from 1 to 30, inclusive");
		return;
	}
	xSize = input;
	totalSpaces = xSize * ySize;
	input = document.querySelector("#minesInput").value;
	if(!verifyMinesNum(input)){
		//alert("ERROR: Number of mines should be from 1 to 1 less than the size of minefield, inclusive");
		return;
	}
	minesToPlace = input;
	let minefield = setupMinefield();
	fillWithMines(minefield);
	updateAllSweeperValues(minefield);
	let minefieldString = getDiscordTextForm(minefield);
	if (!verifyChars(minefieldString)){
		//alert("ERROR: Minefield is larger than the discord character limit");
		minefieldString = "(Generated minefield is larger than the discord character limit.)\n" +
							"(Although row and column limit is 30, if a value near the top end is used, the other dimension should be very small to compensate.)";
		changeFooter("error");
	}
	else changeFooter("ok");
	let textField = document.querySelector("#outputField");
	textField.value = minefieldString;
}

function verifyDimension(input){
	let num = parseInt(input);
	if (num < 1 || num > 30) return false;
	return true;
}

function verifyMinesNum(input){
	let num = parseInt(input);
	if (num < 0 || num > totalSpaces - 1) return false;
	return true;
}

function verifyChars(inputString){
	if (inputString.length > 2000) return false;
	return true;
}

function checkErrors(){
	let ySize = document.querySelector("#rowsInput").value;
	let xSize = document.querySelector("#columnsInput").value;
	if (this.name == "Rows"){
		if (!verifyDimension(ySize)){
			errorFlags.rows = true;
		}
		else errorFlags.rows = false;
	}
	if (this.name == "Columns"){
		if (!verifyDimension(xSize)){
			errorFlags.columns = true;
		}
		else errorFlags.columns = false;
	}
	if (errorFlags.rows == false && errorFlags.columns == false){
		totalSpaces = xSize * ySize;
		if (!verifyMinesNum(document.querySelector("#minesInput").value)){
			errorFlags.mines = true;
		}
		else errorFlags.mines = false;
	}
}

function updateErrorMessageAndButton(){
	let errorField = document.querySelector("#errorField");
	let errorMessage = "<br>Error: <br>";
	if (errorFlags.rows){
		errorMessage += "Number of columns must be in the range of 1 to 30<br>";
	}
	if (errorFlags.columns){
		errorMessage += "Number of rows must be in the range of 1 to 30<br>";
	}
	if (!errorFlags.rows && !errorFlags.columns && errorFlags.mines){
		errorMessage += "Number of mines must be in the range of 0 to (Rows * Columns) minus 1<br>";
	}
	if (!errorFlags.rows && !errorFlags.columns && !errorFlags.mines){
		errorMessage = "";
		document.querySelector("#generateButton").disabled = false;
		changeFooter("ok");
	}
	if (errorMessage != "") {
		document.querySelector("#generateButton").disabled = true;
		changeFooter("error");
		let textField = document.querySelector("#outputField");
		textField.value = "";
	}
	errorField.innerHTML = errorMessage;
}

function changeFooter(changeTo){
	let image = document.querySelector("#footer");
	if (changeTo == "ok") image.setAttribute("src", "images/footer-ok.png");
	if (changeTo == "error") image.setAttribute("src", "images/footer-error.png");
}

function updateAllOnPage(thisCheater = undefined){
	if(this == undefined){
		checkErrors.call(thisCheater);
	}
	else{
		checkErrors.call(this);
	}
	updateErrorMessageAndButton();
	generateAndDisplay();
}

document.body.addEventListener("click", changeHeader);
document.querySelector("button").addEventListener("click", generateAndDisplay);
document.querySelector("#rowsInput").addEventListener("change", updateAllOnPage);
document.querySelector("#columnsInput").addEventListener("change", updateAllOnPage);
document.querySelector("#minesInput").addEventListener("change", updateAllOnPage);
document.querySelector("#rowsInput").addEventListener('keyup', function(event){
	if (event.key == "Enter"){
		updateAllOnPage(document.querySelector("#rowsInput"));
	}
});
document.querySelector("#columnsInput").addEventListener('keyup', function(event){
	if (event.key == "Enter"){
		updateAllOnPage(document.querySelector("#columnsInput"));
	}
});
document.querySelector("#minesInput").addEventListener('keyup', function(event){
	if (event.key == "Enter"){
		updateAllOnPage(document.querySelector("#minesInput"));
	}
});
generateAndDisplay();