// Import the game logic script from the root file
importScripts('gamelogic.js');

/**
 * On a message event as running via web worker.
 * @param {Object}  event 		  The event details
 * @param {Array}   event.data 	  The array of data sent with the request
 * @param {String}  event.data[0] The event command
 * @param {String}  event.data[1] The game board
 * @param {Object}  event.data[2] The Human users ships
 * @param {Double}  event.data[3] The AI Skill level
 * @param {Boolean} event.data[4] Whether it is the first game or not
 */
onmessage = function(event) {
	// Extract the command and parameters
	let command = event.data[0];
	let board = event.data[1], ships = event.data[2], skillLevel = event.data[3], firstGame = event.data[4];

	// Switch the command that was sent
	switch(command) {
		// Move command requested
		case 'move':
			// Get and post the move back to the main thread
			//setTimeout(function() {
				postMessage({move: aiMove(board, ships, skillLevel, firstGame)});
			//}, 350);

			break;

		// If a ship placement is requested
		case 'getBoard':
			// Post the ships back to the user
			postMessage({ships: getAIShipPlacement()});
			break;

		// Chat command requested
		case 'chat':
			// Get a chat message
			let message = aiChat(board, skillLevel, firstGame);

			// If a chat message was returned, post it
			if(message != undefined && message != '') {
				postMessage({message: message});
			}

			break;
	}
}

//skillLevel is the sliding scale, number between 1 and 10
//board is the current board
function aiMove(board, ships, skillLevel, firstGame) {
	let difficulty = skillLevel*10;
	let availableMoves;
	let move;
	let pick;
	let random;
	let huntAbility = false;
	let advancedHuntMode = false;
	let advancedSearchMode = false;
	let cheatMode = false;
	let probablity;

	switch (difficulty){
		case 0:
			//All features are false.
			break;
		case 1:
			huntAbility = true;
			probablity = 0.6;

			break;
		case 2:
			huntAbility = true;
			probablity = 0.4;
			break;
		case 3:
			huntAbility = true;
			probablity = 0.2;
			break;
		case 4:
			huntAbility = true;
			advancedSearchMode = true;
			probablity = 0.6;

			break;
		case 5:
			huntAbility = true;
			advancedSearchMode = true;
			probablity = 0.4;

			break;
		case 6:
			huntAbility = true;
			advancedSearchMode = true;
			probablity = 0.2;

			break;
		case 7:
			huntAbility = true;
			advancedSearchMode = true;
			advancedHuntMode = true;
			probablity = 0.6;

			break;
		case 8:
			huntAbility = true;
			advancedSearchMode = true;
			advancedHuntMode = true;
			probablity = 0.4;

			break;
		case 9:
			huntAbility = true;
			advancedSearchMode = true;
			advancedHuntMode = true;
			probablity = 0.2;

			break;
		case 10:
			huntAbility = true;
			advancedSearchMode = true;
			advancedHuntMode = true;
			cheatMode = true;
			probablity = 0.1
	}

	//Generate a random number between 0 and 1
	random = Math.random();

	//Determine whether to use huntAbility for levels 1 - 3.
	if(difficulty > 0 && difficulty < 4){
		if(random <= probablity){
			huntAbility = false;
		}
	}

	//Determine whether to use advanced search mode for levels 4 - 6
	if(difficulty > 3 && difficulty < 7){
		if(random <= probablity){
			advancedSearchMode = false;
		}
	}

	//Determine whether to use advanced hunt mode for levels 7 - 9
	if(difficulty > 6 && difficulty < 10){
		if(random <= probablity){
			advancedHuntMode = false;
		}
	}

	//Determine whether to use the cheat mode for level 10.
	if(cheatMode == true && random <= probablity){
		cheatMode = true;
	}
	else{
		cheatMode = false;
	}
	console.log("Difficulty: " + difficulty + " Hunt Ability: " + huntAbility + " Advanced Search Mode: " + advancedSearchMode + " Advanced Hunt Mode: " + advancedHuntMode + " Cheat Mode: " + cheatMode);
	//Determine whether there are any hits on the board, hence returning true for huntmode.
	huntMode = checkHits(board);
	//Hunt modes.
	//If the there is a hit and the AI has hunt ability activated. Begin a hunt for the ship.
	if(huntMode == true && huntAbility == true){
		//If the AI has advanced hunt mode activated, use the advanced find hit method.
		if(advancedHuntMode == true){
			move = advancedFindHits(board);
			return{row: move.row, col: move.col};
		}
		else{
			//Otherwise use the standard find hit method to return moves to randomly choose from.
			availableMoves = findHits(board);
		}
	}
	//Search modes.
	else{
		//If cheatMode is activated get an array of cheat moves.
		if(cheatMode == true){
			availableMoves = getCheatMoves(board);
		}
		//If advanced search mode is activated use the advanced get moves method.
		else if(advancedSearchMode == true){
			availableMoves = advancedGetAvailableMoves(board);
		}
		//Otherwise use the standard get moves method.
		else{
			availableMoves = getAvailableMoves(board);
		}
	}
	//Randomly pick a move from the available moves.
	pick = Math.floor(Math.random()* availableMoves.length);
	move = availableMoves[pick];
	//Return the move coordinates.
	return {row: move.row , col: move.col};

}

/*--------------- Search Methods ---------------*/
//Methods to return moves for the AI to take.

//Standard method to return an array of all the potential moves the AI can make.
function getAvailableMoves(board){
	//Array to store move objects.
	let availableMoves = [];
	//Traverse the board to access each cell.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			//If the board position is available for a placement, push it to the moves array.
			if(board[i][j].value == 's' || board[i][j].value == ''){
				availableMoves.push({row: i, col: j});
			}
		}
	}
	return availableMoves;
}

//Advanced version of getAvailableMoves method.
//This method returns availableMoves where the parity of the row and column index is the same.
//Meaning a cross patern will be used to search the board, hence making it more likely to get a hit.
function advancedGetAvailableMoves(board){
	//Array to store move objects.
	let availableMoves = [];
	//Traverse the board to access each cell.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			//If the row and column indexes are both even.
			if(i%2 == 0 && j%2 == 0){
				//If the board position is available for a placement, push it to the moves array.
				if(board[i][j].value == 's' || board[i][j].value == ''){
					availableMoves.push({row: i, col: j});
				}
			}
			//If the row and column indexes are both odd.
			else if(i%2 != 0 && j%2 != 0){
				//If the board position is available for a placement, push it to the moves array.
				if(board[i][j].value == 's' || board[i][j].value == ''){
					availableMoves.push({row: i, col: j});
				}
			}

		}
	}
	//Array of moves is returned.
	return availableMoves;
}

//Cheat Mode.
//This method is for the top difficulty.
//Returns all the positions with ship locations.
function getCheatMoves(board){
	//Array to store move objects.
	let availableMoves = [];
	//Traverse the board to access each cell.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			//If there is a ship in the position, push it to the moves array.
			if(board[i][j].value == 's'){
				availableMoves.push({row: i, col: j});
			}
		}
	}
	//Array of moves is returned.
	return availableMoves;
}



/*--------------- Hunting Methods ---------------*/
//Methods to determine if there is a hit, and use that information to destroy the entire ship.

//Method to return whether it is necessary to enter hunt mode.
function checkHits(board){
	//Traverse the board to access each cell.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			//IF there is a hit return true to begin hunt mode.
			if(board[i][j].value == 'h'){
				return true;
			}
		}
	}
	//Otherwise return false to continue search mode.
	return false;

}

//Method to search the cells around a hit.
function findHits(board){
	//Array to store move objects.
	let availableMoves = [];
	//Traverse the board to access each cell.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			//If there is a hit cell, search its surounding cells.
			if(board[i][j].value == 'h'){
				//If the current row is not the top row.
				if(i != 0){
					//Check if the position above the cell is available for a move.
					if(board[i-1][j].value == '' || board[i-1][j].value == 's'){
						//Push move to array.
						availableMoves.push({row: i - 1, col: j});
					}
				}
				//If the current the row is not the bottom row.
				if(i != 9){
					//Check if the position below the cell is available for a move.
					if(board[i+1][j].value == '' || board[i+1][j].value == 's'){
						//Push move to array.
						availableMoves.push({row: i + 1, col: j});
					}
				}
				//If the current column is not the far left column.
				if(j != 0){
					//Check if the position left of the cell is available for a move.
					if(board[i][j-1].value == '' || board[i][j-1].value == 's'){
						//Push move to array.
						availableMoves.push({row: i, col: j - 1});
					}
				}
				//If the current column is not the far right column.
				if(j != 9){
					//Check if the position right of the cell is available for a move.
					if(board[i][j+1].value == '' || board[i][j+1].value == 's'){
						//Push move to array.
						availableMoves.push({row: i, col: j + 1});
					}

				}

			}
		}
	}
	//Return the array of moves.
	return availableMoves;
}


//Advanced find hit mode for higher difficulties - sinks ships faster than normal version.
function advancedFindHits(board){
	let informedMoves = [];
	let vertical = false;
	let horizontal = false;

	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			if(board[i][j].value == 'h'){
				if(i != 0){
					if(board[i-1][j].value == 'h'){
						vertical = true;
					}
				}
				if(i != 9){
					if(board[i+1][j].value == 'h'){
						vertical = true;
					}
				}

				if(j != 0){
					if(board[i][j-1].value == 'h'){
						horizontal = true;
					}
				}
				if(j != 9){
					if(board[i][j+1].value == 'h'){
						horizontal = true;
					}
				}

				//Select a surounding cell.
				//Above.
				if(horizontal == false){
					if(i != 0){
						if(board[i-1][j].value == '' || board[i-1][j].value == 's'){
							return {row: i - 1, col: j};
						}

						if(board[i-1][j].value == 'h'){
							if(i - 1 != 0){
								if(board[i-1][j].value == '' || board[i-1][j].value == 's'){
									return {row: i - 2, col: j};
								}
							}
						}
					}

					if(i != 9){
						if(board[i+1][j].value == '' || board[i+1][j].value == 's'){
							return {row: i + 1, col: j};
						}

						if(board[i+1][j].value == 'h'){
							if(i + 1 != 9){
								if(board[i+1][j].value == '' || board[i+1][j].value == 's'){
									return {row: i + 2, col: j};
								}
							}
						}
					}
				}
				if(vertical == false){
					if(j != 0){
						if(board[i][j - 1].value == '' || board[i][j-1].value == 's'){
							return {row: i, col: j - 1};
						}

						if(board[i][j-1].value == 'h'){
							if(j - 1 != 0){
								if(board[i][j - 1].value == '' || board[i][j-1].value == 's'){
									return {row: i, col: j - 2};
								}
							}
						}
					}
					if(j != 9){
						if(board[i][j + 1].value == '' || board[i][j + 1].value == 's'){
							return {row: i, col: j + 1};
						}

						if(board[i][j+1].value == 'h'){
							if(j + 1 != 9){
								if(board[i][j + 1].value == '' || board[i][j + 1].value == 's'){
									return {row: i, col: j + 2};
								}
							}
						}
					}
				}


			}
		}
	}

	//If at this point, moves MUST BE left or right. Loop again and make these moves.
	for(let i = 0; i < 10; i++){
		for(let j = 0; j < 10; j++){
			if(board[i][j].value == 'h'){
				if(j != 0){
					if(board[i][j - 1].value == '' || board[i][j-1].value == 's'){
						return {row: i, col: j - 1};
					}

					if(board[i][j-1].value == 'h'){
						if(j - 1 != 0){
							if(board[i][j - 1].value == '' || board[i][j-1].value == 's'){
								return {row: i, col: j - 2};
							}
						}
					}
				}
				if(j != 9){
					if(board[i][j + 1].value == '' || board[i][j + 1].value == 's'){
						return {row: i, col: j + 1};
					}

					if(board[i][j+1].value == 'h'){
						if(j + 1 != 9){
							if(board[i][j + 1].value == '' || board[i][j + 1].value == 's'){
								return {row: i, col: j + 2};
							}
						}
					}
				}
			}
		}
	}



	//Should never reach this point, but return 0, 0 if is the case.
	return ({row: 0, col: 0});
}




// returns a board
function getAIShipPlacement() {

	let pick;
	let directions;
	let xP;
	let yP;
	let shipLength;
	let directionLimit = 0;
	let ships = [];
	let tempBoard = [];

	for(let i=0; i<10; i++) {

		tempBoard.push([]);

		for(let j=0; j<10; j++) {
			// Push a value of the tile
			tempBoard[i].push({value: '', prevMove: '', x: i, y: j});
		}

	}

	for(let i = 0; i < 5; i++){
		switch (i){
			case 0:
				shipLength = 5;
				break;
			case 1:
				shipLength = 4;
				break;
			case 2:
				shipLength = 3;
				break;
			case 3:
				shipLength = 3;
				break;
			case 4:
				shipLength = 2;
		}

		//PICK H OR V.
		pick = Math.random();
		if(pick >= 0.5){
			console.log("Ori pick:  " + pick);
			directions = 'v';
		}
		else if(pick < 0.5){
			console.log("Ori pick:  " + pick);
			directions = 'h';
		}



		//do{
			if(directions = 'h'){
				xP = Math.floor(Math.random()*(10-shipLength));
				yP = Math.floor(Math.random()*10);

			}
			else{
				xP = Math.floor(Math.random()*10);
				yP = Math.floor(Math.random()*(10-shipLength));

			}

			conflictions = false;

			for(let j = 0; j < shipLength; j++) {

				if(directions == 'v') {
					// Check down
					if(xP + j <= 9){
						if(tempBoard[xP+j][yP].value == 's') {
							conflictions = true;
						}
					}
					else{
						conflictions = true;
					}
				}
				else if (directions == 'h') {
					if(yP + j <= 9){
						if(tempBoard[xP][yP+j].value == 's'){
							conflictions = true;
						}
					}
					else{
						conflictions =true;
					}
				}
			}
		}while(conflictions == true);

		for(let j = 0; j < shipLength; j++){
			if(directions = 'v'){
				tempBoard[xP + j][yP].value = 's';
			}
			else{
				tempBoard[xP][yP+j].value = 's';
			}

		}


		ships.push({length: shipLength, direction: 'h', damage: 0, destroyed: false, x: xP, y: yP});
	}





	/*



	let shipsArray = [];
	let ships = [
					{length: 5, direction: 'h', damage: 0, destroyed: false, x: 0, y: 0},
					{length: 4, direction: 'h', damage: 0, destroyed: false, x: 2, y: 0},
					{length: 3, direction: 'h', damage: 0, destroyed: false, x: 4, y: 0},
					{length: 3, direction: 'h', damage: 0, destroyed: false, x: 6, y: 0},
					{length: 2, direction: 'h', damage: 0, destroyed: false, x: 8, y: 0}
				];*/

	/*
	shipsArray.push(ships);

	ships = [
					{length: 5, direction: 'v', damage: 0, destroyed: false, x: 0, y: 0},
					{length: 4, direction: 'v', damage: 0, destroyed: false, x: 0, y: 2},
					{length: 3, direction: 'v', damage: 0, destroyed: false, x: 0, y: 4},
					{length: 3, direction: 'v', damage: 0, destroyed: false, x: 0, y: 6},
					{length: 2, direction: 'v', damage: 0, destroyed: false, x: 0, y: 8}
				];*/





	return ships;



}


/*-----------------------AI Chat Method------------------------*/

function aiChat(board, skillLevel, firstGame){
	//Boolean if the AI has made its first move.

	//Also determine what stage of the game we are at for the AI chat feature.
	let movesMade = 0;

	for(let i=0; i<10; i++){
		for(let j=0; j<10; j++){
			if(board[i][j].value == 'm' || board[i][j].value == 'h' ||  board[i][j].value == 'd') {
				movesMade++;
			}
		}
	}

	//Code for AI commenting on the difficulty.
	//This code outputs to the chat when the AI makes its first move.
	if(movesMade == 0){
		let toReturn = '';

		//Potentially remove this message. - or place it somewhere so it only posts when the player chooses the AI mode.
		if(firstGame == true){
			toReturn += "Hello! I am the Battleships AI! ";
		}

		else {
			toReturn += "Another game! Lets go! ";
		}

		//Comments on the chosen difficulty.
		if(skillLevel == 1){
			toReturn += "Hardest difficulty eh? Admirable, I'm going to be very hard to beat! \
						I may have an advantage over you as well...\
						All abilities activated!";
		}
		else if(skillLevel == 0){
			toReturn += "Wow, easiest difficulty? Really? I thought you were better than this! \
						My moves will be completely random!";
		}
		else if(skillLevel < 1 && skillLevel >= 0.7){
			toReturn += "Level " + skillLevel*10 + " is a respectable difficulty! Well done!  \
						Hunting Ability Activated! Advanced Search Mode Activated! Advanced Hunt Mode Activated(With potential to not work)!";
		}
		else if(skillLevel < 0.7 && skillLevel >= 0.4){
			toReturn += "Hmmm, you have chosen level " + skillLevel*10 + "? You can do better than  this! \
						Hunting Ability Activated! Advanced Search Mode Activated(With potential to not work)!";
		}
		else if(skillLevel < 0.4 && skillLevel >= 0){
			toReturn += "You a beginner? Because " + skillLevel*10 + " is not a hard level! \
						Hunting Ability Activated(With potential to not work!)";
		}

		return toReturn;
	}
	else{
		let toReturn = '';

		//Code for AI commenting on the result of the game.
		/*
		//Code for the AI commenting on winning.
		if(checkWin(???)){
			toReturn += "Yes I win!! In your face ;) ";

			if(skillLevel == 1){
				toReturn +=  "It is the hardest difficulty, so no shame for you. ";
			}
			else if(skillLevel == 0){
				toReturn += "I beat you on the easiest difficulty as well... I wouldn't tell your friends about this... ";
			}

			toReturn += "Want to play again?";
			return toReturn;
		}
		//Code for the AI commenting on losing.
		else if(checkWin(??)){
			toReturn += "You win! Well done, but I'll get you next time... ";

			if(skillLevel != 1){
				toReturn += "Try upping the difficulty if you are confident ;) ";
			}

			toReturn += "Want to play again? ";
			return toReturn;
		}
		*/

	}
}