/*
W = Player one basic piece
V = Player one queen piece

B = Player two basic piece
P = Player two queen piece
*/

const pieceList = new Array();
currentPlayer = "white";

function generateDefaultPositions(){
    
    var id = 0;

    for (let i = 0; i < 8; i++) {
        for (let j = 0; j < 3; j++) {
            if((i+j) % 2 == 0){
                pieceRecord = {id:id, x:i, y:j, player:"white", type:"basic"};
                pieceList.push(pieceRecord);
                id++;
            }
            
        }
    }

    for (let i = 0; i < 8; i++) {
        for (let j = 5; j < 8; j++) {
            if((i+j) % 2 == 0){
                pieceRecord = {id:id, x:i, y:j, player:"black", type:"basic"};
                pieceList.push(pieceRecord);
                id++;
            }
            
        }
    }
}

function getPieceRecord(x,y){
    if (x > 7 || x < 0 || y > 7 || y < 0) {
        return false;
    }
    return pieceList.find(pieceRecord => pieceRecord.x == x && pieceRecord.y == y);
}

function nukePieceRecord(pieceRecord) {
    const index = pieceList.findIndex(record => record.id == pieceRecord.id);
    pieceList.splice(index, 1);
}

function updatePieceRecord(pieceRecord) {
    const index = pieceList.findIndex(record => record.id == pieceRecord.id);
    pieceList[index] = pieceRecord;
}

function updatePieceRecordPosition(pieceRecord, x, y) {
    pieceRecord.x = x;
    pieceRecord.y = y;
    updatePieceRecord(pieceRecord);
    return pieceRecord;
}

function isMoveValid(pieceRecord, x, y){
    
    
    if(0 > y > 7 || 0 > x > 7){
        return false;
    }

    if (getPieceRecord(x,y)) {
        return false;
    }

    const currentX = pieceRecord.x;
    const currentY = pieceRecord.y;

    if (Math.abs(y - currentY) != Math.abs(x - currentX)) {
        return false;
    }

    const player = pieceRecord.player;
    const type = pieceRecord.type;

    //Check correct Y direction if piece is basic
    if (currentY > y && player == "white" && type == "basic") {
        return false;
    }


    const directionY = (y > currentY) ? 1 : -1;
    const directionX = (x > currentX) ? 1 : -1;

    space = 0;
    piecesInWay = 0;

    for (let i = 1; i < (Math.abs(y-currentY)+1); i++) {
        
        const nowX = currentX + (i*directionX);
        const nowY = currentY + (i*directionY);

        if (inWayPieceRecord = getPieceRecord(nowX, nowY)) {

            if(inWayPieceRecord.player == player){
                return false;
            }

            space = 0;
            piecesInWay++;
        }else{
            space++;
            piecesInWay = 0;
        }

        if(piecesInWay > 1){
            return false;
        }

        if (space > 1 && type == "basic") {
            return false;
        }
    }

    return true;
    
}

function getCasualties(oldX, oldY, newX, newY) {
    const directionX = (newX > oldX) ? 1 : -1;
    const directionY = (newY > oldY) ? 1 : -1;

    const casualties = new Array();

    for (let i = 1; i < (Math.abs(newY - oldY) + 1); i++) {
        const x = oldX + (i*directionX);
        const y = oldY + (i*directionY);
        
        pieceRecord = getPieceRecord(x,y);

        if (pieceRecord) {
            casualties.push(pieceRecord);
            
        }
        
    }
    return casualties;
}
function continuableInDirectionForQueen(directionX, directionY, pieceRecord) {
    const pieceX = pieceRecord.x;
    const pieceY = pieceRecord.y;
    const player = pieceRecord.player;
    
    for (let i = 1; i < 8; i++) {
        const x = pieceX + (i*directionX);
        const y = pieceY + (i*directionY);

        if(x > 7 || x < 0 || y > 7 || y < 0 || (x+directionX) > 7 || (x+directionX) < 0 || (y+directionY) > 7 || (y+directionY) < 0 ){
            return false;
        }

        const  record = getPieceRecord(x, y);

        if (record) {
            if (record.player == player || getPieceRecord(x,y)) {
                
            }

        }
        
    }
}
function continuable(pieceRecord){
    const x = pieceRecord.x;
    const y = pieceRecord.y;
    const player = pieceRecord.player;
    const type = pieceRecord.type;

    if(player == "white" && ((getPieceRecord(x+1, y+1) && getPieceRecord(x+1, y+1).player != player && !getPieceRecord(x+2, y+2) && (y+2) < 8 && (x+2) < 8) || ((getPieceRecord(x-1, y+1) && getPieceRecord(x-1, y+1).player != player && !getPieceRecord(x-2, y+2) && (y+2) < 8 && (x-2) > 0)))){
    
        return true;
    }

    if( player == "black" && ((getPieceRecord(x+1, y-1) && getPieceRecord(x+1, y-1).player != player && !getPieceRecord(x+2, y-2) && (y-2) > 0 && (x+2) < 8) || ((getPieceRecord(x-1, y-1) && getPieceRecord(x-1, y-1).player != player && !getPieceRecord(x-2, y-2) && (y-2) > 0 && (x-2) > 0)))){
        
        return true;
    }
    
    if(type == "queen"){
        for (let i = 1; i < 9; i++) {
            nowX = x + i;
            nowY = y + i;
            
        }
    }

    return false;
}

function getOportunities(pieceRecord){
    const player = pieceRecord.player;
    const opportunities = new Array();

    pieceList.forEach(record => {
        if (record.player == player && record != pieceRecord && continuable(record)) {
            
            opportunities.push(pieceRecord);
        }
    });

    return opportunities;
}

function swapPlayers() {   
    currentPlayer = (currentPlayer == "white") ? "black" : "white";
}

function makeMove(pieceRecord, x, y){
    const player = pieceRecord.player;
    
    if (!isMoveValid(pieceRecord, x, y)) {
        return 0;
    }
    
    const oldX = pieceRecord.x;
    const oldY = pieceRecord.y;

    const casualties = getCasualties(oldX, oldY, x, y);

    
    casualties.forEach(casualty => {
        nukePieceRecord(casualty);
    });

    if (casualties.length == 0 && getOportunities(pieceRecord).length != 0) {
            //POTŘREBA DODĚLAT SBÍRÁNÍ DÍLKŮ ZA NESKÁKÁNÍ
    }

    if ((player == "white" && y == 7) || (player == "black"  && y == 0) && pieceRecord.type == "basic") {
        
        pieceRecord.type = "queen";
        
    }

    const updatedPieceRecord = updatePieceRecordPosition(pieceRecord, x, y);
    
    if (continuable(updatedPieceRecord) && casualties.length > 0) {
        return 2;
    }

    
    return 1;
}
generateDefaultPositions();