/****************
 * Name: Koh Wei Jie
 *
 * Purpose of this file: To work as the chessboard for the game.
 * Uses graphics for the board and pieces, as well as drag-and-
 * drop event handling.
 *
 ****************/
 
import java.util.*;
import java.awt.event.*;
import java.lang.Math.*;
import java.awt.*;
import javax.swing.*;
import java.awt.image.*;
import game.*;
 
 
public class Chessboard extends JComponent implements MouseMotionListener, MouseListener{
    private ImageIcon boardbg;
    private ImageIcon redSq;
    private ImageIcon greenSq;
 
    private Dimension totalSize = new Dimension(402, 402);
 
    private final int sqLen = 50;
 
    private String imgDir = "images/";
    private String boardImgDir = imgDir + "board/";
    private String bPiecesImgDir = imgDir + "b_pieces/";
    private String wPiecesImgDir = imgDir + "w_pieces/";
 
    private Board board;
 
    private Piece beingDragged = null;
    private int beingDraggedX = -1;
    private int beingDraggedY = -1;
 
    private int originalX = -1;
    private int originalY = -1;
 
    private boolean isWhite;
    private boolean myTurn;
 
    private ChessController cc;
 
    private Vector<int[]> greenSqLocations = new Vector<int[]>();
 
    public Chessboard(boolean isWhite, ChessController cc){
        this.isWhite = isWhite;
        this.myTurn = isWhite;
        this.cc = cc;
        this.boardbg = new ImageIcon(this.boardImgDir + "board.png");
        this.greenSq = new ImageIcon(this.boardImgDir + "green_square.png");
        this.redSq = new ImageIcon(this.boardImgDir + "red_square.png");
 
        this.board = new Board(isWhite);
 
        this.addMouseMotionListener(this);
        this.addMouseListener(this);
    }
 
    //make this component of a fixed size
    public Dimension getMinimumSize(){ return this.totalSize; }
    public Dimension getMaximumSize(){ return this.totalSize; }
    public Dimension getPreferredSize() { return this.totalSize; }
 
    public void mouseMoved(MouseEvent e){ }
    public void mouseEntered(MouseEvent e){ }
    public void mouseExited(MouseEvent e){ }
    public void mouseClicked(MouseEvent e){ }
 
    public Vector<int[]> calcRedSqLocations(){
        Vector<int[]> canCapture = new Vector<int[]>();
        for (int[] p : this.greenSqLocations){
            if (p != null){
                if (this.board.isOccupied(p[0], p[1]) || this.board.isEnPassantLoc(p[0], p[1])){
                    canCapture.add(p);
                }
            }
        }
        return canCapture;
    }
 
    public void movePiece(int fromX, int fromY, int toX, int toY){
        //called when the opponent moves a piece
        this.board.movePiece(fromX, fromY, toX, toY);
        this.repaint();
        this.myTurn = true;
    }
 
    public void clearBeingMoved(){
        this.beingDragged = null;
        this.beingDraggedX = -1;
        this.beingDraggedY = -1;
        this.greenSqLocations.clear();
        this.repaint();
    }
 
    //Drag and drop
    public void mousePressed(MouseEvent e){
        if (!myTurn){
            return;
        }
 
        Point mouseLoc = e.getPoint();
        int xLoc = (int)(Math.floor(mouseLoc.getX() / this.sqLen));
        int yLoc = (int)(Math.floor(mouseLoc.getY() / this.sqLen));
 
        if (this.board.getPieces()[yLoc][xLoc] != null){
            this.beingDraggedX = xLoc;
            this.beingDraggedY = yLoc;
 
            this.originalX = xLoc;
            this.originalY = yLoc;
 
            this.beingDragged = this.board.getPieces()[yLoc][xLoc];
            if (this.beingDragged.getIsWhite() == this.isWhite){
                this.greenSqLocations = this.beingDragged.possiblePositions(this.board, xLoc, yLoc);
            }
            if (this.greenSqLocations.isEmpty()){
                clearBeingMoved();
            }
        }
    }
 
    public void mouseDragged(MouseEvent e){
        this.repaint();
        if ((!myTurn) || (this.greenSqLocations.size() == 0) || (this.beingDragged.getIsWhite() != this.isWhite)){
            return;
        }
 
        Point mouseLoc = e.getPoint();
        this.beingDraggedX = (int)(Math.floor(mouseLoc.getX() / this.sqLen));
        this.beingDraggedY = (int)(Math.floor(mouseLoc.getY() / this.sqLen));
    }
 
    public void mouseReleased(MouseEvent e){
        this.repaint();
        if (!myTurn || (this.greenSqLocations.size() == 0) || (this.beingDragged.getIsWhite() != this.isWhite)){
            clearBeingMoved();
            return;
        }
 
        Point mouseLoc = e.getPoint();
        int xLoc = (int)(Math.floor(mouseLoc.getX() / this.sqLen));
        int yLoc = (int)(Math.floor(mouseLoc.getY() / this.sqLen));
 
        if (!(xLoc > 7 || yLoc > 7 || xLoc < 0 || yLoc < 0)){
            if (!(xLoc == originalX && yLoc == originalY)){
                for (int[] sq : this.greenSqLocations){
                    if (sq[0] == xLoc && sq[1] == yLoc){
                        this.board.movePiece(originalX, originalY, xLoc, yLoc);
                        this.cc.movePiece(originalX, originalY, xLoc, yLoc);
                        this.myTurn = false;
 
                        clearBeingMoved();
                        this.repaint();
                        break;
                    }
                    this.beingDraggedX = this.originalX;
                    this.beingDraggedY = this.originalY;
                }
                this.greenSqLocations.clear();
            }
            else{
                clearBeingMoved();
            }
        }
        else{
            clearBeingMoved();
            this.repaint();
        }
        this.greenSqLocations.clear();
        this.repaint();
        if (this.board.isCheckMate(!this.isWhite)){
            this.cc.checkmateOpp();
        }
        else if (this.board.isStalemate(!this.isWhite)){
            this.cc.stalemateOpp();
        }
        else if (this.board.isCheck(!this.isWhite)){
            this.cc.checkOpp();
        }
        else if (this.board.canPromote(this.isWhite)){
            String pieces[] = {"Queen", "Rook", "Bishop", "Knight"};
            int promoteTo = JOptionPane.showOptionDialog(null, 
                    "Please select a piece to this pawn to.",
                    "Promotion",
                    JOptionPane.DEFAULT_OPTION, 
                    JOptionPane.PLAIN_MESSAGE, 
                    null, 
                    pieces, 
                    pieces[0]);
 
            int xPos = board.promote(promoteTo, isWhite);
            this.cc.promote(promoteTo, xPos);
            this.repaint();
        }
        this.repaint();
    }
 
    public void promoteOpp(int promoteTo, int xPos){
        switch (promoteTo){
            case 0:
                this.board.getPieces()[7][xPos] = new Queen(!isWhite);
                break;
            case 1:
                this.board.getPieces()[7][xPos] = new Rook(!isWhite);
                break;
            case 2:
                this.board.getPieces()[7][xPos] = new Bishop(!isWhite);
                break;
            case 3:
                this.board.getPieces()[7][xPos] = new Knight(!isWhite);
                break;
        }
    }
 
    protected ImageIcon makePiece(boolean white, String type){
        String colour;
        String dir;
        if (white){
            colour = "w";
            dir = this.wPiecesImgDir;
        }
        else{
            colour = "b";
            dir = this.bPiecesImgDir;
        }
        return new ImageIcon(dir + colour + "_" + type + ".png");
    }
 
    public String genFilename(Piece p){
        String name = "";
        if (p.getIsWhite()){
            name += wPiecesImgDir + "w";
        }
        else{
            name += bPiecesImgDir + "b";
        }
        name += "_";
        name += p.getName() + ".png";
        return name;
    }
 
    public void paint(Graphics g){
        super.paint(g);
        //background image of the checkered board
        g.drawImage(this.boardbg.getImage(), 0, 0, 402, 402, this);
 
        //green squares
        if (this.greenSqLocations != null){
            for (int[] i : greenSqLocations){
                g.drawImage(this.greenSq.getImage(), 
                        i[0] * this.sqLen + 1,
                        i[1] * this.sqLen + 1,
                        this.sqLen,
                        this.sqLen,
                        this);
            }
            for (int[] i : calcRedSqLocations()){
                if (i != null){
                    g.drawImage(this.redSq.getImage(), 
                            i[0] * this.sqLen + 1,
                            i[1] * this.sqLen + 1,
                            this.sqLen,
                            this.sqLen,
                            this);
                }
            }
        }
 
        //individual pieces
        for (int i = 0; i < this.board.getPieces().length; i++){
            for (int j = 0; j < this.board.getPieces()[i].length; j++){
                if (this.board.getPieces()[i][j] != null){
                    //for each piece
                    Piece piece = this.board.getPieces()[i][j];
                    ImageIcon icon = new ImageIcon(genFilename(piece));
                    if (!piece.equals(this.beingDragged)){
                        g.drawImage(icon.getImage(), j * this.sqLen, i * this.sqLen, this.sqLen, this.sqLen, this);
                    }
                }
            }
        }
 
        //the piece being dragged
        if (this.beingDragged != null){
            ImageIcon icon = new ImageIcon(genFilename(this.beingDragged));
            g.drawImage(icon.getImage(), this.beingDraggedX * this.sqLen, this.beingDraggedY * this.sqLen, this.sqLen, this.sqLen, this);
        }
    }
}