// Piece.java
// Author: Jack Morrison
// Date: 4/15/08

import java.awt.*;
import java.util.*;

/**
 An immutable representation of a tetris piece in a particular rotation.
 Each piece is defined by the blocks that make up its body.
 See the Tetris-Architecture.html for an overview.
 
 This is the starter file version -- a few simple things are filled in already
 
 @author	Nick Parlante
 @author        Eric Chown
 @author Laura Toma
 @version	November 30, 2007
*/
public final class Piece {
    /*
      Implementation notes:
      -The starter code does out a few simple things for you
      -Store the body as a Point[] array
      -Do not assume there are 4 points in the body -- use array.length
      to keep the code general
    */
    
    private Point[] body;    
    // The body of the piece, each point is a coordinate specifying a block

    private int[] skirt;     
    // Each element specifies how high the piece will land in the corresponding column

    private int	width;	// The width of the piece for the current rotation

    private int	height;	// The height of the piece for the current rotation

    private Piece next;	// The "next" rotation - note this is how a "piece" is really a list
    
    static private Piece[] pieces;	// singleton array of first rotations
	
    
    
    /**
       Defines a new piece given the Points that make up its body.
       Makes its own copy of the array and the Point inside it.  Does
       not set up the rotations.
       
       This constructor is PRIVATE -- if a client wants a piece
       object, they must use Piece.getPieces().  getPieces() will
       therefore make all of the calls to the constructor.
       
       As with all constructors, your variables should be initialized
       here.  This means you'll need to calculate width and height as
       well as setting up the skirt (doing these things once in the
       constructor means you don't have to do them on the fly during
       game play).  The one exception to this is the "next" variable.
       You'll want to set that in the pieceRow method.
    */
    private Piece(Point[] points) {
	if (points.length>0){
	    // There is at least one block (so height and width
	    // initialize to 1
	    width = 1;
	    height = 1;
	}
	
	// Create the body array
	body = points;

	// Go through the body and find the widest and highest points
	for (int i=0;i<body.length;i++){
	    if (body[i].getX()+1>width){width=(int)body[i].getX()+1;}
	    if (body[i].getY()+1>height){height=(int)body[i].getY()+1;}	    
	}
	
	// Initialize the skirt array with a point for each x-position
	// that is higher than any point in the body could possibly be.
	skirt = new int[width];
	for (int i=0; i<skirt.length;i++){
	    skirt[i]=height+1;
	}
	// Go through the body array and find the proper skirt heights
	for (int i = 0;i<body.length;i++){
	    if (skirt[(int)body[i].getX()]>body[i].getY()){
		skirt[(int)body[i].getX()] = (int)body[i].getY();
	    }
	}
		
	    
	
    }	
    
    
    /**
       Returns the width of the piece measured in blocks.
    */
    public int getWidth() {
	return(width);
    }
    
    /**
       Returns the height of the piece measured in blocks.
    */
    public int getHeight() {
	return(height);
    }
    
    /**
       Returns a pointer to the piece's body. The caller
       should not modify this array.
    */
    public Point[] getBody() {
	return(body);
    }
    
    /**
       Returns a pointer to the piece's skirt. For each x value across
       the piece, the skirt gives the lowest y value in the body.
       This useful for computing where the piece will land.  The
       caller should not modify this array.
    */
    public int[] getSkirt() {
	return(skirt);
    }
    
    
    /**
       Returns a piece that is 90 degrees counter-clockwise rotated
       from the receiver.
       
       Implementation: The Piece class pre-computes all the rotations
       once.  This method just hops from one pre-computed rotation to
       the next in constant time.
    */	
    public Piece nextRotation() {
	return next;
    }
    
    
    /**
       Returns true if two pieces are the same -- their bodies contain
       the same points.  Interestingly, this is not the same as having
       exactly the same body arrays, since the points may not be in
       the same order in the bodies. Used internally to detect if two
       rotations are effectively the same.
    */
    public boolean equals(Piece other) {

	// If the other piece is null, they're not equal.
	if (other==null){return false;}
	// If their widths and heights and array lengths are dissimilar
	// we can return false
	if (other.getWidth()!=getWidth()){return false;}
	if (other.getHeight()!=getHeight()){return false;}
	if (other.getBody().length!=getBody().length){return false;}

	// Go through the body array points
	for (int i=0; i<body.length;i++){
	    Point checkPoint = body[i];

	    // If there is a point in the other array that
	    // equals the checkPoint, then we go on to the
	    // next body point.
	    for (int j=0; j<=other.getBody().length;j++){

		// If we have gone through the entire other array
		// then we must return false since the Pieces are not equal.
		if (j==other.getBody().length){return false;}
		if (other.getBody()[j].equals(checkPoint)){break;}
	    }
	}  
	
	// If we make it through and find equal points in each Piece
	// then they are equal
	return true;
    }
    
    /**
     *  This is where most of your work will be done.  pieceRow takes
     *  the initial rotation of a piece and should create all of the
     *  rest of the rotations in a kind of circular list.  Essentially
     *  you get the body array of the initial configuration of the
     *  Piece, you need to calculate the other body arrays.
    */

    // Takes a starting piece as a parameter (one of the initial rotations)
    // and creates a circular list of the rotations of that piece.
    // ONLY WORKS IF STARTING PIECE IS AN "INITIAL ROTATION"
    public static Piece pieceRow(Piece starter) {
	// Pieces to make
	Piece pieceOne,pieceTwo,finalPiece;

    
    
	// Straight rod
	if (starter.equals(new Piece(parsePoints("0 0	0 1	0 2	0 3")))){
	    finalPiece = new Piece(parsePoints("1 0  2 0  3 0  0 0"));
	    starter.next = finalPiece;
	    finalPiece.next = starter;
	    return starter;	    
	}

	// L piece
	if (starter.equals(new Piece(parsePoints("0 0	0 1	0 2	1 0")))){
	    pieceOne = new Piece(parsePoints("0 0  0 1  1 1     2 1 "));
	    pieceTwo = new Piece(parsePoints("0 2  1 2  1 1     1 0 "));
	    finalPiece = new Piece(parsePoints("0 0  1 0  2 0  2 1"));
	    starter.next = pieceOne;
	    pieceOne.next = pieceTwo;
	    pieceTwo.next = finalPiece;
	    finalPiece.next = starter;
	    return starter;
	}

	// Backward L
	if (starter.equals(new Piece(parsePoints("0 0	1 0	1 1	1 2")))){
	    pieceOne = new Piece(parsePoints("0 1  0 0  1 0  2 0"));
	    pieceTwo = new Piece(parsePoints("0 0  0 1  0 2  1 2"));
	    finalPiece = new Piece(parsePoints("0 1  1 1  2 1 2 0")); 
	    starter.next = pieceOne;
	    pieceOne.next = pieceTwo;
	    pieceTwo.next = finalPiece;
	    finalPiece.next = starter;
	    return starter;				  
	}

	// Dog piece right
	if (starter.equals(new Piece(parsePoints("0 0	1 0	1 1	2 1")))){
	    pieceOne = new Piece(parsePoints("0 2  0 1  1 1  1 0"));
	    starter.next = pieceOne;
	    pieceOne.next = starter;
	    return starter;
	}

	// Dog piece left
	if (starter.equals(new Piece(parsePoints("0 1  1 1  1 0  2 0")))){
	    pieceOne = new Piece(parsePoints("0 0  0 1  1 1  1 2"));
	    starter.next = pieceOne;
	    pieceOne.next = starter;
	    return starter;
	}

	// T piece
	if (starter.equals(new Piece(parsePoints("0 0	1 0	1 1	2 0")))){
	    pieceOne = new Piece(parsePoints("0 0   0 1  1 1  0 2"));
	    pieceTwo = new Piece(parsePoints("0 1  1 1  1 0  2 1"));
	    finalPiece = new Piece(parsePoints("1 2  1 1  0 1   1 0"));
	    starter.next = pieceOne;
	    pieceOne.next = pieceTwo;
	    pieceTwo.next = finalPiece;
	    finalPiece.next = starter;
	    return starter;
	}
	    
	// Otherwise, it's either a square, or an unknown shape
	// so we just link it to itself and return it.
	starter.next = starter;
	return starter;
    }	

	
    /**
       Returns an array containing the first rotation of each of the 7
       standard tetris pieces.  The next (counterclockwise) rotation
       can be obtained from each piece with nextRotation().  In this
       way, the client can iterate through all the rotations until
       eventually getting back to the first rotation.
    */
    public static Piece[] getPieces() {
	// Makes seven calls to pieceRow for each of the seven standard Tetris pieces.  Places
	// the results of each call into an array and returns the array.
	pieces = new Piece[] {
	    pieceRow(new Piece(parsePoints("0 0	0 1	0 2	0 3"))),	// 0
	    pieceRow(new Piece(parsePoints("0 0	0 1	0 2	1 0"))),	// 1
	    pieceRow(new Piece(parsePoints("0 0	1 0	1 1	1 2"))),	// 2
	    pieceRow(new Piece(parsePoints("0 0	1 0	1 1	2 1"))),	// 3
	    pieceRow(new Piece(parsePoints("0 1	1 1	1 0	2 0"))),	// 4
	    pieceRow(new Piece(parsePoints("0 0	0 1	1 0	1 1"))),	// 5
	    pieceRow(new Piece(parsePoints("0 0	1 0	1 1	2 0"))),	// 6
	};
	return pieces;
    }
    
    
    /**
       Given a string of x,y pairs ("0 0 0 1 0 2 1 0"), parses the
       points into a Point[] array.  (Provided code)
    */
    private static Point[] parsePoints(String string) {

	Vector<Point> points = new Vector<Point>();
	StringTokenizer	tok = new StringTokenizer(string);
	try {
	    while(tok.hasMoreTokens()) {
		int x = Integer.parseInt(tok.nextToken());
		int y = Integer.parseInt(tok.nextToken());
		
		points.addElement(new Point(x, y));
	    }
	}
	catch (NumberFormatException e) {
	    throw new RuntimeException("Could not parse x,y string:" + string);	
	    // cheap way to do assert
	}
	
	// Make an array out of the Vector
	Point[] array					       = new Point[points.size()];
	points.copyInto(array);
	return(array);
    }
    
}