UserInput.java

import java.util.Scanner;

public class UserInput {
    private Board board;
    private Scanner input;
    
    public UserInput(Board board, Scanner input) {
        this.board = board;
        this.input = input;
    }

    // This method asks the user to enter their move. It calls
    // the appropriate methods (slideUp, mergeUp, slideDown, mergeDown, etc.)
    // If the choice is not a valid character, nothing happens.
    public  void processUserChoice() {
        char keyPress = Character.toLowerCase(input.next().charAt(0));
        boolean slideDone = false;
        boolean mergeDone = false;
        boolean validMove = false;
        
        switch (keyPress) {
            case 'w':
                slideDone = slideUp();
                mergeDone = mergeUp();
                
                if(mergeDone) {
                    slideDone = slideUp() || slideDone;
                }

                validMove = true;
                break;
            case 'a':
                slideDone = slideLeft();
                mergeDone = mergeLeft();
                
                if(mergeDone) {
                    slideDone = slideLeft() || slideDone;
                }

                validMove = true;
                break;
            case 's':
                slideDone = slideDown();
                mergeDone = mergeDown();
                
                if(mergeDone) {
                    slideDone = slideDown() || slideDone;
                }

                validMove = true;
                break;
            case 'd':
                slideDone = slideRight();
                mergeDone = mergeRight();
                
                if(mergeDone) {
                    slideDone = slideRight() || slideDone;
                }

                validMove = true;
                break;
            default:
                System.out.println(keyPress + " won't do anything. Press either, W, A, S, or D.");
                break;
        }

        if (validMove) {
            if (slideDone || mergeDone) {
                board.placeBlock();
            }

            System.out.println("Score: " + board.getScore());
            board.printBoard();
        }
    }

    // Tries to slide all columns up, returns true if a slide up actually occurred
    public boolean slideUp() {
        boolean slideOccurred = false;
        boolean moved = true;

        while (moved) {
            moved = false;
            
            for (int r = 1; r < board.getBoardRowLength(); r++) {
                for (int c = 0; c < board.getBoardColLength(); c++) {
                    if (board.getBlock(r, c) != 0 && board.getBlock(r - 1, c) == 0) {
                        board.setBlock(r - 1, c, board.getBlock(r, c));
                        board.setBlock(r, c, 0);

                        moved = true;
                        slideOccurred = true;
                    }
                }
            }
        }

        return slideOccurred;
    }

    public  boolean slideDown() {
        boolean slideOccurred = false;
        boolean moved = true;

        while(moved) {
            moved = false;

            for (int r = board.getBoardRowLength() - 2; r >= 0; r--) {
                for (int c = 0; c < board.getBoardColLength(); c++) {
                    if (board.getBlock(r, c) != 0 && board.getBlock(r + 1, c) == 0) {
                        board.setBlock(r + 1, c, board.getBlock(r, c));
                        board.setBlock(r, c, 0);

                        moved = true;
                        slideOccurred = true;
                    }
                }
            }
        }

        return slideOccurred;
    }

    public  boolean slideLeft() {
        boolean slideOccurred = false;
        boolean moved = true;

        while (moved) {
            moved = false;
            
            for (int c = 1; c < board.getBoardColLength(); c++) {
                for (int r = 0; r < board.getBoardRowLength(); r++) {
                    if (board.getBlock(r, c) != 0 && board.getBlock(r, c - 1) == 0) {
                        board.setBlock(r, c - 1, board.getBlock(r, c));
                        board.setBlock(r, c, 0);

                        moved = true;
                        slideOccurred = true;
                    }
                }
            }
        }

        return slideOccurred;
    }

    public  boolean slideRight() {
        boolean slideOccurred = false;
        boolean moved = true;

        while(moved) {
            moved = false;

            for (int c = board.getBoardColLength() - 2; c >= 0; c--) {
                for (int r = 0; r < board.getBoardRowLength(); r++) {
                    if (board.getBlock(r, c) != 0 && board.getBlock(r, c + 1) == 0) {
                        board.setBlock(r, c + 1, board.getBlock(r, c));
                        board.setBlock(r, c, 0);

                        moved = true;
                        slideOccurred = true;
                    }
                }
            }
        }

        return slideOccurred;
    }

    // If the values if any two cells touching in the same column are equal
    // merges the cells to put the sum of the two numbers in the upper cell
    // and a 0 in the lower cell.  Increase score by this sum.
    public  boolean mergeUp() {
        boolean merged = false;

        for (int r = 1; r < board.getBoardRowLength(); r++) {
            for (int c = 0; c < board.getBoardColLength(); c++) {
                if (board.getBlock(r - 1, c) == board.getBlock(r, c) && board.getBlock(r, c) != 0) {
                    board.setBlock(r - 1, c, board.getBlock(r - 1, c) * 2);
                    board.setBlock(r, c, 0);

                    board.addScore(board.getBlock(r - 1, c));
                    merged = true;
                }
            }
        }

        return merged;
    }

    public  boolean mergeDown() {
        boolean merged = false;

        for (int r = board.getBoardRowLength() - 2; r >= 0; r--) {
            for (int c = 0; c < board.getBoardColLength(); c++) {
                if (board.getBlock(r + 1, c) == board.getBlock(r, c) && board.getBlock(r, c) != 0) {
                    board.setBlock(r + 1, c, board.getBlock(r, c) * 2);
                    board.setBlock(r, c, 0);

                    board.addScore(board.getBlock(r + 1, c));
                    merged = true;
                }
            }
        }

        return merged;
    }

    public  boolean mergeLeft() {
        boolean merged = false;

        for (int c = 1; c < board.getBoardColLength(); c++) {
            for (int r = 0; r < board.getBoardRowLength(); r++) {
                if (board.getBlock(r, c - 1) == board.getBlock(r, c) && board.getBlock(r, c) != 0) {
                    board.setBlock(r, c - 1, board.getBlock(r, c) * 2);
                    board.setBlock(r, c, 0);

                    board.addScore(board.getBlock(r, c - 1));
                    merged = true;
                }
            }
        }

        return merged;
    }

    public  boolean mergeRight() {
        boolean merged = false;

        for (int c = board.getBoardColLength() - 2; c >= 0; c--) {
            for (int r = 0; r < board.getBoardRowLength(); r++) {
                if (board.getBlock(r, c + 1) == board.getBlock(r, c) && board.getBlock(r, c) != 0) {
                    board.setBlock(r, c + 1, board.getBlock(r, c) * 2);
                    board.setBlock(r, c, 0);

                    board.addScore(board.getBlock(r, c + 1));
                    merged = true;
                }
            }
        }

        return merged;
    }
}