javasweeper/Difficulty.java

import java.awt.*;
import javax.swing.*;

// Enum with the difficuulty options
public enum Difficulty {
	BEGINNER     (9,  9,  10),
	INTERMEDIATE (16, 16, 40),
	EXPERT       (16, 30, 99),
	CUSTOM;

	// Custom difficulty constraints
	//
	// In actual minesweeper these numbers are 9, 24, 30, 10
	private static final int MIN_SIZE = 8;
	private static final int MAX_ROWS = 40;
	private static final int MAX_COLS = 50;
	private static final int MIN_MINES = 10;
	// In regular minesweeper the mines are capped at just (rows-1)*(cols-1),
	// but we additionally cap it at 999 because the expanded board size means
	// it's possible to hit the number display cap
	private static final int MAX_MINES = 999;

	// Use nonfinal ints with getter methods because custom needs to be able to
	// change its stats
	private int rows;
	private int cols;
	private int mines;

	private Difficulty() {
	}

	private Difficulty(int rows, int cols, int mines) {
		setStats(rows, cols, mines);
	}

	private void setStats(int rows, int cols, int mines) {
		this.rows = rows;
		this.cols = cols;
		this.mines = mines;
	}

	public int getRows() {
		return rows;
	}

	public int getCols() {
		return cols;
	}

	public int getMines() {
		return mines;
	}

	// Show a popup window to select attributes of the custom game, return
	// whether or not it succeeded
	public static boolean setCustom(JFrame frame) {
		Difficulty current = Options.getDifficulty();

		// Use single-item array to store a reference to minesField, because
		// minesField needs to needs to be initialized after rowsField and
		// colsField but RowsColsField needs minesField
		CustomTextField[] minesRef = new CustomTextField[1];
		// Override CustomTextField in order to make it format minesField after
		// editing (when the board size is decreased, so does the max mine
		// count, so we may need to update it)
		class RowsColsField extends CustomTextField {
			private RowsColsField(int defaultValue, int minValue, int maxValue) {
				super(defaultValue, minValue, maxValue);
			}

			@Override
			protected void formatText() {
				super.formatText();
				minesRef[0].formatText();
			}
		}

		// Initialize the text fields
		CustomTextField rowsField = new RowsColsField(current.rows, MIN_SIZE, MAX_ROWS);
		CustomTextField colsField = new RowsColsField(current.cols, MIN_SIZE, MAX_COLS);
		// Override CustomTextField in order to make it dynamically determine
		// the maximum value based on the number of rows and columns
		CustomTextField minesField = minesRef[0] = new CustomTextField(current.mines, MIN_MINES, MAX_MINES) {
			@Override
			protected int getMaxValue() {
				try {
					int rows = Integer.parseInt(rowsField.getText());
					int cols = Integer.parseInt(colsField.getText());
					return getMaxMines(rows, cols);
				} catch (NumberFormatException e) {
					return super.getMaxValue();
				}
			}
		};

		// Because Java is lame and doesn't have builtin tuples we make do with
		// a JComponent[][] to store the structure of the input window
		JComponent[][] items = {
			{ new JLabel("Height:"), rowsField },
			{ new JLabel("Width:"),  colsField },
			{ new JLabel("Mines:"),  minesField },
		};

		// Show the message window now and get the result
		int option = JOptionPane.showConfirmDialog(frame, getMessagePanel(items),
				"Custom Board", JOptionPane.OK_CANCEL_OPTION);
		// If user didn't hit OK, bail out now
		if (option != JOptionPane.OK_OPTION)
			return false;

		// Bail out if fields can't be parsed into integers
		int rows, cols, mines;
		try {
			rows = Integer.parseInt(rowsField.getText());
			cols = Integer.parseInt(colsField.getText());
			mines = Integer.parseInt(minesField.getText());
		} catch (NumberFormatException e) {
			return false;
		}

		// Even though the text fields should technically only allow valid
		// inputs, we should clamp values to the allowed range, just in case
		// something slipped through the focusLost events
		rows = clampInt(rows, MIN_SIZE, MAX_ROWS);
		cols = clampInt(cols, MIN_SIZE, MAX_COLS);
		mines = clampInt(mines, MIN_MINES, getMaxMines(rows, cols));

		// If we nothing changed, return false
		if (current == CUSTOM && CUSTOM.rows == rows && CUSTOM.cols == cols && CUSTOM.mines == mines)
			return false;

		// Everything succeeded, so now actually set the new stats
		CUSTOM.setStats(rows, cols, mines);

		return true;
	}

	// Helper method to implement something that every language except Java
	// already has builtin
	public static int clampInt(int value, int minValue, int maxValue) {
		return Math.max(Math.min(value, maxValue), minValue);
	}

	// The regular formula for maximum mines is the product of rows and columns
	// minus one, but also cap it at 999
	private static int getMaxMines(int rows, int cols) {
		return Math.min((rows - 1) * (cols - 1), MAX_MINES);
	}

	// Create a JPanel that has the items in a custom gridlike layout in which
	// every row is as tall as the tallest element in that row and every column
	// is as wide as the widest element in that column
	private static JPanel getMessagePanel(JComponent[][] items) {
		// The padding between the elements and from the walls
		final int PADDING = 6;
		// The number of columns
		final int COLS = 2;

		// Null layout because the only layout manager that can do what we we
		// want is SpringLayout which the same complexity
		JPanel messagePanel = new JPanel(null);

		// Add the items to the panel, setting the label alignment along the way
		for (JComponent[] row : items) {
			JLabel label = (JLabel) row[0];
			label.setLabelFor(row[1]);
			label.setHorizontalAlignment(JLabel.TRAILING);
			messagePanel.add(label);
			messagePanel.add(row[1]);
		}

		// The maximum width of all the elements of each column
		int[] maxWidths = new int[COLS];
		// The maximum height of each elements of each row
		int[] maxHeights = new int[items.length];
		// The x-position of all elements of each column
		int[] x = new int[COLS + 1];
		// The y-position of all the elements of each row
		int[] y = new int[items.length + 1];
		// The last value of x and y hold the size of the panel itself

		// Set x and maxWidths
		x[0] = PADDING;
		for (int c = 0; c < COLS; c++) {
			// Get the maximum width among items of this row
			int maxWidth = Integer.MIN_VALUE;
			for (int r = 0; r < items.length; r++)
				maxWidth = Math.max(maxWidth, (int) items[r][c].getPreferredSize().getWidth());
			maxWidths[c] = maxWidth;
			// x-coordinate of the next item is the x-coordinate of this one
			// plus this one's width plus padding
			x[c + 1] = x[c] + maxWidth + PADDING;
		}

		// Set y and maxHeights the same way
		y[0] = PADDING;
		for (int r = 0; r < items.length; r++) {
			int maxHeight = Integer.MIN_VALUE;
			for (int c = 0; c < COLS; c++)
				maxHeight = Math.max(maxHeight, (int) items[r][c].getPreferredSize().getHeight());
			maxHeights[r] = maxHeight;
			y[r + 1] = y[r] + maxHeight + PADDING;
		}

		// Actually put into use the values we just got
		for (int r = 0; r < items.length; r++)
			for (int c = 0; c < COLS; c++)
				items[r][c].setBounds(x[c], y[r], maxWidths[c], maxHeights[r]);

		// Use the last values of x and y to set the size of the panel
		messagePanel.setPreferredSize(new Dimension(x[COLS], y[items.length]));

		return messagePanel;
	}
}