Game.java

/*
 * A game of Minesweeper.
 */

import java.util.Scanner;

public class Game {
	private Board board;
	private boolean isOver;
	private boolean isFirstMove;

	public Game() {
		resetGame();
	}

	// Display the title screen and launch into the game should the user
	// request to.
	public void start() {
		printTitle();
		String response = titlePrompt();

		if (response.contentEquals("start")) {
			gameLoop();
		}

		printProgramExit();
	}

	// The main loop of the game.
	private void gameLoop() {
		String response = "yes";
		while (!response.contentEquals("exit") && isYes(response)) {
			while (!response.contentEquals("exit") && !isOver) {
				board.showRemainingMines();
				board.display();
				response = turnPrompt();

				// Handle validated user input.
				if (isScan(response)) {
					// User cannot be allowed to lose on the first move of the game
					// so we have to make sure that the tile they scanned isn't a
					// mine.
					if (isFirstMove) {
						// Keep generating a new board until we get one that
						// doesn't have a mine on the scanned tile.
						while (board.tileIsMine(inputToCoordinate(response))) {
							board = new Board();
						}

						isFirstMove = false;
					}

					board.revealTiles(inputToCoordinate(response));
					gameOverCheck(inputToCoordinate(response));
					if (isOver) {
						if (board.onlyMinesRemain()) {
							board.revealAll();
							board.display();
							System.out.println("Congratulations, you win!");
						}
						else {
							board.revealMines();
							board.display();
							System.out.println("You hit a mine!");
						}
					}
				}
				else if (isMark(response)) {
					board.markTile(inputToCoordinate(response.substring(1)));
				}
			}

			if (!response.contentEquals("exit")) {
				response = playAgainPrompt();
				if (isYes(response)) {
					System.out.println("Starting a new game...");
					resetGame();
				}
			}
		}
	}

	// Display the text-art title of the game.
	private void printTitle() {
		System.out.println("#   #  #####  #   #  #####   ####  #   #  #####  #####  ####   #####  ####");
		System.out.println("## ##    #    ##  #  #      #      #   #  #      #      #   #  #      #   #");
		System.out.println("# # #    #    # # #  ##      ###   # # #  ##     ##     ####   ##     ####");
		System.out.println("#   #    #    #  ##  #          #  # # #  #      #      #      #      #   #");
		System.out.println("#   #  #####  #   #  #####  ####    # #   #####  #####  #      #####  #   #\n");
	}

	// Prompt user for whether they would like to start a game of Minesweeper,
	// exit, or display the help menu
	private String titlePrompt() {
		Scanner input = new Scanner(System.in);

		String response = "";
		while (!response.contentEquals("start") && !response.contentEquals("exit")) {
			System.out.println("Enter 'start' to start a new game, 'exit' to exit, or 'help' to list in-game controls.");
			System.out.print("> ");
			response = input.nextLine();

			boolean valid = response.contentEquals("start") || response.contentEquals("exit") || response.contentEquals("help");
			if (!valid) {
				System.out.println("Please enter a valid option.\n");
			}
			else if (response.contentEquals("help")) {
				printHelp();
			}
		}

		return response;
	}

	// Display a list of valid inputs to the user.
	private void printHelp() {
		System.out.println("\nCommand list:");
		System.out.println("A1   - Where 'A' is a letter from A-I and '1' is a number from 1-9. Scan a tile.");
		System.out.println("!A1  - Mark or unmark a tile.");
		System.out.println("exit - Quit the game.");
		System.out.println("help - Show this menu again.\n");
	}

	// Display a message on program exit thanking the user for playing the game.
	private void printProgramExit() {
		System.out.println("\nThank you for playing!");
	}

	// Ask the user for an input and validate it. Returns the user's move for
	// the turn as a string.
	private String turnPrompt() {
		String response = "";

		Scanner input = new Scanner(System.in);
		boolean valid = false;
		while (!valid || response.contentEquals("help")) {
			System.out.print("> ");
			response = input.nextLine();

			if (response.contentEquals("exit")) {
				valid = true;
			}
			else if (response.contentEquals("help")) {
				valid = true;
				printHelp();
			}
			else if (isScan(response)) {
				if (!board.tileIsRevealed(inputToCoordinate(response))) {
					if (!board.tileIsMarked(inputToCoordinate(response))) {
						valid = true;
					}
					else {
						valid = false;
						System.out.println("You can't scan a tile that is marked!\n");
					}
				}
				else {
					valid = false;
					System.out.println("That tile has already been scanned!\n");
				}
			}
			else if (isMark(response)) {
				if (!board.tileIsRevealed(inputToCoordinate(response.substring(1)))) {
					valid = true;
				}
				else {
					valid = false;
					System.out.println("You can't mark a tile that has already been scanned!\n");
				}
			}
			else {
				valid = false;
				System.out.println("Input not valid! Enter 'help' if needed.\n");
			}
		}

		return response;
	}

	// Takes a string with a length of two and Returns it as a Coordinate
	// matching that tile on the board.
	private Coordinate inputToCoordinate(String str) {
		Coordinate tile = new Coordinate();

		char upper = Character.toUpperCase(str.charAt(0));
		switch (upper) {
		case 'A':
			tile.x = 0;
			break;
		case 'B':
			tile.x = 1;
			break;
		case 'C':
			tile.x = 2;
			break;
		case 'D':
			tile.x = 3;
			break;
		case 'E':
			tile.x = 4;
			break;
		case 'F':
			tile.x = 5;
			break;
		case 'G':
			tile.x = 6;
			break;
		case 'H':
			tile.x = 7;
			break;
		case 'I':
			tile.x = 8;
			break;
		default:
			tile.x = -1;
			break;
		}

		// One is subtracted from the user input row because the rows as
		// indexed in the array start at zero and the rows shown on the
		// board visual presented to the user start at 1.
		tile.y = Character.getNumericValue(str.charAt(1)) - 1;

		return tile;
	}

	// Returns true if the passed string is in the form of a scan command.
	private boolean isScan(String str) {
		if (str.length() == 2) {
			if (isColumn(str.charAt(0)) && isRow(str.charAt(1))) {
				return true;
			}
			else {
				return false;
			}
		}
		else {
			return false;
		}
	}

	// Returns true if the passed string is in the form of a mark command.
	private boolean isMark(String str) {
		if (str.length() == 3) {
			if (str.charAt(0) == '!' && isColumn(str.charAt(1)) && isRow(str.charAt(2))) {
				return true;
			}
			else {
				return false;
			}
		}
		else {
			return false;
		}
	}

	// Takes a character and returns true if the character is within the valid
	// range for columns.
	private boolean isColumn(char ch) {
		boolean isColumn;

		char upper = Character.toUpperCase(ch);

		switch (upper) {
		case 'A':
		case 'B':
		case 'C':
		case 'D':
		case 'E':
		case 'F':
		case 'G':
		case 'H':
		case 'I':
			isColumn = true;
			break;
		default:
			isColumn = false;
			break;
		}

		return isColumn;
	}

	// Takes a character and returns true if that character is within the valid
	// range for rows.
	private boolean isRow(char ch) {
		boolean isRow = false;

		switch (ch) {
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
			isRow = true;
			break;
		default:
			isRow = false;
			break;
		}

		return isRow;
	}

	// End the game if the scanned tile was a mine or if all non-mine tiles
	// have been scanned.
	private void gameOverCheck(Coordinate tile) {
		if (board.tileIsMine(tile) || board.onlyMinesRemain()) {
			isOver = true;
		}
	}

	// Create a new board and reset relevant variables.
	private void resetGame() {
		board = new Board();
		isOver = false;
		isFirstMove = true;
	}

	// Returns true if the passed string can be taken to mean yes.
	private boolean isYes(String str) {
		String upper = str.toUpperCase();
		switch (upper) {
		case "YES":
		case "Y":
			return true;
		default:
			return false;
		}
	}

	// Ask player if they would like to play again and return their response.
	private String playAgainPrompt() {
		String response = "";

		Scanner input = new Scanner(System.in);
		System.out.println("\nWould you like to play again?");
		System.out.print("> ");
		response = input.nextLine();

		return response;
	}
}