// CS7 - Keno project (covering arrays)
//
// This program plays a game of keno with the user.  The user specifies
// how much s/he wants to wager, selects 7 integers between 1 and 80, and
// then finds out the results based on keno scoring.
//
// It is difficult to win much with this version (naturally!), so to 
// increase your chances, just decrease BOARD_MAX (making the range 1 
// through the new value, like 1-60 or something).  You can also increase
// NUM_UPICKS, but if you match more than 7 it will not recognize that.

import tio.*;

class keno {

	static final int BOARD_MAX = 80;
	static final int NUM_UPICKS = 7;
	static final int GAME_PICKS = 20;
	
	public static void main (String[] args) {

		// userPicks holds 7 integers between 1 and 80.
		int [] userPicks = new int[NUM_UPICKS];
		// board is an array of booleans and we use slots 1-80.  20 of these
		// will be set to true indicating which numbers were picked.
		boolean [] board = new boolean[BOARD_MAX+1];
		int wager, winnings, matches;

		System.out.println("Welcome to Keno!");
		System.out.print("How much would you like to wager? (Whole # only):  ");
		wager = Console.in.readInt();
		
		// get the picks from the user then load the random picks on the board
		loadPicks(userPicks);
		printPicks(userPicks);		// print the picks back for the user
		loadBoard(board);
		printBoard(board);			// print the board
		System.out.println();

		// calculate how many matches there are between the user & board
		matches = countMatches(userPicks, board);
		System.out.println("You had " + matches + " matches with the board.");

		// finally, print the winnings, if any.
		winnings = getWinnings(wager, matches);
		if (winnings==0)
			System.out.println("Sorry, you did not win any money.");
		else
			System.out.println("You get back $" + winnings);

	}

	// loads the user's picks into a, does not permit duplicates
	static void loadPicks(int [] a) {
		int candidate=0;
		for (int i=0; i<a.length; i++) {
			candidate = getIntInRange(1, BOARD_MAX);
			while (numberPresent(candidate, 0, i, a)) {
				System.out.println("Sorry, you picked that one already.");
				candidate = getIntInRange(1, BOARD_MAX);
			}
			a[i] = candidate;
		}
	}

	// load the board with 20 (GAME_PICKS) random picks
	static void loadBoard(boolean [] b) {
		int candidate=1;
		for (int i=1; i<GAME_PICKS; i++) {
			candidate = (int)(Math.random() * BOARD_MAX) + 1;
			while (b[candidate])
				candidate = (int)(Math.random() * BOARD_MAX) + 1;
			b[candidate] = true;
		}
	}
	

	// count up the matches between the user's card and automated picks
	static int countMatches(int [] u, boolean [] b) {
		int count=0;
		for (int i=0; i<NUM_UPICKS; i++)
			if (b[u[i]]) count++;
		return count;
	}

	// print the winnings based payoff chart.  mct holds the number of
	// matches and amt is what the person wagered.
	static int getWinnings(int amt, int mct) {
		switch (mct) {
			case 4:
				return amt;
			case 5:
				return amt * 20;
			case 6:
				return amt * 200;
			case 7:
				return amt * 12000;
			default:
				return 0;
		}
	}

	// HELPER METHODS
	
	// tells you if n is in the array a between low and up to but not including
	// high
	static boolean numberPresent(int n, int low, int high, int [] a) {
		for (int i=low; i<high; i++)
			if (a[i] == n)
				return true;
	
		return false;  // if the loop ends, we made it through w/out finding n
	}

	// reads a number between low and high from the keyboard
	static int getIntInRange(int low, int high) {
		int n=low-1;
		while (n < low || n > high) {
			System.out.print("Please enter an integer between " + low + " and "
						+ high + ": ");
			n = Console.in.readInt();
		}
		return n;
	}

	// prints the values in the user's array
	static void printPicks(int a []) {
		System.out.print("Your picks: ");
		for (int i=0; i<a.length; i++)
   		System.out.print(a[i] + " ");
		System.out.println();
	}

	// print the values chosen on the board
	static void printBoard(boolean b []) {
		System.out.print("Board: ");
		for (int i=0; i<b.length; i++)
			if (b[i])
				System.out.print(i + " ");
		System.out.println();
	}

}

/* SAMPLE OUTPUT: 

$ java keno
Welcome to Keno!
How much would you like to wager? (Whole # only):  20
Please enter an integer between 1 and 80: 14
Please enter an integer between 1 and 80: 21
Please enter an integer between 1 and 80: 32
Please enter an integer between 1 and 80: 21
Sorry, you picked that one already.
Please enter an integer between 1 and 80: 23
Please enter an integer between 1 and 80: 88
Please enter an integer between 1 and 80: 8
Please enter an integer between 1 and 80: 12
Please enter an integer between 1 and 80: 76
Your picks: 14 21 32 23 8 12 76
Board: 7 14 18 20 25 27 32 38 40 41 50 53 56 62 63 68 74 77 80

You had 2 matches with the board.
Sorry, you did not win any money.

$

*/