import java.util.InputMismatchException;
import java.util.Scanner;

public class Lab {

	// Configuration
	public static final String TITLE = "Smart Calc";
	public static final String VERSION = "0.1";

	// Variables
	private static Scanner console;

	// Operation
	public static final int ADD = 1;
	public static final int SUBTRACT = 2;
	public static final int MULTIPLY = 3;
	public static final int DIVIDE = 4;
	public static final int REMAINDER = 5;
	public static final int POWER = 6;
	public static final int SQRT = 7;
	public static final int ABS = 8;
	public static final int QUIT = 10;

	// Initialization
	public static void main(String[] args) {
		// Welcome Message
		System.out.println(TITLE + " v." + VERSION);

		// Initialize Scanner
		console = new Scanner(System.in);

		// Grab operator from user
		int operation = getOperator();

		// Return output from operation
		System.out.println("--");
		System.out.println(operate(operation));
	}

	// Grab operation from user input
	private static int getOperator() {
		// Prompt user
		System.out.println("\nPick an operation from the list.");
		displayMenu();

		// Grab input, close scanner, and return
		System.out.print("\n?: "); // Draw attention to input
		int operator = console.nextInt();
		return operator;
	}

	// Display menu options
	private static void displayMenu() {
		System.out.println("Operations:" + "\nADD - " + ADD + "\nSUBTRACT - " + SUBTRACT + "\nMULTIPLY - " + MULTIPLY + "\nDIVIDE - " + DIVIDE + "\nREMAINDER - " + REMAINDER + "\nPOWER - " + POWER + "\nSQUARE_ROOT - " + SQRT + "\nABSOLUTE_VALUE - " + ABS + "\nQUIT - " + QUIT);
	}

	// Determine operation from input
	private static int operate(int operation) {
		// Pick operation from list
		switch (operation) {
		case ADD:
			return add();
		case SUBTRACT:
			return subtract();
		case MULTIPLY:
			return multiply();
		case DIVIDE:
			return divide();
		case REMAINDER:
			return remainder();
		case POWER:
			return power();
		case SQRT:
			return sqrt();
		case ABS:
			return abs();
		case QUIT:
		default:
			return -1; // Quit or Error
		}
	}

	// Get a number, and check if it's a good one
	private static int getIntegerInput(char c) {
		// Grab input
		System.out.print(c + ": ");
		long input = console.nextLong();

		// Grab user's input as long and check if it's in bounds
		if(input >= Integer.MIN_VALUE && input <= Integer.MAX_VALUE) {
			// Return input
			return (int) input;
		} else {
			// Otherwise, try again
			return getIntegerInput(c);
		}

	}

	private static int getIntegerInput() {
		return getIntegerInput('?');
	}

	// Operations
	private static int add() {
		System.out.println("x + y");
		return getIntegerInput('x') + getIntegerInput('y');
	}

	private static int subtract() {
		System.out.println("x - y");
		return getIntegerInput('x') - getIntegerInput('y');
	}

	private static int multiply() {
		System.out.println("x * y");
		return getIntegerInput('x') * getIntegerInput('y');
	}

	private static int divide() {
		System.out.println("x / y");
		return getIntegerInput('x') / getIntegerInput('y');
	}

	private static int remainder() {
		System.out.println("x % y");
		return getIntegerInput('x') % getIntegerInput('y');
	}

	private static int power() {
		System.out.println("x ^ y");
		return (int) Math.pow(getIntegerInput('x'), getIntegerInput('y'));
	}

	private static int sqrt() {
		System.out.println("sqrt(x)");
		return (int) Math.sqrt(getIntegerInput('x'));
	}

	private static int abs() {
		System.out.println("|x|");
		return (int) Math.abs(getIntegerInput('x'));
	}
}