package jcgp.backend.function;

import java.util.ArrayList;
import java.util.Arrays;

import jcgp.backend.exceptions.InvalidArgumentsException;
import jcgp.backend.population.Connection;

public class Arithmetic extends FunctionSet {
	
	public Arithmetic() {
		name = "Arithmetic";
		functionList = new Function[]{
				new Addition(),
				new Subtraction(),
				new Multiplication(),
				new Division()};
		
		allowedFunctions = new ArrayList<Function>(Arrays.asList(functionList));
	}
	
	public static class Addition extends Function {

		private int arity = 2;

		@Override
		public Integer run(Connection... connections) {
			if (connections.length < arity) {
				throw new InvalidArgumentsException("Not enough connections were given.");
			} else {
				Integer arg1 = ((Integer) connections[0].getValue());
				Integer arg2 = ((Integer) connections[1].getValue());
				Integer result = arg1 + arg2;

				return result;
			}
		}

		@Override
		public int getArity() {
			return arity;
		}

		@Override
		public String getName() {
			return "Addition";
		}
	}

	public static class Subtraction extends Function {

		private int arity = 2;

		@Override
		public Integer run(Connection... connections) {
			if (connections.length < arity) {
				throw new InvalidArgumentsException("Not enough connections were given.");
			} else {
				Integer arg1 = ((Integer) connections[0].getValue());
				Integer arg2 = ((Integer) connections[1].getValue());
				Integer result = arg1 - arg2;

				return result;
			}
		}

		@Override
		public int getArity() {
			return arity;
		}

		@Override
		public String getName() {
			return "Subtraction";
		}
	}

	public static class Multiplication extends Function {

		private int arity = 2;

		@Override
		public Integer run(Connection... connections) {
			if (connections.length < arity) {
				throw new InvalidArgumentsException("Not enough connections were given.");
			} else {
				Integer arg1 = ((Integer) connections[0].getValue());
				Integer arg2 = ((Integer) connections[1].getValue());
				Integer result = arg1 * arg2;

				return result;
			} 
		}

		@Override
		public int getArity() {
			return arity;
		}

		@Override
		public String getName() {
			return "Multiplication";
		}
	}

	public static class Division extends Function {

		private int arity = 2;

		@Override
		public Integer run(Connection... connections) {
			if (connections.length < arity) {
				throw new InvalidArgumentsException("Not enough connections were given.");
			} else {
				Integer arg1 = ((Integer) connections[0].getValue());
				Integer arg2 = ((Integer) connections[1].getValue());
				Integer result;
				if (arg2 == 0) {
					result = 0;
				} else {
					result = arg1 / arg2;
				}

				return result;
			} 
		}

		@Override
		public int getArity() {
			return arity;
		}

		@Override
		public String getName() {
			return "Division";
		}
	}
	
}