package speiger.src.collections.utils;

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;

public class SanityChecks
{
	public static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
	private static ForkJoinPool WORK_POOL = ForkJoinPool.commonPool();
	
	public static byte castToByte(int value) {
		if(value > Byte.MAX_VALUE || value < Byte.MIN_VALUE) throw new IllegalStateException("Value ["+value+"] out of Byte[-128,127] range");
		return (byte)value;
	}
	
	public static short castToShort(int value) {
		if(value > Short.MAX_VALUE || value < Short.MIN_VALUE) throw new IllegalStateException("Value ["+value+"] out of Short[-32768,32767] range");
		return (short)value;
	}
	
	public static char castToChar(int value) {
		if(value > Character.MAX_VALUE || value < Character.MIN_VALUE) throw new IllegalStateException("Value ["+value+"] out of Character[0,65535] range");
		return (char)value;
	}
	
	public static float castToFloat(double value) {
		if(Double.isNaN(value)) return Float.NaN;
		if(Double.isInfinite(value)) return value > 0 ? Float.POSITIVE_INFINITY : Float.NEGATIVE_INFINITY;
		if(value < -Float.MAX_VALUE || value > Float.MAX_VALUE) throw new IllegalStateException("Value ["+value+"] out of Float range");
		return (float)value;
	}
	
	public static void checkArrayCapacity(int arraySize, int offset, int accessSize) {
		if(offset < 0) throw new IllegalStateException("Offset is negative ("+offset+")");
		else if(accessSize < 0) throw new IllegalStateException("Size is negative ("+accessSize+")");
		else if(arraySize < offset + accessSize) throw new IndexOutOfBoundsException("Index (" + offset + accessSize + ") is not in size (" + arraySize + ")");
	}
	
	public static boolean canParallelTask() {
		return WORK_POOL.getParallelism() > 1;
	}
	
	public static <T> void invokeTask(ForkJoinTask<T> task) {
		WORK_POOL.invoke(task);
	}
	
	public static void setWorkPool(ForkJoinPool pool) {
		WORK_POOL = pool == null ? ForkJoinPool.commonPool() : pool;
	}
}