package bargainingchips.utilityfunctions;

import bargainingchips.Chip;
import bargainingchips.ChipIssueValue;

/**
 * 
 * This class contains mathematical methods helping computational procedures mostly in utility functions, 
 * namely, 
 *  - Bezier 		// mathematical curve
 *  - comb 			// mathematical combination 
 *  - fc 			// mathematical factorial
 *  - uSlope 		// y value respected to x value at a sloped line
 *  - writeT 		// String list of values (e.g., prices, quantities, etc) assigned to a single variable (e.g. {@link Chip}) 
 * 
 * 
 * @author Faria Nassiri-Mofakham
 *
 */

public class UtilityHelperMethods<T> 
{
	/**
	 * @param input parameter (e.g., an offered price per a {@link Chip}, 
	 * 		  and `n' data points of type T (e.g., as of Double[], Integer[], etc).
	 * 
	 * @return Bezier value of rank `n' for the offered parameter.
	 **/
	public double bezier(T[] desired, Double offered)  
	{
		double bez = 0.0;
		int n= desired.length;
		for (int i=0; i<n; i++)
		{
			bez = ( (offered < (double) desired[0]) ? 1.0 : ( (offered > (double) desired[n-1]) ? 0.0 : comb(n,i)*Math.pow(1-offered, n)*Math.pow(i, n)*(double)desired[i]));
		}
		return ( (bez>1) ? 1 : (bez<0) ? 0 : bez);
	}
	
	/**
	 * @return combination of `n' and `k'
	 **/
	public int comb(int n, int k)  
	{
		return fc(n)/(fc(n-k)*fc(k));
	}

	/**
	 * @return factorial of `n'
	 **/
	public int fc(int n) {  
		int result = 1;
		for (; n > 1; n--) {
			result *= n;
		}
		return result;
	}
	
	/**
	 * @param a param and 2 data points and respected utilities, showing a sloped line
	 * @return utility of param
	 **/	
	public double uSlope(double param, T tData1, T tData2, Double uData1, Double uData2)
	{
		Double data1 = (Double) tData1; 
		Double data2 = (Double) tData2;

		return (param-data1)*(uData1-uData2)/(data1-data2)+uData1;
	}
	
	/**
	 * @return an String list of values assigned to a single variable, e.g. list of quantities or prices per a {@link Chip}
	 **/
	public String writeT(ChipIssueValue<T[]> t)
	{
		String s = "{";
		T[] j;
		for (Chip c: t)
		{
			s += " " + c.toString() + "={";
			j= t.getUnitValue(c);
			//System.out.println("j: "+j);
			for (int k=0; k<j.length; k++)
				s += j[k].toString()+((k<j.length-1) ? ", " : "");
			s += "}";
		}	
		s += " }";
		return s;
	}
}