package pl.wroc.pwr.image.converter;

import pl.wroc.pwr.IOperator;
import pl.wroc.pwr.image.ILabImage;
import pl.wroc.pwr.image.IXYZImage;
import pl.wroc.pwr.image.model.LabImage;

public class XYZtoLabConverter implements IOperator< ILabImage >
{
	/**
	 *
	 */
	private static final long serialVersionUID = -7429159306670738265L;

	private IXYZImage inputImage;
	private ILabImage outputImage;

	public XYZtoLabConverter( IXYZImage image ) {
		this.inputImage = image;
	}

	public void setImage( IXYZImage image ) {
		this.inputImage = image;
	}

	public ILabImage getResult( ) {
		return this.outputImage;
	}

	public ILabImage apply( ) {
		this.outputImage = new LabImage( this.inputImage.getSize( ) );
		for ( int i = 0; i < this.inputImage.getXChannel( ).getMaxIndex( ); i++ )
		{
			float X = this.inputImage.getXChannel( ).getValue( i );
			float Y = this.inputImage.getYChannel( ).getValue( i );
			float Z = this.inputImage.getZChannel( ).getValue( i );

			/* Hunter-Lab
			double L = 10 * Math.sqrt( Y );
			double a = 17.5 * ( ( ( 1.02 * X ) - Y ) / Math.sqrt( Y ) );
			double b = 7 * ( ( Y - ( 0.847 * Z ) ) / Math.sqrt( Y ) );*/

			float ref_X =  95.047f;
			float ref_Y = 100.000f;
			float ref_Z = 108.883f;

			float var_X = X / ref_X;          //ref_X =  95.047  Observer= 2°, Illuminant= D65
			float var_Y = Y / ref_Y;          //ref_Y = 100.000
			float var_Z = Z / ref_Z;          //ref_Z = 108.883

			if ( var_X > 0.008856f )
			{
				var_X = (float)Math.pow( var_X, ( 1.0f / 3.0f ) );
			}
			else
			{
				var_X = ( 7.787f * var_X ) + ( 16.0f / 116.0f );
			}
			if ( var_Y > 0.008856f )
			{
				var_Y = (float)Math.pow( var_Y, ( 1.0f / 3.0f ) );
			}
			else
			{
				var_Y = ( 7.787f * var_Y ) + ( 16.0f / 116.0f );
			}
			if ( var_Z > 0.008856f )
			{
				var_Z = (float)Math.pow( var_Z, ( 1.0f / 3.0f ) );
			}
			else
			{
				var_Z = ( 7.787f * var_Z ) + ( 16.0f / 116.0f );
			}

			float L = ( 116.0f * var_Y ) - 16.0f;
			float a = 500.0f * ( var_X - var_Y );
			float b = 200.0f * ( var_Y - var_Z );

			this.outputImage.getLChannel( ).setValue( i, L );
			this.outputImage.getaChannel( ).setValue( i, a );
			this.outputImage.getbChannel( ).setValue( i, b );
		}
		return this.getResult( );
	}
}