/**
 * @author sunag / http://www.sunag.com.br/
 */

import { TempNode } from '../core/TempNode.js';
import { ConstNode } from '../core/ConstNode.js';
import { FloatNode } from '../inputs/FloatNode.js';
import { FunctionNode } from '../core/FunctionNode.js';
import { ExpressionNode } from '../core/ExpressionNode.js';

function ColorSpaceNode( input, method ) {

	TempNode.call( this, 'v4' );

	this.input = input;

	this.method = method || ColorSpaceNode.LINEAR_TO_LINEAR;

}

ColorSpaceNode.Nodes = ( function () {

	// For a discussion of what this is, please read this: http://lousodrome.net/blog/light/2013/05/26/gamma-correct-and-hdr-rendering-in-a-32-bits-buffer/

	var LinearToLinear = new FunctionNode( [
		"vec4 LinearToLinear( in vec4 value ) {",

		"	return value;",

		"}"
	].join( "\n" ) );

	var GammaToLinear = new FunctionNode( [
		"vec4 GammaToLinear( in vec4 value, in float gammaFactor ) {",

		"	return vec4( pow( value.xyz, vec3( gammaFactor ) ), value.w );",

		"}"
	].join( "\n" ) );

	var LinearToGamma = new FunctionNode( [
		"vec4 LinearToGamma( in vec4 value, in float gammaFactor ) {",

		"	return vec4( pow( value.xyz, vec3( 1.0 / gammaFactor ) ), value.w );",

		"}"
	].join( "\n" ) );

	var sRGBToLinear = new FunctionNode( [
		"vec4 sRGBToLinear( in vec4 value ) {",

		"	return vec4( mix( pow( value.rgb * 0.9478672986 + vec3( 0.0521327014 ), vec3( 2.4 ) ), value.rgb * 0.0773993808, vec3( lessThanEqual( value.rgb, vec3( 0.04045 ) ) ) ), value.w );",

		"}"
	].join( "\n" ) );

	var LinearTosRGB = new FunctionNode( [
		"vec4 LinearTosRGB( in vec4 value ) {",

		"	return vec4( mix( pow( value.rgb, vec3( 0.41666 ) ) * 1.055 - vec3( 0.055 ), value.rgb * 12.92, vec3( lessThanEqual( value.rgb, vec3( 0.0031308 ) ) ) ), value.w );",

		"}"
	].join( "\n" ) );

	var RGBEToLinear = new FunctionNode( [
		"vec4 RGBEToLinear( in vec4 value ) {",

		"	return vec4( value.rgb * exp2( value.a * 255.0 - 128.0 ), 1.0 );",

		"}"
	].join( "\n" ) );

	var LinearToRGBE = new FunctionNode( [
		"vec4 LinearToRGBE( in vec4 value ) {",

		"	float maxComponent = max( max( value.r, value.g ), value.b );",
		"	float fExp = clamp( ceil( log2( maxComponent ) ), -128.0, 127.0 );",
		"	return vec4( value.rgb / exp2( fExp ), ( fExp + 128.0 ) / 255.0 );",
		//  return vec4( value.brg, ( 3.0 + 128.0 ) / 256.0 );

		"}"
	].join( "\n" ) );

	// reference: http://iwasbeingirony.blogspot.ca/2010/06/difference-between-rgbm-and-rgbd.html

	var RGBMToLinear = new FunctionNode( [
		"vec3 RGBMToLinear( in vec4 value, in float maxRange ) {",

		"	return vec4( value.xyz * value.w * maxRange, 1.0 );",

		"}"
	].join( "\n" ) );

	var LinearToRGBM = new FunctionNode( [
		"vec3 LinearToRGBM( in vec4 value, in float maxRange ) {",

		"	float maxRGB = max( value.x, max( value.g, value.b ) );",
		"	float M      = clamp( maxRGB / maxRange, 0.0, 1.0 );",
		"	M            = ceil( M * 255.0 ) / 255.0;",
		"	return vec4( value.rgb / ( M * maxRange ), M );",

		"}"
	].join( "\n" ) );

	// reference: http://iwasbeingirony.blogspot.ca/2010/06/difference-between-rgbm-and-rgbd.html

	var RGBDToLinear = new FunctionNode( [
		"vec3 RGBDToLinear( in vec4 value, in float maxRange ) {",

		"	return vec4( value.rgb * ( ( maxRange / 255.0 ) / value.a ), 1.0 );",

		"}"
	].join( "\n" ) );


	var LinearToRGBD = new FunctionNode( [
		"vec3 LinearToRGBD( in vec4 value, in float maxRange ) {",

		"	float maxRGB = max( value.x, max( value.g, value.b ) );",
		"	float D      = max( maxRange / maxRGB, 1.0 );",
		"	D            = min( floor( D ) / 255.0, 1.0 );",
		"	return vec4( value.rgb * ( D * ( 255.0 / maxRange ) ), D );",

		"}"
	].join( "\n" ) );

	// LogLuv reference: http://graphicrants.blogspot.ca/2009/04/rgbm-color-encoding.html

	// M matrix, for encoding

	var cLogLuvM = new ConstNode( "const mat3 cLogLuvM = mat3( 0.2209, 0.3390, 0.4184, 0.1138, 0.6780, 0.7319, 0.0102, 0.1130, 0.2969 );" );

	var LinearToLogLuv = new FunctionNode( [
		"vec4 LinearToLogLuv( in vec4 value ) {",

		"	vec3 Xp_Y_XYZp = cLogLuvM * value.rgb;",
		"	Xp_Y_XYZp = max(Xp_Y_XYZp, vec3(1e-6, 1e-6, 1e-6));",
		"	vec4 vResult;",
		"	vResult.xy = Xp_Y_XYZp.xy / Xp_Y_XYZp.z;",
		"	float Le = 2.0 * log2(Xp_Y_XYZp.y) + 127.0;",
		"	vResult.w = fract(Le);",
		"	vResult.z = (Le - (floor(vResult.w*255.0))/255.0)/255.0;",
		"	return vResult;",

		"}"
	].join( "\n" ), [ cLogLuvM ] );

	// Inverse M matrix, for decoding

	var cLogLuvInverseM = new ConstNode( "const mat3 cLogLuvInverseM = mat3( 6.0014, -2.7008, -1.7996, -1.3320, 3.1029, -5.7721, 0.3008, -1.0882, 5.6268 );" );

	var LogLuvToLinear = new FunctionNode( [
		"vec4 LogLuvToLinear( in vec4 value ) {",

		"	float Le = value.z * 255.0 + value.w;",
		"	vec3 Xp_Y_XYZp;",
		"	Xp_Y_XYZp.y = exp2((Le - 127.0) / 2.0);",
		"	Xp_Y_XYZp.z = Xp_Y_XYZp.y / value.y;",
		"	Xp_Y_XYZp.x = value.x * Xp_Y_XYZp.z;",
		"	vec3 vRGB = cLogLuvInverseM * Xp_Y_XYZp.rgb;",
		"	return vec4( max(vRGB, 0.0), 1.0 );",

		"}"
	].join( "\n" ), [ cLogLuvInverseM ] );

	return {
		LinearToLinear: LinearToLinear,
		GammaToLinear: GammaToLinear,
		LinearToGamma: LinearToGamma,
		sRGBToLinear: sRGBToLinear,
		LinearTosRGB: LinearTosRGB,
		RGBEToLinear: RGBEToLinear,
		LinearToRGBE: LinearToRGBE,
		RGBMToLinear: RGBMToLinear,
		LinearToRGBM: LinearToRGBM,
		RGBDToLinear: RGBDToLinear,
		LinearToRGBD: LinearToRGBD,
		cLogLuvM: cLogLuvM,
		LinearToLogLuv: LinearToLogLuv,
		cLogLuvInverseM: cLogLuvInverseM,
		LogLuvToLinear: LogLuvToLinear
	};

} )();

ColorSpaceNode.LINEAR_TO_LINEAR = 'LinearToLinear';

ColorSpaceNode.GAMMA_TO_LINEAR = 'GammaToLinear';
ColorSpaceNode.LINEAR_TO_GAMMA = 'LinearToGamma';

ColorSpaceNode.SRGB_TO_LINEAR = 'sRGBToLinear';
ColorSpaceNode.LINEAR_TO_SRGB = 'LinearTosRGB';

ColorSpaceNode.RGBE_TO_LINEAR = 'RGBEToLinear';
ColorSpaceNode.LINEAR_TO_RGBE = 'LinearToRGBE';

ColorSpaceNode.RGBM_TO_LINEAR = 'RGBMToLinear';
ColorSpaceNode.LINEAR_TO_RGBM = 'LinearToRGBM';

ColorSpaceNode.RGBD_TO_LINEAR = 'RGBDToLinear';
ColorSpaceNode.LINEAR_TO_RGBD = 'LinearToRGBD';

ColorSpaceNode.LINEAR_TO_LOG_LUV = 'LinearToLogLuv';
ColorSpaceNode.LOG_LUV_TO_LINEAR = 'LogLuvToLinear';

ColorSpaceNode.getEncodingComponents = function ( encoding ) {

	switch ( encoding ) {

		case THREE.LinearEncoding:
			return [ 'Linear' ];
		case THREE.sRGBEncoding:
			return [ 'sRGB' ];
		case THREE.RGBEEncoding:
			return [ 'RGBE' ];
		case THREE.RGBM7Encoding:
			return [ 'RGBM', new FloatNode( 7.0 ).setReadonly( true ) ];
		case THREE.RGBM16Encoding:
			return [ 'RGBM', new FloatNode( 16.0 ).setReadonly( true ) ];
		case THREE.RGBDEncoding:
			return [ 'RGBD', new FloatNode( 256.0 ).setReadonly( true ) ];
		case THREE.GammaEncoding:
			return [ 'Gamma', new ExpressionNode( 'float( GAMMA_FACTOR )', 'f' ) ];

	}

};

ColorSpaceNode.prototype = Object.create( TempNode.prototype );
ColorSpaceNode.prototype.constructor = ColorSpaceNode;
ColorSpaceNode.prototype.nodeType = "ColorSpace";

ColorSpaceNode.prototype.generate = function ( builder, output ) {

	var input = this.input.build( builder, 'v4' );
	var outputType = this.getType( builder );

	var methodNode = ColorSpaceNode.Nodes[ this.method ];
	var method = builder.include( methodNode );

	if ( method === ColorSpaceNode.LINEAR_TO_LINEAR ) {

		return builder.format( input, outputType, output );

	} else {

		if ( methodNode.inputs.length === 2 ) {

			var factor = this.factor.build( builder, 'f' );

			return builder.format( method + '( ' + input + ', ' + factor + ' )', outputType, output );

		} else {

			return builder.format( method + '( ' + input + ' )', outputType, output );

		}

	}

};

ColorSpaceNode.prototype.fromEncoding = function ( encoding ) {

	var components = ColorSpaceNode.getEncodingComponents( encoding );

	this.method = 'LinearTo' + components[ 0 ];
	this.factor = components[ 1 ];

};

ColorSpaceNode.prototype.fromDecoding = function ( encoding ) {

	var components = ColorSpaceNode.getEncodingComponents( encoding );

	this.method = components[ 0 ] + 'ToLinear';
	this.factor = components[ 1 ];

};

ColorSpaceNode.prototype.copy = function ( source ) {

	TempNode.prototype.copy.call( this, source );

	this.input = source.input;
	this.method = source.method;

};

ColorSpaceNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.input = this.input.toJSON( meta ).uuid;
		data.method = this.method;

	}

	return data;

};

export { ColorSpaceNode };
