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

import { TempNode } from '../core/TempNode.js';

function MathNode( a, bOrMethod, cOrMethod, method ) {

	TempNode.call( this );

	this.a = a;
	typeof bOrMethod !== 'string' ? this.b = bOrMethod : method = bOrMethod;
	typeof cOrMethod !== 'string' ? this.c = cOrMethod : method = cOrMethod;

	this.method = method;

}

// 1 input

MathNode.RAD = 'radians';
MathNode.DEG = 'degrees';
MathNode.EXP = 'exp';
MathNode.EXP2 = 'exp2';
MathNode.LOG = 'log';
MathNode.LOG2 = 'log2';
MathNode.SQRT = 'sqrt';
MathNode.INV_SQRT = 'inversesqrt';
MathNode.FLOOR = 'floor';
MathNode.CEIL = 'ceil';
MathNode.NORMALIZE = 'normalize';
MathNode.FRACT = 'fract';
MathNode.SATURATE = 'saturate';
MathNode.SIN = 'sin';
MathNode.COS = 'cos';
MathNode.TAN = 'tan';
MathNode.ASIN = 'asin';
MathNode.ACOS = 'acos';
MathNode.ARCTAN = 'atan';
MathNode.ABS = 'abs';
MathNode.SIGN = 'sign';
MathNode.LENGTH = 'length';
MathNode.NEGATE = 'negate';
MathNode.INVERT = 'invert';

// 2 inputs

MathNode.MIN = 'min';
MathNode.MAX = 'max';
MathNode.MOD = 'mod';
MathNode.STEP = 'step';
MathNode.REFLECT = 'reflect';
MathNode.DISTANCE = 'distance';
MathNode.DOT = 'dot';
MathNode.CROSS = 'cross';
MathNode.POW = 'pow';

// 3 inputs

MathNode.MIX = 'mix';
MathNode.CLAMP = 'clamp';
MathNode.REFRACT = 'refract';
MathNode.SMOOTHSTEP = 'smoothstep';
MathNode.FACEFORWARD = 'faceforward';

MathNode.prototype = Object.create( TempNode.prototype );
MathNode.prototype.constructor = MathNode;
MathNode.prototype.nodeType = "Math";

MathNode.prototype.getNumInputs = function ( builder ) {

	switch ( this.method ) {

		case MathNode.MIX:
		case MathNode.CLAMP:
		case MathNode.REFRACT:
		case MathNode.SMOOTHSTEP:
		case MathNode.FACEFORWARD:
			
			return 3;

		case MathNode.MIN:
		case MathNode.MAX:
		case MathNode.MOD:
		case MathNode.STEP:
		case MathNode.REFLECT:
		case MathNode.DISTANCE:
		case MathNode.DOT:
		case MathNode.CROSS:
		case MathNode.POW:

			return 2;

		default:

			return 1;

	}

};

MathNode.prototype.getInputType = function ( builder ) {

	var a = builder.getTypeLength( this.a.getType( builder ) );
	var b = this.b ? builder.getTypeLength( this.b.getType( builder ) ) : 0;
	var c = this.c ? builder.getTypeLength( this.c.getType( builder ) ) : 0;

	if ( a > b && a > c ) {

		return this.a.getType( builder );

	} else if ( b > c ) {

		return this.b.getType( builder );

	}

	return this.c.getType( builder );

};

MathNode.prototype.getType = function ( builder ) {

	switch ( this.method ) {

		case MathNode.LENGTH:
		case MathNode.DISTANCE:
		case MathNode.DOT:

			return 'f';

		case MathNode.CROSS:

			return 'v3';

	}

	return this.getInputType( builder );

};

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

	var a, b, c,
		al = this.a ? builder.getTypeLength( this.a.getType( builder ) ) : 0,
		bl = this.b ? builder.getTypeLength( this.b.getType( builder ) ) : 0,
		cl = this.c ? builder.getTypeLength( this.c.getType( builder ) ) : 0,
		inputType = this.getInputType( builder ),
		nodeType = this.getType( builder );

	switch ( this.method ) {

		// 1 input

		case MathNode.NEGATE:

			return builder.format( '( -' + this.a.build( builder, inputType ) + ' )', inputType, output );

		case MathNode.INVERT:

			return builder.format( '( 1.0 - ' + this.a.build( builder, inputType ) + ' )', inputType, output );

		// 2 inputs

		case MathNode.CROSS:

			a = this.a.build( builder, 'v3' );
			b = this.b.build( builder, 'v3' );

			break;

		case MathNode.STEP:

			a = this.a.build( builder, al === 1 ? 'f' : inputType );
			b = this.b.build( builder, inputType );

			break;

		case MathNode.MIN:
		case MathNode.MAX:
		case MathNode.MOD:

			a = this.a.build( builder, inputType );
			b = this.b.build( builder, bl === 1 ? 'f' : inputType );

			break;

		// 3 inputs

		case MathNode.REFRACT:

			a = this.a.build( builder, inputType );
			b = this.b.build( builder, inputType );
			c = this.c.build( builder, 'f' );

			break;

		case MathNode.MIX:

			a = this.a.build( builder, inputType );
			b = this.b.build( builder, inputType );
			c = this.c.build( builder, cl === 1 ? 'f' : inputType );

			break;

		// default

		default:

			a = this.a.build( builder, inputType );
			if ( this.b ) b = this.b.build( builder, inputType );
			if ( this.c ) c = this.c.build( builder, inputType );

			break;

	}

	// build function call

	var params = [];
	params.push( a );
	if (b) params.push( b );
	if (c) params.push( c );

	var numInputs = this.getNumInputs( builder );

	if (params.length !== numInputs) {

		throw Error(`Arguments not match used in "${this.method}". Require ${numInputs}, currently ${params.length}.`);

	}

	return builder.format( this.method + '( ' + params.join(', ') + ' )', nodeType, output );

};

MathNode.prototype.copy = function ( source ) {

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

	this.a = source.a;
	this.b = source.b;
	this.c = source.c;
	this.method = source.method;

};

MathNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.a = this.a.toJSON( meta ).uuid;
		if ( this.b ) data.b = this.b.toJSON( meta ).uuid;
		if ( this.c ) data.c = this.c.toJSON( meta ).uuid;

		data.method = this.method;

	}

	return data;

};

export { MathNode };
