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

import { TempNode } from '../core/TempNode.js';
import { FunctionNode } from '../core/FunctionNode.js';
import { FloatNode } from '../inputs/FloatNode.js';
import { PositionNode } from '../accessors/PositionNode.js';

function CameraNode( scope, camera ) {

	TempNode.call( this, 'v3' );

	this.setScope( scope || CameraNode.POSITION );
	this.setCamera( camera );

}

CameraNode.Nodes = ( function () {

	var depthColor = new FunctionNode( [
		"float depthColor( float mNear, float mFar ) {",

		"	#ifdef USE_LOGDEPTHBUF_EXT",

		"		float depth = gl_FragDepthEXT / gl_FragCoord.w;",

		"	#else",

		"		float depth = gl_FragCoord.z / gl_FragCoord.w;",

		"	#endif",

		"	return 1.0 - smoothstep( mNear, mFar, depth );",

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

	return {
		depthColor: depthColor
	};

} )();

CameraNode.POSITION = 'position';
CameraNode.DEPTH = 'depth';
CameraNode.TO_VERTEX = 'toVertex';

CameraNode.prototype = Object.create( TempNode.prototype );
CameraNode.prototype.constructor = CameraNode;
CameraNode.prototype.nodeType = "Camera";

CameraNode.prototype.setCamera = function ( camera ) {

	this.camera = camera;
	this.updateFrame = camera !== undefined ? this.onUpdateFrame : undefined;

};

CameraNode.prototype.setScope = function ( scope ) {

	switch ( this.scope ) {

		case CameraNode.DEPTH:

			delete this.near;
			delete this.far;

			break;

	}

	this.scope = scope;

	switch ( scope ) {

		case CameraNode.DEPTH:

			var camera = this.camera;

			this.near = new FloatNode( camera ? camera.near : 1 );
			this.far = new FloatNode( camera ? camera.far : 1200 );

			break;

	}

};

CameraNode.prototype.getType = function ( builder ) {

	switch ( this.scope ) {

		case CameraNode.DEPTH:

			return 'f';

	}

	return this.type;

};

CameraNode.prototype.isUnique = function ( builder ) {

	switch ( this.scope ) {

		case CameraNode.DEPTH:
		case CameraNode.TO_VERTEX:

			return true;

	}

	return false;

};

CameraNode.prototype.isShared = function ( builder ) {

	switch ( this.scope ) {

		case CameraNode.POSITION:

			return false;

	}

	return true;

};

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

	var result;

	switch ( this.scope ) {

		case CameraNode.POSITION:

			result = 'cameraPosition';

			break;

		case CameraNode.DEPTH:

			var depthColor = builder.include( CameraNode.Nodes.depthColor );

			result = depthColor + '( ' + this.near.build( builder, 'f' ) + ', ' + this.far.build( builder, 'f' ) + ' )';

			break;

		case CameraNode.TO_VERTEX:

			result = 'normalize( ' + new PositionNode( PositionNode.WORLD ).build( builder, 'v3' ) + ' - cameraPosition )';

			break;

	}

	return builder.format( result, this.getType( builder ), output );

};

CameraNode.prototype.onUpdateFrame = function ( frame ) {

	switch ( this.scope ) {

		case CameraNode.DEPTH:

			var camera = this.camera;

			this.near.value = camera.near;
			this.far.value = camera.far;

			break;

	}

};

CameraNode.prototype.copy = function ( source ) {

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

	this.setScope( source.scope );

	if ( source.camera ) {

		this.setCamera( source.camera );

	}

	switch ( source.scope ) {

		case CameraNode.DEPTH:

			this.near.number = source.near;
			this.far.number = source.far;

			break;

	}

};

CameraNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.scope = this.scope;

		if ( this.camera ) data.camera = this.camera.uuid;

		switch ( this.scope ) {

			case CameraNode.DEPTH:

				data.near = this.near.value;
				data.far = this.far.value;

				break;

		}

	}

	return data;

};

export { CameraNode };
