/**
 * @author alteredq / http://alteredqualia.com/
 * @author Mugen87 / https://github.com/Mugen87
 *
 *	- shows frustum, line of sight and up of the camera
 *	- suitable for fast updates
 * 	- based on frustum visualization in lightgl.js shadowmap example
 *		http://evanw.github.com/lightgl.js/tests/shadowmap.html
 */

import { Camera } from '../cameras/Camera.js';
import { Vector3 } from '../math/Vector3.js';
import { LineSegments } from '../objects/LineSegments.js';
import { Color } from '../math/Color.js';
import { FaceColors } from '../constants.js';
import { LineBasicMaterial } from '../materials/LineBasicMaterial.js';
import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';

var _vector = new Vector3();
var _camera = new Camera();

function CameraHelper( camera ) {

	var geometry = new BufferGeometry();
	var material = new LineBasicMaterial( { color: 0xffffff, vertexColors: FaceColors } );

	var vertices = [];
	var colors = [];

	var pointMap = {};

	// colors

	var colorFrustum = new Color( 0xffaa00 );
	var colorCone = new Color( 0xff0000 );
	var colorUp = new Color( 0x00aaff );
	var colorTarget = new Color( 0xffffff );
	var colorCross = new Color( 0x333333 );

	// near

	addLine( 'n1', 'n2', colorFrustum );
	addLine( 'n2', 'n4', colorFrustum );
	addLine( 'n4', 'n3', colorFrustum );
	addLine( 'n3', 'n1', colorFrustum );

	// far

	addLine( 'f1', 'f2', colorFrustum );
	addLine( 'f2', 'f4', colorFrustum );
	addLine( 'f4', 'f3', colorFrustum );
	addLine( 'f3', 'f1', colorFrustum );

	// sides

	addLine( 'n1', 'f1', colorFrustum );
	addLine( 'n2', 'f2', colorFrustum );
	addLine( 'n3', 'f3', colorFrustum );
	addLine( 'n4', 'f4', colorFrustum );

	// cone

	addLine( 'p', 'n1', colorCone );
	addLine( 'p', 'n2', colorCone );
	addLine( 'p', 'n3', colorCone );
	addLine( 'p', 'n4', colorCone );

	// up

	addLine( 'u1', 'u2', colorUp );
	addLine( 'u2', 'u3', colorUp );
	addLine( 'u3', 'u1', colorUp );

	// target

	addLine( 'c', 't', colorTarget );
	addLine( 'p', 'c', colorCross );

	// cross

	addLine( 'cn1', 'cn2', colorCross );
	addLine( 'cn3', 'cn4', colorCross );

	addLine( 'cf1', 'cf2', colorCross );
	addLine( 'cf3', 'cf4', colorCross );

	function addLine( a, b, color ) {

		addPoint( a, color );
		addPoint( b, color );

	}

	function addPoint( id, color ) {

		vertices.push( 0, 0, 0 );
		colors.push( color.r, color.g, color.b );

		if ( pointMap[ id ] === undefined ) {

			pointMap[ id ] = [];

		}

		pointMap[ id ].push( ( vertices.length / 3 ) - 1 );

	}

	geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
	geometry.setAttribute( 'color', new Float32BufferAttribute( colors, 3 ) );

	LineSegments.call( this, geometry, material );

	this.camera = camera;
	if ( this.camera.updateProjectionMatrix ) this.camera.updateProjectionMatrix();

	this.matrix = camera.matrixWorld;
	this.matrixAutoUpdate = false;

	this.pointMap = pointMap;

	this.update();

}

CameraHelper.prototype = Object.create( LineSegments.prototype );
CameraHelper.prototype.constructor = CameraHelper;

CameraHelper.prototype.update = function () {

	var geometry = this.geometry;
	var pointMap = this.pointMap;

	var w = 1, h = 1;

	// we need just camera projection matrix inverse
	// world matrix must be identity

	_camera.projectionMatrixInverse.copy( this.camera.projectionMatrixInverse );

	// center / target

	setPoint( 'c', pointMap, geometry, _camera, 0, 0, - 1 );
	setPoint( 't', pointMap, geometry, _camera, 0, 0, 1 );

	// near

	setPoint( 'n1', pointMap, geometry, _camera, - w, - h, - 1 );
	setPoint( 'n2', pointMap, geometry, _camera, w, - h, - 1 );
	setPoint( 'n3', pointMap, geometry, _camera, - w, h, - 1 );
	setPoint( 'n4', pointMap, geometry, _camera, w, h, - 1 );

	// far

	setPoint( 'f1', pointMap, geometry, _camera, - w, - h, 1 );
	setPoint( 'f2', pointMap, geometry, _camera, w, - h, 1 );
	setPoint( 'f3', pointMap, geometry, _camera, - w, h, 1 );
	setPoint( 'f4', pointMap, geometry, _camera, w, h, 1 );

	// up

	setPoint( 'u1', pointMap, geometry, _camera, w * 0.7, h * 1.1, - 1 );
	setPoint( 'u2', pointMap, geometry, _camera, - w * 0.7, h * 1.1, - 1 );
	setPoint( 'u3', pointMap, geometry, _camera, 0, h * 2, - 1 );

	// cross

	setPoint( 'cf1', pointMap, geometry, _camera, - w, 0, 1 );
	setPoint( 'cf2', pointMap, geometry, _camera, w, 0, 1 );
	setPoint( 'cf3', pointMap, geometry, _camera, 0, - h, 1 );
	setPoint( 'cf4', pointMap, geometry, _camera, 0, h, 1 );

	setPoint( 'cn1', pointMap, geometry, _camera, - w, 0, - 1 );
	setPoint( 'cn2', pointMap, geometry, _camera, w, 0, - 1 );
	setPoint( 'cn3', pointMap, geometry, _camera, 0, - h, - 1 );
	setPoint( 'cn4', pointMap, geometry, _camera, 0, h, - 1 );

	geometry.getAttribute( 'position' ).needsUpdate = true;

};

function setPoint( point, pointMap, geometry, camera, x, y, z ) {

	_vector.set( x, y, z ).unproject( camera );

	var points = pointMap[ point ];

	if ( points !== undefined ) {

		var position = geometry.getAttribute( 'position' );

		for ( var i = 0, l = points.length; i < l; i ++ ) {

			position.setXYZ( points[ i ], _vector.x, _vector.y, _vector.z );

		}

	}

}

export { CameraHelper };
