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

/**
 * @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
 */

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.addAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
	geometry.addAttribute( '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, pointMap;

	var vector = new Vector3();
	var camera = new Camera();

	function setPoint( point, 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 );

			}

		}

	}

	return function update() {

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

		var w = 1, h = 1;

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

		camera.projectionMatrix.copy( this.camera.projectionMatrix );

		// center / target

		setPoint( "c", 0, 0, - 1 );
		setPoint( "t", 0, 0,  1 );

		// near

		setPoint( "n1", - w, - h, - 1 );
		setPoint( "n2",   w, - h, - 1 );
		setPoint( "n3", - w,   h, - 1 );
		setPoint( "n4",   w,   h, - 1 );

		// far

		setPoint( "f1", - w, - h, 1 );
		setPoint( "f2",   w, - h, 1 );
		setPoint( "f3", - w,   h, 1 );
		setPoint( "f4",   w,   h, 1 );

		// up

		setPoint( "u1",   w * 0.7, h * 1.1, - 1 );
		setPoint( "u2", - w * 0.7, h * 1.1, - 1 );
		setPoint( "u3",         0, h * 2,   - 1 );

		// cross

		setPoint( "cf1", - w,   0, 1 );
		setPoint( "cf2",   w,   0, 1 );
		setPoint( "cf3",   0, - h, 1 );
		setPoint( "cf4",   0,   h, 1 );

		setPoint( "cn1", - w,   0, - 1 );
		setPoint( "cn2",   w,   0, - 1 );
		setPoint( "cn3",   0, - h, - 1 );
		setPoint( "cn4",   0,   h, - 1 );

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

	};

}();


export { CameraHelper };
