/**
 * MeshGouraudMaterial
 *
 * Lambert illumination model with Gouraud (per-vertex) shading
 *
 */

import { UniformsUtils, UniformsLib, ShaderMaterial, Color, MultiplyOperation } from 'three';

const GouraudShader = {

	name: 'GouraudShader',

	uniforms: UniformsUtils.merge( [
		UniformsLib.common,
		UniformsLib.specularmap,
		UniformsLib.envmap,
		UniformsLib.aomap,
		UniformsLib.lightmap,
		UniformsLib.emissivemap,
		UniformsLib.fog,
		UniformsLib.lights,
		{
			emissive: { value: new Color( 0x000000 ) }
		}
	] ),

	vertexShader: /* glsl */`

		#define GOURAUD

		varying vec3 vLightFront;
		varying vec3 vIndirectFront;

		#ifdef DOUBLE_SIDED
			varying vec3 vLightBack;
			varying vec3 vIndirectBack;
		#endif

		#include <common>
		#include <uv_pars_vertex>
		#include <envmap_pars_vertex>
		#include <bsdfs>
		#include <lights_pars_begin>
		#include <color_pars_vertex>
		#include <fog_pars_vertex>
		#include <morphtarget_pars_vertex>
		#include <skinning_pars_vertex>
		#include <shadowmap_pars_vertex>
		#include <logdepthbuf_pars_vertex>
		#include <clipping_planes_pars_vertex>

		void main() {

			#include <uv_vertex>
			#include <color_vertex>
			#include <morphcolor_vertex>

			#include <beginnormal_vertex>
			#include <morphnormal_vertex>
			#include <skinbase_vertex>
			#include <skinnormal_vertex>
			#include <defaultnormal_vertex>

			#include <begin_vertex>
			#include <morphtarget_vertex>
			#include <skinning_vertex>
			#include <project_vertex>
			#include <logdepthbuf_vertex>
			#include <clipping_planes_vertex>

			#include <worldpos_vertex>
			#include <envmap_vertex>

			// inlining legacy <lights_lambert_vertex>

			vec3 diffuse = vec3( 1.0 );

			vec3 geometryPosition = mvPosition.xyz;
			vec3 geometryNormal = normalize( transformedNormal );
			vec3 geometryViewDir = ( isOrthographic ) ? vec3( 0, 0, 1 ) : normalize( -mvPosition.xyz );

			vec3 backGeometryNormal = - geometryNormal;

			vLightFront = vec3( 0.0 );
			vIndirectFront = vec3( 0.0 );
			#ifdef DOUBLE_SIDED
				vLightBack = vec3( 0.0 );
				vIndirectBack = vec3( 0.0 );
			#endif

			IncidentLight directLight;
			float dotNL;
			vec3 directLightColor_Diffuse;

			vIndirectFront += getAmbientLightIrradiance( ambientLightColor );

			#if defined( USE_LIGHT_PROBES )

				vIndirectFront += getLightProbeIrradiance( lightProbe, geometryNormal );

			#endif

			#ifdef DOUBLE_SIDED

				vIndirectBack += getAmbientLightIrradiance( ambientLightColor );

				#if defined( USE_LIGHT_PROBES )

					vIndirectBack += getLightProbeIrradiance( lightProbe, backGeometryNormal );

				#endif

			#endif

			#if NUM_POINT_LIGHTS > 0

				#pragma unroll_loop_start
				for ( int i = 0; i < NUM_POINT_LIGHTS; i ++ ) {

					getPointLightInfo( pointLights[ i ], geometryPosition, directLight );

					dotNL = dot( geometryNormal, directLight.direction );
					directLightColor_Diffuse = directLight.color;

					vLightFront += saturate( dotNL ) * directLightColor_Diffuse;

					#ifdef DOUBLE_SIDED

						vLightBack += saturate( - dotNL ) * directLightColor_Diffuse;

					#endif

				}
				#pragma unroll_loop_end

			#endif

			#if NUM_SPOT_LIGHTS > 0

				#pragma unroll_loop_start
				for ( int i = 0; i < NUM_SPOT_LIGHTS; i ++ ) {

					getSpotLightInfo( spotLights[ i ], geometryPosition, directLight );

					dotNL = dot( geometryNormal, directLight.direction );
					directLightColor_Diffuse = directLight.color;

					vLightFront += saturate( dotNL ) * directLightColor_Diffuse;

					#ifdef DOUBLE_SIDED

						vLightBack += saturate( - dotNL ) * directLightColor_Diffuse;

					#endif
				}
				#pragma unroll_loop_end

			#endif

			#if NUM_DIR_LIGHTS > 0

				#pragma unroll_loop_start
				for ( int i = 0; i < NUM_DIR_LIGHTS; i ++ ) {

					getDirectionalLightInfo( directionalLights[ i ], directLight );

					dotNL = dot( geometryNormal, directLight.direction );
					directLightColor_Diffuse = directLight.color;

					vLightFront += saturate( dotNL ) * directLightColor_Diffuse;

					#ifdef DOUBLE_SIDED

						vLightBack += saturate( - dotNL ) * directLightColor_Diffuse;

					#endif

				}
				#pragma unroll_loop_end

			#endif

			#if NUM_HEMI_LIGHTS > 0

				#pragma unroll_loop_start
				for ( int i = 0; i < NUM_HEMI_LIGHTS; i ++ ) {

					vIndirectFront += getHemisphereLightIrradiance( hemisphereLights[ i ], geometryNormal );

					#ifdef DOUBLE_SIDED

						vIndirectBack += getHemisphereLightIrradiance( hemisphereLights[ i ], backGeometryNormal );

					#endif

				}
				#pragma unroll_loop_end

			#endif

			#include <shadowmap_vertex>
			#include <fog_vertex>

		}`,

	fragmentShader: /* glsl */`

		#define GOURAUD

		uniform vec3 diffuse;
		uniform vec3 emissive;
		uniform float opacity;

		varying vec3 vLightFront;
		varying vec3 vIndirectFront;

		#ifdef DOUBLE_SIDED
			varying vec3 vLightBack;
			varying vec3 vIndirectBack;
		#endif

		#include <common>
		#include <packing>
		#include <dithering_pars_fragment>
		#include <color_pars_fragment>
		#include <uv_pars_fragment>
		#include <map_pars_fragment>
		#include <alphamap_pars_fragment>
		#include <alphatest_pars_fragment>
		#include <aomap_pars_fragment>
		#include <lightmap_pars_fragment>
		#include <emissivemap_pars_fragment>
		#include <envmap_common_pars_fragment>
		#include <envmap_pars_fragment>
		#include <bsdfs>
		#include <lights_pars_begin>
		#include <fog_pars_fragment>
		#include <shadowmap_pars_fragment>
		#include <shadowmask_pars_fragment>
		#include <specularmap_pars_fragment>
		#include <logdepthbuf_pars_fragment>
		#include <clipping_planes_pars_fragment>

		void main() {

			#include <clipping_planes_fragment>

			vec4 diffuseColor = vec4( diffuse, opacity );
			ReflectedLight reflectedLight = ReflectedLight( vec3( 0.0 ), vec3( 0.0 ), vec3( 0.0 ), vec3( 0.0 ) );
			vec3 totalEmissiveRadiance = emissive;

			#include <logdepthbuf_fragment>
			#include <map_fragment>
			#include <color_fragment>
			#include <alphamap_fragment>
			#include <alphatest_fragment>
			#include <specularmap_fragment>
			#include <emissivemap_fragment>

			// accumulation

			#ifdef DOUBLE_SIDED

				reflectedLight.indirectDiffuse += ( gl_FrontFacing ) ? vIndirectFront : vIndirectBack;

			#else

				reflectedLight.indirectDiffuse += vIndirectFront;

			#endif

			#ifdef USE_LIGHTMAP

				vec4 lightMapTexel = texture2D( lightMap, vLightMapUv );
				vec3 lightMapIrradiance = lightMapTexel.rgb * lightMapIntensity;
				reflectedLight.indirectDiffuse += lightMapIrradiance;

			#endif

			reflectedLight.indirectDiffuse *= BRDF_Lambert( diffuseColor.rgb );

			#ifdef DOUBLE_SIDED

				reflectedLight.directDiffuse = ( gl_FrontFacing ) ? vLightFront : vLightBack;

			#else

				reflectedLight.directDiffuse = vLightFront;

			#endif

			reflectedLight.directDiffuse *= BRDF_Lambert( diffuseColor.rgb ) * getShadowMask();

			// modulation

			#include <aomap_fragment>

			vec3 outgoingLight = reflectedLight.directDiffuse + reflectedLight.indirectDiffuse + totalEmissiveRadiance;

			#include <envmap_fragment>

			#include <opaque_fragment>
			#include <tonemapping_fragment>
			#include <colorspace_fragment>
			#include <fog_fragment>
			#include <premultiplied_alpha_fragment>
			#include <dithering_fragment>

		}`

};

//

class MeshGouraudMaterial extends ShaderMaterial {

	constructor( parameters ) {

		super();

		this.isMeshGouraudMaterial = true;

		this.type = 'MeshGouraudMaterial';

		//this.color = new THREE.Color( 0xffffff ); // diffuse

		//this.map = null;

		//this.lightMap = null;
		//this.lightMapIntensity = 1.0;

		//this.aoMap = null;
		//this.aoMapIntensity = 1.0;

		//this.emissive = new THREE.Color( 0x000000 );
		//this.emissiveIntensity = 1.0;
		//this.emissiveMap = null;

		//this.specularMap = null;

		//this.alphaMap = null;

		//this.envMap = null;
		this.combine = MultiplyOperation; // combine has no uniform
		//this.reflectivity = 1;
		//this.refractionRatio = 0.98;

		this.fog = false; // set to use scene fog
		this.lights = true; // set to use scene lights
		this.clipping = false; // set to use user-defined clipping planes

		const shader = GouraudShader;

		this.defines = Object.assign( {}, shader.defines );
		this.uniforms = UniformsUtils.clone( shader.uniforms );
		this.vertexShader = shader.vertexShader;
		this.fragmentShader = shader.fragmentShader;

		const exposePropertyNames = [
			'map', 'lightMap', 'lightMapIntensity', 'aoMap', 'aoMapIntensity',
			'emissive', 'emissiveIntensity', 'emissiveMap', 'specularMap', 'alphaMap',
			'envMap', 'reflectivity', 'refractionRatio', 'opacity', 'diffuse'
		];

		for ( const propertyName of exposePropertyNames ) {

			Object.defineProperty( this, propertyName, {

				get: function () {

					return this.uniforms[ propertyName ].value;

				},

				set: function ( value ) {

					this.uniforms[ propertyName ].value = value;

				}

			} );

		}

		Object.defineProperty( this, 'color', Object.getOwnPropertyDescriptor( this, 'diffuse' ) );

		this.setValues( parameters );

	}

	copy( source ) {

		super.copy( source );

		this.color.copy( source.color );

		this.map = source.map;

		this.lightMap = source.lightMap;
		this.lightMapIntensity = source.lightMapIntensity;

		this.aoMap = source.aoMap;
		this.aoMapIntensity = source.aoMapIntensity;

		this.emissive.copy( source.emissive );
		this.emissiveMap = source.emissiveMap;
		this.emissiveIntensity = source.emissiveIntensity;

		this.specularMap = source.specularMap;

		this.alphaMap = source.alphaMap;

		this.envMap = source.envMap;
		this.combine = source.combine;
		this.reflectivity = source.reflectivity;
		this.refractionRatio = source.refractionRatio;

		this.wireframe = source.wireframe;
		this.wireframeLinewidth = source.wireframeLinewidth;
		this.wireframeLinecap = source.wireframeLinecap;
		this.wireframeLinejoin = source.wireframeLinejoin;

		this.fog = source.fog;

		return this;

	}

}

export { MeshGouraudMaterial };