#ifndef __LIGHTING_INC
#define __LIGHTING_INC

#include "UnityCG.cginc"
#include "AutoLight.cginc"
#include "UnityPBSLighting.cginc"
#include "UnityLightingCommon.cginc"
#include "UnityStandardCoreMinimal.cginc"

#include "features.cginc"
#include "filamented.cginc"
#include "interpolators.cginc"
#include "LightVolumes.cginc"
#include "pbr.cginc"

struct LightCommon {
  float3 V;
  float3 N;
   float NoV;
};

struct LightDirect {
  float3 dir;

   float3 H;
   float NoH;
   float NoL;
   float LoH;
   float LoV;
   float double_LoV;

   float3 color;
};

struct LightIndirect {
  float3 dir;

   float3 H;
   float NoH;
   float NoL;
   float LoH;
   float LoV;
   float double_LoV;

   float3 specular;
   float3 diffuse;

   float3 L00;
   float3 L01r;
   float3 L01g;
   float3 L01b;
};

struct LightData {
  LightCommon common;
  LightDirect direct;
  LightIndirect indirect;
};

float3 getDirectLightDirection(v2f i) {
#if defined(POINT) || defined(POINT_COOKIE) || defined(SPOT)
	return normalize((_WorldSpaceLightPos0 - i.worldPos).xyz);
#else
	return _WorldSpaceLightPos0;
#endif
}

float getShadowAttenuation(v2f i)
{
  UNITY_LIGHT_ATTENUATION(attenuation, i, i.worldPos);
	return attenuation;
}

float4 getDirectLightColorIntensity() {
	// Properly separate light color from intensity like filamented
	if (_LightColor0.w <= 0) return float4(0, 0, 0, 0);
	_LightColor0 += 1e-6f;
	return float4(_LightColor0.xyz / _LightColor0.w, _LightColor0.w);
}

float3 getIndirectSpecular(v2f i, Pbr pbr, float3 view_dir, float3 reflect_dir) {
  UnityGIInput data = InitialiseUnityGIInput(i.worldPos, view_dir);
  float3 env_refl = UnityGI_prefilteredRadiance(data, pbr.roughness_perceptual, reflect_dir);
  return env_refl;
}

float3 yumSH9(float4 n, float3 worldPos, inout LightIndirect light) {
  LightVolumeSH(worldPos, light.L00, light.L01r, light.L01g, light.L01b);
  return light.L00 + float3(
    dot(light.L01r, n.xyz),
    dot(light.L01g, n.xyz),
    dot(light.L01b, n.xyz));
}

float4 getIndirectDiffuse(v2f i, Pbr pbr, inout LightIndirect light) {
  float4 diffuse = 0;
#if defined(FORWARD_BASE_PASS)
  diffuse.xyz += max(0, yumSH9(float4(pbr.normal, 0), i.worldPos, light));
#endif
  return diffuse;
}

void GetLighting(v2f i, Pbr pbr, out LightData data) {
	data = (LightData) 0;
  
	float3 view_dir = normalize(i.eyeVec.xyz);

	data.common.V = -view_dir;
	data.common.N = pbr.normal;
  data.common.NoV = saturate(dot(pbr.normal, data.common.V));
	
	// Direct lighting
	data.direct.dir = getDirectLightDirection(i);
	data.direct.H = normalize(data.common.V + data.direct.dir);
	data.direct.NoL = saturate(dot(pbr.normal, data.direct.dir));
	data.direct.NoH = saturate(dot(pbr.normal, data.direct.H));
  data.direct.LoH = saturate(dot(data.direct.dir, data.direct.H));
  float direct_LoV = dot(data.direct.dir, data.common.V);
  data.direct.LoV = saturate(direct_LoV);
  data.direct.double_LoV = saturate(2.0f * direct_LoV * direct_LoV - 1.0f);
	
	float4 lightColorIntensity = getDirectLightColorIntensity();
	data.direct.color = lightColorIntensity.rgb * lightColorIntensity.w;
	
	// Indirect lighting
  data.indirect.dir = -reflect(data.common.V, pbr.normal);
	data.indirect.H = normalize(data.common.V + data.indirect.dir);
	data.indirect.NoL = saturate(dot(pbr.normal, data.indirect.dir));
	data.indirect.NoH = saturate(dot(pbr.normal, data.indirect.H));
  data.indirect.LoH = saturate(dot(data.indirect.dir, data.indirect.H));
  float indirect_LoV = dot(data.direct.dir, data.common.V);
  data.indirect.LoV = saturate(indirect_LoV);
  data.indirect.double_LoV = saturate(2.0f * indirect_LoV * indirect_LoV - 1.0f);

	data.indirect.diffuse = getIndirectDiffuse(i, pbr, data.indirect);
	data.indirect.specular = getIndirectSpecular(i, pbr, view_dir, data.indirect.dir);
}

#endif  // __LIGHTING_INC