Shader "BrewMonster/UnlitWithShadows"
{
    Properties
    {
        _BaseMap ("Texture", 2D) = "white" {}
        _Color ("Color", Color) = (1,1,1,1)
        _ShadowStrength ("Shadow Strength", Range(0, 1)) = 0.5
        [Toggle(_ALPHATEST_ON)] _AlphaClip("Alpha Clip", Float) = 0
        _Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
        
        // BlendMode options
        [Enum(UnityEngine.Rendering.BlendMode)] _SrcBlend("Src Blend Mode", Float) = 1
        [Enum(UnityEngine.Rendering.BlendMode)] _DstBlend("Dst Blend Mode", Float) = 0
        [Enum(Off, 0, On, 1)] _ZWrite("Z Write", Float) = 1
        
        // Surface options
        [Enum(UnityEngine.Rendering.CullMode)] _Cull("Cull Mode", Float) = 2
        [Toggle(_ALPHAMODULATE_ON)] _AlphaModulate("Alpha Modulate", Float) = 0

        // Material type
        [HideInInspector] _Surface("__surface", Float) = 0.0
    }
    
    // Helper to set render queue and render type based on alpha mode
    CustomEditor "BrewMonsterUnlitShaderGUI"
    
    SubShader
    {
        Tags
        {
            "RenderPipeline" = "UniversalPipeline" 
            "RenderType" = "Opaque"
            "Queue" = "Geometry"
        }
        LOD 100

        // Main pass
        Pass
        {
            Name "ForwardLit"
            Tags { "LightMode"="UniversalForward" }
            
            Blend [_SrcBlend] [_DstBlend]
            ZWrite [_ZWrite]
            Cull [_Cull]

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            // Shadows
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE
            #pragma multi_compile _ _SHADOWS_SOFT
            #pragma multi_compile _ _ADDITIONAL_LIGHT_SHADOWS
            
            // Fog
            #pragma multi_compile_fog
            
            // Alpha features
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _ALPHAMODULATE_ON

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            CBUFFER_START(UnityPerMaterial)
                float4 _BaseMap_ST;
                half4 _Color;
                half _ShadowStrength;
                half _Cutoff;
            CBUFFER_END

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
                float3 normalOS : NORMAL;
            };

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;
                float3 positionWS : TEXCOORD1;
                float3 normalWS : TEXCOORD2;
                float fogCoord : TEXCOORD3;
            };

            Varyings vert(Attributes input)
            {
                Varyings output;

                // Transform position
                VertexPositionInputs vertexInput = GetVertexPositionInputs(input.positionOS.xyz);
                output.positionCS = vertexInput.positionCS;
                output.positionWS = vertexInput.positionWS;

                // Transform normal
                VertexNormalInputs normalInput = GetVertexNormalInputs(input.normalOS);
                output.normalWS = normalInput.normalWS;

                // UV
                output.uv = TRANSFORM_TEX(input.uv, _BaseMap);
                
                // Fog
                output.fogCoord = ComputeFogFactor(vertexInput.positionCS.z);

                return output;
            }

            half4 frag(Varyings input) : SV_Target
            {
                // Sample the texture
                half4 mainTex = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, input.uv);
                half4 color = mainTex * _Color;
                
                // Alpha test
                #ifdef _ALPHATEST_ON
                    clip(color.a - _Cutoff);
                #endif
                
                // Alpha modulate mode (for special effects)
                #ifdef _ALPHAMODULATE_ON
                    color.rgb *= color.a;
                #endif

                // Shadow calculation
                float4 shadowCoord = TransformWorldToShadowCoord(input.positionWS);
                Light mainLight = GetMainLight(shadowCoord);
                half shadowAttenuation = mainLight.shadowAttenuation;

                // Apply shadow
                half shadow = lerp(1.0, shadowAttenuation, _ShadowStrength);
                color.rgb *= shadow;
                
                // Apply fog
                color.rgb = MixFog(color.rgb, input.fogCoord);

                return color;
            }
            ENDHLSL
        }

        // Shadow caster pass
        Pass
        {
            Name "ShadowCaster"
            Tags { "LightMode"="ShadowCaster" }

            ZWrite On
            ZTest LEqual
            ColorMask 0
            Cull [_Cull]

            HLSLPROGRAM
            #pragma vertex ShadowPassVertex
            #pragma fragment ShadowPassFragment

            // Alpha clipping for shadows
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            CBUFFER_START(UnityPerMaterial)
                float4 _BaseMap_ST;
                half4 _Color;
                half _ShadowStrength;
                half _Cutoff;
            CBUFFER_END

            struct Attributes
            {
                float4 positionOS : POSITION;
                float3 normalOS : NORMAL;
                float2 texcoord : TEXCOORD0;
            };

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            float3 _LightDirection;

            float4 GetShadowPositionHClip(Attributes input)
            {
                float3 positionWS = TransformObjectToWorld(input.positionOS.xyz);
                float3 normalWS = TransformObjectToWorldNormal(input.normalOS);
                float4 positionCS = TransformWorldToHClip(ApplyShadowBias(positionWS, normalWS, _LightDirection));

                #if UNITY_REVERSED_Z
                    positionCS.z = min(positionCS.z, UNITY_NEAR_CLIP_VALUE);
                #else
                    positionCS.z = max(positionCS.z, UNITY_NEAR_CLIP_VALUE);
                #endif

                return positionCS;
            }

            Varyings ShadowPassVertex(Attributes input)
            {
                Varyings output;
                output.positionCS = GetShadowPositionHClip(input);
                output.uv = TRANSFORM_TEX(input.texcoord, _BaseMap);
                return output;
            }

            half4 ShadowPassFragment(Varyings input) : SV_TARGET
            {
                #ifdef _ALPHATEST_ON
                    half4 mainTex = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, input.uv);
                    half alpha = mainTex.a * _Color.a;
                    clip(alpha - _Cutoff);
                #endif
                return 0;
            }
            ENDHLSL
        }

        // Depth pass for receiving shadows
        Pass
        {
            Name "DepthOnly"
            Tags { "LightMode"="DepthOnly" }

            ZWrite On
            ColorMask 0
            Cull [_Cull]

            HLSLPROGRAM
            #pragma vertex DepthOnlyVertex
            #pragma fragment DepthOnlyFragment
            
            // Alpha clipping for depth
            #pragma shader_feature_local_fragment _ALPHATEST_ON

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            CBUFFER_START(UnityPerMaterial)
                float4 _BaseMap_ST;
                half4 _Color;
                half _Cutoff;
            CBUFFER_END

            struct Attributes
            {
                float4 position : POSITION;
                float2 texcoord : TEXCOORD0;
            };

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            Varyings DepthOnlyVertex(Attributes input)
            {
                Varyings output;
                output.positionCS = TransformObjectToHClip(input.position.xyz);
                output.uv = TRANSFORM_TEX(input.texcoord, _BaseMap);
                return output;
            }

            half4 DepthOnlyFragment(Varyings input) : SV_TARGET
            {
                #ifdef _ALPHATEST_ON
                    half4 mainTex = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, input.uv);
                    half alpha = mainTex.a * _Color.a;
                    clip(alpha - _Cutoff);
                #endif
                return 0;
            }
            ENDHLSL
        }
    }

    FallBack "Universal Render Pipeline/Lit"
}