Shader "Sukuna/DismantleSlash_Advanced"
{
    Properties
    {
        [Header(Colors)]
        [HDR] _MainColor("Core Color (Black/Dark)", Color) = (0, 0, 0, 1)
        [HDR] _EdgeColor("Edge Glow Color", Color) = (10, 0, 0, 1) // Tăng cường độ mặc định
        _EdgeWidth("Edge Width", Range(0, 1)) = 0.3
        
        [Header(Distortion Settings)]
        _DistortionStrength("Distortion Strength", Range(0, 2)) = 0.5
        _DistortionWidth("Distortion Area Width", Range(0, 2)) = 1.0
        _DistortionMap("Distortion Noise Map", 2D) = "bump" {}
        
        [Header(Animation)]
        _Dissolve("Dissolve", Range(0, 1)) = 0
    }

    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue"="Transparent" "RenderPipeline" = "UniversalPipeline" }
        LOD 100

        Pass
        {
            Name "SlashPass"
            ZWrite Off
            Cull Off
            Blend SrcAlpha OneMinusSrcAlpha

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareOpaqueTexture.hlsl"

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

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;
                float4 screenPos : TEXCOORD1;
            };

            float4 _MainColor;
            float4 _EdgeColor;
            float _EdgeWidth;
            float _DistortionStrength;
            float _DistortionWidth;
            float _Dissolve;
            sampler2D _DistortionMap;

            Varyings vert(Attributes input)
            {
                Varyings output;
                output.positionCS = TransformObjectToHClip(input.positionOS.xyz);
                output.uv = input.uv;
                output.screenPos = ComputeScreenPos(output.positionCS);
                return output;
            }

            half4 frag(Varyings input) : SV_Target
            {
                float x = input.uv.x;
                float y = input.uv.y;

                // Shape Mask (Hình nhát chém từ UV)
                float lengthMask = 1.0 - pow(abs(x * 2.0 - 1.0), 4.0);
                float widthMask = 1.0 - abs(y * 2.0 - 1.0);
                float shape = saturate(widthMask * lengthMask);
                
                // Dissolve Mask
                float alphaMask = saturate(shape - _Dissolve);
                if (alphaMask <= 0) discard;

                // --- DISTORTION CALCULATION ---
                // Tạo một mask riêng cho Distortion, rộng hơn vệt chém chính
                float distortionMask = saturate(widthMask * lengthMask * _DistortionWidth);
                float2 noise = tex2D(_DistortionMap, input.uv * 2.0).rg * 2.0 - 1.0;
                float2 screenUV = input.screenPos.xy / input.screenPos.w;
                
                // Chỉ làm cong vùng xung quanh, giảm dần về 0 ở trung tâm vệt chém (để lõi không bị méo)
                // Chúng ta dùng (1 - edgeMask) để Distortion mạnh ở rìa và yếu ở giữa
                float centerProtection = 1.0 - smoothstep(0.8, 1.0, shape);
                float2 distortedScreenUV = screenUV + noise * _DistortionStrength * 0.05 * distortionMask * centerProtection;
                
                float3 background = SampleSceneColor(distortedScreenUV);

                // --- COLOR CALCULATION ---
                // Đen ở giữa, Đỏ ở viền
                float edgeLerp = smoothstep(1.0 - _EdgeWidth, 1.0, shape);
                float4 finalColor = lerp(_MainColor, _EdgeColor, edgeLerp);
                
                // Trộn với background
                finalColor.rgb = lerp(background, finalColor.rgb, alphaMask);
                finalColor.a = alphaMask;

                return finalColor;
            }
            ENDHLSL
        }
    }
}