#ifndef REPAIR_SURFACE_INCLUDED
#define REPAIR_SURFACE_INCLUDED

void RepairSurface_float(
    float N,
    float3 BaseColor,
    float3 RustColor,
    float RustInitial,
    float RustAmount,
    float PuttyProgress,
    float SandProgress,
    float PaintProgress,
    float PaintSmoothness,
    out float3 Albedo,
    out float Metallic,
    out float Smoothness)
{
    const float e = 0.04;
    const float3 bareMetal   = float3(0.55, 0.56, 0.58);
    const float3 puttyRaw    = float3(0.62, 0.58, 0.50);
    const float3 puttySanded = float3(0.74, 0.72, 0.68);

    // Если деталь целая (RustInitial = 0) — сразу возвращаем чистый родной цвет авто
    if (RustInitial <= 0.001)
    {
        Albedo = BaseColor;
        Metallic = 0.0;
        Smoothness = PaintSmoothness;
        return;
    }

    float sand = saturate(SandProgress);

    // 1. Исходная зона повреждения
    float zone = smoothstep(1.0 - RustInitial, 1.0 - RustInitial + e, N);

    // 2. Шпаклевка (заполняет зачищенный металл от центра к краям)
    float fillEdge = 1.0 - saturate(PuttyProgress) * (RustInitial + e);
    float puttyMask = smoothstep(fillEdge + e, fillEdge, N) * step(0.001, PuttyProgress);
    if (PuttyProgress >= 0.98) puttyMask = 1.0;

    float3 underColor  = lerp(bareMetal, lerp(puttyRaw, puttySanded, sand), puttyMask);
    float  underSmooth = lerp(0.45, lerp(0.05, 0.35, sand), puttyMask);
    float  underMetal  = lerp(0.8, 0.0, puttyMask);

    // 3. Новая краска (закрывает зашлифованную шпаклевку без белых контуров)
    float paintEdge = (1.0 - RustInitial) + saturate(PaintProgress) * (RustInitial + e);
    float paintMask = (1.0 - smoothstep(paintEdge, paintEdge + e, N)) * step(0.001, PaintProgress);
    if (PaintProgress >= 0.98) paintMask = 1.0;

    float damageVisible = zone * (1.0 - paintMask);

    // 4. Текущий остаток ржавчины
    float rust = zone * smoothstep(1.0 - RustAmount, 1.0 - RustAmount + e, N) * step(0.001, RustAmount);

    float3 col = lerp(BaseColor, underColor, damageVisible);
    float  sm  = lerp(PaintSmoothness, underSmooth, damageVisible);
    float  met = lerp(0.0, underMetal, damageVisible);

    col = lerp(col, RustColor, rust);
    sm  = lerp(sm, 0.08, rust);
    met = lerp(met, 0.0, rust);

    Albedo = col;
    Metallic = met;
    Smoothness = sm;
}

void RepairSurface_half(
    half N,
    half3 BaseColor,
    half3 RustColor,
    half RustInitial,
    half RustAmount,
    half PuttyProgress,
    half SandProgress,
    half PaintProgress,
    half PaintSmoothness,
    out half3 Albedo,
    out half Metallic,
    out half Smoothness)
{
    float3 a; float m; float s;
    RepairSurface_float(N, BaseColor, RustColor, RustInitial, RustAmount,
        PuttyProgress, SandProgress, PaintProgress, PaintSmoothness, a, m, s);
    Albedo = a; Metallic = m; Smoothness = s;
}

#endif