#version 450

#define NUM_CASCADES 4

layout (location = 0) in vec3 inNormal;
layout (location = 1) in float inPosViewZ;
layout (location = 2) in vec3 inPosWorld;

layout (location = 0) out vec4 outColor;

layout (binding = 1) uniform ShadowData
{
    mat4 cascadeProjs[NUM_CASCADES];
    vec4 cascadeSplits;
    vec3 lightDir;
} shadowData;

layout (binding = 2) uniform sampler2DArray shadowMapArray;

vec4 color = vec4(1.0, 1.0, 1.0, 1.0);

void main()
{
    // Get cascade index for the current fragment's view position
    uint cascadeIndex = 0;
    for(uint i = 0; i < NUM_CASCADES - 1; ++i)
    {
        if(inPosViewZ > shadowData.cascadeSplits[i])
        {
            cascadeIndex = i + 1;
        }
    }

    if (cascadeIndex == 0) { color = vec4(1.0, 0.0, 0.0, 1.0); }
    if (cascadeIndex == 1) { color = vec4(0.0, 0.0, 1.0, 1.0); }
    if (cascadeIndex == 2) { color = vec4(0.0, 1.0, 0.0, 1.0); }
    if (cascadeIndex == 3) { color = vec4(1.0, 1.0, 0.0, 1.0); }

    vec4 shadowCoord = shadowData.cascadeProjs[cascadeIndex] * vec4(inPosWorld, 1.0);
    shadowCoord.xyz /= shadowCoord.w;
    shadowCoord.xy = shadowCoord.xy * 0.5 + 0.5;

    //if (shadowCoord.z > -1.0 && shadowCoord.z < 0.0) { color = vec4(1.0, 0.0, 1.0, 1.0); } // debugging purposes

    float shadow = 1.0;

    if (shadowCoord.z >= -1.0 && shadowCoord.z <= 1.0
        && shadowCoord.x >= -1.0 && shadowCoord.x <= 1.0
        && shadowCoord.y >= -1.0 && shadowCoord.y <= 1.0 && shadowCoord.w > 0.0
    )
    {
        float shadowDepth = texture(shadowMapArray, vec3(shadowCoord.st, cascadeIndex)).r;

        float bias = 0.005;
        if (shadowDepth < shadowCoord.z - bias)
        {
            shadow = 0.3;
        }
    }

    vec3 lightDir = normalize(shadowData.lightDir);
    vec3 normal = normalize(inNormal);
    float diffuse = max(dot(-lightDir, normal), 0.3);

    outColor = color * diffuse * shadow;
}