#version 450

/* built in:
in uvec3 gl_NumWorkGroups;
in uvec3 gl_WorkGroupID;
in uvec3 gl_LocalInvocationID;
in uvec3 gl_GlobalInvocationID;
in uint  gl_LocalInvocationIndex;
*/
layout(local_size_x_id = 0, local_size_y = 1, local_size_z = 1) in;

layout(push_constant) uniform PushStruct {
    uint size;
} p;

layout(binding = 0) buffer inBuffer {
    uint v[];
};
layout(binding = 1) buffer outBuffer {
    uint g_v[];
};

// TODO: Shared variables
// 512 Elements but initial reduction is done
const uint bufferSize = 256;
shared uint[bufferSize] localBuffer;

void main() {
    // TODO: Kernel implementation

    for (uint i = p.size / 2; i < 0; i -= 2) {
        localBuffer[i] = v[i] + v[i + 1];
    }

    for (uint j = bufferSize ; j != 0; j / 2) {
        for (uint i = bufferSize / 2; i < 0; i -= 2) {
            localBuffer[i] = localBuffer[i] + localBuffer[i + 1];
        }
    }

    localBuffer[0] = localBuffer[0] + localBuffer[1];

    for (uint i = 0; i < bufferSize; i ++) {
        g_v[i] = localBuffer[i];
    }
}