#include <iostream>
#include "Common.h"
#include "PrimitiveTests.h"
#include <random>

ExclusiveScan::ExclusiveScan(size_t max_size)
{
	// Must be power of 2, breaks above 512
	data_size = max_size;

	std::random_device rd;
	std::mt19937 gen(rd());
	std::uniform_int_distribution<int> distr(0, 100);
	for (size_t index = 0; index < data_size; ++index) {
		int val = distr(gen);
		sourceData.push_back(val);
		gpuResult.push_back(val);
	}
}

void ExclusiveScan::gpu_compute(cl::Context* context, cl::CommandQueue* queue, cl::Program* program, cl::Event* Event)
{
	cl_int err = CL_SUCCESS;
	cl::Kernel kernel = cl::Kernel(*program, "exscan_global", &err);
	CheckCLError(err);

	clInputBuffer = cl::Buffer(*context, CL_MEM_READ_ONLY, sizeof(int) * data_size, NULL, &err);
	CheckCLError(err);
	queue->enqueueWriteBuffer(clInputBuffer, true, 0, sizeof(int) * data_size, gpuResult.data());

	kernel.setArg(0, clInputBuffer);

	queue->enqueueNDRangeKernel(kernel,
		cl::NullRange,				// Indexek nem eloffszetelve
		cl::NDRange(data_size, 1),	// Minden elemet egy szál
		cl::NDRange(data_size, 1),				// Workgroup méret? - ez az auto, ha nem indul, 1024-re, onnan csökkent, amig elindul
		NULL,						// 
		Event);
}

void ExclusiveScan::cpu_compute()
{
	for (size_t i = 0; i < data_size; i++) {
		int tmp = 0;
		for (size_t j = 0; j < i; j++) {
			tmp += sourceData[j];
		}
		cpuResult.push_back(tmp);
	}
}

void ExclusiveScan::collect_results(cl::CommandQueue* queue)
{
	queue->enqueueReadBuffer(clInputBuffer, true, 0, sizeof(int) * data_size, gpuResult.data());
}

bool ExclusiveScan::validate_results()
{
	bool success = true;
	for (size_t index = 0; index < data_size; index++) {
		if (cpuResult[index] != gpuResult[index]) {
			int diff = abs(cpuResult[index] - gpuResult[index]);
			std::cout << "Wrong result at [" << index << "]: " << gpuResult[index] << "!=" << cpuResult[index] << ", diff: " << diff << std::endl;
			success = false;
		}
	}
	return success;
}

std::string ExclusiveScan::description()
{
	return std::string("ExclusiveScan (data_size=" + std::to_string(data_size) + ")");
}