/*
Regression Test for the Cauchy Reed Solomon Encoder and Decoder

Copyright 2023 Ahmet Inan <inan@aicodix.de>
*/

#include <cassert>
#include <random>
#include <iostream>
#include <functional>
#include "galois_field.hh"
#include "cauchy_reed_solomon_erasure_coding.hh"

template <typename GF>
void crs_test(int trials)
{
	CODE::CauchyReedSolomonEncoder<GF> encode;
	CODE::CauchyReedSolomonDecoder<GF> decode;
	std::random_device rd;
	std::default_random_engine generator(rd());
	typedef std::uniform_int_distribution<int> distribution;
	auto rnd_cnt = std::bind(distribution(1, std::min(GF::Q / 2, 256)), generator);
	auto rnd_len = std::bind(distribution(1, 1 << 10), generator);
	auto rnd_dat = std::bind(distribution(0, 255), generator);
	while (--trials) {
		int block_count = rnd_cnt();
		int numbers_total = GF::Q - block_count;
		int block_bytes = rnd_len() * sizeof(typename GF::value_type);
		int data_bytes = block_count * block_bytes;
		uint8_t *orig = new uint8_t[data_bytes];
		for (int i = 0; i < data_bytes; ++i)
			orig[i] = rnd_dat();
		uint8_t *blocks = new uint8_t[data_bytes];
		auto numbers = new typename GF::value_type[numbers_total];
		for (int i = 0; i < numbers_total; ++i)
			numbers[i] = i;
		for (int i = 0; i < block_count; i++) {
			auto hat = std::bind(distribution(i, numbers_total - 1), generator);
			std::swap(numbers[i], numbers[hat()]);
		}
		for (int i = 0; i < block_count; ++i)
			encode(orig, blocks + block_bytes * i, numbers[i], block_bytes, block_count);
		uint8_t *data = new uint8_t[data_bytes];
		decode(data, blocks, numbers, block_bytes, block_count);
		for (int i = 0; i < data_bytes; ++i)
			assert(data[i] == orig[i]);
		delete[] numbers;
		delete[] blocks;
		delete[] orig;
		delete[] data;
	}
}

int main()
{
	if (1) {
		typedef CODE::GaloisField<8, 0b100011101, uint8_t> GF;
		GF instance;
		crs_test<GF>(200);
	}
	if (1) {
		typedef CODE::GaloisField<16, 0b10001000000001011, uint16_t> GF;
		GF *instance = new GF();
		crs_test<GF>(100);
		delete instance;
	}
	std::cerr << "Cauchy Reed Solomon regression test passed!" << std::endl;
	return 0;
}