#pragma once

#include <cstdint> //uint64_t
#include <stdexcept> // std::runtime_error

#include "utils/vector.h"
#include "utils/matrix.h"

namespace numerics::detail{

// ---------------- Matrix * Matrix ----------------
	template <typename T>
	inline utils::Matrix<T> matmul_serial(const utils::Matrix<T>& A, const utils::Matrix<T>& B){
		const uint64_t m = A.rows();
		const uint64_t n = A.cols(); // also B.rows()
		const uint64_t p = B.cols();
		if(n != B.rows()){
		    throw std::runtime_error(
		        "matmul: dimension mismatch: A is " +
		        std::to_string(A.rows()) + "x" + std::to_string(A.cols()) +
		        ", B is " +
		        std::to_string(B.rows()) + "x" + std::to_string(B.cols())
		    );
		}
		T tmp;
		utils::Matrix<T> C(m, p, T{0});
		for (uint64_t i = 0; i < m; ++i){
			for (uint64_t j = 0; j < n; ++j){
				tmp = A(i,j);
				for (uint64_t k = 0; k < p; ++k){
					C(i,k) += tmp * B(j,k);
				}
			}
		}
		return C;
	}


} // namespace numerics