#pragma once

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

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

namespace numerics::detail{
	
	// ---------------- Matrix -> Scalar ----------------
	template <typename T>
	utils::Vector<uint64_t> argmax_serial(const utils::Matrix<T>& A) {
	    const uint64_t rows = A.rows();
	    const uint64_t cols = A.cols();
	    utils::Vector<uint64_t> idx(2, 0);
		T max = A(0,0);
		for (uint64_t i = 0; i < rows; ++i){
			for (uint64_t j = 0; j < cols; ++j){
				if (max < A(i,j)){
					max = A(i,j);
					idx[0] = i;
					idx[1] = j;
				}
			}
		}
		return idx;
	}

	// ---------------- Vector -> Scalar ----------------
	template <typename T>
	uint64_t argmax_serial(const utils::Vector<T>& v) {
		const uint64_t N = v.size();
		uint64_t idx = 0;
		T max = v[0];
		for (uint64_t i = 1; i < N; ++i){
			if (max < v[i]){
				max = v[i];
				idx = i;
			}
		}
		return idx;
	}

	// ---------------- Matrix -> Vector ----------------
	template <typename T>
	utils::Vector<uint64_t> argmax_rowwise_serial(const utils::Matrix<T>& A) {
	    const uint64_t rows = A.rows();
	    const uint64_t cols = A.cols();
	    utils::Vector<T> max(rows, T{0});
		utils::Vector<uint64_t> idx(rows, 0);
		for (uint64_t i = 0; i < rows; ++i){
			max[i] = A(i,0);
			for (uint64_t j = 1; j < cols; ++j){
				if (max[i] < A(i,j)){
					max[i] = A(i,j);
					idx[i] = j;

				}
			}
		}
		return idx;
	}

	template <typename T>
	utils::Vector<uint64_t> argmax_colwise_serial(const utils::Matrix<T>& A) {
	    const uint64_t rows = A.rows();
	    const uint64_t cols = A.cols();
		utils::Vector<T> max(cols, T{0});
		utils::Vector<uint64_t> idx(cols, 0);
		for (uint64_t j = 0; j < cols; ++j){
			max[j] = A(0, j);
			for (uint64_t i = 1; i < rows; ++i){
				if (max[j] < A(i,j)){
					max[j] = A(i,j);
					idx[j] = i;
				}
			}
		}
		return idx;
	}
} // namespace numerics