#include "Matrix.h"

#include <algorithm>
#include <cassert>
#include <cmath>
#include <fstream>
#include <iostream>

Matrix::Matrix(const std::string& fileNameInput) {
	Load(fileNameInput);
}

Matrix::Matrix(std::size_t lignes, std::size_t colonnes) : m_Lignes(lignes), m_Colonnes(colonnes) {
	m_Data.resize(m_Lignes * m_Colonnes);
}
Matrix::Matrix(std::size_t lignes, std::size_t colonnes, std::initializer_list<long double>&& initList) :
	m_Lignes(lignes), m_Colonnes(colonnes) {
	m_Data = initList;
	m_Data.resize(m_Lignes * m_Colonnes);
}

Matrix::~Matrix() {}

Matrix Matrix::operator*(const Matrix& other) const {
	if (m_Colonnes != other.m_Lignes) {
		std::cerr << "Mutiplication impossible car la dimensions des matrices est incompatible" << std::endl;
	}

	Matrix result(m_Lignes, other.m_Colonnes);

	for (std::size_t i = 0; i < m_Lignes; ++i) {
		for (std::size_t j = 0; j < other.m_Colonnes; ++j) {
			long double sum = 0;
			for (std::size_t k = 0; k < m_Colonnes; k++) {
				sum += at(i, k) * other.at(k, j);
			}
			result.at(i, j) = sum;
		}
	}
	return result;
}

void Matrix::Print() const {
	for (size_t i = 0; i < m_Lignes; ++i) {
		std::cout << "[ ";
		for (size_t j = 0; j < m_Colonnes; ++j) {
			std::size_t indice = i * m_Lignes + j;
			std::cout << at(i, j) << " ";
		}
		std::cout << "]";
		std::cout << std::endl;
	}
}

void Matrix::PrintDebug() {
#ifndef NDEBUG
	Print();
	std::cout << "\n";
#endif
}

void Matrix::Insert() {
	for (size_t i = 0; i < m_Lignes; ++i) {
		for (size_t j = 0; j < m_Colonnes; ++j) {
			std::cin >> at(i, j);
		}
		std::cout << std::endl;
	}
}

void Matrix::Save(const std::string& fileName) {
	std::ofstream out{fileName};
	if (!out) {
		std::cerr << "Impossible de sauvegarder la matrice !\n";
		return;
	}
	out << m_Lignes << " " << m_Colonnes << "\n";
	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			out << at(i, j) << " ";
		}
		out << "\n";
	}
}

void Matrix::Load(const std::string& filename) {
	std::ifstream in{filename};
	if (!in) {
		std::cerr << "Impossible de charger la matrice !\n";
		return;
	}
	in >> m_Lignes >> m_Colonnes;
	m_Data.resize(m_Lignes * m_Colonnes);
	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			in >> at(i, j);
		}
	}
}

void Matrix::Transpose() {
	Matrix result{m_Colonnes, m_Lignes};
	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			result.at(j, i) = at(i, j);
		}
	}
	*this = result;
}

void Matrix::Identity() {
	assert(m_Lignes == m_Colonnes);
	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = i; j < m_Colonnes; j++) {
			at(i, j) = i == j;
		}
	}
}

Matrix Matrix::Identity(std::size_t taille) {
	Matrix id{taille, taille};
	id.Identity();
	return id;
}

bool Matrix::IsInversed() const {
	for (std::size_t i = 0; i < m_Lignes; ++i) {
		std::size_t j;
		for (j = 0; j < m_Colonnes; ++j) {
			if (!IsEqualZero(at(i, j))) {
				break;
			}
			return false;
		}
	}
	return true;
}

void Matrix::Augmenter(const Matrix& droite) {
	assert(droite.m_Lignes == m_Lignes);
	Matrix temp{m_Lignes, m_Colonnes + droite.m_Colonnes};

	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			temp.at(i, j) = at(i, j);
		}
	}

	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < droite.m_Colonnes; j++) {
			temp.at(i, j + m_Colonnes) = droite.at(i, j);
		}
	}

	*this = temp;
}

bool Matrix::operator==(const Matrix& other) const {
	if (m_Lignes != other.m_Lignes || m_Colonnes != other.m_Colonnes)
		return false;

	for (std::size_t i = 0; i < m_Lignes; i++) {
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			if (!IsEqualZero(at(i, j) - other.at(i, j)))
				return false;
		}
	}

	return true;
}

void Matrix::GaussNonJordan(bool reduite) {
	int r = -1;
	for (std::size_t j = 0; j < m_Colonnes; j++) {
		std::size_t indice_ligne_maximum = r + 1;

		// Recherche maximum
		for (std::size_t i = r + 1; i < m_Lignes; i++) {
			if (std::abs(at(i, j)) > std::abs(at(indice_ligne_maximum, j)))
				indice_ligne_maximum = i;
		}

		// std::cout << "l'indice du maximum est : " << indice_ligne_maximum << "\n\n";

		// Si A[k,j]≠0 alors    (A[k,j] désigne la valeur de la ligne k et de la colonne j)
		if (!IsEqualZero(at(indice_ligne_maximum, j))) {
			r++;

			// PrintDebug();

			// Si k≠r alors
			if (indice_ligne_maximum != r) {
				// Échanger les lignes k et r  (On place la ligne du pivot en position r)
				// std::cout << "On échange les lignes " << indice_ligne_maximum << " et " << r << '\n';
				for (std::size_t k = 0; k < m_Colonnes; k++) {
					std::swap(at(indice_ligne_maximum, k), at(r, k));
				}
			}

			// Pour i de 1 jusqu'à n               (On simplifie les autres lignes)
			for (std::size_t i = (reduite ? 0 : j); i < m_Lignes; i++) {
				// Si i≠r alors
				if (i != r) {
					// Soustraire à la ligne i la ligne r multipliée par A[i,j] (de façon à
					// annuler A[i,j])
					for (int k = m_Colonnes - 1; k >= 0; k--) {
						long double pivot = at(r, j);
						long double anul = at(i, j);
						at(i, k) = at(i, k) * pivot - at(r, k) * anul;
					}
				}
			}
		}
	}
}

void Matrix::GaussJordan(bool reduite) {
	GaussNonJordan(reduite);
	for (std::size_t i = 0; i < m_Lignes; i++) {
		int k = -1;
		for (std::size_t j = 0; j < m_Colonnes; j++) {
			if (!IsEqualZero(at(i, j))) {
				k = j;
				break;
			}
		}
		// ligne de 0
		if (k == -1)
			break;
		// on divise la ligne par (i, k)
		long double annul = at(i, k);
		for (int j = 0; j < m_Colonnes; j++) {
			at(i, j) /= annul;
		}
	}
}

long double& Matrix::operator[](std::size_t indice) {
	return m_Data[indice];
}

long double& Matrix::at(std::size_t ligne, std::size_t colonne) {
	return m_Data[ligne * m_Colonnes + colonne];
}

long double Matrix::at(std::size_t ligne, std::size_t colonne) const {
	return m_Data[ligne * m_Colonnes + colonne];
}

std::size_t Matrix::GetRawCount() const {
	return m_Lignes;
}

std::size_t Matrix::GetColumnCount() const {
	return m_Colonnes;
}

Matrix Matrix::SubMatrix(std::size_t origine_ligne, std::size_t origine_colonne, std::size_t ligne, std::size_t colonne) const {
	assert(m_Lignes >= ligne && m_Colonnes >= colonne);
	Matrix result{ligne, colonne};

	for (std::size_t i = 0; i < ligne; i++) {
		for (std::size_t j = 0; j < colonne; j++) {
			result.at(i, j) = at(i + origine_ligne, j + origine_colonne);
		}
	}

	return result;
}