#include <stdlib.h>
#include <string.h>
#include "matrix.h"

// TODO Matrix-Funktionen implementieren

Matrix createMatrix(unsigned int rows, unsigned int cols)
{
    if(rows == 0 || cols == 0){
        return (Matrix) {0, 0, NULL};       // Compound struct, kann für c99 verwendet werden 
    }
    MatrixType *arr = malloc(rows * cols * sizeof(MatrixType));
    Matrix new_matrix = {rows, cols, arr};
    return new_matrix;
}

void clearMatrix(Matrix *matrix)
{
    free(matrix->buffer);
    matrix->buffer = NULL;
    matrix->rows = 0;
    matrix->cols = 0;
}

void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    if(rowIdx < matrix.rows && colIdx < matrix.cols){
        *(matrix.buffer + rowIdx * matrix.rows + colIdx) = value;
    }
}

MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    if(rowIdx >= matrix.rows || colIdx >= matrix.cols){
        return 0;
    }
    return *(matrix.buffer + rowIdx * matrix.rows + colIdx);
}

Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    int n1 = matrix1.cols;
    int m1 = matrix1.rows;
    int n2 = matrix2.cols;
    int m2 = matrix2.cols;

    if(n1 == 1 && m1 == m2){
        Matrix new_mat = createMatrix(m2, n2);
        for(int i = 0; i < m2; i++){
            for(int j = 0; j < n2; j++){
                *(new_mat.buffer + i * n2 + j) = *(matrix2.buffer + i * n2 + j) + *(matrix1.buffer + i);
            }
        }
        return new_mat;
    }
    
    if(n2 == 1 && m1 == m2){
        Matrix new_mat = createMatrix(m1, n1);
        for(int i = 0; i < m1; i++){
            for(int j = 0; j < n1; j++){
                *(new_mat.buffer + i * n1 + j) = *(matrix1.buffer + i * n1 + j) + *(matrix2.buffer + i);
            }
        }
        return new_mat;
    }

    if(n1 != n2 || m1 != m2){
        return (Matrix) {0, 0, NULL};
    }

    Matrix new_mat = createMatrix(n1, m1);

    for(int i = 0; i < m1; i++){
        for(int j = 0; j < n1; j++){
            *(new_mat.buffer + i * n1 + j) = *(matrix1.buffer + i * n1 + j) + *(matrix2.buffer + i * n1 + j);
        }
    }
    return new_mat;
}

Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
    int m = matrix1.rows;
    int q = matrix1.cols;
    int l = matrix2.cols;

    if(q != matrix2.rows){
        return (Matrix) {0, 0, NULL};
    }

    Matrix new_matrix = createMatrix(m, l);
    MatrixType *new_mat_arr = new_matrix.buffer;

    for(int i = 0; i < m; i++){
        for(int j = 0; j < l; j++){
            int sum = 0;
            for(int k = 0; k < q; k++){
                sum += *(matrix1.buffer + i * q + k) * *(matrix2.buffer + k * l + j);
            }
            *(new_mat_arr + i * l + j) = sum;
        }
    }

    return new_matrix;
}