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

// TODO Matrix-Funktionen implementieren

int getMatrixIndex(unsigned int cols, unsigned int rowIdx, unsigned int colIdx)
{
    return rowIdx * cols + colIdx;
}

Matrix createMatrix(unsigned int rows, unsigned int cols)
{
    Matrix* m = malloc(sizeof(Matrix));
    m->rows = rows;
    m->cols = cols;
    m->storage = malloc(rows * cols * sizeof(MatrixType));
    return m;
}

void clearMatrix(Matrix *matrix)
{
    for (unsigned int i = 0; i < matrix->rows; i++)
    {
        for (unsigned int j = 0; j < matrix->cols; j++)
        {
            setMatrixElement(matrix, i, j, UNDEFINED_MATRIX_VALUE);
        }
    }
}

void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    matrix.storage[getMatrixIndex(matrix.cols, rowIdx, colIdx)] = value;
}

MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    return matrix.storage[getMatrixIndex(matrix.cols, rowIdx, colIdx)];
}

Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    if (matrix1.rows != matrix2.rows || matrix1.cols != matrix2.cols)
    {
        fprintf(stderr, "Fehler: Dimensionen stimmen nicht überein (%ux%u und %ux%u)\n",
                matrix1.rows, matrix1.cols, matrix2.rows, matrix2.cols);
        return (Matrix){ .rows = 0, .cols = 0, .storage = NULL };
    }

    Matrix result = createMatrix(matrix1.rows, matrix1.cols);

    // check, ob genügend Speicher vorhanden
    if (result.storage == NULL) {
        return (Matrix){ .rows = 0, .cols = 0, .storage = NULL };
    }

    for (unsigned int i = 0; i < matrix1.rows; i++)
    {
        for (unsigned int j = 0; j < matrix1.cols; j++)
        {
            unsigned int index = getMatrixIndex(matrix1.cols, i, j);
            result.storage[index] = matrix1.storage[index] + matrix2.storage[index];
        }
    }

    return result;
}

Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
    if (matrix1.cols != matrix2.rows)
    {
        fprintf(stderr, "Fehler: Spalten von Matrix 1 (%u) entsprechen nicht Zeilen von Matrix 2 (%u)\n",
                matrix1.cols, matrix2.rows);
        return (Matrix){ .rows = 0, .cols = 0, .storage = NULL };
    }

    Matrix result = createMatrix(matrix1.rows, matrix2.cols);

    // check, ob genügend Speicher vorhanden
    if (result.storage == NULL) {
        return (Matrix){ .rows = 0, .cols = 0, .storage = NULL };
    }

    for (unsigned int i = 0; i < matrix1.rows; i++)
    {
        for (unsigned int j = 0; j < matrix2.cols; j++)
        {
            MatrixType sum = 0;

            for (unsigned int k = 0; k < matrix1.cols; k++)
            {
                MatrixType val1 = matrix1.storage[i * matrix1.cols + k];
                MatrixType val2 = matrix2.storage[k * matrix2.cols + j];
                sum += val1 * val2;
            }

            result.storage[i * result.cols + j] = sum;
        }
    }

    return result;
}