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

// TODO Matrix-Funktionen implementieren

Matrix createMatrix(unsigned int rows, unsigned int cols)
{
 Matrix m= {NULL,0,0}; //erstellen eine leere Matrix

 if(rows ==0 || cols == 0)  //wenn Dimensionen nicht passen -> leere Matrix zurückgeben
   return m;

 m.buffer = calloc(rows * cols, sizeof(MatrixType));   //array erstellen, in Buffer laden
 if(m.buffer == NULL)  //buffer nicht geklappt-> leere Matrix
   return m;

 m.rows = rows;   //Dimensionen zuweisen
 m.cols = cols:
 return m;   //passende Matrix übergeben
    
}

void clearMatrix(Matrix *matrix)
{
   if(matrix == NULL)  //leere Matrix -> abbruch
     return;
   free(matrix->buffer);  //speicher freigeben
   matrix->buffer = NULL;  //pionter auf null setzen
   matrix->rows = 0;       //matrix auf null setzen
   matrix->cols = 0;
    }
}

void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    if(matrix == NULL)  //leere Matrix -> abbruch
     return;
    if(rowIdx >= matrix.rows|| colIdx >= matrix.cols)
      return;

    matrix.buffer[rowIdx * matrix.cols + colIdx] = value;

}

MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
  if(matrix == NULL)  //leere Matrix -> abbruch
     return UNDEFINED_MATRIX_VALUE;
  if(rowIdx >= matrix.rows|| colIdx >= matrix.cols)
    return UNDEFINED_MATRIX_VALUE;
  return matrix.buffer[rowIdx * matrix.cols + colIdx];
    
}

Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    Matrix result = {NULL,0,0};
    if(matrix1.buffer == NULL || matrix2.buffer == NULL)
      return result;
    if(matrix1.rows !=matrix2.rows && matrix1.rows != 1 && matrix2.rows != 1) // broadcasting check (Matrix Erweiterung)
      return result;
    if(matrix1.cols !=matrix2.cols && matrix1.cols != 1 && matrix2.cols != 1) // broadcasting check (Matrix Erweiterung)
      return result;


    unsigned int rows;
    if (matrix1.rows > matrix2.rows)
      rows = matrix1.rows;
    else
      rows = matrix2.rows;

     unsigned int cols;
    if (matrix1.cols > matrix2.cols)
      rows = matrix1.cols;
    else
      rows = matrix2.cols;

    result = createMatrix(rows, cols);
    if(result.buffer == NULL)
      return result;

    for(unsigned int i = 0; i < rows; i++)
      {
      unsigned int r1 = (matrix1.rows == 1) ? 0 : i;
      unsigned int r2 = (matrix2.rows == 1) ? 0 : i;

        	 for(unsigned int j = 0; j < cols; j++)
                   {
                   unsigned int c1 = (matrix1.cols == 1) ? 0 : j;
                   unsigned int c2 = (matrix2.cols == 1) ? 0 : j;

                   MatrixType v1 = matrix1.buffer[r1 * matrix1.cols + c1];
                   MatrixType v2 = matrix2.buffer[r2 * matrix1.cols + c2];
                   result.buffer[i*cols+j] = v1 + v2
	}
}
return result;
}

Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
Matrix result = (Matrix){NULL,0,0};
if(matrix1.buffer == NULL || matrix2.buffer == NULL)
  return result;

if (matrix1.cols != matrix2.rows)
  return result;

unsigned int rows = matrix1.rows;
unsigned int cols = matrix2.cols;
unsigned int inner = matrix1.cols;

result = createMatrix(rows, cols);
if(result.buffer == NULL)
  return result;

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

    for(unsigned int k = 0; k < inner; k++)
      {
      MatrixType v1 = matrix1.buffer[i * matrix1.cols + k];
      MatrixType v2 = matrix2.buffer[k * matrix2.cols + j];
      sum += v1 * v2;
      }

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