#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){ // check if dimensions are valid
     Matrix empty = {.rows =0, .cols=0, .buffer =NULL}; //return empty matrix if invalid
     return empty;
    }
    MatrixType *buffer = malloc(rows * cols* sizeof(MatrixType)); //allocate memory
    if (buffer == NULL){ //check if memory allocation succeeded
        Matrix empty = {.rows =0, .cols=0, .buffer =NULL}; //return empty matrix if out of memory 
        return empty;
    }
    Matrix result ={.rows = rows, .cols = cols, .buffer = buffer}; // create and return matrix
    return result;
        
    
    
}

void clearMatrix(Matrix *matrix)
{ free(matrix-> buffer); // free the buffer memory
  matrix -> buffer = NULL; // set all members to 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){ // check if indices are valid 
    return; // do nothing if out of bounds
}
    unsigned int index = rowIdx * matrix.cols + colIdx; // calculate index using row-major formula
    matrix.buffer[index] = value ; // set value at that index
    
}

MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{  if (rowIdx >= matrix.rows || colIdx >= matrix.cols){  //check if indices are valid
    return UNDEFINED_MATRIX_VALUE;
}

unsigned int index = rowIdx * matrix.cols + colIdx; //calculate index using row-major formula
return matrix.buffer [index]; // return the value at that index
    
}

Matrix add(const Matrix matrix1, const Matrix matrix2)
{ if (matrix1.rows != matrix2.rows){ // check row compatibility
    Matrix empty = {.rows =0, .cols=0, .buffer = NULL};
    return empty;
}
  if (matrix1.cols!= matrix2.cols && matrix2.cols !=1 && matrix1.cols != 1){ // check column compatibility (allow broadcasting ) 
    Matrix empty = {.rows =0, .cols=0, .buffer =NULL};
    return empty;
  }
    unsigned int resultRows = matrix1.rows; //determine result dimensions
    unsigned int resultCols = (matrix1.cols > matrix2.cols) ? matrix1.cols: matrix2.cols;
     //Allocate memory for the result buffer 
  MatrixType *resultBuffer = malloc(resultRows * resultCols * sizeof(MatrixType)); 
  if (resultBuffer == NULL){
    Matrix empty = {.rows =0, .cols=0, .buffer=NULL};
    return empty;
  } 
  // add elements element-wise with broadcasting 
  for (unsigned int row =0; row < resultRows; ++row){
    for (unsigned int col =0; col < resultCols; ++col){
        //Handle broadcasting: if matrix2 has 1 column, use column 0
        unsigned int col1 = (matrix1.cols ==1)? 0 : col;
        MatrixType val1 = getMatrixAt (matrix1, row, col1);
        unsigned int col2 = (matrix2.cols==1) ? 0 : col;
        MatrixType val2 = getMatrixAt(matrix2, row, col2);

        unsigned int resultIndex = row * resultCols + col;
        resultBuffer[resultIndex] = val1 +val2;
    }
  } 
  Matrix result = {.rows = resultRows, .cols = resultCols, .buffer= resultBuffer};
  return result; //create and return result
    
}

Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{  if (matrix1.cols != matrix2.rows){ // check compatibility
    Matrix empty = {.rows =0, .cols=0, .buffer =NULL};
    return empty;
}
 unsigned int resultRows = matrix1.rows; // determine result dimensions
 unsigned int resultCols = matrix2.cols;

 MatrixType *resultBuffer = malloc( resultRows * resultCols * sizeof(MatrixType)); // allocate memory 
 if (resultBuffer == NULL){
    Matrix empty = {.rows =0, .cols=0, .buffer= NULL};
    return empty;
 }
 for (unsigned int i =0; i < resultRows; ++i){
    for (unsigned int j =0; j< resultCols; ++j){
        MatrixType sum = 0.0;
        for (unsigned int k =0; k< matrix1.cols; ++k){
            MatrixType val1 =getMatrixAt(matrix1, i,k);
            MatrixType val2 = getMatrixAt(matrix2, k,j);
            sum += val1 * val2;
        }


        unsigned int resultIndex = i * resultCols + j;
        resultBuffer [resultIndex] = sum;
    }
 }
  Matrix result = {.rows = resultRows, .cols = resultCols, .buffer =resultBuffer};
  return result;

    
}