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

// TODO Matrix-Funktionen implementieren

/*
Alte Funktion
Matrix createMatrix(unsigned int rows, unsigned int cols)
{
    Matrix m;
    m.rows = rows;
    m.cols = cols;
    m.data = NULL;

    if(rows == 0 || cols == 0){
        m.rows = m.cols = 0;
        return m;
    }

    m.data = malloc(rows * sizeof *m.data);
    
    if(!m.data){
        m.rows = m.cols = 0;
        return m;
    }
    for(unsigned int i = 0; i < rows; i++){
        m.data[i] = malloc(cols * sizeof *m.data[i]);
      
      if(!m.data[i]){
        for(unsigned int j = 0; j < i; j++){
            free(m.data[j]);
        }
        free(m.data);
        m.data = NULL;
        m.rows = m.cols = 0;
        return m;
      }
        
    }
    return m;
}
*/

Matrix createMatrix(size_t rows, size_t cols)
{
    Matrix m;
    m.rows = rows;
    m.cols = cols;
    m.buffer = NULL;

    if(rows == 0 || cols == 0){
        m.rows = m.cols = 0;
        return m;
    }

    // Single allocation for entire matrix
    m.buffer = malloc(rows * cols * sizeof(MatrixType));
    
    if(!m.buffer){
        m.rows = m.cols = 0;
        return m;
    }
    
    // Initialize (optional)
    for(unsigned int i = 0; i < rows * cols; i++){
        m.buffer[i] = UNDEFINED_MATRIX_VALUE;
    }
    
    return m;
}


void clearMatrix(Matrix *matrix)
{
    for (int i = 0; i < matrix->rows; i++) {
        for (int j = 0; j < matrix->cols;j++) {
            matrix->buffer[i + matrix->rows * j] = UNDEFINED_MATRIX_VALUE;
        }
    }
    free(matrix->buffer);
    matrix->rows = 0;
    matrix->cols = 0;
    matrix->buffer = NULL;
}

void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    //checks, if the given incies are allowed
    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)
{
    //checks, if the given indices are allowed
    if((rowIdx) < matrix.rows && (colIdx) < matrix.cols) {
        MatrixType returnVal;
        returnVal = matrix.buffer[rowIdx + matrix.rows*(colIdx)];
        return returnVal;
    }
    else return 0;
}

/*
Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    //check if the matrices are able to be added (same size)
    if (matrix1.cols == matrix2.cols && matrix1.rows == matrix2.rows){
        //size of the matrices should be the same, if the addition is supposed to happen
        // Matrix outputMatrix = createMatrix(matrix1.rows, matrix1.cols);
        Matrix outputMatrix = createMatrix(matrix1.rows, matrix1.cols);
        for (int i = 0; i < matrix1.rows;i++) {
            for (int j = 0; j < matrix1.cols; j++) {
                // how this should work in normal Matrix version:
                // outputmatrix.buffer[i][j] = matrix1.buffer[i][j] + matrix2.buffer[i][j];
                outputMatrix.buffer[i + outputMatrix.rows* j] = matrix1.buffer[i + matrix1.rows* j] + matrix2.buffer[i + matrix2.rows * j];
            }
        }
        return outputMatrix;
    } else {
        //the matrix could not be added, since the matrix sizes are not set correct.
        Matrix m;
        m.rows = 0; 
        m.cols = 0;
        m.buffer = NULL;
        return m;
    }

}
*/

Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    //check if the matrices are able to be added (same size)
    if (matrix1.cols != matrix2.cols && matrix1.rows != matrix2.rows){
        Matrix m = {NULL, 0, 0};
        return m;
    }
        

    //size of the matrices should be the same, if the addition is supposed to happen
    // Matrix outputMatrix = createMatrix(matrix1.rows, matrix1.cols);
    Matrix outputMatrix = createMatrix(matrix1.rows, matrix1.cols);

    if(!outputMatrix.buffer){
        Matrix m = {NULL, 0, 0};
        return m;
    }

    for (int i = 0; i < matrix1.rows;i++) {
        for (int j = 0; j < matrix1.cols; j++) {
            // how this should work in normal Matrix version:
            // outputmatrix.buffer[i][j] = matrix1.buffer[i][j] + matrix2.buffer[i][j];
            outputMatrix.buffer[i * outputMatrix.cols + j] = matrix1.buffer[i * matrix1.cols + j] + matrix2.buffer[i * matrix2.cols + j];
        }
    }
    return outputMatrix;

}

/*
Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
    
    //check, if the matrices can be multiplied
    if (matrix1.rows == matrix2.cols) {
        Matrix outputMatrix = createMatrix(matrix1.rows, matrix2.cols);
        //Matrix outputMatrix = createMatrix(matrix2.cols, matrix1.rows);
        for(int i = 0; i < matrix1.rows; i++) {
            for (int j = 0; j < matrix2.cols; j++) {
                for (int k = 0; k < matrix2.rows; k++) {
                    // how this should work in normal Matrix version:
                    // outputMatrix.buffer[i][j] = matrix1.buffer[i][k] * matrix2.buffer[k][j];
                    outputMatrix.buffer[i + outputMatrix.rows * j] += matrix1.buffer[i + matrix1.rows * k] * matrix2.buffer[k + matrix2.rows * j];
                }
            }
        }
        return outputMatrix;
    } else {
        //the matrix could not be added, since the matrix sizes are not set correct.
        Matrix m;
        m.rows = 0; 
        m.cols = 0;
        m.buffer = NULL;
        return m;
    }
}
*/


Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
    if(matrix1.cols != matrix2.rows){
        Matrix m = {NULL, 0, 0};
        return m;
    }
    
    Matrix outputMatrix = createMatrix(matrix1.rows, matrix2.cols);
    if(!outputMatrix.buffer){
        Matrix m = {NULL, 0, 0};
        return m;
    }

    //Matrix outputMatrix = createMatrix(matrix2.cols, matrix1.rows);
    for(int i = 0; i < matrix1.rows; i++) {
        for (int j = 0; j < matrix2.cols; j++) {
            MatrixType sum = 0;

            for (int k = 0; k < matrix1.cols; k++) {
                // how this should work in normal Matrix version:
                // outputMatrix.buffer[i][j] = matrix1.buffer[i][k] * matrix2.buffer[k][j];
                //outputMatrix.buffer[i + outputMatrix.rows * j] += matrix1.buffer[i + matrix1.rows * k] * matrix2.buffer[k + matrix2.rows * j];
                sum += matrix1.buffer[i * matrix1.cols + k] * matrix2.buffer[j + matrix2.cols * k];
            }
            outputMatrix.buffer[i * outputMatrix.cols + j] = sum;

        }
    }
    return outputMatrix;
}