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

// TODO Matrix-Funktionen implementieren

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++) {
            // Normally one would expect to work matrices like this, but it is supposed to be the other way around. 
            // matrix->buffer[i + matrix->rows * j] = UNDEFINED_MATRIX_VALUE;
            matrix->buffer[j + matrix->cols * i] = 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) {
        // Normally one would expect to work matrices like this, but it is supposed to be the other way around. 
        // matrix.buffer[rowIdx + matrix.rows*(colIdx)] = value;
        matrix.buffer[colIdx + matrix.cols * rowIdx] = 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;
        // Normally one would expect to work matrices like this, but it is supposed to be the other way around.
        // returnVal = matrix.buffer[rowIdx + matrix.rows*(colIdx)];
        returnVal = matrix.buffer[colIdx + rowIdx * matrix.cols];
        return returnVal;
    }
    else return 0;
}

Matrix add(const Matrix matrix1, const Matrix matrix2)
{

    bool doBroadcast = false;
    Matrix larger, smaller;
    
    if(matrix1.rows == matrix2.rows && matrix1.cols == matrix2.cols){
        larger = matrix1;
        smaller = matrix2;
    }
    else if (matrix1.rows == matrix2.rows && matrix2.cols == 1)
    {
        larger = matrix1;
        smaller = matrix2;
        doBroadcast = true;
    }
    else if (matrix1.rows == matrix2.rows && matrix1.cols == 1)
    {
        larger = matrix2;
        smaller = matrix1;
        doBroadcast = true;
    }
    else{
        Matrix m = {NULL, 0, 0};
        return m;
    }

    Matrix outputMatrix = createMatrix(larger.rows, larger.cols);
    if(doBroadcast){
        for(int i = 0; i < outputMatrix.rows; i++){
            MatrixType broadcastValue = smaller.buffer[i];
            for(int j = 0; j < outputMatrix.cols; j++){
                outputMatrix.buffer[i * outputMatrix.cols + j] = larger.buffer[i * larger.cols + j] + broadcastValue; 
            }
        }
    } else{
        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)
{
    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++) {
            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];
                outputMatrix.buffer[i * outputMatrix.cols + j] += matrix1.buffer[i * matrix1.cols + k] * matrix2.buffer[j + matrix2.cols * k];
            }
        }
    }
    return outputMatrix;
}