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

// Matrix erstellen
Matrix createMatrix(unsigned int rows, unsigned int cols)
{
    Matrix m;
    if (rows == 0 || cols == 0) {
        m.rows = 0;
        m.cols = 0;
        m.buffer = NULL;
        return m;
    }

    m.rows = rows;
    m.cols = cols;
    m.buffer = (MatrixType*)calloc(rows * cols, sizeof(MatrixType));
    if (!m.buffer) {
        m.rows = 0;
        m.cols = 0;
    }
    return m;
}

// Speicher freigeben
void clearMatrix(Matrix *matrix)
{
    if (!matrix || !matrix->buffer) return;
    free(matrix->buffer);
    matrix->buffer = NULL;
    matrix->rows = 0;
    matrix->cols = 0;
}

// Wert setzen
void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
{
    if (rowIdx >= matrix.rows || colIdx >= matrix.cols) return;
    matrix.buffer[rowIdx * matrix.cols + colIdx] = value;
}

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

// Addition (mit Broadcasting-Unterstützung für Bias)
Matrix add(const Matrix matrix1, const Matrix matrix2)
{
    Matrix result;
    
    // Fall 1: Exakte Dimensionen (Element-weise Addition)
    if (matrix1.rows == matrix2.rows && matrix1.cols == matrix2.cols) {
        result = createMatrix(matrix1.rows, matrix1.cols);
        for (unsigned int i = 0; i < matrix1.rows * matrix1.cols; i++)
            result.buffer[i] = matrix1.buffer[i] + matrix2.buffer[i];
        return result;
    }
    
    // Fall 2: matrix1 ist (zeilen x 1) Spaltenvektor, matrix2 ist (zeilen x spalten)
    // Broadcasting: matrix1's Spalte wird zu jeder Spalte von matrix2 addiert
    if (matrix1.rows == matrix2.rows && matrix1.cols == 1) {
        result = createMatrix(matrix2.rows, matrix2.cols);
        for (unsigned int col = 0; col < matrix2.cols; col++) {
            for (unsigned int row = 0; row < matrix2.rows; row++) {
                MatrixType val1 = matrix1.buffer[row * matrix1.cols + 0];
                MatrixType val2 = matrix2.buffer[row * matrix2.cols + col];
                result.buffer[row * result.cols + col] = val1 + val2;
            }
        }
        return result;
    }
    
    // Fall 3: matrix2 ist (zeilen x 1) Spaltenvektor, matrix1 ist (zeilen x spalten)
    // Broadcasting: matrix2's Spalte wird zu jeder Spalte von matrix1 addiert
    if (matrix2.rows == matrix1.rows && matrix2.cols == 1) {
        result = createMatrix(matrix1.rows, matrix1.cols);
        for (unsigned int col = 0; col < matrix1.cols; col++) {
            for (unsigned int row = 0; row < matrix1.rows; row++) {
                MatrixType val1 = matrix1.buffer[row * matrix1.cols + col];
                MatrixType val2 = matrix2.buffer[row * matrix2.cols + 0];
                result.buffer[row * result.cols + col] = val1 + val2;
            }
        }
        return result;
    }
    
    // Ungültige Dimensionen - leere Matrix zurückgeben
    result.rows = 0;
    result.cols = 0;
    result.buffer = NULL;
    return result;
}

// Multiplikation
Matrix multiply(const Matrix matrix1, const Matrix matrix2)
{
    Matrix result;
    
    // Überprüfe ob Multiplikation möglich ist (Spalten matrix1 == Zeilen matrix2)
    if (matrix1.cols != matrix2.rows) {
        result.rows = 0;
        result.cols = 0;
        result.buffer = NULL;
        return result;
    }

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

    // Berechne alle Elemente des Ergebnisses
    for (unsigned int i = 0; i < matrix1.rows; i++)
    {
        for (unsigned int j = 0; j < matrix2.cols; j++)
        {
            // Skalarprodukt: Reihe i von matrix1 × Spalte j von matrix2
            MatrixType sum = 0;
            for (unsigned int k = 0; k < matrix1.cols; k++)
                sum += matrix1.buffer[i * matrix1.cols + k] * matrix2.buffer[k * matrix2.cols + j];
            result.buffer[i * result.cols + j] = sum;
        }
    }

    return result;
}