#ifndef GRID_H_
#define GRID_H_

/**
 * @file Grid.hpp
 * @brief API of Grid class, that holds a matrix with concenctrations and a
 *        respective matrix/matrices of alpha coefficients.
 *
 */

#include <Eigen/Core>
#include <Eigen/Sparse>

class Grid {
public:
  /**
   * @brief Constructs a new 1D-Grid object of a given length, which holds a
   * matrix with concentrations and a respective matrix of alpha coefficients.
   *        The domain length is per default the same as the length. The
   * concentrations are all 20 by default and the alpha coefficients are 1.
   *
   * @param length Length of the 1D-Grid. Must be greater than 3.
   */
  Grid(int length);

  /**
   * @brief Constructs a new 2D-Grid object of given dimensions, which holds a
   * matrix with concentrations and the respective matrices of alpha coefficient
   * for each direction. The domain in x- and y-direction is per default equal
   * to the col length and row length, respectively. The concentrations are all
   * 20 by default across the entire grid and the alpha coefficients 1 in both
   * directions.
   *
   * @param row Length of the 2D-Grid in y-direction. Must be greater than 3.
   * @param col Length of the 2D-Grid in x-direction. Must be greater than 3.
   */
  Grid(int row, int col);

  /**
   * @brief Sets the concentrations matrix for a 1D or 2D-Grid.
   *
   * @param concentrations An Eigen3 MatrixXd holding the concentrations. Matrix
   * must have correct dimensions as defined in row and col. (Or length, in 1D
   * case).
   */
  void setConcentrations(Eigen::MatrixXd concentrations);

  /**
   * @brief Gets the concentrations matrix for a Grid.
   *
   * @return MatrixXd An Eigen3 matrix holding the concentrations and having the
   *                  same dimensions as the grid.
   */
  const Eigen::MatrixXd getConcentrations();

  /**
   * @brief Set the alpha coefficients of a 1D-Grid. Grid must be one
   * dimensional.
   *
   * @param alpha An Eigen3 MatrixXd with 1 row holding the alpha coefficients.
   * Matrix columns must have same size as length of grid.
   */
  void setAlpha(Eigen::MatrixXd alpha);

  /**
   * @brief Set the alpha coefficients of a 2D-Grid. Grid must be two
   * dimensional.
   *
   * @param alphaX An Eigen3 MatrixXd holding the alpha coefficients in
   * x-direction. Matrix must be of same size as the grid.
   * @param alphaY An Eigen3 MatrixXd holding the alpha coefficients in
   * y-direction. Matrix must be of same size as the grid.
   */
  void setAlpha(Eigen::MatrixXd alphaX, Eigen::MatrixXd alphaY);

  /**
   * @brief Gets the matrix of alpha coefficients of a 1D-Grid. Grid must be one
   * dimensional.
   *
   * @return MatrixXd A matrix with 1 row holding the alpha coefficients.
   */
  const Eigen::MatrixXd getAlpha();

  /**
   * @brief Gets the matrix of alpha coefficients in x-direction of a 2D-Grid.
   * Grid must be two dimensional.
   *
   * @return MatrixXd A matrix holding the alpha coefficients in x-direction.
   */
  const Eigen::MatrixXd getAlphaX();

  /**
   * @brief Gets the matrix of alpha coefficients in y-direction of a 2D-Grid.
   * Grid must be two dimensional.
   *
   * @return MatrixXd A matrix holding the alpha coefficients in y-direction.
   */
  const Eigen::MatrixXd getAlphaY();

  /**
   * @brief Gets the dimensions of the grid.
   *
   * @return int Dimensions, either 1 or 2.
   */
  int getDim();

  /**
   * @brief Gets length of 1D grid. Must be one dimensional grid.
   *
   * @return int Length of 1D grid.
   */
  int getLength();

  /**
   * @brief Gets the number of rows of the grid.
   *
   * @return int Number of rows.
   */
  int getRow();

  /**
   * @brief Gets the number of columns of the grid.
   *
   * @return int Number of columns.
   */
  int getCol();

  /**
   * @brief Sets the domain length of a 1D-Grid. Grid must be one dimensional.
   *
   * @param domainLength A double value of the domain length. Must be positive.
   */
  void setDomain(double domainLength);

  /**
   * @brief Sets the domain size of a 2D-Grid. Grid must be two dimensional.
   *
   * @param domainRow A double value of the domain size in y-direction. Must be
   * positive.
   * @param domainCol A double value of the domain size in x-direction. Must be
   * positive.
   */
  void setDomain(double domainRow, double domainCol);

  /**
   * @brief Gets the delta value for 1D-Grid. Grid must be one dimensional.
   *
   * @return double Delta value.
   */
  double getDelta();

  /**
   * @brief Gets the delta value in x-direction.
   *
   * @return double Delta value in x-direction.
   */
  double getDeltaCol();

  /**
   * @brief Gets the delta value in y-direction. Must be two dimensional grid.
   *
   * @return double Delta value in y-direction.
   */
  double getDeltaRow();

private:
  int col;                        // number of grid columns
  int row;                        // number of grid rows
  int dim;                        // 1D or 2D
  double domainCol;               // number of domain columns
  double domainRow;               // number of domain rows
  double deltaCol;                // delta in x-direction (between columns)
  double deltaRow;                // delta in y-direction (between rows)
  Eigen::MatrixXd concentrations; // Matrix holding grid concentrations
  Eigen::MatrixXd alphaX; // Matrix holding alpha coefficients in x-direction
  Eigen::MatrixXd alphaY; // Matrix holding alpha coefficients in y-direction
};

#endif // GRID_H_