#ifndef __JFUNCTIONOBJECT1D__
#define __JFUNCTIONOBJECT1D__

#include "JLang/JSinglePointer.hh"
#include "JLang/JClass.hh"
#include "JMath/JZero.hh"
#include "JIO/JSerialisable.hh"
#include "JTools/JFunctional.hh"
#include "JTools/JConstantFunction1D.hh"


/**
 * \author mdejong
 */

namespace JTOOLS {}
namespace JPP { using namespace JTOOLS; }

namespace JTOOLS {

  using JIO::JReader;
  using JIO::JWriter;


  /**
   * Template implementation of function object in one dimension using an external function.
   *
   * This class implements the JFunction1D interface.
   */
  template<class JArgument_t, class JResult_t>
  class JExternalFunction1D : 
    public JFunction1D<JArgument_t, JResult_t>
  {
  public:

    typedef JFunction1D<JArgument_t, JResult_t>                         function_type;
    typedef typename function_type::argument_type                       argument_type;
    typedef typename function_type::result_type                         result_type;

    typedef result_type (*pointerToFunction)(const argument_type);


    /**
     * Constructor.
     *
     * \param  function        pointer to function
     */
    JExternalFunction1D(pointerToFunction function) :
      function_type(),
      __f(function)
    {}


    /**
     * Function value evaluation.
     *
     * \param  pX              pointer to abscissa values
     * \return                 function value
     */
    virtual result_type evaluate(const argument_type* pX) const override 
    {
      return __f(*pX);
    }


  protected:
    /**
     * Function compilation.
     */
    virtual void do_compile() override 
    {}


    pointerToFunction __f;
  };


  /**
   * Template implementation of function object in one dimension.
   *
   * This class implements the JFunction1D interface.
   */
  template<class JArgument_t, class JResult_t>
  class JFunctionObject1D : 
    public JFunction1D<JArgument_t, JResult_t>
  {
  public:

    
    typedef JFunction1D<JArgument_t, JResult_t>                         function_type;
    typedef typename function_type::argument_type                       argument_type;
    typedef typename function_type::result_type                         result_type;


    /**
     * Default constructor.
     */
    JFunctionObject1D() :
      function_type(),
      function()
    {}


    /**
     * Constructor.
     *
     * \param  y               constant value
     */
    JFunctionObject1D(typename JLANG::JClass<result_type>::argument_type y) :
      function_type(),
      function(new JConstantFunction1D<JArgument_t, JResult_t>(y))
    {}


    /**
     * Constructor.
     *
     * \param  f               pointer to external function
     */
    JFunctionObject1D(result_type (*f)(const argument_type)) :
      function_type(),
      function(new JExternalFunction1D<JArgument_t, JResult_t>(f))
    {}


    /**
     * Function value evaluation.
     *
     * \param  pX              pointer to abscissa values
     * \return                 function value
     */
    virtual result_type evaluate(const argument_type* pX) const override 
    {
      return function->evaluate(pX);
    }


  protected:
    /**
     * Function compilation.
     */
    virtual void do_compile() override 
    {
      function->compile();
    }


    JLANG::JSinglePointer<function_type> function;
  };
}

#endif