/*
 * SetValue.hpp
 *
 *  Created on: Jun 25, 2012
 *      Author: heber
 */

#ifndef SETVALUE_HPP_
#define SETVALUE_HPP_


// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <boost/function.hpp>
#include <boost/shared_ptr.hpp>

#include "IndexSet.hpp"
#include "IndexSetContainer.hpp"
#include "ZeroInstance.hpp"

#include "CodePatterns/Cacheable.hpp"
#include "CodePatterns/Log.hpp"
#include "CodePatterns/Observer/Observable.hpp"

class SetValueTest;

template <class T>
class SetValue : public Observable
{
  //!> grant unit test access to allow setting static function
  friend class SetValueTest;
  //!> grant OrthogonalSummation access to static lookup functions
  template <class TT> friend class OrthogonalSummation;
  //!> grant Summation access to static lookup functions
  template <class TT> friend class Summation;
public:
  typedef boost::shared_ptr< SetValue<T> > ptr;

  SetValue(const IndexSet_ptr &_indices, const T &_value) :
    Observable("SubsetValue"),
    value(_value),
    indices(_indices),
    contribution(this,boost::bind(&SetValue<T>::calcSum,this),"contribution")
  {};

  SetValue & operator+=(const SetValue &other) {
    if (indices->contains(*other.indices)) {
      OBSERVE;
      value += other.value;
    }
    return *this;
  }

  SetValue & operator-=(const SetValue &other) {
    if (indices->contains(*other.indices)) {
      OBSERVE;
      value -= other.value;
    }
    return *this;
  }

  const IndexSet_ptr& getIndexSet() const {
    return indices;
  }

  /** Getter for the contribution.
   *
   * @return contribution
   */
  const T getContribution() const {
    return *contribution;
  }

  /** Getter for the value.
   *
   * @return value
   */
  const T getValue() const {
    return value;
  }

  /** Setter for the value.
   *
   * This function is observed to notify all sets that contain us of a change.
   *
   * @param _value value to set value to
   */
  void setValue(const T& _value) {
    OBSERVE;
    value = _value;
  }

private:
  // prohibit copies
  SetValue(const SetValue<T> &_value);

private:
  //!> static lookup function to get to the subsets
  static boost::function< IndexSetContainer::ptr & (const IndexSet_ptr &)> lookupSubset;

  //!> static lookup function to get the SetValue for a specific IndexSet
  static boost::function< typename SetValue<T>::ptr & (const IndexSet_ptr &)> lookupValue;

  /** Calculates the contribution for this subset.
   *
   * We calculate by value minus the summed contributions(!) from all subsets
   * of this subset. If the value is ZeroInstance<T> however, we set its
   * contribution to zero, as it is designated thereby as not contributing.
   *
   * \note This is internal function that is bound to the Cacheable contribution.
   *
   * @return value minus the summed contribution's from all subsets
   */
  const T calcSum() {
    LOG(2, "DEBUG: Summing up contribution for " << *indices << ".");
    // we initialize with value
    T result = getValue();
    // ZeroInstance<T>() is a specific value, if set, this subset does not contribute
    if (result != ZeroInstance<T>()) { // compare directly, not numerically!
      // then subtract contributions from all subsets
      const IndexSetContainer::ptr &container = lookupSubset(indices);
      if (container) {
        const IndexSetContainer::Container_t &subsets = container->getContainer();
        for (IndexSetContainer::Container_t::const_iterator iter = subsets.begin();
            iter != subsets.end(); ++iter) {
          LOG(3, "DEBUG: Current subset is " << **iter << ".");
          // NOTE: our subset is not contained in the number of subsets
          typename SetValue<T>::ptr ptr = lookupValue(*iter);
          if (ptr)
            result -= ptr->getContribution();
          else
            ELOG(1, "Cannot find " << **iter << " via lookup.");
        }
      } else {
        ELOG(1, "Cannot find subsets for " << *indices << " via lookup.");
      }
    } // else we return ZeroInstance<T>() as contribution
    return result;
  }

private:
  //!> value associated with this IndexSet
  T value;

  //!> shared_ptr to the index set
  IndexSet_ptr indices;

  //!> stores the (orthogonal) contribution for this SubsetValue
  Cacheable<T> contribution;
};

template <class T>
boost::function< IndexSetContainer::ptr & (const IndexSet_ptr &)> SetValue<T>::lookupSubset = NULL;

template <class T>
boost::function< typename SetValue<T>::ptr & (const IndexSet_ptr &)> SetValue<T>::lookupValue = NULL;

#endif /* SETVALUE_HPP_ */