/*********************************************************************
* Software License Agreement (BSD License)
*
*  Copyright (c) 2011, Rice University
*  All rights reserved.
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*   * Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   * Redistributions in binary form must reproduce the above
*     copyright notice, this list of conditions and the following
*     disclaimer in the documentation and/or other materials provided
*     with the distribution.
*   * Neither the name of the Rice University nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
*  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
*  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
*  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
*  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
*  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
*  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
*  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
*  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
*  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
*  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*********************************************************************/

/* Author: Ioan Sucan */

#ifndef OMPL_BASE_PLANNER_TERMINATION_CONDITION_
#define OMPL_BASE_PLANNER_TERMINATION_CONDITION_

#include <boost/function.hpp>
#include <boost/shared_ptr.hpp>
#include <ompl/base/ProblemDefinition.h>
#include <ompl/util/Time.h>

namespace ompl
{

    namespace base
    {

        /** \brief Signature for functions that decide whether termination
            conditions have been met for a planner, even if no
            solution is found. This is usually reaching a time or
            memory limit. If the function returns true, the planner is
            signaled to terminate its computation. Otherwise,
            computation continues while this function returns false,
            until a solution is found. */
        typedef boost::function<bool()> PlannerTerminationConditionFn;

        /** \brief Encapsulate a termination condition for a motion
            planner. Planners will call operator() to decide whether
            they should terminate before a solution is found or
            not. operator() will return true if either the implemented
            condition is met (the call to eval() returns true) or if
            the user called terminate(true). */
        class PlannerTerminationCondition
        {
        public:

            /** \brief Construct a termination condition. By default, eval() will call the externally specified function \e fn to decide whether
                the planner should terminate. */
            PlannerTerminationCondition(const PlannerTerminationConditionFn &fn);

            /** \brief Construct a termination condition that is evaluated every \e period seconds. The evaluation of
                the condition consists of calling \e fn() in a separate thread. Calls to eval() will always return the
                last value computed by the call to \e fn(). */
            PlannerTerminationCondition(const PlannerTerminationConditionFn &fn, double period);

            ~PlannerTerminationCondition()
            {
            }

            /** \brief Return true if the planner should stop its computation */
            bool operator()() const
            {
                return eval();
            }

            /** \brief Cast as true if the planner should stop its computation */
            operator bool() const
            {
                return eval();
            }

            /** \brief Notify that the condition for termination should become true, regardless of what eval() returns.
                This function may be called while the condition is being evaluated by other threads. */
            void terminate() const;

            /** \brief The implementation of some termination condition. By default, this just calls \e fn_() */
            bool eval() const;

        private:

            class PlannerTerminationConditionImpl;
            boost::shared_ptr<PlannerTerminationConditionImpl> impl_;
        };

        /** \brief Simple termination condition that always returns false. The termination condition will never be met */
        PlannerTerminationCondition plannerNonTerminatingCondition();

        /** \brief Simple termination condition that always returns true. The termination condition will always be met */
        PlannerTerminationCondition plannerAlwaysTerminatingCondition();

        /** \brief Combine two termination conditions into one. If either termination condition returns true, this one will return true as well. */
        PlannerTerminationCondition plannerOrTerminationCondition(const PlannerTerminationCondition &c1, const PlannerTerminationCondition &c2);

        /** \brief Combine two termination conditions into one. Both termination conditions need to return true for this one to return true. */
        PlannerTerminationCondition plannerAndTerminationCondition(const PlannerTerminationCondition &c1, const PlannerTerminationCondition &c2);

        /** \brief Return a termination condition that will become true \e duration seconds in the future (wall-time) */
        PlannerTerminationCondition timedPlannerTerminationCondition(double duration);

        /** \brief Return a termination condition that will become true \e duration in the future (wall-time) */
        PlannerTerminationCondition timedPlannerTerminationCondition(time::duration duration);

        /** \brief Return a termination condition that will become true \e duration seconds in the future (wall-time), but is checked in a separate thread, every \e interval seconds; \e interval must be less than \e duration */
        PlannerTerminationCondition timedPlannerTerminationCondition(double duration, double interval);

        /** \brief Return a termination condition that will become true as soon as the problem definition has an exact solution */
        PlannerTerminationCondition exactSolnPlannerTerminationCondition(ompl::base::ProblemDefinitionPtr pdef);

        /** \brief A class to run a planner for a specific number of iterations. Casts to a PTC for use with Planner::solve */
        class IterationTerminationCondition
        {
        public:
            /** \brief Construct a termination condition that can be evaluated numIterations times before returning true. */
            IterationTerminationCondition(unsigned int numIterations);

            /** \brief Increment the number of times eval has been called and check if the planner should now terminate. */
            bool eval();

            /** \brief Reset the number of times the IterationTeriminationCondition has been called. */
            void reset();

            /** \brief Cast to a PlannerTerminationCondition */
            operator PlannerTerminationCondition();

        private:
            /** \brief The max number of iterations the condition can be called before returning true. */
            unsigned int maxCalls_;
            /** \brief The number of times called so far.*/
            unsigned int timesCalled_;
        };
    }
}

#endif
