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/* Author: Luis G. Torres, Jonathan Gammell */

#include <ompl/base/SpaceInformation.h>
#include <ompl/base/objectives/PathLengthOptimizationObjective.h>
#include <ompl/base/objectives/StateCostIntegralObjective.h>
#include <ompl/base/objectives/MaximizeMinClearanceObjective.h>
#include <ompl/base/spaces/RealVectorStateSpace.h>
// For ompl::msg::setLogLevel
#include "ompl/util/Console.h"

// The supported optimal planners, in alphabetical order
#include <ompl/geometric/planners/informedtrees/AITstar.h>
#include <ompl/geometric/planners/informedtrees/BITstar.h>
#include <ompl/geometric/planners/cforest/CForest.h>
#include <ompl/geometric/planners/fmt/FMT.h>
#include <ompl/geometric/planners/fmt/BFMT.h>
#include <ompl/geometric/planners/prm/PRMstar.h>
#include <ompl/geometric/planners/rrt/InformedRRTstar.h>
#include <ompl/geometric/planners/rrt/RRTstar.h>
#include <ompl/geometric/planners/rrt/SORRTstar.h>


// For boost program options
#include <boost/program_options.hpp>
// For string comparison (boost::iequals)
#include <boost/algorithm/string.hpp>
// For std::make_shared
#include <memory>

#include <fstream>


namespace ob = ompl::base;
namespace og = ompl::geometric;
/// @cond IGNORE

// An enum of supported optimal planners, alphabetical order
enum optimalPlanner
{
    PLANNER_AITSTAR,
    PLANNER_BFMTSTAR,
    PLANNER_BITSTAR,
    PLANNER_CFOREST,
    PLANNER_FMTSTAR,
    PLANNER_INF_RRTSTAR,
    PLANNER_PRMSTAR,
    PLANNER_RRTSTAR,
    PLANNER_SORRTSTAR,
};

// An enum of the supported optimization objectives, alphabetical order
enum planningObjective
{
    OBJECTIVE_PATHCLEARANCE,
    OBJECTIVE_PATHLENGTH,
    OBJECTIVE_THRESHOLDPATHLENGTH,
    OBJECTIVE_WEIGHTEDCOMBO
};

// Parse the command-line arguments
bool argParse(int argc, char** argv, double *runTimePtr, optimalPlanner *plannerPtr, planningObjective *objectivePtr, std::string *outputFilePtr);

// Our "collision checker". For this demo, our robot's state space
// lies in [0,1]x[0,1], with a circular obstacle of radius 0.25
// centered at (0.5,0.5). Any states lying in this circular region are
// considered "in collision".
class ValidityChecker : public ob::StateValidityChecker
{
public:
    ValidityChecker(const ob::SpaceInformationPtr& si) :
        ob::StateValidityChecker(si) {}

    // Returns whether the given state's position overlaps the
    // circular obstacle
    bool isValid(const ob::State* state) const override
    {
        return this->clearance(state) > 0.0;
    }

    // Returns the distance from the given state's position to the
    // boundary of the circular obstacle.
    double clearance(const ob::State* state) const override
    {
        // We know we're working with a RealVectorStateSpace in this
        // example, so we downcast state into the specific type.
        const auto* state2D =
            state->as<ob::RealVectorStateSpace::StateType>();

        // Extract the robot's (x,y) position from its state
        double x = state2D->values[0];
        double y = state2D->values[1];

        // Distance formula between two points, offset by the circle's
        // radius
        return sqrt((x-0.5)*(x-0.5) + (y-0.5)*(y-0.5)) - 0.25;
    }
};

ob::OptimizationObjectivePtr getPathLengthObjective(const ob::SpaceInformationPtr& si);

ob::OptimizationObjectivePtr getThresholdPathLengthObj(const ob::SpaceInformationPtr& si);

ob::OptimizationObjectivePtr getClearanceObjective(const ob::SpaceInformationPtr& si);

ob::OptimizationObjectivePtr getBalancedObjective1(const ob::SpaceInformationPtr& si);

ob::OptimizationObjectivePtr getBalancedObjective2(const ob::SpaceInformationPtr& si);

ob::OptimizationObjectivePtr getPathLengthObjWithCostToGo(const ob::SpaceInformationPtr& si);

ob::PlannerPtr allocatePlanner(ob::SpaceInformationPtr si, optimalPlanner plannerType)
{
    switch (plannerType)
    {
        case PLANNER_AITSTAR:
        {
            return std::make_shared<og::AITstar>(si);
            break;
        }
        case PLANNER_BFMTSTAR:
        {
            return std::make_shared<og::BFMT>(si);
            break;
        }
        case PLANNER_BITSTAR:
        {
            return std::make_shared<og::BITstar>(si);
            break;
        }
        case PLANNER_CFOREST:
        {
            return std::make_shared<og::CForest>(si);
            break;
        }
        case PLANNER_FMTSTAR:
        {
            return std::make_shared<og::FMT>(si);
            break;
        }
        case PLANNER_INF_RRTSTAR:
        {
            return std::make_shared<og::InformedRRTstar>(si);
            break;
        }
        case PLANNER_PRMSTAR:
        {
            return std::make_shared<og::PRMstar>(si);
            break;
        }
        case PLANNER_RRTSTAR:
        {
            return std::make_shared<og::RRTstar>(si);
            break;
        }
        case PLANNER_SORRTSTAR:
        {
            return std::make_shared<og::SORRTstar>(si);
            break;
        }
        default:
        {
            OMPL_ERROR("Planner-type enum is not implemented in allocation function.");
            return ob::PlannerPtr(); // Address compiler warning re: no return value.
            break;
        }
    }
}

ob::OptimizationObjectivePtr allocateObjective(const ob::SpaceInformationPtr& si, planningObjective objectiveType)
{
    switch (objectiveType)
    {
        case OBJECTIVE_PATHCLEARANCE:
            return getClearanceObjective(si);
            break;
        case OBJECTIVE_PATHLENGTH:
            return getPathLengthObjective(si);
            break;
        case OBJECTIVE_THRESHOLDPATHLENGTH:
            return getThresholdPathLengthObj(si);
            break;
        case OBJECTIVE_WEIGHTEDCOMBO:
            return getBalancedObjective1(si);
            break;
        default:
            OMPL_ERROR("Optimization-objective enum is not implemented in allocation function.");
            return ob::OptimizationObjectivePtr();
            break;
    }
}

void plan(double runTime, optimalPlanner plannerType, planningObjective objectiveType, const std::string& outputFile)
{
    // Construct the robot state space in which we're planning. We're
    // planning in [0,1]x[0,1], a subset of R^2.
    auto space(std::make_shared<ob::RealVectorStateSpace>(2));

    // Set the bounds of space to be in [0,1].
    space->setBounds(0.0, 1.0);

    // Construct a space information instance for this state space
    auto si(std::make_shared<ob::SpaceInformation>(space));

    // Set the object used to check which states in the space are valid
    si->setStateValidityChecker(std::make_shared<ValidityChecker>(si));

    si->setup();

    // Set our robot's starting state to be the bottom-left corner of
    // the environment, or (0,0).
    ob::ScopedState<> start(space);
    start->as<ob::RealVectorStateSpace::StateType>()->values[0] = 0.0;
    start->as<ob::RealVectorStateSpace::StateType>()->values[1] = 0.0;

    // Set our robot's goal state to be the top-right corner of the
    // environment, or (1,1).
    ob::ScopedState<> goal(space);
    goal->as<ob::RealVectorStateSpace::StateType>()->values[0] = 1.0;
    goal->as<ob::RealVectorStateSpace::StateType>()->values[1] = 1.0;

    // Create a problem instance
    auto pdef(std::make_shared<ob::ProblemDefinition>(si));

    // Set the start and goal states
    pdef->setStartAndGoalStates(start, goal);

    // Create the optimization objective specified by our command-line argument.
    // This helper function is simply a switch statement.
    pdef->setOptimizationObjective(allocateObjective(si, objectiveType));

    // Construct the optimal planner specified by our command line argument.
    // This helper function is simply a switch statement.
    ob::PlannerPtr optimizingPlanner = allocatePlanner(si, plannerType);

    // Set the problem instance for our planner to solve
    optimizingPlanner->setProblemDefinition(pdef);
    optimizingPlanner->setup();

    // attempt to solve the planning problem in the given runtime
    ob::PlannerStatus solved = optimizingPlanner->solve(runTime);

    if (solved)
    {
        // Output the length of the path found
        std::cout
            << optimizingPlanner->getName()
            << " found a solution of length "
            << pdef->getSolutionPath()->length()
            << " with an optimization objective value of "
            << pdef->getSolutionPath()->cost(pdef->getOptimizationObjective()) << std::endl;

        // If a filename was specified, output the path as a matrix to
        // that file for visualization
        if (!outputFile.empty())
        {
            std::ofstream outFile(outputFile.c_str());
            std::static_pointer_cast<og::PathGeometric>(pdef->getSolutionPath())->
                printAsMatrix(outFile);
            outFile.close();
        }
    }
    else
        std::cout << "No solution found." << std::endl;
}

int main(int argc, char** argv)
{
    // The parsed arguments
    double runTime;
    optimalPlanner plannerType;
    planningObjective objectiveType;
    std::string outputFile;

    // Parse the arguments, returns true if successful, false otherwise
    if (argParse(argc, argv, &runTime, &plannerType, &objectiveType, &outputFile))
    {
        // Plan
        plan(runTime, plannerType, objectiveType, outputFile);

        // Return with success
        return 0;
    }
    // Return with error
    return -1;
}

/** Returns a structure representing the optimization objective to use
    for optimal motion planning. This method returns an objective
    which attempts to minimize the length in configuration space of
    computed paths. */
ob::OptimizationObjectivePtr getPathLengthObjective(const ob::SpaceInformationPtr& si)
{
    return std::make_shared<ob::PathLengthOptimizationObjective>(si);
}

/** Returns an optimization objective which attempts to minimize path
    length that is satisfied when a path of length shorter than 1.51
    is found. */
ob::OptimizationObjectivePtr getThresholdPathLengthObj(const ob::SpaceInformationPtr& si)
{
    auto obj(std::make_shared<ob::PathLengthOptimizationObjective>(si));
    obj->setCostThreshold(ob::Cost(1.51));
    return obj;
}

/** Defines an optimization objective which attempts to steer the
    robot away from obstacles. To formulate this objective as a
    minimization of path cost, we can define the cost of a path as a
    summation of the costs of each of the states along the path, where
    each state cost is a function of that state's clearance from
    obstacles.

    The class StateCostIntegralObjective represents objectives as
    summations of state costs, just like we require. All we need to do
    then is inherit from that base class and define our specific state
    cost function by overriding the stateCost() method.
 */
class ClearanceObjective : public ob::StateCostIntegralObjective
{
public:
    ClearanceObjective(const ob::SpaceInformationPtr& si) :
        ob::StateCostIntegralObjective(si, true)
    {
    }

    // Our requirement is to maximize path clearance from obstacles,
    // but we want to represent the objective as a path cost
    // minimization. Therefore, we set each state's cost to be the
    // reciprocal of its clearance, so that as state clearance
    // increases, the state cost decreases.
    ob::Cost stateCost(const ob::State* s) const override
    {
        return ob::Cost(1 / (si_->getStateValidityChecker()->clearance(s) +
            std::numeric_limits<double>::min()));
    }
};

/** Return an optimization objective which attempts to steer the robot
    away from obstacles. */
ob::OptimizationObjectivePtr getClearanceObjective(const ob::SpaceInformationPtr& si)
{
    return std::make_shared<ClearanceObjective>(si);
}

/** Create an optimization objective which attempts to optimize both
    path length and clearance. We do this by defining our individual
    objectives, then adding them to a MultiOptimizationObjective
    object. This results in an optimization objective where path cost
    is equivalent to adding up each of the individual objectives' path
    costs.

    When adding objectives, we can also optionally specify each
    objective's weighting factor to signify how important it is in
    optimal planning. If no weight is specified, the weight defaults to
    1.0.
*/
ob::OptimizationObjectivePtr getBalancedObjective1(const ob::SpaceInformationPtr& si)
{
    auto lengthObj(std::make_shared<ob::PathLengthOptimizationObjective>(si));
    auto clearObj(std::make_shared<ClearanceObjective>(si));
    auto opt(std::make_shared<ob::MultiOptimizationObjective>(si));
    opt->addObjective(lengthObj, 10.0);
    opt->addObjective(clearObj, 1.0);

    return ob::OptimizationObjectivePtr(opt);
}

/** Create an optimization objective equivalent to the one returned by
    getBalancedObjective1(), but use an alternate syntax.
 */
ob::OptimizationObjectivePtr getBalancedObjective2(const ob::SpaceInformationPtr& si)
{
    auto lengthObj(std::make_shared<ob::PathLengthOptimizationObjective>(si));
    auto clearObj(std::make_shared<ClearanceObjective>(si));

    return 10.0*lengthObj + clearObj;
}

/** Create an optimization objective for minimizing path length, and
    specify a cost-to-go heuristic suitable for this optimal planning
    problem. */
ob::OptimizationObjectivePtr getPathLengthObjWithCostToGo(const ob::SpaceInformationPtr& si)
{
    auto obj(std::make_shared<ob::PathLengthOptimizationObjective>(si));
    obj->setCostToGoHeuristic(&ob::goalRegionCostToGo);
    return obj;
}

/** Parse the command line arguments into a string for an output file and the planner/optimization types */
bool argParse(int argc, char** argv, double* runTimePtr, optimalPlanner *plannerPtr, planningObjective *objectivePtr, std::string *outputFilePtr)
{
    namespace bpo = boost::program_options;

    // Declare the supported options.
    bpo::options_description desc("Allowed options");
    desc.add_options()
        ("help,h", "produce help message")
        ("runtime,t", bpo::value<double>()->default_value(1.0), "(Optional) Specify the runtime in seconds. Defaults to 1 and must be greater than 0.")
        ("planner,p", bpo::value<std::string>()->default_value("RRTstar"), "(Optional) Specify the optimal planner to use, defaults to RRTstar if not given. Valid options are AITstar, BFMTstar, BITstar, CForest, FMTstar, InformedRRTstar, PRMstar, RRTstar, and SORRTstar.") //Alphabetical order
        ("objective,o", bpo::value<std::string>()->default_value("PathLength"), "(Optional) Specify the optimization objective, defaults to PathLength if not given. Valid options are PathClearance, PathLength, ThresholdPathLength, and WeightedLengthAndClearanceCombo.") //Alphabetical order
        ("file,f", bpo::value<std::string>()->default_value(""), "(Optional) Specify an output path for the found solution path.")
        ("info,i", bpo::value<unsigned int>()->default_value(0u), "(Optional) Set the OMPL log level. 0 for WARN, 1 for INFO, 2 for DEBUG. Defaults to WARN.");
    bpo::variables_map vm;
    bpo::store(bpo::parse_command_line(argc, argv, desc), vm);
    bpo::notify(vm);

    // Check if the help flag has been given:
    if (vm.count("help") != 0u)
    {
        std::cout << desc << std::endl;
        return false;
    }

    // Set the log-level
    unsigned int logLevel = vm["info"].as<unsigned int>();

    // Switch to setting the log level:
    if (logLevel == 0u)
    {
        ompl::msg::setLogLevel(ompl::msg::LOG_WARN);
    }
    else if (logLevel == 1u)
    {
        ompl::msg::setLogLevel(ompl::msg::LOG_INFO);
    }
    else if (logLevel == 2u)
    {
        ompl::msg::setLogLevel(ompl::msg::LOG_DEBUG);
    }
    else
    {
        std::cout << "Invalid log-level integer." << std::endl << std::endl << desc << std::endl;
        return false;
    }

    // Get the runtime as a double
    *runTimePtr = vm["runtime"].as<double>();

    // Sanity check
    if (*runTimePtr <= 0.0)
    {
        std::cout << "Invalid runtime." << std::endl << std::endl << desc << std::endl;
        return false;
    }

    // Get the specified planner as a string
    std::string plannerStr = vm["planner"].as<std::string>();

    // Map the string to the enum
    if (boost::iequals("AITstar", plannerStr)) {
        *plannerPtr = PLANNER_AITSTAR;
    }
    else if (boost::iequals("BFMTstar", plannerStr))
    {
        *plannerPtr = PLANNER_BFMTSTAR;
    }
    else if (boost::iequals("BITstar", plannerStr))
    {
        *plannerPtr = PLANNER_BITSTAR;
    }
    else if (boost::iequals("CForest", plannerStr))
    {
        *plannerPtr = PLANNER_CFOREST;
    }
    else if (boost::iequals("FMTstar", plannerStr))
    {
        *plannerPtr = PLANNER_FMTSTAR;
    }
    else if (boost::iequals("InformedRRTstar", plannerStr))
    {
        *plannerPtr = PLANNER_INF_RRTSTAR;
    }
    else if (boost::iequals("PRMstar", plannerStr))
    {
        *plannerPtr = PLANNER_PRMSTAR;
    }
    else if (boost::iequals("RRTstar", plannerStr))
    {
        *plannerPtr = PLANNER_RRTSTAR;
    }
    else if (boost::iequals("SORRTstar", plannerStr))
    {
        *plannerPtr = PLANNER_SORRTSTAR;
    }
    else
    {
        std::cout << "Invalid planner string." << std::endl << std::endl << desc << std::endl;
        return false;
    }

    // Get the specified objective as a string
    std::string objectiveStr = vm["objective"].as<std::string>();

    // Map the string to the enum
    if (boost::iequals("PathClearance", objectiveStr))
    {
        *objectivePtr = OBJECTIVE_PATHCLEARANCE;
    }
    else if (boost::iequals("PathLength", objectiveStr))
    {
        *objectivePtr = OBJECTIVE_PATHLENGTH;
    }
    else if (boost::iequals("ThresholdPathLength", objectiveStr))
    {
        *objectivePtr = OBJECTIVE_THRESHOLDPATHLENGTH;
    }
    else if (boost::iequals("WeightedLengthAndClearanceCombo", objectiveStr))
    {
        *objectivePtr = OBJECTIVE_WEIGHTEDCOMBO;
    }
    else
    {
        std::cout << "Invalid objective string." << std::endl << std::endl << desc << std::endl;
        return false;
    }

    // Get the output file string and store it in the return pointer
    *outputFilePtr = vm["file"].as<std::string>();

    // Looks like we parsed the arguments successfully
    return true;
}
/// @endcond
