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/* Author: Ioan Sucan */

#include "ompl/geometric/planners/rrt/LazyRRT.h"
#include "ompl/base/goals/GoalSampleableRegion.h"
#include "ompl/tools/config/SelfConfig.h"
#include <cassert>

ompl::geometric::LazyRRT::LazyRRT(const base::SpaceInformationPtr &si) : base::Planner(si, "LazyRRT")
{
    specs_.directed = true;
    goalBias_ = 0.05;
    maxDistance_ = 0.0;
    lastGoalMotion_ = nullptr;

    Planner::declareParam<double>("range", this, &LazyRRT::setRange, &LazyRRT::getRange, "0.:1.:10000.");
    Planner::declareParam<double>("goal_bias", this, &LazyRRT::setGoalBias, &LazyRRT::getGoalBias, "0.:.05:1.");
}

ompl::geometric::LazyRRT::~LazyRRT()
{
    freeMemory();
}

void ompl::geometric::LazyRRT::setup()
{
    Planner::setup();
    tools::SelfConfig sc(si_, getName());
    sc.configurePlannerRange(maxDistance_);

    if (!nn_)
        nn_.reset(tools::SelfConfig::getDefaultNearestNeighbors<Motion *>(this));
    nn_->setDistanceFunction([this](const Motion *a, const Motion *b)
                             {
                                 return distanceFunction(a, b);
                             });
}

void ompl::geometric::LazyRRT::clear()
{
    Planner::clear();
    sampler_.reset();
    freeMemory();
    if (nn_)
        nn_->clear();
    lastGoalMotion_ = nullptr;
}

void ompl::geometric::LazyRRT::freeMemory()
{
    if (nn_)
    {
        std::vector<Motion *> motions;
        nn_->list(motions);
        for (auto &motion : motions)
        {
            if (motion->state)
                si_->freeState(motion->state);
            delete motion;
        }
    }
}

ompl::base::PlannerStatus ompl::geometric::LazyRRT::solve(const base::PlannerTerminationCondition &ptc)
{
    checkValidity();
    base::Goal *goal = pdef_->getGoal().get();
    base::GoalSampleableRegion *goal_s = dynamic_cast<base::GoalSampleableRegion *>(goal);

    while (const base::State *st = pis_.nextStart())
    {
        auto *motion = new Motion(si_);
        si_->copyState(motion->state, st);
        motion->valid = true;
        nn_->add(motion);
    }

    if (nn_->size() == 0)
    {
        OMPL_ERROR("%s: There are no valid initial states!", getName().c_str());
        return base::PlannerStatus::INVALID_START;
    }

    if (!sampler_)
        sampler_ = si_->allocStateSampler();

    OMPL_INFORM("%s: Starting planning with %u states already in datastructure", getName().c_str(), nn_->size());

    Motion *solution = nullptr;
    double distsol = -1.0;
    auto *rmotion = new Motion(si_);
    base::State *rstate = rmotion->state;
    base::State *xstate = si_->allocState();

    bool solutionFound = false;

    while (ptc == false && !solutionFound)
    {
        /* sample random state (with goal biasing) */
        if (goal_s && rng_.uniform01() < goalBias_ && goal_s->canSample())
            goal_s->sampleGoal(rstate);
        else
            sampler_->sampleUniform(rstate);

        /* find closest state in the tree */
        Motion *nmotion = nn_->nearest(rmotion);
        assert(nmotion != rmotion);
        base::State *dstate = rstate;

        /* find state to add */
        double d = si_->distance(nmotion->state, rstate);
        if (d > maxDistance_)
        {
            si_->getStateSpace()->interpolate(nmotion->state, rstate, maxDistance_ / d, xstate);
            dstate = xstate;
        }

        /* create a motion */
        auto *motion = new Motion(si_);
        si_->copyState(motion->state, dstate);
        motion->parent = nmotion;
        nmotion->children.push_back(motion);
        nn_->add(motion);

        double dist = 0.0;
        if (goal->isSatisfied(motion->state, &dist))
        {
            distsol = dist;
            solution = motion;
            solutionFound = true;
            lastGoalMotion_ = solution;

            // Check that the solution is valid:
            // construct the solution path
            std::vector<Motion *> mpath;
            while (solution != nullptr)
            {
                mpath.push_back(solution);
                solution = solution->parent;
            }

            // check each segment along the path for validity
            for (int i = mpath.size() - 1; i >= 0 && solutionFound; --i)
                if (!mpath[i]->valid)
                {
                    if (si_->checkMotion(mpath[i]->parent->state, mpath[i]->state))
                        mpath[i]->valid = true;
                    else
                    {
                        removeMotion(mpath[i]);
                        solutionFound = false;
                        lastGoalMotion_ = nullptr;
                    }
                }

            if (solutionFound)
            {
                // set the solution path
                auto path(std::make_shared<PathGeometric>(si_));
                for (int i = mpath.size() - 1; i >= 0; --i)
                    path->append(mpath[i]->state);

                pdef_->addSolutionPath(path, false, distsol, getName());
            }
        }
    }

    si_->freeState(xstate);
    si_->freeState(rstate);
    delete rmotion;

    OMPL_INFORM("%s: Created %u states", getName().c_str(), nn_->size());

    return solutionFound ? base::PlannerStatus::EXACT_SOLUTION : base::PlannerStatus::TIMEOUT;
}

void ompl::geometric::LazyRRT::removeMotion(Motion *motion)
{
    nn_->remove(motion);

    /* remove self from parent list */

    if (motion->parent)
    {
        for (unsigned int i = 0; i < motion->parent->children.size(); ++i)
            if (motion->parent->children[i] == motion)
            {
                motion->parent->children.erase(motion->parent->children.begin() + i);
                break;
            }
    }

    /* remove children */
    for (auto &i : motion->children)
    {
        i->parent = nullptr;
        removeMotion(i);
    }

    if (motion->state)
        si_->freeState(motion->state);
    delete motion;
}

void ompl::geometric::LazyRRT::getPlannerData(base::PlannerData &data) const
{
    Planner::getPlannerData(data);

    std::vector<Motion *> motions;
    if (nn_)
        nn_->list(motions);

    if (lastGoalMotion_)
        data.addGoalVertex(base::PlannerDataVertex(lastGoalMotion_->state, 1));

    for (auto &motion : motions)
    {
        if (motion->parent == nullptr)
            data.addStartVertex(base::PlannerDataVertex(motion->state));
        else
            data.addEdge(base::PlannerDataVertex(motion->parent ? motion->parent->state : nullptr),
                         base::PlannerDataVertex(motion->state));

        data.tagState(motion->state, motion->valid ? 1 : 0);
    }
}
