#ifndef NAVMESHWALKSIMPLE_H
#define NAVMESHWALKSIMPLE_H

#include "../NavMesh.h"
#include "../NavMeshLocation.h"
#include "../../geo/Heading.h"

#include "NavMeshSub.h"
#include "NavMeshWalkParams.h"
#include "NavMeshWalkEval.h"

namespace NM {

	template <typename Tria> class NavMeshWalkSimple {

	private:

		const NavMesh<Tria>& mesh;

		std::vector<NavMeshWalkEval<Tria>*> evals;

		int hits = 0;
		int misses = 0;

	public:


		/** single result */
		struct ResultEntry {
			NavMeshLocation<Tria> location;
			Heading heading;
			double probability;
			ResultEntry() : heading(0) {;}
		};

		/** list of results */
		using ResultList = std::vector<ResultEntry>;

	public:

		/** ctor */
		NavMeshWalkSimple(const NavMesh<Tria>& mesh) : mesh(mesh) {

		}

		/** add a new evaluator to the walker */
		void addEvaluator(NavMeshWalkEval<Tria>* eval) {
			this->evals.push_back(eval);
		}



		ResultEntry getOne(const NavMeshWalkParams<Tria>& params) {

			ResultEntry re;

			// to-be-walked distance;
			const float toBeWalkedDist = params.getToBeWalkedDistance();
			const float toBeWalkedDistSafe = 0.75 + toBeWalkedDist * 1.1;

			// construct reachable region
			NavMeshSub<Tria> reachable(params.start, toBeWalkedDistSafe);

			// get the to-be-reached destination's position (using start+distance+heading)
			const Point2 dir = params.heading.asVector();
			const Point2 dst = params.start.pos.xy() + (dir * toBeWalkedDist);

			const Tria* dstTria = reachable.getContainingTriangle(dst);

			// is above destination reachable?
			if (dstTria) {

				re.heading = params.heading;										// heading was OK -> keep
				re.location.pos = dstTria->toPoint3(dst);							// new destination position
				re.location.tria = dstTria;											// new destination triangle
				++hits;

			} else {

				NavMeshRandom<Tria> rnd = reachable.getRandom();					// random-helper
				re.location = rnd.draw();											// get a random destianation
				re.heading = Heading(params.start.pos.xy(), re.location.pos.xy());	// update the heading
				++misses;

			}

			const int total = (hits + misses);
			if (total % 10000 == 0) {
				std::cout << "hits: " << (hits*100/total) << "%" << std::endl;
			}

			// calculate probability
			const NavMeshPotentialWalk<Tria> pwalk(params, re.location);
			re.probability = 1.0;
			for (const NavMeshWalkEval<Tria>* eval : evals) {
				const double p1 = eval->getProbability(pwalk);
				re.probability *= p1;
			}

			// done
			return re;

		}

		ResultList getMany(const NavMeshWalkParams<Tria>& params) {
			return {getOne(params)};
		}


	};

}

#endif // NAVMESHWALKSIMPLE_H