/*
 * © Copyright 2014 – Urheberrechtshinweis
 * Alle Rechte vorbehalten / All Rights Reserved
 *
 * Programmcode ist urheberrechtlich geschuetzt.
 * Das Urheberrecht liegt, soweit nicht ausdruecklich anders gekennzeichnet, bei Frank Ebner.
 * Keine Verwendung ohne explizite Genehmigung.
 * (vgl. § 106 ff UrhG / § 97 UrhG)
 */

#ifndef FLOORPLAN_3D_OBJPOOL_H
#define FLOORPLAN_3D_OBJPOOL_H

#include <vector>
#include "../../../geo/Triangle3.h"
#include <unordered_map>

#include "OBJReader.h"
#include "../Obstacle3.h"

// LINUX ONLY
//#include <dirent.h>
//#include <stdio.h>
#include "../../../data/File.h"


#include "../../../misc/Debug.h"


namespace Floorplan3D {

	/**
	 * load several named 3D models for quick re-use
	 */
	class OBJPool {

	private:

		static constexpr const char* name = "OBJ-Pool";

		/** singleton */
		OBJPool() {;}

		bool initDone = false;
		std::unordered_map<std::string, Obstacle3D> cache;

	public:

		/** singleton access */
		static OBJPool& get() {
			static OBJPool instance;
			return instance;
		}

		/** init with *.obj data folder */
		void init(const std::string& folder) {

			scanFolder(folder);
			initDone = true;

		}

		/** init with multiple *.obj data folder */
		void init(const std::initializer_list<std::string>& folders) {

			for (const std::string& folder : folders) {
				try {
					scanFolder(folder);
				} catch (...) {;}
			}
			initDone = true;

		}

		/** get all triangles for the given object (if known) */
		const Obstacle3D& getObject(const std::string& name) {

			// ensure the cache is initialized
			if (!initDone) {
				throw Exception("OBJPool: not initialized. call init(folder) first");
			}

			static Obstacle3D empty;

			// find the entry
			const auto& it = cache.find(name);
			if (it == cache.end()) {return empty;}
			return it->second;

		}

	private:

		/** scan the given folder for all *.obj files */
		void scanFolder(const std::string& folder) {

			FS::File d(folder);
			if (!d.exists()) {
				throw Exception("OBJPool: folder not found: " + folder);
			}

			for (const FS::File& f : d.listFiles()) {
				std::string name = f.getFilename();
				if (endsWith(name, ".obj")) {
					//std::string name = entry.path().filename().string();
					name = name.substr(0, name.length() - 4);	// without extension
					load(f.getPath(), name);
				}
			}

		}

		inline bool endsWith(std::string const & value, std::string const & ending) {
			if (ending.size() > value.size()) return false;
			return std::equal(ending.rbegin(), ending.rend(), value.rbegin());
		}

		/** load the given .obj file into the cache */
		void load(const std::string& absName, const std::string& name) {

			OBJReader reader;
			reader.readFile(absName);
			//reader.readFile("/mnt/vm/paper/diss/code/IndoorMap/res/mdl/" + file + ".obj");	// todo

			// create triangles
			Obstacle3D obs;
			for (const OBJReader::Object& obj : reader.getData().objects) {
				for (const OBJReader::Face& face : obj.faces) {
					const Triangle3 tria(face.vnt[0].vertex, face.vnt[1].vertex, face.vnt[2].vertex);
					obs.triangles.push_back(tria);
				}
			}

			Log::add(this->name, "loaded: " + absName + " [" + std::to_string(obs.triangles.size()) + " triangles]", true);

			// store
			cache[name] = obs;

		}

	};

}

#endif // FLOORPLAN_3D_OBJPOOL_H