/*************************************************************************/
/*  world_2d.cpp                                                         */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
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/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
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/* distribute, sublicense, and/or sell copies of the Software, and to    */
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/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
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/*************************************************************************/
#include "world_2d.h"
#include "servers/visual_server.h"
#include "servers/physics_2d_server.h"
#include "servers/spatial_sound_2d_server.h"
#include "globals.h"
#include "scene/2d/visibility_notifier_2d.h"
#include "scene/main/viewport.h"
#include "scene/2d/camera_2d.h"
#include "globals.h"

struct SpatialIndexer2D {


	struct CellRef {

		int ref;

		_FORCE_INLINE_ int inc() {
			ref++;
			return ref;
		}
		_FORCE_INLINE_ int dec() {
			ref--;
			return ref;
		}

		_FORCE_INLINE_ CellRef() {
			ref=0;
		}
	};



	struct CellKey {

		union {
			struct {
				int32_t x;
				int32_t y;
			};
			uint64_t key;
		};

		bool operator==(const CellKey& p_key) const { return key==p_key.key; }
		_FORCE_INLINE_ bool operator<(const CellKey& p_key) const {
			return key < p_key.key;
		}

	};

	struct CellData {

		Map<VisibilityNotifier2D*,CellRef> notifiers;
	};


	Map<CellKey,CellData> cells;
	int cell_size;

	Map<VisibilityNotifier2D*,Rect2> notifiers;

	struct ViewportData {

		Map<VisibilityNotifier2D*,uint64_t> notifiers;
		Rect2 rect;
	};

	Map<Viewport*,ViewportData> viewports;

	bool changed;

	uint64_t pass;


	void _notifier_update_cells(VisibilityNotifier2D *p_notifier,const Rect2& p_rect,bool p_add) {

		Point2i begin = p_rect.pos;
		begin/=cell_size;
		Point2i end = p_rect.pos+p_rect.size;
		end/=cell_size;
		for(int i=begin.x;i<=end.x;i++) {

			for(int j=begin.y;j<=end.y;j++) {

				CellKey ck;
				ck.x=i;
				ck.y=j;
				Map<CellKey,CellData>::Element *E=cells.find(ck);

				if (p_add) {

					if (!E)
						E=cells.insert(ck,CellData());
					E->get().notifiers[p_notifier].inc();
				} else {

					ERR_CONTINUE(!E);
					if (E->get().notifiers[p_notifier].dec()==0) {

						E->get().notifiers.erase(p_notifier);
						if (E->get().notifiers.empty()) {
							cells.erase(E);
						}
					}
				}
			}
		}
	}

	void _notifier_add(VisibilityNotifier2D* p_notifier,const Rect2& p_rect) {

		ERR_FAIL_COND(notifiers.has(p_notifier));
		notifiers[p_notifier]=p_rect;
		_notifier_update_cells(p_notifier,p_rect,true);
		changed=true;
	}

	void _notifier_update(VisibilityNotifier2D* p_notifier,const Rect2& p_rect) {

		Map<VisibilityNotifier2D*,Rect2>::Element *E=notifiers.find(p_notifier);
		ERR_FAIL_COND(!E);
		if (E->get()==p_rect)
			return;

		_notifier_update_cells(p_notifier,p_rect,true);
		_notifier_update_cells(p_notifier,E->get(),false);
		E->get()=p_rect;
		changed=true;
	}

	void _notifier_remove(VisibilityNotifier2D* p_notifier) {

		Map<VisibilityNotifier2D*,Rect2>::Element *E=notifiers.find(p_notifier);
		ERR_FAIL_COND(!E);
		_notifier_update_cells(p_notifier,E->get(),false);
		notifiers.erase(p_notifier);

		List<Viewport*> removed;
		for (Map<Viewport*,ViewportData>::Element*F=viewports.front();F;F=F->next()) {

			Map<VisibilityNotifier2D*,uint64_t>::Element*G=F->get().notifiers.find(p_notifier);

			if (G) {
				F->get().notifiers.erase(G);
				removed.push_back(F->key());
			}
		}

		while(!removed.empty()) {

			p_notifier->_exit_viewport(removed.front()->get());
			removed.pop_front();
		}

		changed=true;
	}

	void _add_viewport(Viewport* p_viewport,const Rect2& p_rect) {

		ERR_FAIL_COND(viewports.has(p_viewport));
		ViewportData vd;
		vd.rect=p_rect;
		viewports[p_viewport]=vd;
		changed=true;

	}

	void _update_viewport(Viewport* p_viewport, const Rect2& p_rect) {

		Map<Viewport*,ViewportData>::Element *E= viewports.find(p_viewport);
		ERR_FAIL_COND(!E);
		if (E->get().rect==p_rect)
			return;
		E->get().rect=p_rect;
		changed=true;
	}

	void _remove_viewport(Viewport* p_viewport) {
		ERR_FAIL_COND(!viewports.has(p_viewport));
		List<VisibilityNotifier2D*> removed;
		for(Map<VisibilityNotifier2D*,uint64_t>::Element *E=viewports[p_viewport].notifiers.front();E;E=E->next()) {

			removed.push_back(E->key());
		}

		while(!removed.empty()) {
			removed.front()->get()->_exit_viewport(p_viewport);
			removed.pop_front();
		}

		viewports.erase(p_viewport);
	}

	void _update() {


		if (!changed)
			return;

		for (Map<Viewport*,ViewportData>::Element *E=viewports.front();E;E=E->next()) {

			Point2i begin = E->get().rect.pos;
			begin/=cell_size;
			Point2i end = E->get().rect.pos+E->get().rect.size;
			end/=cell_size;
			pass++;
			List<VisibilityNotifier2D*> added;
			List<VisibilityNotifier2D*> removed;

			int visible_cells=(end.x-begin.x)*(end.y-begin.y);

			if (visible_cells>10000) {

				//well you zoomed out a lot, it's your problem. To avoid freezing in the for loops below, we'll manually check cell by cell

				for (Map<CellKey,CellData>::Element *F=cells.front();F;F=F->next()) {

					const CellKey &ck=F->key();

					if (ck.x<begin.x || ck.x>end.x)
						continue;
					if (ck.y<begin.y || ck.y>end.y)
						continue;

					//notifiers in cell
					for (Map<VisibilityNotifier2D*,CellRef>::Element *G=F->get().notifiers.front();G;G=G->next()) {

						Map<VisibilityNotifier2D*,uint64_t>::Element *H=E->get().notifiers.find(G->key());
						if (!H) {

							H=E->get().notifiers.insert(G->key(),pass);
							added.push_back(G->key());
						} else {
							H->get()=pass;
						}
					}
				}

			} else {

				//check cells in grid fashion
				for(int i=begin.x;i<=end.x;i++) {

					for(int j=begin.y;j<=end.y;j++) {

						CellKey ck;
						ck.x=i;
						ck.y=j;

						Map<CellKey,CellData>::Element *F=cells.find(ck);
						if (!F) {
							continue;
						}


						//notifiers in cell
						for (Map<VisibilityNotifier2D*,CellRef>::Element *G=F->get().notifiers.front();G;G=G->next()) {

							Map<VisibilityNotifier2D*,uint64_t>::Element *H=E->get().notifiers.find(G->key());
							if (!H) {

								H=E->get().notifiers.insert(G->key(),pass);
								added.push_back(G->key());
							} else {
								H->get()=pass;
							}
						}
					}
				}
			}

			for (Map<VisibilityNotifier2D*,uint64_t>::Element *F=E->get().notifiers.front();F;F=F->next()) {

				if (F->get()!=pass)
					removed.push_back(F->key());
			}

			while(!added.empty()) {
				added.front()->get()->_enter_viewport(E->key());
				added.pop_front();
			}

			while(!removed.empty()) {
				E->get().notifiers.erase(removed.front()->get());
				removed.front()->get()->_exit_viewport(E->key());
				removed.pop_front();
			}
		}

		changed=false;
	}


	SpatialIndexer2D() {

		pass=0;
		changed=false;
		cell_size=100; //should be configurable with GLOBAL_DEF("") i guess
	}

};



void World2D::_register_viewport(Viewport* p_viewport,const Rect2& p_rect) {

	indexer->_add_viewport(p_viewport,p_rect);
}

void World2D::_update_viewport(Viewport* p_viewport,const Rect2& p_rect){

	indexer->_update_viewport(p_viewport,p_rect);

}
void World2D::_remove_viewport(Viewport* p_viewport){

	indexer->_remove_viewport(p_viewport);
}

void World2D::_register_notifier(VisibilityNotifier2D* p_notifier, const Rect2 &p_rect){

	indexer->_notifier_add(p_notifier,p_rect);

}
void World2D::_update_notifier(VisibilityNotifier2D* p_notifier,const Rect2& p_rect){

	indexer->_notifier_update(p_notifier,p_rect);
}
void World2D::_remove_notifier(VisibilityNotifier2D* p_notifier){

	indexer->_notifier_remove(p_notifier);
}

void World2D::_update() {

	indexer->_update();
}


RID World2D::get_canvas() {

	return canvas;
}

RID World2D::get_space() {

	return space;
}

RID World2D::get_sound_space() {

	return sound_space;
}

void World2D::_bind_methods() {

	ClassDB::bind_method(_MD("get_canvas"),&World2D::get_canvas);
	ClassDB::bind_method(_MD("get_space"),&World2D::get_space);
	ClassDB::bind_method(_MD("get_sound_space"),&World2D::get_sound_space);

	ClassDB::bind_method(_MD("get_direct_space_state:Physics2DDirectSpaceState"),&World2D::get_direct_space_state);

}

Physics2DDirectSpaceState *World2D::get_direct_space_state() {

	return Physics2DServer::get_singleton()->space_get_direct_state(space);
}


World2D::World2D() {

	canvas = VisualServer::get_singleton()->canvas_create();
	space = Physics2DServer::get_singleton()->space_create();
	sound_space = SpatialSound2DServer::get_singleton()->space_create();

	//set space2D to be more friendly with pixels than meters, by adjusting some constants
	Physics2DServer::get_singleton()->space_set_active(space,true);
	Physics2DServer::get_singleton()->area_set_param(space,Physics2DServer::AREA_PARAM_GRAVITY,GLOBAL_DEF("physics/2d/default_gravity",98));
	Physics2DServer::get_singleton()->area_set_param(space,Physics2DServer::AREA_PARAM_GRAVITY_VECTOR,GLOBAL_DEF("physics/2d/default_gravity_vector",Vector2(0,1)));
	Physics2DServer::get_singleton()->area_set_param(space,Physics2DServer::AREA_PARAM_LINEAR_DAMP,GLOBAL_DEF("physics/2d/default_linear_damp",0.1));
	Physics2DServer::get_singleton()->area_set_param(space,Physics2DServer::AREA_PARAM_ANGULAR_DAMP,GLOBAL_DEF("physics/2d/default_angular_damp",1));
	indexer = memnew( SpatialIndexer2D );

}


World2D::~World2D() {

	VisualServer::get_singleton()->free(canvas);
	Physics2DServer::get_singleton()->free(space);
	SpatialSound2DServer::get_singleton()->free(sound_space);
	memdelete(indexer);
}