/* Copyright (C) 2021 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "precompiled.h"

#include "simulation2/system/Component.h"
#include "ICmpUnitMotionManager.h"

#include "simulation2/MessageTypes.h"
#include "simulation2/components/ICmpUnitMotion.h"
#include "simulation2/system/EntityMap.h"

#include "ps/CLogger.h"
#include "ps/Profile.h"

class CCmpUnitMotionManager : public ICmpUnitMotionManager
{
public:
	static void ClassInit(CComponentManager& componentManager)
	{
		componentManager.SubscribeToMessageType(MT_TurnStart);
		componentManager.SubscribeToMessageType(MT_Update_Final);
		componentManager.SubscribeToMessageType(MT_Update_MotionUnit);
		componentManager.SubscribeToMessageType(MT_Update_MotionFormation);
	}

	DEFAULT_COMPONENT_ALLOCATOR(UnitMotionManager)

	EntityMap<MotionState> m_Units;
	EntityMap<MotionState> m_FormationControllers;

	// Temporary vector, reconstructed each turn (stored here to avoid memory reallocations).
	std::vector<EntityMap<MotionState>::iterator> m_MovingUnits;

	bool m_ComputingMotion;

	static std::string GetSchema()
	{
		return "<a:component type='system'/><empty/>";
	}

	virtual void Init(const CParamNode& UNUSED(paramNode))
	{
		m_MovingUnits.reserve(40);
	}

	virtual void Deinit()
	{
	}

	virtual void Serialize(ISerializer& UNUSED(serialize))
	{
	}

	virtual void Deserialize(const CParamNode& paramNode, IDeserializer& UNUSED(deserialize))
	{
		Init(paramNode);
	}

	virtual void HandleMessage(const CMessage& msg, bool UNUSED(global))
	{
		switch (msg.GetType())
		{
			case MT_TurnStart:
			{
				OnTurnStart();
				break;
			}
			case MT_Update_MotionFormation:
			{
				fixed dt = static_cast<const CMessageUpdate_MotionFormation&>(msg).turnLength;
				m_ComputingMotion = true;
				MoveFormations(dt);
				m_ComputingMotion = false;
				break;
			}
			case MT_Update_MotionUnit:
			{
				fixed dt = static_cast<const CMessageUpdate_MotionUnit&>(msg).turnLength;
				m_ComputingMotion = true;
				MoveUnits(dt);
				m_ComputingMotion = false;
				break;
			}
		}
	}

	virtual void Register(entity_id_t ent, bool formationController);
	virtual void Unregister(entity_id_t ent);

	virtual bool ComputingMotion() const
	{
		return m_ComputingMotion;
	}

	void OnTurnStart();

	void MoveUnits(fixed dt);
	void MoveFormations(fixed dt);
	void Move(EntityMap<MotionState>& ents, fixed dt);
};

void CCmpUnitMotionManager::Register(entity_id_t ent, bool formationController)
{
	MotionState state = {
		CmpPtr<ICmpPosition>(GetSimContext(), ent),
		CmpPtr<ICmpUnitMotion>(GetSimContext(), ent),
		CFixedVector2D(),
		CFixedVector2D(),
		fixed::Zero(),
		fixed::Zero(),
		false,
		false
	};
	if (!formationController)
		m_Units.insert(ent, state);
	else
		m_FormationControllers.insert(ent, state);
}

void CCmpUnitMotionManager::Unregister(entity_id_t ent)
{
	EntityMap<MotionState>::iterator it = m_Units.find(ent);
	if (it != m_Units.end())
	{
		m_Units.erase(it);
		return;
	}
	it = m_FormationControllers.find(ent);
	if (it != m_FormationControllers.end())
		m_FormationControllers.erase(it);
}

void CCmpUnitMotionManager::OnTurnStart()
{
	for (EntityMap<MotionState>::value_type& data : m_FormationControllers)
		data.second.cmpUnitMotion->OnTurnStart();

	for (EntityMap<MotionState>::value_type& data : m_Units)
		data.second.cmpUnitMotion->OnTurnStart();
}

void CCmpUnitMotionManager::MoveUnits(fixed dt)
{
	Move(m_Units, dt);
}

void CCmpUnitMotionManager::MoveFormations(fixed dt)
{
	Move(m_FormationControllers, dt);
}

void CCmpUnitMotionManager::Move(EntityMap<MotionState>& ents, fixed dt)
{
	m_MovingUnits.clear();
	for (EntityMap<MotionState>::iterator it = ents.begin(); it != ents.end(); ++it)
	{
		it->second.cmpUnitMotion->PreMove(it->second);
		if (!it->second.needUpdate)
			continue;
		m_MovingUnits.push_back(it);
		it->second.initialPos = it->second.cmpPosition->GetPosition2D();
		it->second.initialAngle = it->second.cmpPosition->GetRotation().Y;
		it->second.pos = it->second.initialPos;
		it->second.angle = it->second.initialAngle;
	}

	for (EntityMap<MotionState>::iterator& it : m_MovingUnits)
		it->second.cmpUnitMotion->Move(it->second, dt);

	for (EntityMap<MotionState>::iterator& it : m_MovingUnits)
		it->second.cmpUnitMotion->PostMove(it->second, dt);
}


REGISTER_COMPONENT_TYPE(UnitMotionManager)