// ChunkSender.cpp

// Interfaces to the cChunkSender class representing the thread that waits for chunks becoming ready (loaded / generated) and sends them to clients





#include "Globals.h"
#include "ChunkSender.h"
#include "World.h"
#include "BlockEntities/BlockEntity.h"
#include "Protocol/ChunkDataSerializer.h"
#include "ClientHandle.h"





////////////////////////////////////////////////////////////////////////////////
// cNotifyChunkSender:

void cNotifyChunkSender::Call(int a_ChunkX, int a_ChunkZ)
{
	m_ChunkSender->ChunkReady(a_ChunkX, a_ChunkZ);
}





////////////////////////////////////////////////////////////////////////////////
// cChunkSender:

cChunkSender::cChunkSender(void) :
	super("ChunkSender"),
	m_World(nullptr),
	m_RemoveCount(0),
	m_Notify(nullptr)
{
	m_Notify.SetChunkSender(this);
}





cChunkSender::~cChunkSender()
{
	Stop();
}





bool cChunkSender::Start(cWorld * a_World)
{
	m_ShouldTerminate = false;
	m_World = a_World;
	return super::Start();
}





void cChunkSender::Stop(void)
{
	m_ShouldTerminate = true;
	m_evtQueue.Set();
	Wait();
}





void cChunkSender::ChunkReady(int a_ChunkX, int a_ChunkZ)
{
	// This is probably never gonna be called twice for the same chunk, and if it is, we don't mind, so we don't check
	{
		cCSLock Lock(m_CS);
		m_ChunksReady.push_back(cChunkCoords(a_ChunkX, a_ChunkZ));
	}
	m_evtQueue.Set();
}





void cChunkSender::QueueSendChunkTo(int a_ChunkX, int a_ChunkZ, eChunkPriority a_Priority, cClientHandle * a_Client)
{
	ASSERT(a_Client != nullptr);
	{
		sSendChunk Chunk(a_ChunkX, a_ChunkZ, a_Client);

		cCSLock Lock(m_CS);
		if (
			std::find(m_SendChunksLowPriority.begin(), m_SendChunksLowPriority.end(), Chunk) != m_SendChunksLowPriority.end() ||
			std::find(m_SendChunksMediumPriority.begin(), m_SendChunksMediumPriority.end(), Chunk) != m_SendChunksMediumPriority.end() ||
			std::find(m_SendChunksHighPriority.begin(), m_SendChunksHighPriority.end(), Chunk) != m_SendChunksHighPriority.end()
		)
		{
			// Already queued, bail out
			return;
		}

		switch (a_Priority)
		{
			case E_CHUNK_PRIORITY_LOW:
			{
				m_SendChunksLowPriority.push_back(Chunk);
				break;
			}
			case E_CHUNK_PRIORITY_MEDIUM:
			{
				m_SendChunksMediumPriority.push_back(Chunk);
				break;
			}
			case E_CHUNK_PRIORITY_HIGH:
			{
				m_SendChunksHighPriority.push_back(Chunk);
				break;
			}
		}
	}
	m_evtQueue.Set();
}





void cChunkSender::RemoveClient(cClientHandle * a_Client)
{
	{
		cCSLock Lock(m_CS);
		for (sSendChunkList::iterator itr = m_SendChunksLowPriority.begin(); itr != m_SendChunksLowPriority.end();)
		{
			if (itr->m_Client == a_Client)
			{
				itr = m_SendChunksLowPriority.erase(itr);
				continue;
			}
			++itr;
		}  // for itr - m_SendChunksLowPriority[]
		for (sSendChunkList::iterator itr = m_SendChunksMediumPriority.begin(); itr != m_SendChunksMediumPriority.end();)
		{
			if (itr->m_Client == a_Client)
			{
				itr = m_SendChunksMediumPriority.erase(itr);
				continue;
			}
			++itr;
		}  // for itr - m_SendChunksMediumPriority[]
		for (sSendChunkList::iterator itr = m_SendChunksHighPriority.begin(); itr != m_SendChunksHighPriority.end();)
		{
			if (itr->m_Client == a_Client)
			{
				itr = m_SendChunksHighPriority.erase(itr);
				continue;
			}
			++itr;
		}  // for itr - m_SendChunksHighPriority[]
		m_RemoveCount++;
	}
	m_evtQueue.Set();
	m_evtRemoved.Wait();  // Wait for removal confirmation
}





void cChunkSender::Execute(void)
{
	while (!m_ShouldTerminate)
	{
		cCSLock Lock(m_CS);
		while (m_ChunksReady.empty() && m_SendChunksLowPriority.empty() && m_SendChunksMediumPriority.empty() && m_SendChunksHighPriority.empty())
		{
			int RemoveCount = m_RemoveCount;
			m_RemoveCount = 0;
			cCSUnlock Unlock(Lock);
			for (int i = 0; i < RemoveCount; i++)
			{
				m_evtRemoved.Set();  // Notify that the removed clients are safe to be deleted
			}
			m_evtQueue.Wait();
			if (m_ShouldTerminate)
			{
				return;
			}
		}  // while (empty)

		if (!m_SendChunksHighPriority.empty())
		{
			// Take one from the queue:
			sSendChunk Chunk(m_SendChunksHighPriority.front());
			m_SendChunksHighPriority.pop_front();
			Lock.Unlock();

			SendChunk(Chunk.m_ChunkX, Chunk.m_ChunkZ, Chunk.m_Client);
		}
		else if (!m_ChunksReady.empty())
		{
			// Take one from the queue:
			cChunkCoords Coords(m_ChunksReady.front());
			m_ChunksReady.pop_front();
			Lock.Unlock();
			
			SendChunk(Coords.m_ChunkX, Coords.m_ChunkZ, nullptr);
		}
		else if (!m_SendChunksMediumPriority.empty())
		{
			// Take one from the queue:
			sSendChunk Chunk(m_SendChunksMediumPriority.front());
			m_SendChunksMediumPriority.pop_front();
			Lock.Unlock();

			SendChunk(Chunk.m_ChunkX, Chunk.m_ChunkZ, Chunk.m_Client);
		}
		else
		{
			// Take one from the queue:
			sSendChunk Chunk(m_SendChunksLowPriority.front());
			m_SendChunksLowPriority.pop_front();
			Lock.Unlock();

			SendChunk(Chunk.m_ChunkX, Chunk.m_ChunkZ, Chunk.m_Client);
		}
		Lock.Lock();
		int RemoveCount = m_RemoveCount;
		m_RemoveCount = 0;
		Lock.Unlock();
		for (int i = 0; i < RemoveCount; i++)
		{
			m_evtRemoved.Set();  // Notify that the removed clients are safe to be deleted
		}
	}  // while (!mShouldTerminate)
}





void cChunkSender::SendChunk(int a_ChunkX, int a_ChunkZ, cClientHandle * a_Client)
{
	ASSERT(m_World != nullptr);
	
	// Ask the client if it still wants the chunk:
	if ((a_Client != nullptr) && !a_Client->WantsSendChunk(a_ChunkX, a_ChunkZ))
	{
		return;
	}

	// If the chunk has no clients, no need to packetize it:
	if (!m_World->HasChunkAnyClients(a_ChunkX, a_ChunkZ))
	{
		return;
	}

	// If the chunk is not valid, do nothing - whoever needs it has queued it for loading / generating
	if (!m_World->IsChunkValid(a_ChunkX, a_ChunkZ))
	{
		return;
	}

	// If the chunk is not lighted, queue it for relighting and get notified when it's ready:
	if (!m_World->IsChunkLighted(a_ChunkX, a_ChunkZ))
	{
		m_World->QueueLightChunk(a_ChunkX, a_ChunkZ, &m_Notify);
		return;
	}

	// Query and prepare chunk data:
	if (!m_World->GetChunkData(a_ChunkX, a_ChunkZ, *this))
	{
		return;
	}
	cChunkDataSerializer Data(m_BlockTypes, m_BlockMetas, m_BlockLight, m_BlockSkyLight, m_BiomeMap);

	// Send:
	if (a_Client == nullptr)
	{
		m_World->BroadcastChunkData(a_ChunkX, a_ChunkZ, Data);
	}
	else
	{
		a_Client->SendChunkData(a_ChunkX, a_ChunkZ, Data);
	}

	// Send block-entity packets:
	for (sBlockCoords::iterator itr = m_BlockEntities.begin(); itr != m_BlockEntities.end(); ++itr)
	{
		if (a_Client == nullptr)
		{
			m_World->BroadcastBlockEntity(itr->m_BlockX, itr->m_BlockY, itr->m_BlockZ);
		}
		else
		{
			m_World->SendBlockEntity(itr->m_BlockX, itr->m_BlockY, itr->m_BlockZ, *a_Client);
		}
	}  // for itr - m_Packets[]
	m_BlockEntities.clear();

	// TODO: Send entity spawn packets
}





void cChunkSender::BlockEntity(cBlockEntity * a_Entity)
{
	m_BlockEntities.push_back(sBlockCoord(a_Entity->GetPosX(), a_Entity->GetPosY(), a_Entity->GetPosZ()));
}




void cChunkSender::Entity(cEntity *)
{
	// Nothing needed yet, perhaps in the future when we save entities into chunks we'd like to send them upon load, too ;)
}





void cChunkSender::BiomeData(const cChunkDef::BiomeMap * a_BiomeMap)
{
	for (size_t i = 0; i < ARRAYCOUNT(m_BiomeMap); i++)
	{
		if ((*a_BiomeMap)[i] < 255)
		{
			// Normal MC biome, copy as-is:
			m_BiomeMap[i] = (unsigned char)((*a_BiomeMap)[i]);
		}
		else
		{
			// TODO: MCS-specific biome, need to map to some basic MC biome:
			ASSERT(!"Unimplemented MCS-specific biome");
		}
	}  // for i - m_BiomeMap[]
}