// Copyright (C) 2007 EQ2EMulator Development Team - GPL v3 License

#pragma once

#include <queue>
#include <map>
#include <vector>
#include <deque>
#include <string>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <chrono>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>

#include "log.hpp"
#include "timer.hpp"
#include "eq_stream.hpp"
#include "../packet/packet_dump.hpp"
#include "../opcodes/opcodes.hpp"
#include "../opcodes/opcode_manager.hpp"

#ifdef WORLD
	#include "../../WorldServer/client.h"
	extern ClientList client_list;
#endif

#define STREAM_TIMEOUT 45000

class EQStreamFactory
{
public:
	char* listen_ip_address;

	// Default constructor - initializes factory with stream type only
	EQStreamFactory(EQStreamType type)
	{
		ReaderRunning = false;
		WriterRunning = false;
		CombinePacketRunning = false;
		StreamType = type;
		Port = 0;
		sock = -1;
		listen_ip_address = nullptr;
	}

	// Constructor with port - initializes factory with stream type and port
	EQStreamFactory(EQStreamType type, int port)
	{
		StreamType = type;
		Port = port;
		listen_ip_address = nullptr;
		sock = -1;
		ReaderRunning = false;
		WriterRunning = false;
		CombinePacketRunning = false;
	}

	// Destructor - cleans up allocated resources
	~EQStreamFactory()
	{
		if (listen_ip_address) {
			delete[] listen_ip_address;
		}
	}

	// Retrieves the next available stream from the new streams queue
	EQStream* Pop()
	{
		if (!NewStreams.size())
			return nullptr;

		EQStream* s = nullptr;
		std::lock_guard<std::mutex> lock(MNewStreams);
		if (NewStreams.size()) {
			s = NewStreams.front();
			NewStreams.pop();
			s->PutInUse();
		}
		return s;
	}

	// Adds a new stream to the new streams queue
	void Push(EQStream* s)
	{
		std::lock_guard<std::mutex> lock(MNewStreams);
		NewStreams.push(s);
	}

	// Opens the socket and starts the reader/writer/combine packet threads
	bool Open()
	{
		struct sockaddr_in address;

		// Setup internet address information for bind() call
		memset(&address, 0, sizeof(address));
		address.sin_family = AF_INET;
		address.sin_port = htons(Port);

#if defined(LOGIN) || defined(MINILOGIN)
		if (listen_ip_address)
			address.sin_addr.s_addr = inet_addr(listen_ip_address);
		else
			address.sin_addr.s_addr = htonl(INADDR_ANY);
#else
		address.sin_addr.s_addr = htonl(INADDR_ANY);
#endif

		// Setup UDP socket for new clients
		sock = socket(AF_INET, SOCK_DGRAM, 0);
		if (sock < 0) {
			return false;
		}

		if (::bind(sock, (struct sockaddr*)&address, sizeof(address)) < 0) {
			sock = -1;
			return false;
		}

		// Set socket to non-blocking mode
		fcntl(sock, F_SETFL, O_NONBLOCK);

#ifdef LOGIN
		LogWrite(LOGIN__DEBUG, 0, "Login", "Starting factory Reader");
		LogWrite(LOGIN__DEBUG, 0, "Login", "Starting factory Writer");
#elif WORLD
		LogWrite(WORLD__DEBUG, 0, "World", "Starting factory Reader");
		LogWrite(WORLD__DEBUG, 0, "World", "Starting factory Writer");
#endif

		// Start threads for packet processing
		std::thread(&EQStreamFactory::ReaderLoop, this).detach();
		std::thread(&EQStreamFactory::WriterLoop, this).detach();
		std::thread(&EQStreamFactory::CombinePacketLoop, this).detach();

		return true;
	}

	// Opens with specified port override
	bool Open(unsigned long port)
	{
		Port = port;
		return Open();
	}

	// Closes the factory and cleans up all connections
	void Close()
	{
		CheckTimeout(true);
		Stop();
		if (sock != -1) {
			close(sock);
			sock = -1;
		}
	}

	// Main reader loop - processes incoming packets from clients
	void ReaderLoop()
	{
		fd_set readset;
		std::map<std::string, EQStream*>::iterator stream_itr;
		int num;
		int length;
		unsigned char buffer[2048];
		sockaddr_in from;
		socklen_t socklen = sizeof(sockaddr_in);
		timeval sleep_time;

		ReaderRunning = true;
		while (sock != -1) {
			{
				std::lock_guard<std::mutex> lock(MReaderRunning);
				if (!ReaderRunning)
					break;
			}

			FD_ZERO(&readset);
			FD_SET(sock, &readset);

			sleep_time.tv_sec = 30;
			sleep_time.tv_usec = 0;
			
			if ((num = select(sock + 1, &readset, nullptr, nullptr, &sleep_time)) < 0) {
				// Socket error occurred
			}
			else if (num == 0) {
				continue; // Timeout, no data available
			}

			if (FD_ISSET(sock, &readset)) {
				if ((length = recvfrom(sock, buffer, 2048, 0, (struct sockaddr*)&from, &socklen)) < 2) {
					// Invalid packet received
				}
				else {
					char temp[25];
					sprintf(temp, "%u.%d", ntohl(from.sin_addr.s_addr), ntohs(from.sin_port));
					
					std::lock_guard<std::mutex> streams_lock(MStreams);
					if ((stream_itr = Streams.find(temp)) == Streams.end() || buffer[1] == OP_SessionRequest) {
						// New session request or existing session requesting new connection
						if (buffer[1] == OP_SessionRequest) {
							if (stream_itr != Streams.end() && stream_itr->second)
								stream_itr->second->SetState(CLOSED);
							
							EQStream* s = new EQStream(from);
							s->SetFactory(this);
							s->SetStreamType(StreamType);
							Streams[temp] = s;
							WriterWork.notify_one();
							Push(s);
							s->Process(buffer, length);
							s->SetLastPacketTime(Timer::GetCurrentTime2());
						}
					}
					else {
						EQStream* curstream = stream_itr->second;
						// Don't process packets for closed connections
						if (curstream->CheckClosed()) {
							curstream = nullptr;
						}
						else {
							curstream->PutInUse();
						}
						
						if (curstream) {
							curstream->Process(buffer, length);
							curstream->SetLastPacketTime(Timer::GetCurrentTime2());
							curstream->ReleaseFromUse();
						}
					}
				}
			}
		}
	}

	// Checks for timed out connections and removes them
	void CheckTimeout(bool remove_all = false)
	{
		// Lock streams for the entire timeout check operation
		std::lock_guard<std::mutex> lock(MStreams);
		
		unsigned long now = Timer::GetCurrentTime2();
		std::map<std::string, EQStream*>::iterator stream_itr;
		
		for (stream_itr = Streams.begin(); stream_itr != Streams.end();) {
			EQStream* s = stream_itr->second;
			EQStreamState state = s->GetState();
			
			if (state == CLOSING && !s->HasOutgoingData()) {
				stream_itr->second->SetState(CLOSED);
				state = CLOSED;
			}
			else if (s->CheckTimeout(now, STREAM_TIMEOUT)) {
				const char* stateString;
				switch (state) {
				case ESTABLISHED:
					stateString = "Established";
					break;
				case CLOSING:
					stateString = "Closing";
					break;
				case CLOSED:
					stateString = "Closed";
					break;
				case WAIT_CLOSE:
					stateString = "Wait-Close";
					break;
				default:
					stateString = "Unknown";
					break;
				}
				LogWrite(WORLD__DEBUG, 0, "World", "Timeout up!, state=%s (%u)", stateString, state);
				
				if (state == ESTABLISHED) {
					s->Close();
				}
				else if (state == WAIT_CLOSE) {
					s->SetState(CLOSING);
					state = CLOSING;
				}
				else if (state == CLOSING) {
					// Timeout in closing state, force close
					s->SetState(CLOSED);
					state = CLOSED;
				}
			}
			
			// Check for closed connections to remove
			if (remove_all || state == CLOSED) {
				if (!remove_all && s->getTimeoutDelays() < 2) {
					s->addTimeoutDelay();
					// Give time for other threads to finish with stream
				}
				else {
					// Safe to delete the stream now
#ifdef LOGIN
					LogWrite(LOGIN__DEBUG, 0, "Login", "Removing connection...");
#else
					LogWrite(WORLD__DEBUG, 0, "World", "Removing connection...");
#endif
					std::map<std::string, EQStream*>::iterator temp = stream_itr;
					stream_itr++;
					
#ifdef WORLD
					client_list.RemoveConnection(temp->second);
#endif
					EQStream* stream = temp->second;
					Streams.erase(temp);
					delete stream;
					continue;
				}
			}
			stream_itr++;
		}
	}

	// Processes packet combining for streams that need it
	void CombinePacketLoop()
	{
		std::deque<EQStream*> combine_que;
		CombinePacketRunning = true;
		bool packets_waiting = false;
		
		while (sock != -1) {
			if (!CombinePacketRunning)
				break;
			
			{
				std::lock_guard<std::mutex> lock(MStreams);
				std::map<std::string, EQStream*>::iterator stream_itr;
				for (stream_itr = Streams.begin(); stream_itr != Streams.end(); stream_itr++) {
					if (!stream_itr->second) {
						continue;
					}
					if (stream_itr->second->combine_timer && stream_itr->second->combine_timer->Check())
						combine_que.push_back(stream_itr->second);
				}
			}
			
			EQStream* stream = nullptr;
			packets_waiting = false;
			while (combine_que.size()) {
				stream = combine_que.front();
				if (stream->CheckActive()) {
					if (!stream->CheckCombineQueue())
						packets_waiting = true;
				}
				combine_que.pop_front();
			}
			
			if (!packets_waiting)
				std::this_thread::sleep_for(std::chrono::milliseconds(25));
			
			std::this_thread::sleep_for(std::chrono::milliseconds(1));
		}
	}

	// Main writer loop - sends outgoing packets to clients
	void WriterLoop()
	{
		std::map<std::string, EQStream*>::iterator stream_itr;
		std::vector<EQStream*> wants_write;
		std::vector<EQStream*>::iterator cur, end;
		std::deque<EQStream*> resend_que;
		bool decay = false;
		uint32_t stream_count;
		
		Timer DecayTimer(20);
		
		WriterRunning = true;
		DecayTimer.Enable();
		
		while (sock != -1) {
			Timer::SetCurrentTime();
			
			{
				std::lock_guard<std::mutex> lock(MWriterRunning);
				if (!WriterRunning)
					break;
			}
			
			wants_write.clear();
			decay = DecayTimer.Check();
			
			// Copy streams into separate list to avoid keeping MStreams locked during writes
			{
				std::lock_guard<std::mutex> lock(MStreams);
				for (stream_itr = Streams.begin(); stream_itr != Streams.end(); stream_itr++) {
					if (!stream_itr->second) {
						Streams.erase(stream_itr);
						break;
					}
					
					// Decay bytes sent if timer expired
					if (decay)
						stream_itr->second->Decay();
					
					if (stream_itr->second->HasOutgoingData()) {
						stream_itr->second->PutInUse();
						wants_write.push_back(stream_itr->second);
					}
					
					if (stream_itr->second->resend_que_timer->Check())
						resend_que.push_back(stream_itr->second);
				}
			}
			
			// Perform actual packet writes
			cur = wants_write.begin();
			end = wants_write.end();
			for (; cur != end; cur++) {
				(*cur)->Write(sock);
				(*cur)->ReleaseFromUse();
			}
			
			// Process resend queue
			while (resend_que.size()) {
				resend_que.front()->CheckResend(sock);
				resend_que.pop_front();
			}
			
			std::this_thread::sleep_for(std::chrono::milliseconds(10));
			
			{
				std::lock_guard<std::mutex> lock(MStreams);
				stream_count = Streams.size();
			}
			
			if (!stream_count) {
				// No streams available, wait for work signal
				std::unique_lock<std::mutex> writer_lock(WriterWorkMutex);
				WriterWork.wait(writer_lock);
			}
		}
	}

	// Stops all factory operations
	void Stop()
	{
		StopReader();
		StopWriter();
		StopCombinePacket();
	}

	// Stops the reader thread
	void StopReader()
	{
		std::lock_guard<std::mutex> lock(MReaderRunning);
		ReaderRunning = false;
	}

	// Stops the writer thread
	void StopWriter()
	{
		{
			std::lock_guard<std::mutex> lock(MWriterRunning);
			WriterRunning = false;
		}
		WriterWork.notify_one();
	}

	// Stops the combine packet thread
	void StopCombinePacket()
	{
		std::lock_guard<std::mutex> lock(MCombinePacketRunning);
		CombinePacketRunning = false;
	}

	// Signals the writer thread that work is available
	void SignalWriter()
	{
		WriterWork.notify_one();
	}

private:
	int sock;									// Socket file descriptor
	int Port;									// Port number to listen on
	
	bool ReaderRunning;							// Reader thread running flag
	std::mutex MReaderRunning;					// Mutex for reader thread state
	bool WriterRunning;							// Writer thread running flag
	std::mutex MWriterRunning;					// Mutex for writer thread state
	bool CombinePacketRunning;					// Combine packet thread running flag
	std::mutex MCombinePacketRunning;			// Mutex for combine packet thread state
	
	std::condition_variable WriterWork;			// Condition variable for writer thread work signal
	std::mutex WriterWorkMutex;					// Mutex for writer work condition variable
	
	EQStreamType StreamType;					// Type of streams this factory creates
	
	std::queue<EQStream*> NewStreams;			// Queue of newly created streams
	std::mutex MNewStreams;						// Mutex for new streams queue
	
	std::map<std::string, EQStream*> Streams;	// Map of active streams by IP:Port
	std::mutex MStreams;						// Mutex for streams map
};