// TCPLinkImpl.h

// Declares the cTCPLinkImpl class implementing the TCP link functionality

// This is an internal header, no-one outside OSSupport should need to include it; use Network.h instead





#pragma once

#include "Network.h"
#include <event2/event.h>
#include <event2/bufferevent.h>





// fwd:
class cServerHandleImpl;
typedef SharedPtr<cServerHandleImpl> cServerHandleImplPtr;
class cTCPLinkImpl;
typedef SharedPtr<cTCPLinkImpl> cTCPLinkImplPtr;
typedef std::vector<cTCPLinkImplPtr> cTCPLinkImplPtrs;





class cTCPLinkImpl:
	public cTCPLink
{
	typedef cTCPLink super;

public:
	/** Creates a new link based on the given socket.
	Used for connections accepted in a server using cNetwork::Listen().
	a_Address and a_AddrLen describe the remote peer that has connected.
	The link is created disabled, you need to call Enable() to start the regular communication. */
	cTCPLinkImpl(evutil_socket_t a_Socket, cCallbacksPtr a_LinkCallbacks, cServerHandleImplPtr a_Server, const sockaddr * a_Address, socklen_t a_AddrLen);

	/** Destroys the LibEvent handle representing the link. */
	~cTCPLinkImpl();

	/** Queues a connection request to the specified host.
	a_ConnectCallbacks must be valid.
	Returns a link that has the connection request queued, or NULL for failure. */
	static cTCPLinkImplPtr Connect(const AString & a_Host, UInt16 a_Port, cTCPLink::cCallbacksPtr a_LinkCallbacks, cNetwork::cConnectCallbacksPtr a_ConnectCallbacks);

	/** Enables communication over the link.
	Links are created with communication disabled, so that creation callbacks can be called first.
	This function then enables the regular communication to be reported.
	The a_Self parameter is used so that the socket can keep itself alive as long as the callbacks are coming. */
	void Enable(cTCPLinkImplPtr a_Self);

	// cTCPLink overrides:
	virtual bool Send(const void * a_Data, size_t a_Length) override;
	virtual AString GetLocalIP(void) const override { return m_LocalIP; }
	virtual UInt16 GetLocalPort(void) const override { return m_LocalPort; }
	virtual AString GetRemoteIP(void) const override { return m_RemoteIP; }
	virtual UInt16 GetRemotePort(void) const override { return m_RemotePort; }
	virtual void Shutdown(void) override;
	virtual void Close(void) override;

protected:

	/** Callbacks to call when the connection is established.
	May be NULL if not used. Only used for outgoing connections (cNetwork::Connect()). */
	cNetwork::cConnectCallbacksPtr m_ConnectCallbacks;

	/** The LibEvent handle representing this connection. */
	bufferevent * m_BufferEvent;

	/** The server handle that has created this link.
	Only valid for incoming connections, nullptr for outgoing connections. */
	cServerHandleImplPtr m_Server;

	/** The IP address of the local endpoint. Valid only after the socket has been connected. */
	AString m_LocalIP;

	/** The port of the local endpoint. Valid only after the socket has been connected. */
	UInt16 m_LocalPort;

	/** The IP address of the remote endpoint. Valid only after the socket has been connected. */
	AString m_RemoteIP;

	/** The port of the remote endpoint. Valid only after the socket has been connected. */
	UInt16 m_RemotePort;

	/** SharedPtr to self, used to keep this object alive as long as the callbacks are coming.
	Initialized in Enable(), cleared in Close() and EventCallback(RemoteClosed). */
	cTCPLinkImplPtr m_Self;


	/** Creates a new link to be queued to connect to a specified host:port.
	Used for outgoing connections created using cNetwork::Connect().
	To be used only by the Connect() factory function.
	The link is created disabled, you need to call Enable() to start the regular communication. */
	cTCPLinkImpl(const cCallbacksPtr a_LinkCallbacks);

	/** Callback that LibEvent calls when there's data available from the remote peer. */
	static void ReadCallback(bufferevent * a_BufferEvent, void * a_Self);

	/** Callback that LibEvent calls when there's a non-data-related event on the socket. */
	static void EventCallback(bufferevent * a_BufferEvent, short a_What, void * a_Self);

	/** Sets a_IP and a_Port to values read from a_Address, based on the correct address family. */
	static void UpdateAddress(const sockaddr * a_Address, socklen_t a_AddrLen, AString & a_IP, UInt16 & a_Port);

	/** Updates m_LocalIP and m_LocalPort based on the metadata read from the socket. */
	void UpdateLocalAddress(void);

	/** Updates m_RemoteIP and m_RemotePort based on the metadata read from the socket. */
	void UpdateRemoteAddress(void);
};