/*
 *
 * (C) 2003-2020 Anope Team
 * Contact us at team@anope.org
 *
 * Please read COPYING and README for further details.
 *
 * Based on the original code of Epona by Lara.
 * Based on the original code of Services by Andy Church.
 */

#ifndef SOCKETS_H
#define SOCKETS_H

#ifndef _WIN32
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#endif

#include "anope.h"

#define NET_BUFSIZE 65535

/** A sockaddr union used to combine IPv4 and IPv6 sockaddrs
 */
union CoreExport sockaddrs
{
	sockaddr sa;
	sockaddr_in sa4;
	sockaddr_in6 sa6;

	/** Construct the object, sets everything to 0
	 */
	sockaddrs(const Anope::string &address = "");

	/** Memset the object to 0
	 */
	void clear();

	/** Get address family.
	 */
	int family() const;

	/** Get the size of the sockaddr we represent
	 * @return The size
	 */
	size_t size() const;

	/** Get the port represented by this addr
	 * @return The port, or -1 on fail
	 */
	int port() const;

	/** Get the address represented by this addr
	 * @return The address
	 */
	Anope::string addr() const;

	/** Get the reverse address represented by this addr
	 * @return The reverse address
	 */
	Anope::string reverse() const;

	/* Is this address ipv6? */
	bool ipv6() const;

	/** Check if this sockaddr has data in it
	 */
	bool valid() const;

	/** Compares with sockaddr with another. Compares address type, port, and address
	 * @return true if they are the same
	 */
	bool operator==(const sockaddrs &other) const;
	/* The same as above but not */
	inline bool operator!=(const sockaddrs &other) const { return !(*this == other); }

	/** The equivalent of inet_pton
	 * @param type AF_INET or AF_INET6
	 * @param address The address to place in the sockaddr structures
	 * @param pport An option port to include in the  sockaddr structures
	 * @throws A socket exception if given invalid IPs
	 */
	void pton(int type, const Anope::string &address, int pport = 0);

	/** The equivalent of inet_ntop
	 * @param type AF_INET or AF_INET6
	 * @param address The in_addr or in_addr6 structure
	 * @throws A socket exception if given an invalid structure
	 */
	void ntop(int type, const void *src);
};

class CoreExport cidr
{
	sockaddrs addr;
	Anope::string cidr_ip;
	unsigned short cidr_len;
 public:
	cidr(const Anope::string &ip);
	cidr(const Anope::string &ip, unsigned char len);
	cidr(const sockaddrs &ip, unsigned char len);
	Anope::string mask() const;
	bool match(const sockaddrs &other);
	bool valid() const;

	bool operator<(const cidr &other) const;
	bool operator==(const cidr &other) const;
	bool operator!=(const cidr &other) const;

	struct CoreExport hash
	{
		size_t operator()(const cidr &s) const;
	};
};

class SocketException : public CoreException
{
 public:
	/** Constructor for socket exceptions
	 * @param message Error message
	 */
	SocketException(const Anope::string &message) : CoreException(message) { }

	/** Destructor
	 * @throws Nothing
	 */
	virtual ~SocketException() throw() { }
};

enum SocketFlag
{
	SF_DEAD = 1,
	SF_READABLE,
	SF_WRITABLE,
	SF_CONNECTING,
	SF_CONNECTED,
	SF_ACCEPTING,
	SF_ACCEPTED,
	SF_SIZE
};

class CoreExport SocketIO
{
 public:
	virtual ~SocketIO() { }

	/** Receive something from the buffer
	 * @param s The socket
	 * @param buf The buf to read to
	 * @param sz How much to read
	 * @return Number of bytes received
	 */
	virtual int Recv(Socket *s, char *buf, size_t sz);

	/** Write something to the socket
	 * @param s The socket
	 * @param buf The data to write
	 * @param size The length of the data
	 */
	virtual int Send(Socket *s, const char *buf, size_t sz);
	int Send(Socket *s, const Anope::string &buf);

	/** Accept a connection from a socket
	 * @param s The socket
	 * @return The new socket
	 */
	virtual ClientSocket *Accept(ListenSocket *s);

	/** Finished accepting a connection from a socket
	 * @param s The socket
	 * @return SF_ACCEPTED if accepted, SF_ACCEPTING if still in process, SF_DEAD on error
	 */
	virtual SocketFlag FinishAccept(ClientSocket *cs);

	/** Bind a socket
	 * @param s The socket
	 * @param ip The IP to bind to
	 * @param port The optional port to bind to
	 */
	virtual void Bind(Socket *s, const Anope::string &ip, int port = 0);

	/** Connect the socket
	 * @param s The socket
	 * @param target IP to connect to
	 * @param port to connect to
	 */
	virtual void Connect(ConnectionSocket *s, const Anope::string &target, int port);

	/** Called to potentially finish a pending connection
	 * @param s The socket
	 * @return SF_CONNECTED on success, SF_CONNECTING if still pending, and SF_DEAD on error.
	 */
	virtual SocketFlag FinishConnect(ConnectionSocket *s);

	/** Called when the socket is destructing
	 */
	virtual void Destroy() { }
};

class CoreExport Socket
{
 protected:
	/* Socket FD */
	int sock;
	/* Is this an IPv6 socket? */
	bool ipv6;

 public:
	std::bitset<SF_SIZE> flags;

	/* Sockaddrs for bind() (if it's bound) */
	sockaddrs bindaddr;

	/* I/O functions used for this socket */
	SocketIO *io;

	/** Empty constructor, should not be called.
	 */
	Socket();

	/** Constructor, possibly creates the socket and adds it to the engine
	 * @param sock The socket to use, -1 if we need to create our own
	 * @param ipv6 true if using ipv6
	 * @param type The socket type, defaults to SOCK_STREAM
	 */
	Socket(int sock, bool ipv6 = false, int type = SOCK_STREAM);

	/** Destructor, closes the socket and removes it from the engine
	 */
	virtual ~Socket();

	/** Get the socket FD for this socket
	 * @return the fd
	 */
	int GetFD() const;

	/** Check if this socket is IPv6
	 * @return true or false
	 */
	bool IsIPv6() const;

	/** Mark a socket as (non)blocking
	 * @param state true to enable blocking, false to disable blocking
	 * @return true if the socket is now blocking
	 */
	bool SetBlocking(bool state);

	/** Bind the socket to an ip and port
	 * @param ip The ip
	 * @param port The port
	 */
	void Bind(const Anope::string &ip, int port = 0);

	/** Called when there either is a read or write event.
	 * @return true to continue to call ProcessRead/ProcessWrite, false to not continue
	 */
	virtual bool Process();

	/** Called when there is something to be received for this socket
	 * @return true on success, false to drop this socket
	 */
	virtual bool ProcessRead();

	/** Called when the socket is ready to be written to
	 * @return true on success, false to drop this socket
	 */
	virtual bool ProcessWrite();

	/** Called when there is an error for this socket
	 * @return true on success, false to drop this socket
	 */
	virtual void ProcessError();
};

class CoreExport BufferedSocket : public virtual Socket
{
 protected:
	/* Things read from the socket */
	Anope::string read_buffer;
	/* Things to be written to the socket */
	Anope::string write_buffer;
	/* How much data was received from this socket on this recv() */
	int recv_len;

 public:
	BufferedSocket();
	virtual ~BufferedSocket();

	/** Called when there is something to be received for this socket
	 * @return true on success, false to drop this socket
	 */
	bool ProcessRead() anope_override;

	/** Called when the socket is ready to be written to
	 * @return true on success, false to drop this socket
	 */
	bool ProcessWrite() anope_override;

	/** Gets the new line from the input buffer, if any
	 */
	const Anope::string GetLine();

	/** Write to the socket
	* @param message The message
	*/
 protected:
	virtual void Write(const char *buffer, size_t l);
 public:
	void Write(const char *message, ...);
	void Write(const Anope::string &message);

	/** Get the length of the read buffer
	 * @return The length of the read buffer
	 */
	int ReadBufferLen() const;

	/** Get the length of the write buffer
	 * @return The length of the write buffer
	 */
	int WriteBufferLen() const;
};

class CoreExport BinarySocket : public virtual Socket
{
 protected:
	struct DataBlock
	{
		char *orig;
		char *buf;
		size_t len;

		DataBlock(const char *b, size_t l);
		~DataBlock();
	};

	/* Data to be written out */
	std::deque<DataBlock *> write_buffer;

 public:
	BinarySocket();
	virtual ~BinarySocket();

	/** Called when there is something to be received for this socket
	 * @return true on success, false to drop this socket
	 */
	bool ProcessRead() anope_override;

	/** Called when the socket is ready to be written to
	 * @return true on success, false to drop this socket
	 */
	bool ProcessWrite() anope_override;

	/** Write data to the socket
	 * @param buffer The data to write
	 * @param l The length of the data; if 0 then this function returns without doing anything
	 */
	virtual void Write(const char *buffer, size_t l);
	void Write(const char *message, ...);
	void Write(const Anope::string &message);

	/** Called with data from the socket
	 * @param buffer The data
	 * @param l The length of buffer
	 * @return true to continue reading, false to drop the socket
	 */
	virtual bool Read(const char *buffer, size_t l);
};

class CoreExport ListenSocket : public virtual Socket
{
 public:
	/** Constructor
	 * @param bindip The IP to bind to
	 * @param port The port to listen on
	 * @param ipv6 true for ipv6
	 */
	ListenSocket(const Anope::string &bindip, int port, bool ipv6);
	virtual ~ListenSocket();

	/** Process what has come in from the connection
	 * @return false to destroy this socket
	 */
	bool ProcessRead();

	/** Called when a connection is accepted
	 * @param fd The FD for the new connection
	 * @param addr The sockaddr for where the connection came from
	 * @return The new socket
	 */
	virtual ClientSocket *OnAccept(int fd, const sockaddrs &addr) = 0;
};

class CoreExport ConnectionSocket : public virtual Socket
{
 public:
	/* Sockaddrs for connection ip/port */
	sockaddrs conaddr;

	/** Connect the socket
	 * @param TargetHost The target host to connect to
	 * @param Port The target port to connect to
	 */
	void Connect(const Anope::string &TargetHost, int Port);

	/** Called when there either is a read or write event.
	 * Used to determine whether or not this socket is connected yet.
	 * @return true to continue to call ProcessRead/ProcessWrite, false to not continue
	 */
	bool Process() anope_override;

	/** Called when there is an error for this socket
	 * @return true on success, false to drop this socket
	 */
	void ProcessError() anope_override;

	/** Called on a successful connect
	 */
	virtual void OnConnect();

	/** Called when a connection is not successful
	 * @param error The error
	 */
	virtual void OnError(const Anope::string &error);
};

class CoreExport ClientSocket : public virtual Socket
{
 public:
	/* Listen socket this connection came from */
	ListenSocket *ls;
	/* Clients address */
	sockaddrs clientaddr;

	/** Constructor
	 * @param ls Listen socket this connection is from
	 * @param addr Address the connection came from
	 */
	ClientSocket(ListenSocket *ls, const sockaddrs &addr);

	/** Called when there either is a read or write event.
	 * Used to determine whether or not this socket is connected yet.
	 * @return true to continue to call ProcessRead/ProcessWrite, false to not continue
	 */
	bool Process() anope_override;

	/** Called when there is an error for this socket
	 * @return true on success, false to drop this socket
	 */
	void ProcessError() anope_override;

	/** Called when a client has been accepted() successfully.
	 */
	virtual void OnAccept();

	/** Called when there was an error accepting the client
	 */
	virtual void OnError(const Anope::string &error);
};

class CoreExport Pipe : public Socket
{
 public:
	/** The FD of the write pipe
	 * this->sock is the readfd
	 */
	int write_pipe;

	Pipe();
	~Pipe();

	/** Called when data is to be read, reads the data then calls OnNotify
	 */
	bool ProcessRead() anope_override;

	/** Write data to this pipe
	 * @param data The data to write
	 * @param sz The amount of data to wirite
	 */
	void Write(const char *data, size_t sz);
	inline void Write(const Anope::string &data) { this->Write(data.c_str(), data.length() + 1); }

	/** Read data from this pipe
	 * @param data A buffer to read data into
	 * @param sz The size of the buffer
	 * @return The amount of data read
	 */
	int Read(char *data, size_t sz);

	/** Mark the write end of this pipe (non)blocking
	 * @param state true to enable blocking, false to disable blocking
	 * @return true if the socket is now blocking
	 */
	bool SetWriteBlocking(bool state);

	/** Called when this pipe needs to be woken up
	 * Is the same as Write("\0", 1)
	 */
	void Notify();

	/** Called after ProcessRead comes back from Notify(), overload to do something useful
	 */
	virtual void OnNotify() = 0;
};

extern CoreExport uint32_t TotalRead;
extern CoreExport uint32_t TotalWritten;
extern CoreExport SocketIO NormalSocketIO;

#endif // SOCKET_H
