/*
 * Copyright (c) 2008-2021 Jonathan Schleifer <js@nil.im>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#import "OFObject.h"
#import "OFKernelEventObserver.h"
#import "OFRunLoop.h"
#import "OFSocket.h"

OF_ASSUME_NONNULL_BEGIN

/** @file */

@class OFData;
@class OFSequencedPacketSocket;

#ifdef OF_HAVE_BLOCKS
/**
 * @brief A block which is called when a packet has been received.
 *
 * @param length The length of the packet
 * @param exception An exception which occurred while receiving or `nil` on
 *		    success
 * @return A bool whether the same block should be used for the next receive
 */
typedef bool (^OFSequencedPacketSocketAsyncReceiveBlock)(size_t length,
    id _Nullable exception);

/**
 * @brief A block which is called when a packet has been sent.
 *
 * @param data The data which was sent
 * @param exception An exception which occurred while reading or `nil` on
 *		    success
 * @return The data to repeat the send with or nil if it should not repeat
 */
typedef OFData *_Nullable (^OFSequencedPacketSocketAsyncSendDataBlock)(
    OFData *_Nonnull data, id _Nullable exception);

/**
 * @brief A block which is called when the socket accepted a connection.
 *
 * @param acceptedSocket The socket which has been accepted
 * @param exception An exception which occurred while accepting the socket or
 *		    `nil` on success
 * @return A bool whether the same block should be used for the next incoming
 *	   connection
 */
typedef bool (^OFSequencedPacketSocketAsyncAcceptBlock)(
    OFSequencedPacketSocket *acceptedSocket, id _Nullable exception);
#endif

/**
 * @protocol OFSequencedPacketSocketDelegate OFSequencedPacketSocket.h \
 *	     ObjFW/OFSequencedPacketSocket.h
 *
 * @brief A delegate for OFSequencedPacketSocket.
 */
@protocol OFSequencedPacketSocketDelegate <OFObject>
@optional
/**
 * @brief This method is called when a packet has been received.
 *
 * @param socket The sequenced packet socket which received a packet
 * @param buffer The buffer the packet has been written to
 * @param length The length of the packet
 * @param exception An exception that occurred while receiving, or nil on
 *		    success
 * @return A bool whether the same block should be used for the next receive
 */
-	  (bool)socket: (OFSequencedPacketSocket *)socket
  didReceiveIntoBuffer: (void *)buffer
		length: (size_t)length
	     exception: (nullable id)exception;

/**
 * @brief This method is called when a packet has been sent.
 *
 * @param socket The sequenced packet socket which sent a packet
 * @param data The data which was sent
 * @param exception An exception that occurred while sending, or nil on success
 * @return The data to repeat the send with or nil if it should not repeat
 */
- (nullable OFData *)socket: (OFSequencedPacketSocket *)socket
		didSendData: (OFData *)data
		  exception: (nullable id)exception;

/**
 * @brief A method which is called when a socket accepted a connection.
 *
 * @param socket The socket which accepted the connection
 * @param acceptedSocket The socket which has been accepted
 * @param exception An exception that occurred while accepting, or nil on
 *		    success
 * @return A bool whether to accept the next incoming connection
 */
-    (bool)socket: (OFSequencedPacketSocket *)socket
  didAcceptSocket: (OFSequencedPacketSocket *)acceptedSocket
	exception: (nullable id)exception;
@end

/**
 * @class OFSequencedPacketSocket OFSequencedPacketSocket.h \
 *	  ObjFW/OFSequencedPacketSocket.h
 *
 * @brief A base class for sequenced packet sockets.
 *
 * @warning Even though the OFCopying protocol is implemented, it does *not*
 *	    return an independent copy of the socket, but instead retains it.
 *	    This is so that the socket can be used as a key for a dictionary,
 *	    so context can be associated with a socket. Using a socket in more
 *	    than one thread at the same time is not thread-safe, even if copy
 *	    was called to create one "instance" for every thread!
 */
@interface OFSequencedPacketSocket: OFObject <OFCopying,
    OFReadyForReadingObserving, OFReadyForWritingObserving>
{
	OFSocketHandle _socket;
	bool _canBlock, _listening;
	OFSocketAddress _remoteAddress;
	id _Nullable _delegate;
	OF_RESERVE_IVARS(OFSequencedPacketSocket, 4)
}

/**
 * @brief Whether the socket can block.
 *
 * By default, a socket can block.
 */
@property (nonatomic) bool canBlock;

/**
 * @brief Whether the socket is a listening socket.
 */
@property (readonly, nonatomic, getter=isListening) bool listening;

/**
 * @brief The remote address.
 *
 * @note This only works for accepted sockets!
 */
@property (readonly, nonatomic) const OFSocketAddress *remoteAddress;

/**
 * @brief The delegate for asynchronous operations on the socket.
 *
 * @note The delegate is retained for as long as asynchronous operations are
 *	 still ongoing.
 */
@property OF_NULLABLE_PROPERTY (assign, nonatomic)
    id <OFSequencedPacketSocketDelegate> delegate;

/**
 * @brief Returns a new, autoreleased OFSequencedPacketSocket.
 *
 * @return A new, autoreleased OFSequencedPacketSocket
 */
+ (instancetype)socket;

/**
 * @brief Receives a packet and stores it into the specified buffer.
 *
 * If the buffer is too small, the receive operation fails.
 *
 * @param buffer The buffer to write the packet to
 * @param length The length of the buffer
 * @return The length of the received packet
 */
- (size_t)receiveIntoBuffer: (void *)buffer length: (size_t)length;

/**
 * @brief Asynchronously receives a packet and stores it into the specified
 *	  buffer.
 *
 * If the buffer is too small, the receive operation fails.
 *
 * @param buffer The buffer to write the packet to
 * @param length The length of the buffer
 */
- (void)asyncReceiveIntoBuffer: (void *)buffer length: (size_t)length;

/**
 * @brief Asynchronously receives a packet and stores it into the specified
 *	  buffer.
 *
 * If the buffer is too small, the receive operation fails.
 *
 * @param buffer The buffer to write the packet to
 * @param length The length of the buffer
 * @param runLoopMode The run loop mode in which to perform the async receive
 */
- (void)asyncReceiveIntoBuffer: (void *)buffer
			length: (size_t)length
		   runLoopMode: (OFRunLoopMode)runLoopMode;

#ifdef OF_HAVE_BLOCKS
/**
 * @brief Asynchronously receives a packet and stores it into the specified
 *	  buffer.
 *
 * If the buffer is too small, the receive operation fails.
 *
 * @param buffer The buffer to write the packet to
 * @param length The length of the buffer
 * @param block The block to call when the packet has been received. If the
 *		block returns true, it will be called again with the same
 *		buffer and maximum length when more packets have been received.
 *		If you want the next method in the queue to handle the packet
 *		received next, you need to return false from the method.
 */
- (void)asyncReceiveIntoBuffer: (void *)buffer
			length: (size_t)length
			 block: (OFSequencedPacketSocketAsyncReceiveBlock)block;

/**
 * @brief Asynchronously receives a packet and stores it into the specified
 *	  buffer.
 *
 * If the buffer is too small, the receive operation fails.
 *
 * @param buffer The buffer to write the packet to
 * @param length The length of the buffer
 * @param runLoopMode The run loop mode in which to perform the async receive
 * @param block The block to call when the packet has been received. If the
 *		block returns true, it will be called again with the same
 *		buffer and maximum length when more packets have been received.
 *		If you want the next method in the queue to handle the packet
 *		received next, you need to return false from the method.
 */
- (void)asyncReceiveIntoBuffer: (void *)buffer
			length: (size_t)length
		   runLoopMode: (OFRunLoopMode)runLoopMode
			 block: (OFSequencedPacketSocketAsyncReceiveBlock)block;
#endif

/**
 * @brief Sends the specified packet.
 *
 * @param buffer The buffer to send as a packet
 * @param length The length of the buffer
 */
- (void)sendBuffer: (const void *)buffer length: (size_t)length;

/**
 * @brief Asynchronously sends the specified packet.
 *
 * @param data The data to send as a packet
 */
- (void)asyncSendData: (OFData *)data;

/**
 * @brief Asynchronously sends the specified packet.
 *
 * @param data The data to send as a packet
 * @param runLoopMode The run loop mode in which to perform the async send
 */
- (void)asyncSendData: (OFData *)data runLoopMode: (OFRunLoopMode)runLoopMode;

#ifdef OF_HAVE_BLOCKS
/**
 * @brief Asynchronously sends the specified packet.
 *
 * @param data The data to send as a packet
 * @param block The block to call when the packet has been sent. It should
 *		return the data for the next send with the same callback or nil
 *		if it should not repeat.
 */
- (void)asyncSendData: (OFData *)data
		block: (OFSequencedPacketSocketAsyncSendDataBlock)block;

/**
 * @brief Asynchronously sends the specified packet.
 *
 * @param data The data to send as a packet
 * @param runLoopMode The run loop mode in which to perform the async send
 * @param block The block to call when the packet has been sent. It should
 *		return the data for the next send with the same callback or nil
 *		if it should not repeat.
 */
- (void)asyncSendData: (OFData *)data
	  runLoopMode: (OFRunLoopMode)runLoopMode
		block: (OFSequencedPacketSocketAsyncSendDataBlock)block;
#endif

/**
 * @brief Listen on the socket.
 *
 * @param backlog Maximum length for the queue of pending connections.
 */
- (void)listenWithBacklog: (int)backlog;

/**
 * @brief Listen on the socket.
 */
- (void)listen;

/**
 * @brief Accept an incoming connection.
 *
 * @return An autoreleased sequenced packet socket for the accepted connection.
 */
- (instancetype)accept;

/**
 * @brief Asynchronously accept an incoming connection.
 */
- (void)asyncAccept;

/**
 * @brief Asynchronously accept an incoming connection.
 *
 * @param runLoopMode The run loop mode in which to perform the async accept
 */
- (void)asyncAcceptWithRunLoopMode: (OFRunLoopMode)runLoopMode;

#ifdef OF_HAVE_BLOCKS
/**
 * @brief Asynchronously accept an incoming connection.
 *
 * @param block The block to execute when a new connection has been accepted.
 *		Returns whether the next incoming connection should be accepted
 *		by the specified block as well.
 */
- (void)asyncAcceptWithBlock: (OFSequencedPacketSocketAsyncAcceptBlock)block;

/**
 * @brief Asynchronously accept an incoming connection.
 *
 * @param runLoopMode The run loop mode in which to perform the async accept
 * @param block The block to execute when a new connection has been accepted.
 *		Returns whether the next incoming connection should be accepted
 *		by the specified block as well.
 */
- (void)
    asyncAcceptWithRunLoopMode: (OFRunLoopMode)runLoopMode
			 block: (OFSequencedPacketSocketAsyncAcceptBlock)block;
#endif

/**
 * @brief Cancels all pending asynchronous requests on the socket.
 */
- (void)cancelAsyncRequests;

/**
 * @brief Closes the socket so that it can neither receive nor send any more
 *	  datagrams.
 */
- (void)close;
@end

OF_ASSUME_NONNULL_END
