# Copyright, 2017, by Samuel G. D. Williams. <http://www.codeotaku.com>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

require_relative 'socket'
require_relative 'stream'
require 'fcntl'

module Async
	module IO
		# Asynchronous TCP socket wrapper.
		class TCPSocket < IPSocket
			wraps ::TCPSocket
			
			class StreamWrapper
				def initialize(io)
					@io = io
				end
				
				def sync= value
					@io.sync = value
				end
				
				def close
					@io.close
				end
				
				def read(*args)
					@io.sysread(*args)
				end
				
				def write(*args)
					@io.syswrite(*args)
				end
				
				def flush
					@io.flush
				end
			end
			
			def initialize(remote_host, remote_port = nil, local_host = nil, local_port = nil)
				if remote_host.is_a? ::TCPSocket
					super(remote_host)
				else
					remote_address = Addrinfo.tcp(remote_host, remote_port)
					local_address = Addrinfo.tcp(local_host, local_port) if local_host
					
					# We do this unusual dance to avoid leaking an "open" socket instance.
					socket = Socket.connect(remote_address, local_address)
					fd = socket.fcntl(Fcntl::F_DUPFD)
					Async.logger.debug(self) {"Connected to #{remote_address.inspect}: #{fd}"}
					socket.close
					
					super(::TCPSocket.for_fd(fd))
					
					# The equivalent blocking operation. Unfortunately there is no trivial way to make this non-blocking.
					# super(::TCPSocket.new(remote_host, remote_port, local_host, local_port))
				end
				
				@buffer = Stream.new(StreamWrapper.new(self))
			end
			
			class << self
				alias open new
			end
			
			include Peer
			
			attr :buffer
			
			def_delegators :@buffer, :gets, :puts, :flush
			
			def write(*)
				@buffer.flush
				
				super
			end
			
			def read(size)
				@buffer.read_partial(size)
			end
		end
		
		# Asynchronous TCP server wrappper.
		class TCPServer < TCPSocket
			wraps ::TCPServer, :listen
			
			def initialize(*args)
				if args.first.is_a? ::TCPServer
					super(args.first)
				else
					# We assume this operation doesn't block (for long):
					super(::TCPServer.new(*args))
				end
			end
			
			def accept(task: Task.current)
				peer, address = async_send(:accept_nonblock)
				
				wrapper = TCPSocket.new(peer)
				
				return wrapper, address unless block_given?
				
				begin
					yield wrapper, address
				ensure
					wrapper.close
				end
			end
			
			alias accept_nonblock accept
			alias sysaccept accept
			
			include Server
		end
	end
end