require "option_parser"
require "ipc"
require "socket"
require "./colors"

require "json"

require "socket"
require "http/server"
require "base64"
require "digest"
require "./utils"

# All modifications to standard libraries go there.
require "./lib_modifications.cr"

class CLI
	# service instance parameters
	# they can be changed via the cli
	class_property service_name   : String = "websocket"
	class_property host           : String = "0.0.0.0"
	class_property port_to_listen : UInt16 = 1234
	class_property timer_delay    : Int32  = 30_000  # 30 seconds
	class_property verbosity      : Int32  = 1
end

OptionParser.parse do |parser|
	parser.on "-l host", "--l host", "IP address to listen on." do |h|
		CLI.host = h
	end

	parser.on "-p port", "--port port", "Port to listen on." do |port|
		CLI.port_to_listen = port.to_u16
	end

	parser.on "-s service-name", "--service-name service-name", "Service name." do |name|
		CLI.service_name = name
	end

	parser.on "-t timer-delay", "--timer-delay timer-delay", "Timer delay (in seconds)" do |t|
		CLI.timer_delay = t.to_i32 * 1000 # stored in ms
	end

	parser.on "-v verbosity-level", "--verbosity level", "Verbosity." do |opt|
		CLI.verbosity = opt.to_i
	end

	parser.on "-h", "--help", "Show this help" do
		puts parser
		exit 0
	end
end

def sending_ping_messages
	puts "sending ping messages"
end

# def sending_ping_messages(context : InstanceStorage)
# 	context.fd_to_websocket.each do |fd, ws|
# 		begin
# 			ws.ping "hello from #{fd}"
# 		rescue e
# 			puts "#{CRED}Exception: #{e}#{CRESET}, already closed client #{fd}"
# 			begin
# 				context.remove_fd fd
# 			rescue e
# 				puts "#{CRED}Cannot remove #{fd} from clients: #{e}#{CRESET}"
# 			end
# 		end
# 	end
# end

# def closing_client (fdclient : Int, context : InstanceStorage)
# 	context.remove_fd fdclient
# end

def ws_http_upgrade(client)
	request = HTTP::Request.from_io client

	if request.nil?
		raise "#REQUEST IS NIL"
	end

	if request.is_a? HTTP::Status && request == HTTP::Status::BAD_REQUEST
		raise "BAD REQUEST DAZE~"
	end

	if request.is_a? HTTP::Status
		raise "Not bad request but still pretty bad: #{request.to_s}"
	end

	# FIXME: check they actually wanted to upgrade to websocket
	key = request.headers["Sec-WebSocket-Key"]
	response_key = Digest::SHA1.base64digest key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
	# puts response_key

	# HTTP inside bru
	headers_header = "HTTP/1.1 101 Switching Protocols"
	headers = HTTP::Headers {
		"Upgrade" => "websocket",
		"Connection" => "Upgrade",
		"Sec-WebSocket-Accept" => response_key
	}

	headers = headers.map { |key, value| "#{key}: #{value[0]}\r\n" }.join

	# requested service, fd
	req_service = request.path.lchop
	if req_service.empty?
		puts "closing the client"
		client.close
	end

	return req_service
end

def other_function(client, req_service, context : InstanceStorage)
	# The client may ask to transcript JSON-based messages into IPC messages.
	# To that end, the client may send the name of the service it wants to reach with the prefix ".JSON".

	if req_service.ends_with? ".JSON"
		context.is_json[client.fd] = true
		req_service = req_service.gsub /.JSON$/, ""
	else
		context.is_json[client.fd] = false
	end

	websocket_connection_procedure req_service, client.fd, context

	# TODO: if trackerd, send the IP address of the client
	if req_service == "tracker"
		puts "tracker - sending the IP address"
		puts "connection from #{client.remote_address}"
		sfd = context.switchtable[client.fd]
		# message = IPC::Message.from_json(JSON).to_packet
		# => JSON has to include these attributes: mtype, utype, payload
		# message = IPC::Message.new mtype, utype, payload
		remote_address = client.remote_address.address
		message = IPC::Message.new 1, 1.to_u8, "{\"ipaddress\": \"#{remote_address}\"}"
		serv = WrappedTCPFileDescriptor.new(fd: sfd, family: Socket::Family::INET)
		serv.send message.to_packet
	end

	# puts "#{headers_header}\n#{headers.to_s}\r\n"
	client.send "#{headers_header}\n#{headers.to_s}\r\n"

	wsclient = WebSocket.new client
	wsclient.on_pong do |m|
		puts "pong #{m}"
	end
	context.is_client[client.fd] = true

	# listen to the client's file descriptor
	context.service << client.fd
	# puts "#{CBLUE}new client: #{client.fd}#{CRESET}"

	# registering the client into storing structures to avoid being garbage collected
	context.fd_to_tcpsocket[client.fd] = client
	context.fd_to_websocket[client.fd] = wsclient
end

# def websocket_switching_procedure (activefd : Int, context : InstanceStorage)
# 	begin
# 		if context.is_client[activefd]
# 			# The client is a WebSocket on top of a TCP connection
# 			client = context.fd_to_tcpsocket[activefd]
# 			wsclient = context.fd_to_websocket[activefd]
# 			loop do
# 				begin
# 					message = wsclient.run_once
# 				rescue e
# 					puts "#{CRED}Exception (receiving a message)#{CRESET} #{e}"
# 					context.remove_fd activefd
# 					return
# 				end
# 
# 				# Checking the internals of WebSocket, then the contained IO within, to know if there is still something to read in the socket.
# 				still_something_to_read = ! wsclient.ws.io.empty?
# 
# 				if wsclient.closed?
# 					# puts "#{CBLUE}client is closed#{CRESET}"
# 					context.remove_fd client.fd
# 					return
# 				end
# 
# 				if message.nil?
# 					puts "#{CRED}message is nil#{CRESET}"
# 					context.remove_fd client.fd
# 					return
# 				end
# 
# 				case message
# 				when WebSocket::Error
# 					puts "#{CRED}An error occured#{CRESET}"
# 					context.remove_fd client.fd
# 					return
# 				when WebSocket::Ping
# 					# puts "#{CBLUE}Received a ping message#{CRESET}"
# 					next if still_something_to_read
# 					break
# 				when WebSocket::Pong
# 					# puts "#{CBLUE}Received a pong message#{CRESET}"
# 					next if still_something_to_read
# 					break
# 				when WebSocket::Close
# 					# puts "#{CBLUE}Received a close message#{CRESET}"
# 					context.remove_fd client.fd
# 					return
# 				when WebSocket::NotFinal
# 					# puts "#{CBLUE}Received only part of a message#{CRESET}"
# 					next if still_something_to_read
# 					break
# 				when Bytes
# 					# TODO: when receiving a binary message
# 					# we should test the format and maybe its content
# 					# puts "#{CBLUE}Received a binary message#{CRESET}"
# 				end
# 
# 				if context.is_json[activefd] && message.is_a?(String)
# 					message = IPC::Message.from_json(message).to_packet
# 				end
# 
# 				# client => service
# 				fdservice = context.switchtable[activefd]
# 
# 				# XXX: this is not a TCP fd, but since behind the scene this is compatible, I'm hacking a bit
# 				# Also, I changed the "finalize" method of the TCPFileDescriptor class not to close the socket
# 				# when the object is GC.
# 				serv = WrappedTCPFileDescriptor.new(fd: fdservice, family: Socket::Family::INET)
# 				#serv = context.fd_to_ipcconnection[fdservice]
# 				serv.send message
# 
# 				break unless still_something_to_read
# 
# 			end # loop over the remaining messages to read on the websocket
# 		else
# 			# service => client
# 			fdclient = context.switchtable[activefd]
# 			wsclient = context.fd_to_websocket[fdclient]
# 
# 			serv = context.fd_to_ipcconnection[activefd]
# 			message = serv.read
# 
# 			if context.is_json[fdclient]
# 				buf = message.to_json
# 			else
# 				buf = message.to_packet
# 			end
# 
# 			wsclient.send buf
# 		end
# 	rescue e
# 		puts "#{CRED}Exception during message transfer:#{CRESET} #{e}"
# 		if context.is_client[activefd]
# 			closing_client activefd, context
# 		else
# 			clientfd = context.switchtable[activefd]
# 			closing_client clientfd, context
# 		end
# 	end
# end

# # first message from the client: requested service name
# # 1. connection to the service
# # 2. listening on the service fd
# # 3. bounding both file descriptors (through switchtable hash)
# # 4. indicating that the client is connected (in is_client)
# def websocket_connection_procedure (requested_service : String, clientfd : Int32, context : InstanceStorage)
# 	begin
# 		# 2. establishing a connection to the service
# 		newservice = IPC::Connection.new requested_service
# 		context.fd_to_ipcconnection[newservice.fd] = newservice
# 
# 		# 3. listening on the client fd and the service fd
# 		context.service << newservice.fd
# 
# 		# cannot perform automatic switching due to websockets headers
# 		# future version of the libipc lib should include some workaround, probably
# 		# service.switch.add fdclient, newservice.fd
# 
# 		# 4. bounding the client and the service fd
# 		context.switchtable[clientfd] = newservice.fd
# 		context.switchtable[newservice.fd] = clientfd
# 
# 		# 5. the client is then connected, send it a message
# 		context.is_client[clientfd] = true
# 		context.is_client[newservice.fd] = false
# 	rescue e
# 		puts "#{CRED}Exception during connection to the service:#{CRESET} #{e}"
# 		context.remove_fd clientfd
# 	end
# end

def handle_new_clients(service, server)
	# TODO: this is a lot of C-like notation, should be changed.
	# In the client accept function
	#   1. accept TCP/WS connection
	client = server.accept

	#   2. upgrade HTTP connections and get the service name in the URI path.
	req_service = ws_http_upgrade client

	puts "requested service: #{req_service}"
	unless client.nil?
		client.not_nil!.close
	end

	#   3. connect to the service via ipc_connection_switched
	LibIPC.ipc_connection_switched service.pointer, req_service
	puts "ipc_connection_switched: OK"

	#   4. add client fd in the context, type = switched via ipc_ctx_fd_type
	service << client.fd
	service.pp
	LibIPC.ipc_ctx_fd_type service.pointer, client.fd, LibIPC::ConnectionType::Switched
	puts "ipc_ctx_fd_type: OK"

	#   5. add both fd in switched via ipc_switching_add
	switchdb = service.context.switchdb
	LibIPC.ipc_switching_add pointerof(switchdb),
		client.fd,
		service.context.pollfd[service.context.size - 1].fd
	puts "ipc_switching_add: OK"

	proc_cb_in  = ->my_cb_in(Int32, Pointer(LibIPC::Message))
	proc_cb_out = ->my_cb_out(Int32, Pointer(LibIPC::Message))

	#   6. change client callbacks via ipc_switching_callbacks
	#      only the client callbacks are changed, since the associated server is a simple libipc service
	LibIPC.ipc_switching_callbacks service.pointer, client.fd,
		proc_cb_in,
		proc_cb_out
	puts "ipc_switching_callbacks: OK"

	puts "#{CBLUE}new client:#{CRESET} #{client.fd}" unless CLI.verbosity == 0
rescue e
	puts "Exception: #{CRED}#{e}#{CRESET}"
	unless client.nil?
		client.not_nil!.close
	end
end

def my_cb_out(fd : Int32, pm : Pointer(LibIPC::Message))
	puts "OUT fd is #{fd}"
	return LibIPC::IPCCB::NoError
end

def my_cb_in(fd : Int32, pm : Pointer(LibIPC::Message))
	puts "IN fd is #{fd}"
	return LibIPC::IPCCB::NoError
end


def main
	# by default, listen on any IP address
	server  = TCPServer.new(CLI.host, CLI.port_to_listen)
	service = IPC::Server.new CLI.service_name
	service << server.fd
	# Every few seconds, the service should trigger the timer
	# Allowing the sending of Ping messages to clients
	service.base_timer = CLI.timer_delay
	service.timer      = CLI.timer_delay

	# context = InstanceStorage.new service

	service.loop do |event|
		puts "current state of the context:"
		service.pp
		case event
		when IPC::Event::Timer
			if CLI.verbosity > 0
				puts "#{CORANGE}IPC::Event::Timer#{CRESET}"
			end
			sending_ping_messages # context
		when IPC::Event::Connection
			if CLI.verbosity > 0
				puts "#{CBLUE}IPC::Event::Connection#{CRESET}: #{event.fd}"
			end
		when IPC::Event::Disconnection
			if CLI.verbosity > 0
				puts "#{CBLUE}IPC::Event::Disconnection#{CRESET}: #{event.fd}"
			end
		when IPC::Event::ExtraSocket
			if CLI.verbosity > 0
				puts "#{CBLUE}IPC::Event::ExtraSocket#{CRESET}: #{event.fd}"
			end

			if server.fd != event.fd
				raise "Error: the only extra socket should be the TCP/WS server"
			end

			handle_new_clients(service, server)

		when IPC::Event::Switch
			if CLI.verbosity > 0
				puts "\033[36mIPC::Event::Switch#{CRESET}: from fd #{event.fd}"
			end

			raise "Not implemented."

		when IPC::Event::MessageSent
			if CLI.verbosity > 0
				puts "Message sent, for #{event.fd}"
			end

		when IPC::Event::MessageReceived
			if CLI.verbosity > 0
				puts "#{CBLUE}IPC::Event::Message#{CRESET}: #{event.fd}"
			end

			raise "Not implemented."
		end
	end
end

main