Overview

Current networking sucks, this PR aims to completely redesign and rewrite the entire networking component of the game.
This includes:

• Server module
  • Almost everything will be brand new, 90% of the original classes will be deleted
• Client module
  • We will now use Netty even on the client instead of a custom pure socket solution.
• Shared module
  • Many of the classes will be used across both server and client so the shared module will get a lot bigger.

New network communication system

• Currently using TCP sockets with SSL encryption and Gzip compression with binary messages.
  • Entire Java objects are being sent and received
  • This should make this really efficient in terms of traffic (not that it even mattered that much)
  • Possible to use different backends like WebSockets/HTTP/UDP without that much of a rewrite
• Compared to old messages (or packets), current ones are much more sparse, I have managed to remove a lot of useless messages or merge them into existing ones, which helps with the responsiveness of the client (It had to wait on soo many messages).
• Build on top of Netty 4.1

Implementation

• PacketReceiveHandler is the main listener for all packets received. The packet is routed to the listener based on a header and each listener can specify which packet it accepts.
• Multiple PacketReceiveHandler are grouped together into HandlerGroup, which can be used to register/deregister multiple listeners. This enables me to create logical "phases" e.g ClientInitialization, LobbySelect, Game etc. each with their own group that is registered/deregistered when the Client enters the phase.

How much is currently implemented

• Basic network core
• Ping keep-alive system
  • Just to check if the sockets are still live
• Only ClientIntialization is done, meaning up to the screen with choosing Game Type (Single, Multi, Dual).
• Disconnect is not handled properly yet.
• Should be usable through maven:exec goal as before

Removed features

• Reconnecting - I found out there is a reconnecting feature, but decided to not implement it yet
• Number of player thread - apparently there was a running thread on the client which asked every few seconds for a number of players in lobbies (WTF, WHY?). The functionality of this is going to be incorporated into the network communication.

TODO

• Finish the redesign to be at least able to play a multiplayer game.
• Fix tests
• Write new network tests
• Add JavaDocs (I should really do this one)
• Create a Sequence diagram to visualize how the network communication works and what messages does it send.

@PhilippvK If you have any questions or suggestions, feel free to comment.
Fixes #99, #70, #93, #69, #63