Andy Xiao (andyxiao)
Prachi Nawathe (nawathe)
Main Files: Server.hs, Client.hs, TUI.hs, Tests.hs
State is stored using TVar and a couple Maps. Messages are communicated between clients/threads using TChan. We make use of the STM monad to abstract IO logic away from state logic.
main creates a new connection socket to listen for new connections. It also initializes the state and starts the main loop connLoop.
connLoop listens for new connections on the connection socket. With each new connection, a new socket is created and a thread is spawned to handle back and forth requests on that socket (clientLoop).
clientLoop handles a single client connections. It spawns a thread to listen for new messages on the client's room/thread channel. On the main thread, it waits for new messages from the client and handles them by calling handleInput. Since some commands require responses, it then sends back some responses to the client.
handleInput handles a message from the client and updates the state accordingly + returns any responses in an STM [Response]. Commands are given with colon notation (for example :s newroom or :g).
This file mainly contains the network connection logic and then starts the brick app. The code for the brick app is in TUI.hs
main gets some user data, creates a connection socket to the server, and starts the brick terminal UI. It also spawns 2 threads: one to listen for messages from the server and then send them to the brick app event handler (through BChan) and another to periodically (every 5 seconds) send an event to tell the brick app to pull the newest room list.
State contains all the rooms, messages for the user's current room/thread, user name, a form for user input, and a socket connection to the server.
The draw functions create 3 main widgets: one to list all the rooms, one to list all of the messages, and one for the user to input messages.
The event handler can be broken up into 3 parts. First, keyboard events such as ESC to quit and Enter to send a message using the socket. Second, network listener events which can be either a clear screen event, update room list event, or a normal message event. Third, form events when the user types in the message input widget.
Since we ran into difficulty with abstracting all the pure functionality (since our state had TChan components requiring the STM monad), we created our own unit tests to check the state within the STM monad.
We used brick which also required the use of vty and microlens-platform. We also used the STM monad in stm.