Fred is dead. Everyone is dead. During one of your scavenging missions as the sole survivor of the nuclear apocalypse, you've found a worn out server with some unknown program on it. The barely legible label reads "Tic Tac Toe" - a meaningless phrase in a strange language.
After some preliminary testing you've figured out this server is running a game of sorts but needs a client to function. Using your expert python skills you set out to make the client.
After doing some analysis on the server binary, you've discovered that it is ran using the following syntax:
./tictacServer [PORT]
Where PORT is an optional command line argument specifying the port the server should bind to. If none is provided, it will default to 6969.
After being invoked, the server will wait and listen to incoming connections - it can only handle one client at a time. When a client connects, the transmission follows a client-server model. Using the implemented network protocol, the client sends requests and the server responds. The server handles keeping track of the game state and CPU opponent. Your client needs to handle its own main game loop and board rendering, requesting from the server where appropriate.
There is a lot of freedom in how your client functions but at minimum the features required are as follows:
The client is called as follows:
./python3 tictacClient.py
The server keeps track of the game state and handles the CPU opponent. To facilitate the game, the client sends packets in the form:
HEAD:BODY
Where HEAD is the four character header of the packet and BODY is the body of the packet. Note that some packets do not have a body. For these packets, the colon can be left off.
Below is a list of all the packets used in the protocol:
NEWG
This packet has no body and causes the server to initialize a new game board and randomly determine if the CPU or player moves first (is X). The reply is a BORD packet.
ENDG
This packet has no body and causes the server to end the current game and reset the board. The reply is an OVER packet with the body as: no winner and the current state of the board.
CLOS
This packet has no body and causes the server to close the connection to the client. The reply is a CLOS packet.
MOVE
This packet is sent to the server during an active game to signify the player has moved. The body is the coordinates of the move in the form of x,y. Ex. MOVE:1,1 places the player's move in the middle of the grid. The server handles error checking and will return an EROR packet if there is an error. If there is no error, the server will return either an OVER packet if the game is over or a BORD packet if the game is still ongoing.
BORD
This packet is sent to the client when the board has been updated (after a move or load). The body is nine comma separated integers indicating the board state. 0 is X, 1 is O and 2 means the space is empty. For example, BORD:2,2,2,2,0,2,2,2,2 means that X is in the middle space and the rest are empty.
LOAD
This packet is sent to the server to load a saved game. The user should provide a file name with the saved game as its contents before this packet is sent. The body of this packet is the character the player is (X or O) and nine comma separated integers representing the board state as above. For example: LOAD:X,0,1,0,2,1,2,1,2,1 loads a game board where the client is X. The reply is a BORD packet with the loaded game state.
EROR
This packet is sent by the server to indicate something went wrong. The body is the error message. UNKNOWN CMD is sent when the packet header sent by the client is unknown. BAD MOVE is sent when the MOVE packet contains an invalid move. NO GAME is sent when the client is trying to MOVE before a game has started.
OVER
This packet is sent by the server to indicate the game is over. The body contains the winner (if there is any) and the current state of the board. C means the client won the game, S means the server did and N means no one won. For example: OVER:C,0,0,0,1,1,2,2,2,2 is sent when the client won playing as X.
The client loads a configuration file on startup or if the option is selected from the main menu. The config file looks like the following:
[BASIC]
saveDir=/tmp/savedGames
score=/tmp/scores.txt
[NETWORKING]
serverIP=127.0.0.1
port=6969
[FILTER_SCORE]
scoreTimeFrom=Nov 10 07:00
scoreTimeTo=Nov 16 07:00
Where saveDir is the directory containing the saved games. score is the file containing the cumulative score. serverIP is the IP address of the machine running tictactoeServer and port is the destination port of the client. The fields in FILTER SCORE specify the time range that "Display score" counts. Your script needs to parse this file correctly and apply the options appropriately.