Tic-tac-toe, noughts and crosses, or Xs and Os is a paper-and-pencil game for two players who take turns marking the spaces in a three-by-three grid with X or O. The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row is the winner. Wikipedia
Run mix deps.get to download all dependencies and mix compile to compile the application. Unit tests can be run with mix test and the module can also be used with iex -S mix with the following example:
iex> grid = [
...> %TicTacToe.Entities.Square{player: 1, x: 0, y: 0},
...> %TicTacToe.Entities.Square{player: 1, x: 0, y: 1},
...> %TicTacToe.Entities.Square{player: 1, x: 0, y: 2}]
iex> TicTacToe.GameEngine.winner(grid, 1)
true
To run the API simply use iex -S mix phx.server to start Phoenix. You can test the API with the following commands:
curl -X GET http://localhost:4000/api/game/new
This will return a GUID of the game in progress. To take a turn you can PUT like so:
curl -H 'Content-Type: application/json' -H 'Accept: application/json' -X PUT -d '{"x": 0,"y": 0,"player": 1}' http://localhost:4000/api/game/<GUID>
Once there is a winner it will be shown in the payload:
{"grid":[
{"player":1,"x":0,"y":0},{"player":null,"x":0,"y":1},{"player":null,"x":0,"y":2},{"player":1,"x":1,"y":0},{"player":null,"x":1,"y":1},{"player":null,"x":1,"y":2},{"player":1,"x":2,"y":0},{"player":null,"x":2,"y":1},{"player":null,"x":2,"y":2}],
"id":"84c7475e-ea58-11ec-b992-acde48001122",
"winner":1}
This module utilises GenServer to maintain a game of Tic-tac-toe for a process with OTP. Via this turns can be taken and retrieved for a player.
The beginning state in the GenServer is the Tic-tac-toe grid which is built with GridFactory.build() this grid is maintained for the process in GenServer. Each grid is represented by a square with an x and y co-ordinate as shown below:
The game engine is then able to calculate if there is a winner. It loops through the grid values and check for every possible winning combination for that player as shown in the image below:
