#+TITLE: Remote Snake API

#+OPTIONS: toc:nil
#+LATEX_HEADER: \usepackage{fullpage}

* General Description
  - All transmissions will be based on UDP since latency is important
  - All UDP datagrams between *client and server* will contain _plain json data_
  - All data should be sent in *one* datagram
  - All utf-8 characters in UDP datagram are in lower case
* Communications 
** Initialisation
   1. Client sent:
      #+BEGIN_SRC json
        {
            "type": "new-game"
        }
      #+END_SRC
   2. Server can reply:
      #+BEGIN_SRC json
        {
            "type": "state",
            "game-id": 1,
            "game-over": false,
            "snake": [[1,2],[1,3]],
            "food": [[6,7]]
        }  
      #+END_SRC
** Gameplay
*** Change Direction
    1. When client is playing a game, it can ask the server to change snake direction:
       #+BEGIN_SRC json
         {
             "type": "update",
             "game-id": 1,
             "direction": "left",
         }
       #+END_SRC
    2. Then, server can reply:
       #+BEGIN_SRC json
         {
             "type": "state",
             "game-id": 1,
             "game-over": false,
             "snake": [[0,2],[1,2]],
             "food": [[6,7]]
         }  
       #+END_SRC
*** Refresh Screen
    1. When no key are pressed (the snake is simply going forward). So, client can send:
       #+BEGIN_SRC json
         {
             "type": "update",
             "game-id": 1,
             "direction": null
         }
       #+END_SRC
    2. Server can reply:
       #+BEGIN_SRC json
         {
             "type": "state",
             "game-id": 1,
             "game-over": false,
             "snake": [[1,2],[0,2]],
             "food": [[6,7]]
         }  
       #+END_SRC
*** End Game
    - When game is over, server will send the following state message (switch "game-over" to true):
       #+BEGIN_SRC json
         {
             "type": "state",
             "game-id": 1,
             "game-over": true,
             "snake": [[0,2],[1,2]],
             "food": [[6,7]]
         }  
       #+END_SRC
    - No reply is expected from the client and server will be in charge to free local memory.