git.cworth.org Git - empires-server/blob - empires.js

   1 const express = require("express");
   2 const cors = require("cors");
   3 const body_parser = require("body-parser");
   4 const path = require("path");
   5 const nunjucks = require("nunjucks");
   6
   7 const app = express();
   8 app.use(cors());
   9 app.use(body_parser.urlencoded({ extended: false }));
  10 app.use(body_parser.json());
  11
  12 nunjucks.configure("templates", {
  13   autoescape: true,
  14   express: app
  15 });
  16
  17 const GameState = {
  18   JOIN:    1,
  19   REVEAL:  2,
  20   CAPTURE: 3,
  21   properties: {
  22     1: {name: "join"},
  23     2: {name: "reveal"},
  24     3: {name: "capture"}
  25   }
  26 };
  27
  28 /**
  29  * Shuffles array in place.
  30  * @param {Array} a items An array containing the items.
  31  */
  32 function shuffle(a) {
  33   if (a === undefined)
  34     return;
  35
  36   var j, x, i;
  37   for (i = a.length - 1; i > 0; i--) {
  38     j = Math.floor(Math.random() * (i + 1));
  39     x = a[i];
  40     a[i] = a[j];
  41     a[j] = x;
  42   }
  43 }
  44
  45 class Game {
  46   constructor() {
  47     this._players = [];
  48     this.characters_to_reveal = null;
  49     this.next_player_id = 1;
  50     this.clients = [];
  51     this.next_client_id = 1;
  52     this.state = GameState.JOIN;
  53
  54     /* Send a comment to every connected client every 15 seconds. */
  55     setInterval(() => {this.broadcast_string(":");}, 15000);
  56   }
  57
  58   add_player(name, character) {
  59     const new_player = {id: this.next_player_id,
  60                        name: name,
  61                        character: character,
  62                        captures: [],
  63                        };
  64     this._players.push(new_player);
  65     this.next_player_id++;
  66     /* The syntax here is using an anonymous function to create a new
  67       object from new_player with just the subset of fields that we
  68       want. */
  69     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  70     this.broadcast_event("player-join", player_data);
  71   }
  72
  73   remove_player(id) {
  74     const index = this._players.findIndex(player => player.id === id);
  75     this._players.splice(index, 1);
  76
  77     this.broadcast_event("player-leave", `{"id": ${id}}`);
  78   }
  79
  80   reset() {
  81     this._players = [];
  82     this.characters_to_reveal = null;
  83     this.next_player_id = 1;
  84
  85     this.change_state(GameState.JOIN);
  86
  87     this.broadcast_event("players", "{}");
  88   }
  89
  90   reveal_next() {
  91     /* Don't try to reveal anything if we aren't in the reveal state. */
  92     if (this.state != GameState.REVEAL) {
  93       clearInterval(this.reveal_interval);
  94       return;
  95     }
  96
  97     if (this.reveal_index >= this.characters_to_reveal.length) {
  98       clearInterval(this.reveal_interval);
  99       this.broadcast_event("character-reveal", '{"character":""}');
 100       return;
 101     }
 102     const character = this.characters_to_reveal[this.reveal_index];
 103     this.reveal_index++;
 104     const character_data = JSON.stringify({"character":character});
 105     this.broadcast_event("character-reveal", character_data);
 106   }
 107
 108   reveal() {
 109     this.change_state(GameState.REVEAL);
 110
 111     if (this.characters_to_reveal === null) {
 112       this.characters_to_reveal = [];
 113       this.characters_to_reveal = this._players.reduce((characters, player) => {
 114         characters.push(player.character);
 115         return characters;
 116       }, []);
 117       shuffle(this.characters_to_reveal);
 118     }
 119
 120     this.reveal_index = 0;
 121
 122     this.reveal_interval = setInterval(this.reveal_next.bind(this), 3000);
 123   }
 124
 125   start() {
 126     this.change_state(GameState.CAPTURE);
 127   }
 128
 129   capture(captor_id, captee_id) {
 130     /* TODO: Fix to fail on already-captured players (or to move the
 131      * captured player from an old captor to a new—need to clarify in
 132      * the API specification which we want here. */
 133     let captor = this._players.find(player => player.id === captor_id);
 134     captor.captures.push(captee_id);
 135
 136     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
 137   }
 138
 139   liberate(captee_id) {
 140     let captor = this._players.find(player => player.captures.includes(captee_id));
 141     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
 142   }
 143
 144   restart() {
 145     for (const player of this._players) {
 146       player.captures = [];
 147     }
 148   }
 149
 150   get characters() {
 151     return this._players.map(player => player.character);
 152   }
 153
 154   get empires() {
 155     return this._players.map(player => ({id: player.id, captures: player.captures}));
 156   }
 157
 158   get players() {
 159     return this._players.map(player => ({id: player.id, name: player.name }));
 160   }
 161
 162   add_client(response) {
 163     const id = this.next_client_id;
 164     this.clients.push({id: id,
 165                        response: response});
 166     this.next_client_id++;
 167
 168     return id;
 169   }
 170
 171   remove_client(id) {
 172     this.clients = this.clients.filter(client => client.id !== id);
 173   }
 174
 175   /* Send a string to all clients */
 176   broadcast_string(str) {
 177     this.clients.forEach(client => client.response.write(str + '\n'));
 178   }
 179
 180   /* Send an event to all clients.
 181    *
 182    * An event has both a declared type and a separate data block.
 183    * It also ends with two newlines (to mark the end of the event).
 184    */
 185   broadcast_event(type, data) {
 186     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
 187   }
 188
 189   game_state_event_data(old_state, new_state) {
 190     var old_state_name;
 191     if (old_state)
 192       old_state_name = GameState.properties[old_state].name;
 193     else
 194       old_state_name = "none";
 195     const new_state_name = GameState.properties[new_state].name;
 196
 197     return `{"old_state":"${old_state_name}","new_state":"${new_state_name}"}`;
 198   }
 199
 200   /* Inform clients about a state change. */
 201   broadcast_state_change() {
 202     const event_data = this.game_state_event_data(this.old_state, this.state);
 203     this.broadcast_event("game-state", event_data);
 204   }
 205
 206   /* Change game state and broadcast the change to all clients. */
 207   change_state(state) {
 208     /* Do nothing if there is no actual change happening. */
 209     if (state === this.state)
 210       return;
 211
 212     this.old_state = this.state;
 213     this.state = state;
 214
 215     this.broadcast_state_change();
 216   }
 217 }
 218
 219 function handle_events(request, response) {
 220   const game = request.game;
 221   /* These headers will keep the connection open so we can stream events. */
 222   const headers = {
 223     "Content-type": "text/event-stream",
 224     "Connection": "keep-alive",
 225     "Cache-Control": "no-cache"
 226   };
 227   response.writeHead(200, headers);
 228
 229   /* Now that a client has connected, first we need to stream all of
 230    * the existing players (if any). */
 231   if (game._players.length > 0) {
 232     const players_json = JSON.stringify(game.players);
 233     const players_data = `event: players\ndata: ${players_json}\n\n`;
 234     response.write(players_data);
 235   }
 236
 237   /* And we need to inform the client of the current game state.
 238    *
 239    * In fact, we need to cycle through each state transition from the
 240    * beginning so the client can see each.
 241    */
 242   var old_state = null;
 243   for (var state = GameState.JOIN; state <= game.state; state++) {
 244     var event_data = game.game_state_event_data(old_state, state);
 245     response.write("event: game-state\n" + "data: " + event_data + "\n\n");
 246     old_state = state;
 247   }
 248
 249   /* Add this new client to our list of clients. */
 250   const id = game.add_client(response);
 251
 252   /* And queue up cleanup to be triggered on client close. */
 253   request.on('close', () => {
 254     game.remove_client(id);
 255   });
 256 }
 257
 258 app.get('/', (request, response) => {
 259   if (! request.session.nickname)
 260     response.render('choose-nickname.html');
 261   else
 262     response.sendFile(path.join(__dirname, './game.html'));
 263 });
 264
 265 app.post('/register', (request, response) => {
 266   const game = request.game;
 267   var name = request.session.nickname;;
 268
 269   /* If the request includes a name, that overrides the session nickname. */
 270   if (request.body.name)
 271     name = request.body.name;
 272
 273   game.add_player(name, request.body.character);
 274   response.send();
 275 });
 276
 277 app.post('/deregister/:id', (request, response) => {
 278   const game = request.game;
 279   game.remove_player(parseInt(request.params.id));
 280   response.send();
 281 });
 282
 283 app.post('/reveal', (request, response) => {
 284   const game = request.game;
 285   game.reveal();
 286   response.send();
 287 });
 288
 289 app.post('/start', (request, response) => {
 290   const game = request.game;
 291   game.start();
 292   response.send();
 293 });
 294
 295 app.post('/reset', (request, response) => {
 296   const game = request.game;
 297   game.reset();
 298   response.send();
 299 });
 300
 301 app.post('/capture/:captor/:captee', (request, response) => {
 302   const game = request.game;
 303   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 304   response.send();
 305 });
 306
 307 app.post('/liberate/:id', (request, response) => {
 308   const game = request.game;
 309   game.liberate(parseInt(request.params.id));
 310   response.send();
 311 });
 312
 313 app.post('/restart', (request, response) => {
 314   const game = request.game;
 315   game.restart(parseInt(request.params.id));
 316     response.send();
 317 });
 318
 319 app.get('/characters', (request, response) => {
 320   const game = request.game;
 321   response.send(game.characters);
 322 });
 323
 324 app.get('/empires', (request, response) => {
 325   const game = request.game;
 326   response.send(game.empires);
 327 });
 328
 329 app.get('/players', (request, response) => {
 330   const game = request.game;
 331   response.send(game.players);
 332 });
 333
 334 app.get('/events', handle_events);
 335
 336 exports.app = app;
 337 exports.Game = Game;