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._spectators = [];
  48     this.next_spectator_id = 1;
  49     this._players = [];
  50     this.next_player_id = 1;
  51     this.characters_to_reveal = null;
  52     this.clients = [];
  53     this.next_client_id = 1;
  54     this.state = GameState.JOIN;
  55
  56     /* Send a comment to every connected client every 15 seconds. */
  57     setInterval(() => {this.broadcast_string(":");}, 15000);
  58   }
  59
  60   add_spectator(name, session_id) {
  61     /* Don't add another spectator that matches an existing session. */
  62     const existing = this._spectators.findIndex(
  63       spectator => spectator.session_id === session_id);
  64     if (existing >= 0)
  65       return existing.id;
  66
  67     const new_spectator = {id: this.next_spectator_id,
  68                            name: name,
  69                            session_id: session_id
  70                           };
  71     this._spectators.push(new_spectator);
  72     this.next_spectator_id++;
  73     this.broadcast_event("spectator-join", JSON.stringify(new_spectator));
  74
  75     return new_spectator.id;
  76   }
  77
  78   remove_spectator(id) {
  79     const index = this._spectators.findIndex(spectator => spectator.id === id);
  80     this._spectators.splice(index, 1);
  81
  82     this.broadcast_event("spectator-leave", `{"id": ${id}}`);
  83   }
  84
  85   add_player(name, character) {
  86     const new_player = {id: this.next_player_id,
  87                        name: name,
  88                        character: character,
  89                        captures: [],
  90                        };
  91     this._players.push(new_player);
  92     this.next_player_id++;
  93     /* The syntax here is using an anonymous function to create a new
  94       object from new_player with just the subset of fields that we
  95       want. */
  96     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  97     this.broadcast_event("player-join", player_data);
  98   }
  99
 100   remove_player(id) {
 101     const index = this._players.findIndex(player => player.id === id);
 102     this._players.splice(index, 1);
 103
 104     this.broadcast_event("player-leave", `{"id": ${id}}`);
 105   }
 106
 107   reset() {
 108     this._players = [];
 109     this.characters_to_reveal = null;
 110     this.next_player_id = 1;
 111
 112     this.change_state(GameState.JOIN);
 113
 114     this.broadcast_event("spectators", "{}");
 115     this.broadcast_event("players", "{}");
 116   }
 117
 118   reveal_next() {
 119     /* Don't try to reveal anything if we aren't in the reveal state. */
 120     if (this.state != GameState.REVEAL) {
 121       clearInterval(this.reveal_interval);
 122       return;
 123     }
 124
 125     if (this.reveal_index >= this.characters_to_reveal.length) {
 126       clearInterval(this.reveal_interval);
 127       this.broadcast_event("character-reveal", '{"character":""}');
 128       return;
 129     }
 130     const character = this.characters_to_reveal[this.reveal_index];
 131     this.reveal_index++;
 132     const character_data = JSON.stringify({"character":character});
 133     this.broadcast_event("character-reveal", character_data);
 134   }
 135
 136   reveal() {
 137     this.change_state(GameState.REVEAL);
 138
 139     if (this.characters_to_reveal === null) {
 140       this.characters_to_reveal = [];
 141       this.characters_to_reveal = this._players.reduce((characters, player) => {
 142         characters.push(player.character);
 143         return characters;
 144       }, []);
 145       shuffle(this.characters_to_reveal);
 146     }
 147
 148     this.reveal_index = 0;
 149
 150     this.reveal_interval = setInterval(this.reveal_next.bind(this), 3000);
 151   }
 152
 153   start() {
 154     this.change_state(GameState.CAPTURE);
 155   }
 156
 157   capture(captor_id, captee_id) {
 158     /* TODO: Fix to fail on already-captured players (or to move the
 159      * captured player from an old captor to a new—need to clarify in
 160      * the API specification which we want here. */
 161     let captor = this._players.find(player => player.id === captor_id);
 162     captor.captures.push(captee_id);
 163
 164     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
 165   }
 166
 167   liberate(captee_id) {
 168     let captor = this._players.find(player => player.captures.includes(captee_id));
 169     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
 170   }
 171
 172   restart() {
 173     for (const player of this._players) {
 174       player.captures = [];
 175     }
 176   }
 177
 178   get characters() {
 179     return this._players.map(player => player.character);
 180   }
 181
 182   get empires() {
 183     return this._players.map(player => ({id: player.id, captures: player.captures}));
 184   }
 185
 186   get spectators() {
 187     /* We return only "id" and "name" here (specifically not session_id!). */
 188     return this._spectators.map(spectator => ({
 189       id: spectator.id,
 190       name: spectator.name
 191     }));
 192   }
 193
 194   get players() {
 195     return this._players.map(player => ({id: player.id, name: player.name }));
 196   }
 197
 198   add_client(response) {
 199     const id = this.next_client_id;
 200     this.clients.push({id: id,
 201                        response: response});
 202     this.next_client_id++;
 203
 204     return id;
 205   }
 206
 207   remove_client(id) {
 208     this.clients = this.clients.filter(client => client.id !== id);
 209   }
 210
 211   /* Send a string to all clients */
 212   broadcast_string(str) {
 213     this.clients.forEach(client => client.response.write(str + '\n'));
 214   }
 215
 216   /* Send an event to all clients.
 217    *
 218    * An event has both a declared type and a separate data block.
 219    * It also ends with two newlines (to mark the end of the event).
 220    */
 221   broadcast_event(type, data) {
 222     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
 223   }
 224
 225   game_state_event_data(old_state, new_state) {
 226     var old_state_name;
 227     if (old_state)
 228       old_state_name = GameState.properties[old_state].name;
 229     else
 230       old_state_name = "none";
 231     const new_state_name = GameState.properties[new_state].name;
 232
 233     return `{"old_state":"${old_state_name}","new_state":"${new_state_name}"}`;
 234   }
 235
 236   /* Inform clients about a state change. */
 237   broadcast_state_change() {
 238     const event_data = this.game_state_event_data(this.old_state, this.state);
 239     this.broadcast_event("game-state", event_data);
 240   }
 241
 242   /* Change game state and broadcast the change to all clients. */
 243   change_state(state) {
 244     /* Do nothing if there is no actual change happening. */
 245     if (state === this.state)
 246       return;
 247
 248     this.old_state = this.state;
 249     this.state = state;
 250
 251     this.broadcast_state_change();
 252   }
 253 }
 254
 255 function handle_events(request, response) {
 256   const game = request.game;
 257   /* These headers will keep the connection open so we can stream events. */
 258   const headers = {
 259     "Content-type": "text/event-stream",
 260     "Connection": "keep-alive",
 261     "Cache-Control": "no-cache"
 262   };
 263   response.writeHead(200, headers);
 264
 265   /* Now that a client has connected, first we need to stream all of
 266    * the existing spectators and players (if any). */
 267   if (game._spectators.length > 0) {
 268     const spectators_json = JSON.stringify(game.spectators);
 269     const spectators_data = `event: spectators\ndata: ${spectators_json}\n\n`;
 270     response.write(spectators_data);
 271   }
 272
 273   if (game._players.length > 0) {
 274     const players_json = JSON.stringify(game.players);
 275     const players_data = `event: players\ndata: ${players_json}\n\n`;
 276     response.write(players_data);
 277   }
 278
 279   /* And we need to inform the client of the current game state.
 280    *
 281    * In fact, we need to cycle through each state transition from the
 282    * beginning so the client can see each.
 283    */
 284   var old_state = null;
 285   for (var state = GameState.JOIN; state <= game.state; state++) {
 286     var event_data = game.game_state_event_data(old_state, state);
 287     response.write("event: game-state\n" + "data: " + event_data + "\n\n");
 288     old_state = state;
 289   }
 290
 291   /* Add this new client to our list of clients. */
 292   const id = game.add_client(response);
 293
 294   /* And queue up cleanup to be triggered on client close. */
 295   request.on('close', () => {
 296     game.remove_client(id);
 297   });
 298 }
 299
 300 app.get('/', (request, response) => {
 301   if (! request.session.nickname)
 302     response.render('choose-nickname.html', { game_name: "Empires" });
 303   else
 304     response.render('empires-game.html');
 305 });
 306
 307 app.post('/spectator', (request, response) => {
 308   const game = request.game;
 309   var name = request.session.nickname;
 310
 311   /* If the request includes a name, that overrides the session nickname. */
 312   if (request.body.name)
 313     name = request.body.name;
 314
 315   const id = game.add_spectator(name, request.session.id);
 316   response.send(JSON.stringify(id));
 317 });
 318
 319 app.delete('/spectator/:id', (request, response) => {
 320   const game = request.game;
 321   game.remove_spectator(parseInt(request.params.id));
 322   response.send();
 323 });
 324
 325 app.post('/register', (request, response) => {
 326   const game = request.game;
 327   var name = request.session.nickname;;
 328
 329   /* If the request includes a name, that overrides the session nickname. */
 330   if (request.body.name)
 331     name = request.body.name;
 332
 333   game.add_player(name, request.body.character);
 334   response.send();
 335 });
 336
 337 app.post('/deregister/:id', (request, response) => {
 338   const game = request.game;
 339   game.remove_player(parseInt(request.params.id));
 340   response.send();
 341 });
 342
 343 app.post('/reveal', (request, response) => {
 344   const game = request.game;
 345   game.reveal();
 346   response.send();
 347 });
 348
 349 app.post('/start', (request, response) => {
 350   const game = request.game;
 351   game.start();
 352   response.send();
 353 });
 354
 355 app.post('/reset', (request, response) => {
 356   const game = request.game;
 357   game.reset();
 358   response.send();
 359 });
 360
 361 app.post('/capture/:captor/:captee', (request, response) => {
 362   const game = request.game;
 363   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 364   response.send();
 365 });
 366
 367 app.post('/liberate/:id', (request, response) => {
 368   const game = request.game;
 369   game.liberate(parseInt(request.params.id));
 370   response.send();
 371 });
 372
 373 app.post('/restart', (request, response) => {
 374   const game = request.game;
 375   game.restart(parseInt(request.params.id));
 376     response.send();
 377 });
 378
 379 app.get('/characters', (request, response) => {
 380   const game = request.game;
 381   response.send(game.characters);
 382 });
 383
 384 app.get('/empires', (request, response) => {
 385   const game = request.game;
 386   response.send(game.empires);
 387 });
 388
 389 app.get('/spectators', (request, response) => {
 390   const game = request.game;
 391   response.send(game.spectators);
 392 });
 393
 394 app.get('/players', (request, response) => {
 395   const game = request.game;
 396   response.send(game.players);
 397 });
 398
 399 app.get('/events', handle_events);
 400
 401 exports.app = app;
 402 exports.Game = Game;