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

   1 const express = require("express");
   2 const Game = require("./game.js");
   3
   4 const engine_name = "empires";
   5
   6 const router = express.Router();
   7
   8 const GameState = {
   9   JOIN:    1,
  10   REVEAL:  2,
  11   CAPTURE: 3,
  12   properties: {
  13     1: {name: "join"},
  14     2: {name: "reveal"},
  15     3: {name: "capture"}
  16   }
  17 };
  18
  19 /**
  20  * Shuffles array in place.
  21  * @param {Array} a items An array containing the items.
  22  */
  23 function shuffle(a) {
  24   if (a === undefined)
  25     return;
  26
  27   var j, x, i;
  28   for (i = a.length - 1; i > 0; i--) {
  29     j = Math.floor(Math.random() * (i + 1));
  30     x = a[i];
  31     a[i] = a[j];
  32     a[j] = x;
  33   }
  34 }
  35
  36 class Empires extends Game {
  37   constructor() {
  38     super(engine_name);
  39     this._spectators = [];
  40     this.next_spectator_id = 1;
  41     this._players = [];
  42     this.next_player_id = 1;
  43     this.characters_to_reveal = null;
  44     this.state = GameState.JOIN;
  45
  46     /* Send a comment to every connected client every 15 seconds. */
  47     setInterval(() => {this.broadcast_string(":");}, 15000);
  48   }
  49
  50   add_spectator(name, session_id) {
  51     /* Don't add another spectator that matches an existing session. */
  52     const existing = this._spectators.findIndex(
  53       spectator => spectator.session_id === session_id);
  54     if (existing >= 0)
  55       return existing.id;
  56
  57     const new_spectator = {id: this.next_spectator_id,
  58                            name: name,
  59                            session_id: session_id
  60                           };
  61     this._spectators.push(new_spectator);
  62     this.next_spectator_id++;
  63     this.broadcast_event("spectator-join", JSON.stringify(new_spectator));
  64
  65     return new_spectator.id;
  66   }
  67
  68   remove_spectator(id) {
  69     const index = this._spectators.findIndex(spectator => spectator.id === id);
  70     this._spectators.splice(index, 1);
  71
  72     this.broadcast_event("spectator-leave", `{"id": ${id}}`);
  73   }
  74
  75   add_player(name, character) {
  76     const new_player = {id: this.next_player_id,
  77                        name: name,
  78                        character: character,
  79                        captures: [],
  80                        };
  81     this._players.push(new_player);
  82     this.next_player_id++;
  83     /* The syntax here is using an anonymous function to create a new
  84       object from new_player with just the subset of fields that we
  85       want. */
  86     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  87     this.broadcast_event("player-join", player_data);
  88   }
  89
  90   remove_player(id) {
  91     const index = this._players.findIndex(player => player.id === id);
  92     this._players.splice(index, 1);
  93
  94     this.broadcast_event("player-leave", `{"id": ${id}}`);
  95   }
  96
  97   reset() {
  98     this._players = [];
  99     this.characters_to_reveal = null;
 100     this.next_player_id = 1;
 101
 102     this.change_state(GameState.JOIN);
 103
 104     this.broadcast_event("spectators", "{}");
 105     this.broadcast_event("players", "{}");
 106   }
 107
 108   reveal_next() {
 109     /* Don't try to reveal anything if we aren't in the reveal state. */
 110     if (this.state != GameState.REVEAL) {
 111       clearInterval(this.reveal_interval);
 112       return;
 113     }
 114
 115     if (this.reveal_index >= this.characters_to_reveal.length) {
 116       clearInterval(this.reveal_interval);
 117       this.broadcast_event("character-reveal", '{"character":""}');
 118       return;
 119     }
 120     const character = this.characters_to_reveal[this.reveal_index];
 121     this.reveal_index++;
 122     const character_data = JSON.stringify({"character":character});
 123     this.broadcast_event("character-reveal", character_data);
 124   }
 125
 126   reveal() {
 127     this.change_state(GameState.REVEAL);
 128
 129     if (this.characters_to_reveal === null) {
 130       this.characters_to_reveal = [];
 131       this.characters_to_reveal = this._players.reduce((characters, player) => {
 132         characters.push(player.character);
 133         return characters;
 134       }, []);
 135       shuffle(this.characters_to_reveal);
 136     }
 137
 138     this.reveal_index = 0;
 139
 140     this.reveal_interval = setInterval(this.reveal_next.bind(this), 3000);
 141   }
 142
 143   start() {
 144     this.change_state(GameState.CAPTURE);
 145   }
 146
 147   capture(captor_id, captee_id) {
 148     /* TODO: Fix to fail on already-captured players (or to move the
 149      * captured player from an old captor to a new—need to clarify in
 150      * the API specification which we want here. */
 151     let captor = this._players.find(player => player.id === captor_id);
 152     captor.captures.push(captee_id);
 153
 154     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
 155   }
 156
 157   liberate(captee_id) {
 158     let captor = this._players.find(player => player.captures.includes(captee_id));
 159     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
 160   }
 161
 162   restart() {
 163     for (const player of this._players) {
 164       player.captures = [];
 165     }
 166   }
 167
 168   get characters() {
 169     return this._players.map(player => player.character);
 170   }
 171
 172   get empires() {
 173     return this._players.map(player => ({id: player.id, captures: player.captures}));
 174   }
 175
 176   get spectators() {
 177     /* We return only "id" and "name" here (specifically not session_id!). */
 178     return this._spectators.map(spectator => ({
 179       id: spectator.id,
 180       name: spectator.name
 181     }));
 182   }
 183
 184   get players() {
 185     return this._players.map(player => ({id: player.id, name: player.name }));
 186   }
 187
 188   game_state_event_data(old_state, new_state) {
 189     var old_state_name;
 190     if (old_state)
 191       old_state_name = GameState.properties[old_state].name;
 192     else
 193       old_state_name = "none";
 194     const new_state_name = GameState.properties[new_state].name;
 195
 196     return `{"old_state":"${old_state_name}","new_state":"${new_state_name}"}`;
 197   }
 198
 199   /* Inform clients about a state change. */
 200   broadcast_state_change() {
 201     const event_data = this.game_state_event_data(this.old_state, this.state);
 202     this.broadcast_event("game-state", event_data);
 203   }
 204
 205   /* Change game state and broadcast the change to all clients. */
 206   change_state(state) {
 207     /* Do nothing if there is no actual change happening. */
 208     if (state === this.state)
 209       return;
 210
 211     this.old_state = this.state;
 212     this.state = state;
 213
 214     this.broadcast_state_change();
 215   }
 216 }
 217
 218 function handle_events(request, response) {
 219   const game = request.game;
 220   /* These headers will keep the connection open so we can stream events. */
 221   const headers = {
 222     "Content-type": "text/event-stream",
 223     "Connection": "keep-alive",
 224     "Cache-Control": "no-cache"
 225   };
 226   response.writeHead(200, headers);
 227
 228   /* Now that a client has connected, first we need to stream all of
 229    * the existing spectators and players (if any). */
 230   if (game._spectators.length > 0) {
 231     const spectators_json = JSON.stringify(game.spectators);
 232     const spectators_data = `event: spectators\ndata: ${spectators_json}\n\n`;
 233     response.write(spectators_data);
 234   }
 235
 236   if (game._players.length > 0) {
 237     const players_json = JSON.stringify(game.players);
 238     const players_data = `event: players\ndata: ${players_json}\n\n`;
 239     response.write(players_data);
 240   }
 241
 242   /* And we need to inform the client of the current game state.
 243    *
 244    * In fact, we need to cycle through each state transition from the
 245    * beginning so the client can see each.
 246    */
 247   var old_state = null;
 248   for (var state = GameState.JOIN; state <= game.state; state++) {
 249     var event_data = game.game_state_event_data(old_state, state);
 250     response.write("event: game-state\n" + "data: " + event_data + "\n\n");
 251     old_state = state;
 252   }
 253
 254   /* Add this new client to our list of clients. */
 255   const id = game.add_client(response);
 256
 257   /* And queue up cleanup to be triggered on client close. */
 258   request.on('close', () => {
 259     game.remove_client(id);
 260   });
 261 }
 262
 263 router.get('/', (request, response) => {
 264   if (! request.session.nickname)
 265     response.render('choose-nickname.html', { game_name: "Empires" });
 266   else
 267     response.render('empires-game.html');
 268 });
 269
 270 router.post('/spectator', (request, response) => {
 271   const game = request.game;
 272   var name = request.session.nickname;
 273
 274   /* If the request includes a name, that overrides the session nickname. */
 275   if (request.body.name)
 276     name = request.body.name;
 277
 278   const id = game.add_spectator(name, request.session.id);
 279   response.send(JSON.stringify(id));
 280 });
 281
 282 router.delete('/spectator/:id', (request, response) => {
 283   const game = request.game;
 284   game.remove_spectator(parseInt(request.params.id));
 285   response.send();
 286 });
 287
 288 router.post('/register', (request, response) => {
 289   const game = request.game;
 290   var name = request.session.nickname;;
 291
 292   /* If the request includes a name, that overrides the session nickname. */
 293   if (request.body.name)
 294     name = request.body.name;
 295
 296   game.add_player(name, request.body.character);
 297   response.send();
 298 });
 299
 300 router.post('/deregister/:id', (request, response) => {
 301   const game = request.game;
 302   game.remove_player(parseInt(request.params.id));
 303   response.send();
 304 });
 305
 306 router.post('/reveal', (request, response) => {
 307   const game = request.game;
 308   game.reveal();
 309   response.send();
 310 });
 311
 312 router.post('/start', (request, response) => {
 313   const game = request.game;
 314   game.start();
 315   response.send();
 316 });
 317
 318 router.post('/reset', (request, response) => {
 319   const game = request.game;
 320   game.reset();
 321   response.send();
 322 });
 323
 324 router.post('/capture/:captor/:captee', (request, response) => {
 325   const game = request.game;
 326   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 327   response.send();
 328 });
 329
 330 router.post('/liberate/:id', (request, response) => {
 331   const game = request.game;
 332   game.liberate(parseInt(request.params.id));
 333   response.send();
 334 });
 335
 336 router.post('/restart', (request, response) => {
 337   const game = request.game;
 338   game.restart(parseInt(request.params.id));
 339     response.send();
 340 });
 341
 342 router.get('/characters', (request, response) => {
 343   const game = request.game;
 344   response.send(game.characters);
 345 });
 346
 347 router.get('/empires', (request, response) => {
 348   const game = request.game;
 349   response.send(game.empires);
 350 });
 351
 352 router.get('/spectators', (request, response) => {
 353   const game = request.game;
 354   response.send(game.spectators);
 355 });
 356
 357 router.get('/players', (request, response) => {
 358   const game = request.game;
 359   response.send(game.players);
 360 });
 361
 362 router.get('/events', handle_events);
 363
 364 exports.router = router;
 365 exports.name = engine_name;
 366 exports.Game = Empires;