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.clients = [];
  45     this.next_client_id = 1;
  46     this.state = GameState.JOIN;
  47
  48     /* Send a comment to every connected client every 15 seconds. */
  49     setInterval(() => {this.broadcast_string(":");}, 15000);
  50   }
  51
  52   add_spectator(name, session_id) {
  53     /* Don't add another spectator that matches an existing session. */
  54     const existing = this._spectators.findIndex(
  55       spectator => spectator.session_id === session_id);
  56     if (existing >= 0)
  57       return existing.id;
  58
  59     const new_spectator = {id: this.next_spectator_id,
  60                            name: name,
  61                            session_id: session_id
  62                           };
  63     this._spectators.push(new_spectator);
  64     this.next_spectator_id++;
  65     this.broadcast_event("spectator-join", JSON.stringify(new_spectator));
  66
  67     return new_spectator.id;
  68   }
  69
  70   remove_spectator(id) {
  71     const index = this._spectators.findIndex(spectator => spectator.id === id);
  72     this._spectators.splice(index, 1);
  73
  74     this.broadcast_event("spectator-leave", `{"id": ${id}}`);
  75   }
  76
  77   add_player(name, character) {
  78     const new_player = {id: this.next_player_id,
  79                        name: name,
  80                        character: character,
  81                        captures: [],
  82                        };
  83     this._players.push(new_player);
  84     this.next_player_id++;
  85     /* The syntax here is using an anonymous function to create a new
  86       object from new_player with just the subset of fields that we
  87       want. */
  88     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  89     this.broadcast_event("player-join", player_data);
  90   }
  91
  92   remove_player(id) {
  93     const index = this._players.findIndex(player => player.id === id);
  94     this._players.splice(index, 1);
  95
  96     this.broadcast_event("player-leave", `{"id": ${id}}`);
  97   }
  98
  99   reset() {
 100     this._players = [];
 101     this.characters_to_reveal = null;
 102     this.next_player_id = 1;
 103
 104     this.change_state(GameState.JOIN);
 105
 106     this.broadcast_event("spectators", "{}");
 107     this.broadcast_event("players", "{}");
 108   }
 109
 110   reveal_next() {
 111     /* Don't try to reveal anything if we aren't in the reveal state. */
 112     if (this.state != GameState.REVEAL) {
 113       clearInterval(this.reveal_interval);
 114       return;
 115     }
 116
 117     if (this.reveal_index >= this.characters_to_reveal.length) {
 118       clearInterval(this.reveal_interval);
 119       this.broadcast_event("character-reveal", '{"character":""}');
 120       return;
 121     }
 122     const character = this.characters_to_reveal[this.reveal_index];
 123     this.reveal_index++;
 124     const character_data = JSON.stringify({"character":character});
 125     this.broadcast_event("character-reveal", character_data);
 126   }
 127
 128   reveal() {
 129     this.change_state(GameState.REVEAL);
 130
 131     if (this.characters_to_reveal === null) {
 132       this.characters_to_reveal = [];
 133       this.characters_to_reveal = this._players.reduce((characters, player) => {
 134         characters.push(player.character);
 135         return characters;
 136       }, []);
 137       shuffle(this.characters_to_reveal);
 138     }
 139
 140     this.reveal_index = 0;
 141
 142     this.reveal_interval = setInterval(this.reveal_next.bind(this), 3000);
 143   }
 144
 145   start() {
 146     this.change_state(GameState.CAPTURE);
 147   }
 148
 149   capture(captor_id, captee_id) {
 150     /* TODO: Fix to fail on already-captured players (or to move the
 151      * captured player from an old captor to a new—need to clarify in
 152      * the API specification which we want here. */
 153     let captor = this._players.find(player => player.id === captor_id);
 154     captor.captures.push(captee_id);
 155
 156     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
 157   }
 158
 159   liberate(captee_id) {
 160     let captor = this._players.find(player => player.captures.includes(captee_id));
 161     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
 162   }
 163
 164   restart() {
 165     for (const player of this._players) {
 166       player.captures = [];
 167     }
 168   }
 169
 170   get characters() {
 171     return this._players.map(player => player.character);
 172   }
 173
 174   get empires() {
 175     return this._players.map(player => ({id: player.id, captures: player.captures}));
 176   }
 177
 178   get spectators() {
 179     /* We return only "id" and "name" here (specifically not session_id!). */
 180     return this._spectators.map(spectator => ({
 181       id: spectator.id,
 182       name: spectator.name
 183     }));
 184   }
 185
 186   get players() {
 187     return this._players.map(player => ({id: player.id, name: player.name }));
 188   }
 189
 190   add_client(response) {
 191     const id = this.next_client_id;
 192     this.clients.push({id: id,
 193                        response: response});
 194     this.next_client_id++;
 195
 196     return id;
 197   }
 198
 199   remove_client(id) {
 200     this.clients = this.clients.filter(client => client.id !== id);
 201   }
 202
 203   /* Send a string to all clients */
 204   broadcast_string(str) {
 205     this.clients.forEach(client => client.response.write(str + '\n'));
 206   }
 207
 208   /* Send an event to all clients.
 209    *
 210    * An event has both a declared type and a separate data block.
 211    * It also ends with two newlines (to mark the end of the event).
 212    */
 213   broadcast_event(type, data) {
 214     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
 215   }
 216
 217   game_state_event_data(old_state, new_state) {
 218     var old_state_name;
 219     if (old_state)
 220       old_state_name = GameState.properties[old_state].name;
 221     else
 222       old_state_name = "none";
 223     const new_state_name = GameState.properties[new_state].name;
 224
 225     return `{"old_state":"${old_state_name}","new_state":"${new_state_name}"}`;
 226   }
 227
 228   /* Inform clients about a state change. */
 229   broadcast_state_change() {
 230     const event_data = this.game_state_event_data(this.old_state, this.state);
 231     this.broadcast_event("game-state", event_data);
 232   }
 233
 234   /* Change game state and broadcast the change to all clients. */
 235   change_state(state) {
 236     /* Do nothing if there is no actual change happening. */
 237     if (state === this.state)
 238       return;
 239
 240     this.old_state = this.state;
 241     this.state = state;
 242
 243     this.broadcast_state_change();
 244   }
 245 }
 246
 247 function handle_events(request, response) {
 248   const game = request.game;
 249   /* These headers will keep the connection open so we can stream events. */
 250   const headers = {
 251     "Content-type": "text/event-stream",
 252     "Connection": "keep-alive",
 253     "Cache-Control": "no-cache"
 254   };
 255   response.writeHead(200, headers);
 256
 257   /* Now that a client has connected, first we need to stream all of
 258    * the existing spectators and players (if any). */
 259   if (game._spectators.length > 0) {
 260     const spectators_json = JSON.stringify(game.spectators);
 261     const spectators_data = `event: spectators\ndata: ${spectators_json}\n\n`;
 262     response.write(spectators_data);
 263   }
 264
 265   if (game._players.length > 0) {
 266     const players_json = JSON.stringify(game.players);
 267     const players_data = `event: players\ndata: ${players_json}\n\n`;
 268     response.write(players_data);
 269   }
 270
 271   /* And we need to inform the client of the current game state.
 272    *
 273    * In fact, we need to cycle through each state transition from the
 274    * beginning so the client can see each.
 275    */
 276   var old_state = null;
 277   for (var state = GameState.JOIN; state <= game.state; state++) {
 278     var event_data = game.game_state_event_data(old_state, state);
 279     response.write("event: game-state\n" + "data: " + event_data + "\n\n");
 280     old_state = state;
 281   }
 282
 283   /* Add this new client to our list of clients. */
 284   const id = game.add_client(response);
 285
 286   /* And queue up cleanup to be triggered on client close. */
 287   request.on('close', () => {
 288     game.remove_client(id);
 289   });
 290 }
 291
 292 router.get('/', (request, response) => {
 293   if (! request.session.nickname)
 294     response.render('choose-nickname.html', { game_name: "Empires" });
 295   else
 296     response.render('empires-game.html');
 297 });
 298
 299 router.post('/spectator', (request, response) => {
 300   const game = request.game;
 301   var name = request.session.nickname;
 302
 303   /* If the request includes a name, that overrides the session nickname. */
 304   if (request.body.name)
 305     name = request.body.name;
 306
 307   const id = game.add_spectator(name, request.session.id);
 308   response.send(JSON.stringify(id));
 309 });
 310
 311 router.delete('/spectator/:id', (request, response) => {
 312   const game = request.game;
 313   game.remove_spectator(parseInt(request.params.id));
 314   response.send();
 315 });
 316
 317 router.post('/register', (request, response) => {
 318   const game = request.game;
 319   var name = request.session.nickname;;
 320
 321   /* If the request includes a name, that overrides the session nickname. */
 322   if (request.body.name)
 323     name = request.body.name;
 324
 325   game.add_player(name, request.body.character);
 326   response.send();
 327 });
 328
 329 router.post('/deregister/:id', (request, response) => {
 330   const game = request.game;
 331   game.remove_player(parseInt(request.params.id));
 332   response.send();
 333 });
 334
 335 router.post('/reveal', (request, response) => {
 336   const game = request.game;
 337   game.reveal();
 338   response.send();
 339 });
 340
 341 router.post('/start', (request, response) => {
 342   const game = request.game;
 343   game.start();
 344   response.send();
 345 });
 346
 347 router.post('/reset', (request, response) => {
 348   const game = request.game;
 349   game.reset();
 350   response.send();
 351 });
 352
 353 router.post('/capture/:captor/:captee', (request, response) => {
 354   const game = request.game;
 355   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 356   response.send();
 357 });
 358
 359 router.post('/liberate/:id', (request, response) => {
 360   const game = request.game;
 361   game.liberate(parseInt(request.params.id));
 362   response.send();
 363 });
 364
 365 router.post('/restart', (request, response) => {
 366   const game = request.game;
 367   game.restart(parseInt(request.params.id));
 368     response.send();
 369 });
 370
 371 router.get('/characters', (request, response) => {
 372   const game = request.game;
 373   response.send(game.characters);
 374 });
 375
 376 router.get('/empires', (request, response) => {
 377   const game = request.game;
 378   response.send(game.empires);
 379 });
 380
 381 router.get('/spectators', (request, response) => {
 382   const game = request.game;
 383   response.send(game.spectators);
 384 });
 385
 386 router.get('/players', (request, response) => {
 387   const game = request.game;
 388   response.send(game.players);
 389 });
 390
 391 router.get('/events', handle_events);
 392
 393 exports.router = router;
 394 exports.name = engine_name;
 395 exports.Game = Empires;