1package server
2
3import (
4 "context"
5 "encoding/json"
6 "errors"
7 "log"
8 "sync"
9 "time"
10
11 "github.com/gofrs/uuid"
12 "github.com/speps/go-hashids"
13 "github.com/zikaeroh/codies/internal/game"
14 "github.com/zikaeroh/codies/internal/protocol"
15 "go.uber.org/atomic"
16 "golang.org/x/sync/errgroup"
17 "nhooyr.io/websocket"
18 "nhooyr.io/websocket/wsjson"
19)
20
21const maxRooms = 1000
22
23var (
24 ErrRoomExists = errors.New("server: rooms exist")
25 ErrTooManyRooms = errors.New("server: too many rooms")
26)
27
28type Server struct {
29 clientCount atomic.Int64
30 roomCount atomic.Int64
31 doPrune chan struct{}
32 ready chan struct{}
33
34 mu sync.Mutex
35
36 ctx context.Context
37 rooms map[string]*Room
38 roomIDs map[string]*Room
39
40 hid *hashids.HashID
41 nextID int64
42}
43
44func NewServer() *Server {
45 hd := hashids.NewData()
46 hd.MinLength = 8
47 hd.Salt = uuid.Must(uuid.NewV4()).String() // IDs are only valid for this server instance; ok to randomize salt.
48 hid, err := hashids.NewWithData(hd)
49 if err != nil {
50 panic(err)
51 }
52
53 return &Server{
54 ready: make(chan struct{}),
55 doPrune: make(chan struct{}, 1),
56 rooms: make(map[string]*Room),
57 roomIDs: make(map[string]*Room),
58 hid: hid,
59 }
60}
61
62func (s *Server) Run(ctx context.Context) error {
63 s.ctx = ctx
64
65 close(s.ready)
66 ticker := time.NewTicker(5 * time.Minute)
67 defer ticker.Stop()
68
69 for {
70 select {
71 case <-ctx.Done():
72 return ctx.Err()
73
74 case <-s.doPrune:
75 s.prune()
76
77 case <-ticker.C:
78 s.prune()
79 }
80 }
81}
82
83func (s *Server) FindRoom(name string) *Room {
84 <-s.ready
85
86 s.mu.Lock()
87 defer s.mu.Unlock()
88 return s.rooms[name]
89}
90
91func (s *Server) FindRoomByID(id string) *Room {
92 <-s.ready
93
94 s.mu.Lock()
95 defer s.mu.Unlock()
96 return s.roomIDs[id]
97}
98
99func (s *Server) CreateRoom(name, password string) (*Room, error) {
100 <-s.ready
101
102 s.mu.Lock()
103 defer s.mu.Unlock()
104
105 room := s.rooms[name]
106 if room != nil {
107 return nil, ErrRoomExists
108 }
109
110 if len(s.rooms) >= maxRooms {
111 return nil, ErrTooManyRooms
112 }
113
114 id, err := s.hid.EncodeInt64([]int64{s.nextID})
115 if err != nil {
116 return nil, err
117 }
118 s.nextID++
119
120 ctx, cancel := context.WithCancel(s.ctx)
121
122 room = &Room{
123 Name: name,
124 Password: password,
125 ID: id,
126 clientCount: &s.clientCount,
127 roomCount: &s.roomCount,
128 ctx: ctx,
129 cancel: cancel,
130 room: game.NewRoom(nil),
131 players: make(map[game.PlayerID]noteSender),
132 turnSeconds: 60,
133 }
134
135 room.lastSeen.Store(time.Now())
136
137 room.room.NewGame()
138
139 s.rooms[name] = room
140 s.roomIDs[room.ID] = room
141 s.roomCount.Inc()
142 metricRooms.Inc()
143
144 log.Printf("created new room '%s' (%s)", name, room.ID)
145
146 if s.nextID%100 == 0 {
147 s.triggerPrune()
148 }
149
150 return room, nil
151}
152
153func (s *Server) triggerPrune() {
154 select {
155 case s.doPrune <- struct{}{}:
156 default:
157 }
158}
159
160func (s *Server) prune() {
161 s.mu.Lock()
162 defer s.mu.Unlock()
163
164 toRemove := make([]string, 0, 1)
165
166 for name, room := range s.rooms {
167 lastSeen := room.lastSeen.Load().(time.Time)
168 if time.Since(lastSeen) > 10*time.Minute {
169 toRemove = append(toRemove, name)
170 }
171 }
172
173 if len(toRemove) == 0 {
174 return
175 }
176
177 for _, name := range toRemove {
178 room := s.rooms[name]
179 room.mu.Lock()
180 room.stopTimer()
181 room.mu.Unlock()
182
183 room.cancel()
184 delete(s.rooms, name)
185 delete(s.roomIDs, room.ID)
186 s.roomCount.Dec()
187 metricRooms.Dec()
188 }
189
190 log.Printf("pruned %d rooms", len(toRemove))
191}
192
193func (s *Server) Stats() (rooms, clients int) {
194 s.mu.Lock()
195 defer s.mu.Unlock()
196 return len(s.rooms), int(s.clientCount.Load())
197}
198
199type Room struct {
200 Name string
201 Password string
202 ID string
203
204 ctx context.Context
205 cancel context.CancelFunc
206 clientCount *atomic.Int64
207 roomCount *atomic.Int64
208
209 mu sync.Mutex
210 room *game.Room
211 players map[game.PlayerID]noteSender
212 state *stateCache
213 lastSeen atomic.Value
214
215 timed bool
216 turnSeconds int
217 turnDeadline *time.Time
218 turnTimer *time.Timer
219
220 hideBomb bool
221}
222
223type noteSender func(protocol.ServerNote)
224
225func (r *Room) HandleConn(playerID uuid.UUID, nickname string, c *websocket.Conn) {
226 metricClients.Inc()
227 defer metricClients.Dec()
228
229 clientCount := r.clientCount.Inc()
230 log.Printf("client connected to room '%s' (%s); %v clients currently connected to %v rooms", r.Name, r.ID, clientCount, r.roomCount.Load())
231
232 defer func() {
233 clientCount := r.clientCount.Dec()
234 log.Printf("client disconnected from room '%s' (%s); %v clients currently connected to %v rooms", r.Name, r.ID, clientCount, r.roomCount.Load())
235 }()
236
237 defer c.Close(websocket.StatusGoingAway, "going away")
238 g, ctx := errgroup.WithContext(r.ctx)
239
240 r.mu.Lock()
241 r.players[playerID] = func(s protocol.ServerNote) {
242 if ctx.Err() != nil {
243 return
244 }
245
246 // It's not safe to start more group goroutines concurrently; just use a regular
247 // goroutine and hope that errors here will be reflected later via ping/receive failures.
248 go func() {
249 ctx, cancel := context.WithTimeout(ctx, time.Second)
250 defer cancel()
251 if err := wsjson.Write(ctx, c, &s); err != nil {
252 return
253 }
254 metricSent.Inc()
255 }()
256 }
257 r.room.AddPlayer(playerID, nickname)
258 r.sendAll()
259 r.mu.Unlock()
260
261 defer func() {
262 r.mu.Lock()
263 defer r.mu.Unlock()
264 delete(r.players, playerID)
265 r.room.RemovePlayer(playerID)
266 r.sendAll()
267 }()
268
269 g.Go(func() error {
270 ticker := time.NewTicker(time.Minute)
271 defer ticker.Stop()
272
273 for {
274 select {
275 case <-ctx.Done():
276 return ctx.Err()
277 case <-ticker.C:
278 }
279
280 if err := c.Ping(ctx); err != nil {
281 return err
282 }
283
284 r.lastSeen.Store(time.Now())
285 }
286 })
287
288 g.Go(func() error {
289 for {
290 var note protocol.ClientNote
291
292 if err := wsjson.Read(ctx, c, ¬e); err != nil {
293 return err
294 }
295
296 r.lastSeen.Store(time.Now())
297 metricReceived.Inc()
298
299 if err := r.handleNote(playerID, ¬e); err != nil {
300 log.Println("error handling note:", err)
301 return err
302 }
303 }
304 })
305
306 _ = g.Wait()
307}
308
309func (r *Room) handleNote(playerID game.PlayerID, note *protocol.ClientNote) error {
310 r.mu.Lock()
311 defer r.mu.Unlock()
312
313 // The client's version was wrong; reject and send them the current state.
314 if note.Version != r.room.Version {
315 r.sendOne(playerID, r.players[playerID])
316 return nil
317 }
318
319 before := r.room.Version
320 resetTimer := false
321
322 defer func() {
323 if r.room.Version != before {
324 if r.timed && resetTimer {
325 r.startTimer()
326 }
327 r.sendAll()
328 }
329 }()
330
331 switch note.Method {
332 case protocol.RevealMethod:
333 var params protocol.RevealParams
334 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
335 return err
336 }
337 prevTurn := r.room.Turn
338 r.room.Reveal(playerID, params.Row, params.Col)
339 resetTimer = prevTurn != r.room.Turn
340
341 case protocol.NewGameMethod:
342 var params protocol.NewGameParams
343 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
344 return err
345 }
346 resetTimer = true
347 r.room.NewGame()
348
349 case protocol.EndTurnMethod:
350 var params protocol.EndTurnParams
351 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
352 return err
353 }
354 resetTimer = true
355 r.room.EndTurn(playerID)
356
357 case protocol.RandomizeTeamsMethod:
358 var params protocol.RandomizeTeamsParams
359 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
360 return err
361 }
362 r.room.RandomizeTeams()
363
364 case protocol.ChangeTeamMethod:
365 var params protocol.ChangeTeamParams
366 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
367 return err
368 }
369 r.room.ChangeTeam(playerID, params.Team)
370
371 case protocol.ChangeNicknameMethod:
372 var params protocol.ChangeNicknameParams
373 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
374 return err
375 }
376
377 // Sync with protocol.go's validation method.
378 if len(params.Nickname) == 0 || len(params.Nickname) > 16 {
379 return nil
380 }
381
382 r.room.AddPlayer(playerID, params.Nickname)
383
384 case protocol.ChangeRoleMethod:
385 var params protocol.ChangeRoleParams
386 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
387 return err
388 }
389 r.room.ChangeRole(playerID, params.Spymaster)
390
391 case protocol.ChangePackMethod:
392 var params protocol.ChangePackParams
393 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
394 return err
395 }
396 r.room.ChangePack(params.Num, params.Enable)
397
398 case protocol.ChangeTurnModeMethod:
399 var params protocol.ChangeTurnModeParams
400 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
401 return err
402 }
403 r.changeTurnMode(params.Timed)
404
405 case protocol.ChangeTurnTimeMethod:
406 var params protocol.ChangeTurnTimeParams
407 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
408 return err
409 }
410 r.changeTurnTime(params.Seconds)
411
412 case protocol.AddPacksMethod:
413 var params protocol.AddPacksParams
414 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
415 return err
416 }
417 for _, p := range params.Packs {
418 if len(p.Words) < 25 {
419 continue
420 }
421 r.room.AddPack(p.Name, p.Words)
422 }
423
424 case protocol.RemovePackMethod:
425 var params protocol.RemovePackParams
426 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
427 return err
428 }
429 r.room.RemovePack(params.Num)
430
431 case protocol.ChangeHideBombMethod:
432 var params protocol.ChangeHideBombParams
433 if err := json.Unmarshal(note.Params, ¶ms); err != nil {
434 return err
435 }
436 r.changeHideBomb(params.HideBomb)
437
438 default:
439 log.Printf("unhandled method: %s", note.Method)
440 }
441
442 return nil
443}
444
445// Must be called with r.mu locked.
446func (r *Room) sendAll() {
447 for playerID, sender := range r.players {
448 r.sendOne(playerID, sender)
449 }
450}
451
452// Must be called with r.mu locked.
453func (r *Room) sendOne(playerID game.PlayerID, sender noteSender) {
454 state := r.createStateFor(playerID)
455 note := protocol.StateNote(state)
456 sender(note)
457}
458
459// Must be called with r.mu locked.
460func (r *Room) createStateFor(playerID game.PlayerID) *protocol.State {
461 if r.state == nil || r.state.version != r.room.Version {
462 r.state = r.createStateCache()
463 }
464
465 if r.room.Players[playerID].Spymaster {
466 return r.state.spymaster
467 }
468 return r.state.guesser
469}
470
471type stateCache struct {
472 version int
473 guesser *protocol.State
474 spymaster *protocol.State
475}
476
477func (r *Room) createStateCache() *stateCache {
478 return &stateCache{
479 version: r.room.Version,
480 guesser: r.createRoomState(false),
481 spymaster: r.createRoomState(true),
482 }
483}
484
485func (r *Room) createRoomState(spymaster bool) *protocol.State {
486 room := r.room
487
488 s := &protocol.State{
489 Version: room.Version,
490 Teams: make([][]*protocol.StatePlayer, len(room.Teams)),
491 Turn: room.Turn,
492 Winner: room.Winner,
493 Board: make([][]*protocol.StateTile, room.Board.Rows),
494 WordsLeft: room.Board.WordCounts,
495 Lists: make([]*protocol.StateWordList, len(room.WordLists)),
496 HideBomb: r.hideBomb,
497 }
498
499 if r.turnDeadline != nil {
500 s.Timer = &protocol.StateTimer{
501 TurnTime: r.turnSeconds,
502 TurnEnd: *r.turnDeadline,
503 }
504 }
505
506 for team, members := range room.Teams {
507 for _, id := range members {
508 p := room.Players[id]
509 s.Teams[team] = append(s.Teams[team], &protocol.StatePlayer{
510 PlayerID: id,
511 Nickname: p.Nickname,
512 Spymaster: p.Spymaster,
513 })
514 }
515
516 if s.Teams[team] == nil {
517 s.Teams[team] = []*protocol.StatePlayer{}
518 }
519 }
520
521 for row := range s.Board {
522 tiles := make([]*protocol.StateTile, room.Board.Cols)
523 for col := range tiles {
524 tile := room.Board.Get(row, col)
525 sTile := &protocol.StateTile{
526 Word: tile.Word,
527 Revealed: tile.Revealed,
528 }
529
530 if spymaster || tile.Revealed || room.Winner != nil {
531 view := &protocol.StateView{
532 Team: tile.Team,
533 Neutral: tile.Neutral,
534 Bomb: tile.Bomb,
535 }
536
537 if view.Bomb && !tile.Revealed && room.Winner == nil && r.hideBomb {
538 view.Neutral = true
539 view.Bomb = false
540 }
541
542 sTile.View = view
543 }
544
545 tiles[col] = sTile
546 }
547
548 s.Board[row] = tiles
549 }
550
551 for i, wl := range room.WordLists {
552 s.Lists[i] = &protocol.StateWordList{
553 Name: wl.Name,
554 Count: wl.List.Len(),
555 Custom: wl.Custom,
556 Enabled: wl.Enabled,
557 }
558 }
559
560 return s
561}
562
563// Must be called with r.mu locked.
564func (r *Room) changeTurnMode(timed bool) {
565 if r.timed == timed {
566 return
567 }
568
569 r.timed = timed
570
571 if timed {
572 r.startTimer()
573 } else {
574 r.stopTimer()
575 }
576
577 r.room.Version++
578}
579
580// Must be called with r.mu locked.
581func (r *Room) changeTurnTime(seconds int) {
582 if seconds <= 0 || r.turnSeconds == seconds {
583 return
584 }
585
586 r.turnSeconds = seconds
587
588 if r.timed {
589 r.startTimer()
590 }
591
592 r.room.Version++
593}
594
595func (r *Room) timerEndTurn() {
596 r.mu.Lock()
597 defer r.mu.Unlock()
598
599 stopped := r.stopTimer()
600 if !stopped {
601 // Room was pruned.
602 return
603 }
604
605 r.turnTimer = nil
606 r.turnDeadline = nil
607
608 if r.room.Winner != nil || r.turnSeconds == 0 {
609 return
610 }
611
612 r.room.ForceEndTurn()
613 r.startTimer()
614 r.sendAll()
615}
616
617// Must be called with r.mu locked.
618func (r *Room) stopTimer() (stopped bool) {
619 if r.turnTimer != nil {
620 r.turnTimer.Stop()
621 stopped = true
622 }
623 r.turnTimer = nil
624 r.turnDeadline = nil
625 return stopped
626}
627
628// Must be called with r.mu locked.
629func (r *Room) startTimer() {
630 if !r.timed {
631 panic("startTimer called on non-timed room")
632 }
633
634 if r.turnTimer != nil {
635 r.turnTimer.Stop()
636 }
637
638 dur := time.Second * time.Duration(r.turnSeconds)
639 deadline := time.Now().Add(dur)
640 r.turnDeadline = &deadline
641 r.turnTimer = time.AfterFunc(dur, r.timerEndTurn)
642}
643
644// Must be called with r.mu locked.
645func (r *Room) changeHideBomb(HideBomb bool) {
646 if r.hideBomb == HideBomb {
647 return
648 }
649
650 r.hideBomb = HideBomb
651 r.room.Version++
652 r.sendAll()
653}