first commit

backend/internal/service/room_service.go

@@ -0,0 +1,84 @@
+package service
+
+import (
+	"errors"
+	"fmt"
+	"math/rand/v2"
+	"time"
+
+	"filefast/backend/internal/model"
+	"filefast/backend/internal/store"
+)
+
+type RoomService struct {
+	store *store.MemoryStore
+	ttl   time.Duration
+}
+
+func NewRoomService(store *store.MemoryStore, ttl time.Duration) *RoomService {
+	return &RoomService{
+		store: store,
+		ttl:   ttl,
+	}
+}
+
+func (s *RoomService) CreateRoom(creatorDeviceID string) (model.Room, error) {
+	if creatorDeviceID == "" {
+		return model.Room{}, errors.New("creator_device_id is required")
+	}
+
+	now := time.Now()
+	for range 20 {
+		code := fmt.Sprintf("%04d", rand.IntN(10000))
+		if room, ok := s.store.GetRoom(code); ok && room.ExpiresAt.After(now) && room.Status != model.RoomStatusExpired {
+			continue
+		}
+
+		room := model.Room{
+			Code:            code,
+			CreatorDeviceID: creatorDeviceID,
+			Status:          model.RoomStatusWaiting,
+			CreatedAt:       now,
+			ExpiresAt:       now.Add(s.ttl),
+		}
+		return s.store.UpsertRoom(room), nil
+	}
+
+	return model.Room{}, errors.New("failed to allocate room code")
+}
+
+func (s *RoomService) JoinRoom(code, joinerDeviceID string) (model.Room, error) {
+	room, ok := s.store.GetRoom(code)
+	if !ok {
+		return model.Room{}, errors.New("room not found")
+	}
+
+	now := time.Now()
+	if !room.ExpiresAt.After(now) {
+		room.Status = model.RoomStatusExpired
+		s.store.UpsertRoom(room)
+		return model.Room{}, errors.New("room expired")
+	}
+
+	if room.Status != model.RoomStatusWaiting {
+		return model.Room{}, errors.New("room unavailable")
+	}
+
+	room.JoinerDeviceID = joinerDeviceID
+	room.Status = model.RoomStatusJoined
+	return s.store.UpsertRoom(room), nil
+}
+
+func (s *RoomService) CancelRoom(code, requesterID string) (model.Room, error) {
+	room, ok := s.store.GetRoom(code)
+	if !ok {
+		return model.Room{}, errors.New("room not found")
+	}
+
+	if room.CreatorDeviceID != requesterID {
+		return model.Room{}, errors.New("only creator can cancel room")
+	}
+
+	room.Status = model.RoomStatusCanceled
+	return s.store.UpsertRoom(room), nil
+}