add fetching message history

structs.go

@@ -24,12 +24,42 @@ type User struct {
 }
 
 type Connection struct {
-	Id          uuid.UUID                       `json:"id"`
-	CreatedAt   time.Time                       `json:"createdAt"`
-	MessagesBuf [MaxDirectMsgCache]*Message     `json:"-"`
-	RequestorId uint32                          `json:"requestorId"`
-	RecipientId uint32                          `json:"recipientId"`
-	State       ConnectionState.ConnectionState `json:"state"`
+	Mu             sync.RWMutex                    `json:"-"`
+	Id             uuid.UUID                       `json:"id"`
+	CreatedAt      time.Time                       `json:"createdAt"`
+	MessagesBuff   [MaxDirectMsgCache]*Message     `json:"-"`
+	NextBuffIdx    uint32                          `json:"-"`
+	HaveOverflowed bool                            `json:"-"`
+	RequestorId    uint32                          `json:"requestorId"`
+	RecipientId    uint32                          `json:"recipientId"`
+	State          ConnectionState.ConnectionState `json:"state"`
+}
+
+func (conn *Connection) AddMessageToBuff(message *Message) {
+	conn.Mu.Lock()
+	defer conn.Mu.Unlock()
+
+	conn.MessagesBuff[conn.NextBuffIdx%MaxDirectMsgCache] = message
+	conn.NextBuffIdx++
+	if conn.NextBuffIdx >= MaxDirectMsgCache {
+		conn.HaveOverflowed = true
+	}
+}
+
+// GetSortedMessagesBuff returns arr, length
+func (conn *Connection) GetSortedMessagesBuff() (*[MaxDirectMsgCache]*Message, uint32) {
+	conn.Mu.RLock()
+	defer conn.Mu.RUnlock()
+
+	if !conn.HaveOverflowed {
+		return &conn.MessagesBuff, conn.NextBuffIdx
+	}
+
+	sorted := new([MaxDirectMsgCache]*Message)
+	for i := uint32(0); i < MaxDirectMsgCache; i++ {
+		sorted[i] = conn.MessagesBuff[(conn.NextBuffIdx+i)%MaxDirectMsgCache]
+	}
+	return sorted, MaxDirectMsgCache
 }
 
 type Message struct {
@@ -37,7 +67,7 @@ type Message struct {
 	Content        string    `json:"content"`
 	CreatedAt      time.Time `json:"createdAt"`
 	Sender         uint32    `json:"sender"`
-	Receiver       uint32    `json:"receiver"`
+	Receiver       uuid.UUID `json:"receiver"`
 	IsGroupMessage bool      `json:"isGroupMessage"`
 }