GSM: implement full state machine

Author: facchinm

src/GSMConnectionManager.h

@@ -31,45 +31,168 @@ class GSMConnectionManager : public ConnectionManager {
   GSM gsmAccess;
   GPRS gprs;
 private:
+
+  void changeConnectionState(NetworkConnectionState _newState);
+
+  const int CHECK_INTERVAL_IDLE = 100;
+  const int CHECK_INTERVAL_INIT = 100;
+  const int CHECK_INTERVAL_CONNECTING = 500;
+  const int CHECK_INTERVAL_GETTIME = 1000;
+  const int CHECK_INTERVAL_CONNECTED = 10000;
+  const int CHECK_INTERVAL_RETRYING = 5000;
+  const int CHECK_INTERVAL_DISCONNECTED = 1000;
+  const int CHECK_INTERVAL_ERROR = 500;
+
   const char *pin, *apn, *login, *pass;
-  unsigned long lastNetworkCheck, lastNetworkStep;
+  unsigned long lastConnectionTickTime, lastNetworkStep;
+  int connectionTickTimeInterval;
 };
 
 static const unsigned long NETWORK_CONNECTION_INTERVAL = 30000;
 
 GSMConnectionManager::GSMConnectionManager(const char *pin, const char *apn, const char *login, const char *pass) :
-  pin(pin), apn(apn), login(login), pass(pass), lastNetworkCheck(millis()) {
+  pin(pin),
+  apn(apn),
+  login(login),
+  pass(pass),
+  lastConnectionTickTime(millis()),
+  connectionTickTimeInterval(CHECK_INTERVAL_IDLE) {
 }
 
 unsigned long GSMConnectionManager::getTime() {
   return gsmAccess.getTime();
 }
 
 void GSMConnectionManager::init() {
-  if (gsmAccess.begin(pin) == GSM_READY && gprs.attachGPRS(apn, login, pass) == GPRS_READY) {
-    Serial.println("GPRS connected");
-    int pingResult = gprs.ping("google.com");
-    if (pingResult >= 0) {
-      Serial.print("SUCCESS! RTT = ");
-      Serial.print(pingResult);
-      Serial.println(" ms");
-    }
+  char msgBuffer[120];
+  if (gsmAccess.begin(pin) == GSM_READY) {
+    *msgBuffer = 0;
+    sprintf(msgBuffer, "SIM card ok");
+    debugMessage(msgBuffer, 2);
+    gsmAccess.setTimeout(CHECK_INTERVAL_RETRYING);
   } else {
-    Serial.println("GPRS not connected");
+    *msgBuffer = 0;
+    sprintf(msgBuffer, "SIM not present");
+    debugMessage(msgBuffer, 2);
     while(1);
   }
 }
 
-void GSMConnectionManager::check() {
-  if (millis() - lastNetworkCheck < NETWORK_CONNECTION_INTERVAL) {
-    return;
+void GSMConnectionManager::changeConnectionState(NetworkConnectionState _newState) {
+  netConnectionState = _newState;
+  int newInterval = CHECK_INTERVAL_IDLE;
+  switch (_newState) {
+    case CONNECTION_STATE_INIT:
+      newInterval = CHECK_INTERVAL_INIT;
+      break;
+    case CONNECTION_STATE_CONNECTING:
+      newInterval = CHECK_INTERVAL_CONNECTING;
+      break;
+    case CONNECTION_STATE_GETTIME:
+      newInterval = CHECK_INTERVAL_GETTIME;
+      break;
+    case CONNECTION_STATE_CONNECTED:
+      newInterval = CHECK_INTERVAL_CONNECTED;
+      break;
+    case CONNECTION_STATE_DISCONNECTED:
+      newInterval = CHECK_INTERVAL_DISCONNECTED;
+      break;
   }
+  connectionTickTimeInterval = newInterval;
+  lastConnectionTickTime = millis();
+}
 
-  Serial.print("<<Network Status: ");
-  if (gprs.attachGPRS(apn, login, pass) == GPRS_READY) {
-    Serial.println("CONNECTED");
-    lastNetworkCheck = millis();
-  } else {
-    Serial.println("NOT CONNECTED");
+void GSMConnectionManager::check() {
+  char msgBuffer[120];
+  unsigned long now = millis();
+  int networkStatus = 0;
+  if (now - lastConnectionTickTime > connectionTickTimeInterval) {
+    switch (netConnectionState) {
+      case CONNECTION_STATE_IDLE:
+        init();
+        changeConnectionState(CONNECTION_STATE_INIT);
+        break;
+      case CONNECTION_STATE_INIT:
+        // blocking call with 4th parameter == true
+        networkStatus = gprs.attachGPRS(apn, login, pass, true);
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "GPRS.attachGPRS(): %d", networkStatus);
+        debugMessage(msgBuffer, 2);
+        if (networkStatus == ERROR) {
+          debugMessage("GPRS attach failed\nMake sure the antenna is connected", 0);
+          changeConnectionState(CONNECTION_STATE_INIT);
+          lastConnectionTickTime = now;
+          return;
+        }
+        changeConnectionState(CONNECTION_STATE_CONNECTING);
+        break;
+      case CONNECTION_STATE_CONNECTING:
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "Trying to ping external world");
+        debugMessage(msgBuffer, 2);
+
+        networkStatus = gprs.ping("google.com");
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "GSM.ping(): %d", networkStatus);
+        debugMessage(msgBuffer, 2);
+        if (networkStatus < 0) {
+          *msgBuffer = 0;
+          sprintf(msgBuffer, "Ping failed");
+          debugMessage(msgBuffer, 0);
+
+          *msgBuffer = 0;
+          sprintf(msgBuffer, "Retrying in  \"%d\" milliseconds", connectionTickTimeInterval);
+          debugMessage(msgBuffer, 2);
+          changeConnectionState(CONNECTION_STATE_INIT);
+          return;
+        } else {
+          *msgBuffer = 0;
+          sprintf(msgBuffer, "Connected!");
+          debugMessage(msgBuffer, 2);
+          changeConnectionState(CONNECTION_STATE_GETTIME);
+          return;
+        }
+        break;
+      case CONNECTION_STATE_GETTIME:
+        debugMessage("Acquiring Time from Network", 3);
+        unsigned long networkTime;
+        networkTime = getTime();
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "Network Time: %u", networkTime);
+        debugMessage(msgBuffer, 3);
+        if(networkTime > lastValidTimestamp){
+          lastValidTimestamp = networkTime;
+          changeConnectionState(CONNECTION_STATE_CONNECTED);
+        }
+        break;
+      case CONNECTION_STATE_CONNECTED:
+        // keep testing connection
+        networkStatus = gsmAccess.isAccessAlive();
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "GPRS.isAccessAlive(): %d", networkStatus);
+        debugMessage(msgBuffer, 2);
+        if (networkStatus != 1) {
+          changeConnectionState(CONNECTION_STATE_DISCONNECTED);
+          return;
+        }
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "Still connected");
+        debugMessage(msgBuffer, 2);
+        break;
+      case CONNECTION_STATE_DISCONNECTED:
+        gprs.detachGPRS();
+
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "DISC | GPRS.status(): %d", gprs.status());
+        debugMessage(msgBuffer, 1);
+        *msgBuffer = 0;
+        sprintf(msgBuffer, "Connection lost.");
+        debugMessage(msgBuffer, 0);
+        debugMessage("Attempting reconnection", 1);
+        changeConnectionState(CONNECTION_STATE_CONNECTING);
+        //wifiClient.stop();
+        break;
+    }
+    lastConnectionTickTime = now;
   }
 }