Add priority WiFi failover

docs/UART_PROTOCOL.md

@@ -190,3 +190,18 @@ Pico sends:
     {"type":"wifi_clear"}
 
 AP mode remains enabled as the recovery path.
+
+## WiFi Priority
+
+WiFi configuration supports multiple saved networks.
+
+Lower priority numbers are tried first.
+
+Example:
+
+    {"type":"config_wifi","networks":[{"ssid":"Starlink","password":"password","priority":1},{"ssid":"Home WiFi","password":"password","priority":2}]}
+
+Runtime behavior:
+
+    If STA disconnects, the ESP32 retries saved networks by priority every 30 seconds.
+    AP mode remains available as a recovery path.

firmware/esp32/overland-controller/overland-controller.ino

@@ -83,10 +83,13 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
         <div class="tempList" style="margin-top:12px">
           <input id="w1s" placeholder="Network 1 SSID">
           <input id="w1p" placeholder="Network 1 password" type="password">
+          <input id="w1r" placeholder="Network 1 priority, lower = first" inputmode="numeric">
           <input id="w2s" placeholder="Network 2 SSID">
           <input id="w2p" placeholder="Network 2 password" type="password">
+          <input id="w2r" placeholder="Network 2 priority, lower = first" inputmode="numeric">
           <input id="w3s" placeholder="Network 3 SSID">
           <input id="w3p" placeholder="Network 3 password" type="password">
+          <input id="w3r" placeholder="Network 3 priority, lower = first" inputmode="numeric">
           <button onclick="saveWifi()">Save WiFi</button>
           <button onclick="connectWifi()">Connect Now</button>
         </div>
@@ -169,6 +172,8 @@ async function loadWifiConfig(){
       const n=nets[i]||{};
       const s=$("w"+(i+1)+"s");
       if(s) s.value=n.ssid||"";
+      const pr=$("w"+(i+1)+"r");
+      if(pr) pr.value=n.priority||i+1;
     }
   }catch(e){}
 }
@@ -177,7 +182,8 @@ async function saveWifi(){
   for(let i=1;i<=3;i++){
     const ssid=$("w"+i+"s").value.trim();
     const password=$("w"+i+"p").value;
-    if(ssid) networks.push({ssid,password});
+    const priority=parseInt($("w"+i+"r").value||i,10);
+    if(ssid) networks.push({ssid,password,priority});
   }
   await fetch("/config/wifi",{
     method:"POST",
@@ -218,8 +224,11 @@ Preferences wifiPrefs;
 const int MAX_WIFI_NETWORKS = 3;
 String staSsids[MAX_WIFI_NETWORKS];
 String staPasswords[MAX_WIFI_NETWORKS];
+int staPriorities[MAX_WIFI_NETWORKS];
 int wifiNetworkCount = 0;
 String activeStaSsid = "";
+unsigned long lastStaReconnectAttempt = 0;
+const unsigned long STA_RECONNECT_INTERVAL_MS = 30000;
 
 void loadWifiConfig() {
     wifiPrefs.begin("wifi", true);
@@ -232,6 +241,7 @@ void loadWifiConfig() {
     for (int i = 0; i < MAX_WIFI_NETWORKS; i++) {
         staSsids[i] = wifiPrefs.getString(("ssid" + String(i)).c_str(), "");
         staPasswords[i] = wifiPrefs.getString(("pass" + String(i)).c_str(), "");
+        staPriorities[i] = wifiPrefs.getInt(("priority" + String(i)).c_str(), i + 1);
     }
 
     // Migration path from old single-network config
@@ -242,6 +252,7 @@ void loadWifiConfig() {
         if (oldSsid.length() > 0) {
             staSsids[0] = oldSsid;
             staPasswords[0] = oldPassword;
+            staPriorities[0] = 1;
             wifiNetworkCount = 1;
         }
     }
@@ -257,6 +268,7 @@ void saveWifiConfig() {
     for (int i = 0; i < MAX_WIFI_NETWORKS; i++) {
         wifiPrefs.putString(("ssid" + String(i)).c_str(), staSsids[i]);
         wifiPrefs.putString(("pass" + String(i)).c_str(), staPasswords[i]);
+        wifiPrefs.putInt(("priority" + String(i)).c_str(), staPriorities[i]);
     }
 
     // Keep legacy keys updated for easier debugging
@@ -277,9 +289,30 @@ void clearWifiConfig() {
     for (int i = 0; i < MAX_WIFI_NETWORKS; i++) {
         staSsids[i] = "";
         staPasswords[i] = "";
+        staPriorities[i] = i + 1;
     }
 }
 
+int findNextWifiIndexByPriority(bool tried[]) {
+    int bestIndex = -1;
+    int bestPriority = 1000000;
+
+    for (int i = 0; i < wifiNetworkCount; i++) {
+        if (tried[i]) continue;
+        if (staSsids[i].length() == 0) continue;
+
+        int priority = staPriorities[i];
+        if (priority <= 0) priority = i + 1;
+
+        if (priority < bestPriority) {
+            bestPriority = priority;
+            bestIndex = i;
+        }
+    }
+
+    return bestIndex;
+}
+
 void connectStaWifi() {
     if (wifiNetworkCount <= 0) {
         Serial.println("STA WiFi not configured.");
@@ -289,12 +322,20 @@ void connectStaWifi() {
     WiFi.disconnect(false);
     activeStaSsid = "";
 
-    for (int i = 0; i < wifiNetworkCount; i++) {
+    bool tried[MAX_WIFI_NETWORKS] = {false, false, false};
-        if (staSsids[i].length() == 0) {
+
-            continue;
+    for (int attempt = 0; attempt < wifiNetworkCount; attempt++) {
+        int i = findNextWifiIndexByPriority(tried);
+
+        if (i < 0) {
+            break;
         }
 
-        Serial.print("Connecting STA WiFi to: ");
+        tried[i] = true;
+
+        Serial.print("Connecting STA WiFi priority ");
+        Serial.print(staPriorities[i]);
+        Serial.print(" to: ");
         Serial.println(staSsids[i]);
 
         WiFi.begin(staSsids[i].c_str(), staPasswords[i].c_str());
@@ -323,6 +364,19 @@ void connectStaWifi() {
     Serial.println("All STA WiFi attempts failed. AP remains available.");
 }
 
+void maintainStaWifi() {
+    if (wifiNetworkCount <= 0) return;
+
+    if (WiFi.status() == WL_CONNECTED) return;
+
+    if (millis() - lastStaReconnectAttempt < STA_RECONNECT_INTERVAL_MS) return;
+
+    lastStaReconnectAttempt = millis();
+
+    Serial.println("STA WiFi disconnected. Trying saved networks by priority...");
+    connectStaWifi();
+}
+
 void printNetworkStatus() {
     Serial.println("Network:");
     Serial.print("  AP IP: ");
@@ -441,6 +495,14 @@ void buildStatusDocument(JsonDocument& doc) {
     network["sta_ssid"] = activeStaSsid;
     network["sta_ip"] = WiFi.status() == WL_CONNECTED ? WiFi.localIP().toString() : "";
     network["saved_network_count"] = wifiNetworkCount;
+    JsonArray savedNetworks = network.createNestedArray("saved_networks");
+    for (int i = 0; i < wifiNetworkCount; i++) {
+        JsonObject saved = savedNetworks.createNestedObject();
+        saved["index"] = i + 1;
+        saved["ssid"] = staSsids[i];
+        saved["priority"] = staPriorities[i];
+        saved["active"] = staSsids[i] == activeStaSsid;
+    }
 
     JsonObject alarmObj = doc.createNestedObject("alarms");
     alarmObj["low_soc"] = alarms.lowSoc;
@@ -958,6 +1020,7 @@ void handleDebugSerial() {
 
     if (command.startsWith("wifi ssid ")) {
         staSsids[0] = command.substring(10);
+        staPriorities[0] = 1;
         if (wifiNetworkCount < 1) wifiNetworkCount = 1;
         Serial.println("OK WiFi SSID 1 updated");
         Serial.println("Run: wifi save");
@@ -966,6 +1029,7 @@ void handleDebugSerial() {
 
     if (command.startsWith("wifi pass ")) {
         staPasswords[0] = command.substring(10);
+        staPriorities[0] = 1;
         if (wifiNetworkCount < 1) wifiNetworkCount = 1;
         Serial.println("OK WiFi password 1 updated");
         Serial.println("Run: wifi save");
@@ -986,8 +1050,21 @@ void handleDebugSerial() {
             return;
         }
 
-        staSsids[wifiNetworkCount] = rest.substring(0, split);
+        String ssid = rest.substring(0, split);
-        staPasswords[wifiNetworkCount] = rest.substring(split + 1);
+        String passAndPriority = rest.substring(split + 1);
+        int secondSplit = passAndPriority.indexOf('|');
+        String password = passAndPriority;
+        int priority = wifiNetworkCount + 1;
+
+        if (secondSplit >= 0) {
+            password = passAndPriority.substring(0, secondSplit);
+            priority = passAndPriority.substring(secondSplit + 1).toInt();
+            if (priority <= 0) priority = wifiNetworkCount + 1;
+        }
+
+        staSsids[wifiNetworkCount] = ssid;
+        staPasswords[wifiNetworkCount] = password;
+        staPriorities[wifiNetworkCount] = priority;
         wifiNetworkCount++;
 
         Serial.println("OK WiFi network added");
@@ -1310,6 +1387,7 @@ void sendWifiConfigJson() {
         JsonObject network = networks.createNestedObject();
         network["index"] = i + 1;
         network["ssid"] = staSsids[i];
+        network["priority"] = staPriorities[i];
         network["password_set"] = staPasswords[i].length() > 0;
     }
 
@@ -1348,23 +1426,30 @@ void handleUpdateWifiConfig() {
                 continue;
             }
 
+            int priority = network["priority"] | (wifiNetworkCount + 1);
+            if (priority <= 0) priority = wifiNetworkCount + 1;
+
             staSsids[wifiNetworkCount] = ssid;
             staPasswords[wifiNetworkCount] = password;
+            staPriorities[wifiNetworkCount] = priority;
             wifiNetworkCount++;
         }
 
         for (int i = wifiNetworkCount; i < MAX_WIFI_NETWORKS; i++) {
             staSsids[i] = "";
             staPasswords[i] = "";
+            staPriorities[i] = i + 1;
         }
     } else {
         if (doc["ssid"].is<String>()) {
             staSsids[0] = doc["ssid"].as<String>();
+            staPriorities[0] = 1;
             if (wifiNetworkCount < 1) wifiNetworkCount = 1;
         }
 
         if (doc["password"].is<String>()) {
             staPasswords[0] = doc["password"].as<String>();
+            staPriorities[0] = 1;
             if (wifiNetworkCount < 1) wifiNetworkCount = 1;
         }
     }
@@ -1635,6 +1720,7 @@ void setup() {
 
 void loop() {
     server.handleClient();
+    maintainStaWifi();
     handleDebugSerial();
     updateBms();
     updateAlarms();