refactor: move sender role logic into sender_state_machine

src/main.cpp

@@ -12,6 +12,7 @@
 #include "display_ui.h"
 #include "test_mode.h"
 #include "sd_logger.h"
+#include "sender_state_machine.h"
 #include <stdarg.h>
 #include <math.h>
 #ifdef ARDUINO_ARCH_ESP32
@@ -151,6 +152,7 @@ enum class TxBuildError : uint8_t {
 };
 
 static TxBuildError g_last_tx_build_error = TxBuildError::None;
+static SenderStateMachine g_sender_state_machine;
 
 static void watchdog_kick();
 static void finish_inflight_batch();
@@ -1277,21 +1279,10 @@ void setup() {
   display_set_self_ids(g_short_id, g_device_id);
 
   if (g_role == DeviceRole::Sender) {
-    power_sender_init();
-    power_configure_unused_pins_sender();
-    meter_init();
-#ifdef ARDUINO_ARCH_ESP32
-    if (!meter_reader_start()) {
-      serial_debug_printf("meter: using inline polling fallback");
-    }
-#endif
-    g_last_sample_ms = millis() - METER_SAMPLE_INTERVAL_MS;
-    g_last_send_ms = millis();
-    g_last_sync_request_ms = millis() - SYNC_REQUEST_INTERVAL_MS;
-    g_time_acquired = false;
-    g_sender_faults_reset_after_first_sync = false;
-    g_sender_faults_reset_hour_utc = UINT32_MAX;
-    update_battery_cache();
+    SenderStateMachineConfig sender_cfg = {};
+    sender_cfg.short_id = g_short_id;
+    sender_cfg.device_id = g_device_id;
+    g_sender_state_machine.begin(sender_cfg);
   } else {
     power_receiver_init();
     lora_receive_continuous();
@@ -1815,7 +1806,7 @@ void loop() {
 #endif
 
   if (g_role == DeviceRole::Sender) {
-    sender_loop();
+    g_sender_state_machine.loop();
   } else {
     receiver_loop();
   }

src/sender_state_machine.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <Arduino.h>
+
+struct SenderStateMachineConfig {
+  uint16_t short_id;
+  const char *device_id;
+};
+
+struct SenderStats {
+  uint8_t queue_depth;
+  uint8_t build_count;
+  uint16_t inflight_batch_id;
+  uint16_t last_sent_batch_id;
+  uint16_t last_acked_batch_id;
+  uint8_t retry_count;
+  bool ack_pending;
+  uint32_t ack_timeout_total;
+  uint32_t ack_retry_total;
+  uint32_t ack_miss_streak;
+  uint32_t rx_window_ms;
+  uint32_t sleep_ms;
+};
+
+class SenderStateMachine {
+public:
+  bool begin(const SenderStateMachineConfig &config);
+  void loop();
+  SenderStats stats() const;
+
+private:
+  enum class State : uint8_t {
+    Syncing = 0,
+    Normal = 1,
+    Catchup = 2,
+    WaitAck = 3
+  };
+
+  void handleMeterRead(uint32_t now_ms);
+  void maybeSendBatch(uint32_t now_ms);
+  void handleAckWindow(uint32_t now_ms);
+  bool applyTimeFromAck(uint8_t time_valid, uint32_t ack_epoch);
+  void validateInvariants();
+};