From 371b9fdbb867d5873b6348f02d3b10072b3b4c7a Mon Sep 17 00:00:00 2001
From: Lloyd <lloyd@rightup.co.uk>
Date: Mon, 19 Jan 2026 11:52:23 +0000
Subject: [PATCH] fix: update airtime calculations to use config values in
 AirtimeManager

---
 repeater/airtime.py | 30 +++++++++++++++++++-----------
 repeater/engine.py  | 11 ++++-------
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/repeater/airtime.py b/repeater/airtime.py
index 7dfef85..bd8ae26 100644
--- a/repeater/airtime.py
+++ b/repeater/airtime.py
@@ -9,10 +9,17 @@ logger = logging.getLogger("AirtimeManager")
 class AirtimeManager:
     def __init__(self, config: dict):
         self.config = config
+        self.radio_config = config.get("radio", {})
         self.max_airtime_per_minute = config.get("duty_cycle", {}).get(
             "max_airtime_per_minute", 3600
         )
 
+        # Store radio settings for airtime calculations
+        self.spreading_factor = self.radio_config.get("spreading_factor", 7)
+        self.bandwidth = self.radio_config.get("bandwidth", 125000)
+        self.coding_rate = self.radio_config.get("coding_rate", 5)
+        self.preamble_length = self.radio_config.get("preamble_length", 8)
+
         # Track airtime in rolling window
         self.tx_history = []  # [(timestamp, airtime_ms), ...]
         self.window_size = 60  # seconds
@@ -21,10 +28,10 @@ class AirtimeManager:
     def calculate_airtime(
         self,
         payload_len: int,
-        spreading_factor: int = 7,
-        bandwidth_hz: int = 125000,
-        coding_rate: int = 5,
-        preamble_len: int = 8,
+        spreading_factor: int = None,
+        bandwidth_hz: int = None,
+        coding_rate: int = None,
+        preamble_len: int = None,
         crc_enabled: bool = True,
         explicit_header: bool = True,
     ) -> float:
@@ -35,19 +42,20 @@ class AirtimeManager:
         
         Args:
             payload_len: Payload length in bytes
-            spreading_factor: SF7-SF12 (default: 7)
-            bandwidth_hz: Bandwidth in Hz (default: 125000)
-            coding_rate: CR denominator, 5=4/5, 6=4/6, 7=4/7, 8=4/8 (default: 5)
-            preamble_len: Preamble symbols (default: 8)
+            spreading_factor: SF7-SF12 (uses config value if None)
+            bandwidth_hz: Bandwidth in Hz (uses config value if None)
+            coding_rate: CR denominator, 5=4/5, 6=4/6, 7=4/7, 8=4/8 (uses config value if None)
+            preamble_len: Preamble symbols (uses config value if None)
             crc_enabled: Whether CRC is enabled (default: True)
             explicit_header: Whether explicit header mode is used (default: True)
         
         Returns:
             Airtime in milliseconds
         """
-        sf = spreading_factor
-        bw_khz = bandwidth_hz / 1000
-        cr = coding_rate
+        sf = spreading_factor or self.spreading_factor
+        bw_khz = (bandwidth_hz or self.bandwidth) / 1000
+        cr = coding_rate or self.coding_rate
+        preamble_len = preamble_len or self.preamble_length
         crc = 1 if crc_enabled else 0
         h = 0 if explicit_header else 1  # H=0 for explicit, H=1 for implicit
         
diff --git a/repeater/engine.py b/repeater/engine.py
index 3b3ee36..3a34e69 100644
--- a/repeater/engine.py
+++ b/repeater/engine.py
@@ -153,10 +153,7 @@ class RepeaterHandler(BaseHandler):
             forwarded_path = list(fwd_pkt.path) if fwd_pkt.path else []
 
             # Check duty-cycle before scheduling TX
-            packet_bytes = (
-                fwd_pkt.write_to() if hasattr(fwd_pkt, "write_to") else fwd_pkt.payload or b""
-            )
-            airtime_ms = PacketTimingUtils.estimate_airtime_ms(len(packet_bytes), self.radio_config)
+            airtime_ms = self.airtime_mgr.calculate_airtime(fwd_pkt.get_raw_length())
 
             can_tx, wait_time = self.airtime_mgr.can_transmit(airtime_ms)
 
@@ -584,8 +581,8 @@ class RepeaterHandler(BaseHandler):
 
         import random
 
-        packet_len = len(packet.payload) if packet.payload else 0
-        airtime_ms = PacketTimingUtils.estimate_airtime_ms(packet_len, self.radio_config)
+        packet_len = packet.get_raw_length()
+        airtime_ms = self.airtime_mgr.calculate_airtime(packet_len)
 
         route_type = packet.header & PH_ROUTE_MASK
 
@@ -660,7 +657,7 @@ class RepeaterHandler(BaseHandler):
                 # Record airtime after successful TX
                 if airtime_ms > 0:
                     self.airtime_mgr.record_tx(airtime_ms)
-                packet_size = len(fwd_pkt.payload)
+                packet_size = fwd_pkt.get_raw_length()
                 logger.info(
                     f"Retransmitted packet ({packet_size} bytes, {airtime_ms:.1f}ms airtime)"
                 )