refactor: remove dead code from isr.py

- Drop unused struct import, AudioDevice.extra/description fields
- Remove unused get_preferred_backend() and the backend priority
  machinery (only one backend exists)
- Deduplicate SoundcardRecorder.close_current_file via super()
- Remove duplicate config-exists check in main()
- Simplify --list-devices output: drop dead monitor grouping and the
  nonexistent pipewire backend example

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

isr.py

@@ -10,7 +10,6 @@ import os
 import sys
 import time
 import wave
-import struct
 import signal
 import logging
 import threading
@@ -18,7 +17,7 @@ import configparser
 import subprocess
 import shutil
 from abc import ABC, abstractmethod
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from datetime import datetime, timedelta
 from pathlib import Path
 from typing import Optional, Dict, Any, List, Callable
@@ -57,8 +56,6 @@ class AudioDevice:
     backend: str                     # Backend name ('alsa')
     is_default: bool = False         # Is system default
     is_monitor: bool = False         # Is a monitor/loopback source
-    description: str = ""            # Extended description
-    extra: Dict[str, Any] = field(default_factory=dict)
 
     def __str__(self):
         flags = []
@@ -74,7 +71,6 @@ class AudioBackend(ABC):
     """Abstract base for audio capture backends."""
 
     name: str = "base"
-    priority: int = 0  # Higher = preferred
 
     @classmethod
     @abstractmethod
@@ -99,7 +95,6 @@ class ALSABackend(AudioBackend):
     """ALSA backend using arecord (raw PCM output, no sound server required)."""
 
     name = "alsa"
-    priority = 5  # Lowest priority — direct hardware access, use when no sound server runs
 
     @classmethod
     def is_available(cls) -> bool:
@@ -251,19 +246,12 @@ class AudioSystem:
     def get_backend(self, name: str) -> Optional[AudioBackend]:
         return self._backends.get(name)
 
-    def get_preferred_backend(self) -> Optional[AudioBackend]:
-        """Get the highest priority available backend."""
-        if not self._backends:
-            return None
-        return max(self._backends.values(), key=lambda b: b.__class__.priority)
-
     def list_all_devices(self) -> List[AudioDevice]:
         """List devices from all available backends."""
         all_devices = []
         seen_names = set()
 
-        # Get devices from backends in priority order
+        for cls in self._backend_classes:
-        for cls in sorted(self._backend_classes, key=lambda c: -c.priority):
             if cls.name in self._backends:
                 for dev in cls.list_devices():
                     # Deduplicate by name (same device may appear in multiple backends)
@@ -733,16 +721,9 @@ class SoundcardRecorder(BaseRecorder):
                 self.audio_buffer.clear()
 
     def close_current_file(self):
-        """Close current recording file."""
+        """Flush any buffered audio, then close the current recording file."""
         self._flush_buffer_to_file()
-        if self.current_file:
+        super().close_current_file()
-            try:
-                self.current_file.close()
-                self.logger.info(f"[{self.name}] Closed: {self.current_filename}")
-            except Exception as e:
-                self.logger.error(f"[{self.name}] Error closing file: {e}")
-            self.current_file = None
-            self.current_filename = None
 
     def record(self):
         """Main recording loop."""
@@ -990,22 +971,15 @@ def list_audio_devices():
     print(" ISR Audio Device Discovery")
     print("=" * 70)
 
-    # Check available backends
+    if not ALSABackend.is_available():
-    available_backends = []
-    if ALSABackend.is_available():
-        available_backends.append(('alsa', 'ALSA (arecord)', 5))
-
-    if not available_backends:
         print("\n  No audio backends available!")
-        print("\n  Install one of:")
+        print("\n  Install ALSA utilities:")
-        print("    sudo apt install alsa-utils     (ALSA, always available on Linux)")
+        print("    sudo apt install alsa-utils")
         print()
         return
 
     print("\n Available Backends:")
-    for name, label, priority in sorted(available_backends, key=lambda x: -x[2]):
+    print("   - ALSA (arecord)")
-        marker = " (preferred)" if priority == max(b[2] for b in available_backends) else ""
-        print(f"   - {label}{marker}")
 
     # Initialize audio system and list devices
     audio_system = AudioSystem(logger)
@@ -1016,30 +990,10 @@ def list_audio_devices():
         print()
         return
 
-    # Group by type
-    monitors = [d for d in devices if d.is_monitor]
-    inputs = [d for d in devices if not d.is_monitor]
-
-    if inputs:
     print("\n Input Devices:")
     print(" " + "-" * 68)
-        for dev in inputs:
+    for dev in devices:
-            flags = []
+        flag_str = " [DEFAULT]" if dev.is_default else ""
-            if dev.is_default:
-                flags.append("DEFAULT")
-            flag_str = f" [{', '.join(flags)}]" if flags else ""
-            print(f"\n   {dev.name}{flag_str}")
-            print(f"   ID: {dev.id}  |  Backend: {dev.backend}")
-            print(f"   Channels: {dev.channels}  |  Sample Rate: {dev.sample_rate} Hz")
-
-    if monitors:
-        print("\n Monitor/Loopback Sources:")
-        print(" " + "-" * 68)
-        for dev in monitors:
-            flags = ["MONITOR"]
-            if dev.is_default:
-                flags.append("DEFAULT")
-            flag_str = f" [{', '.join(flags)}]"
         print(f"\n   {dev.name}{flag_str}")
         print(f"   ID: {dev.id}  |  Backend: {dev.backend}")
         print(f"   Channels: {dev.channels}  |  Sample Rate: {dev.sample_rate} Hz")
@@ -1048,10 +1002,9 @@ def list_audio_devices():
     print(" Configuration Examples:")
     print("-" * 70)
     print("   device = default       # Use system default input")
-    print("   device = monitor       # Use first monitor/loopback source")
     print("   device = <name>        # Match by partial name")
-    print("   device = <id>          # Use exact backend ID")
+    print("   device = <id>          # Use exact ALSA ID, e.g. hw:0,0")
-    print("   backend = pipewire     # Force specific backend")
+    print("   device = <pcm>         # Any ALSA PCM name from asound.conf, e.g. shared_mic")
     print("=" * 70 + "\n")
 
 
@@ -1061,17 +1014,11 @@ def main():
         list_audio_devices()
         return
 
-    # Get config file
+    # Get config file (RecorderManager exits with a usage message if it's missing)
     config_file = 'config.ini'
     if len(sys.argv) > 1:
         config_file = sys.argv[1]
 
-    if not os.path.exists(config_file):
-        print(f"Error: Configuration file '{config_file}' not found!")
-        print("Usage: python ISR.py [config.ini]")
-        print("       python ISR.py --list-devices")
-        sys.exit(1)
-
     # Docker sends SIGTERM before SIGKILL — treat it the same as Ctrl+C
     def _sigterm(sig, frame):
         raise KeyboardInterrupt()