now a working radio controller

lib_denon.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import argparse
+import socket
 import ssl
 import sys
 from collections.abc import Callable
@@ -10,6 +11,8 @@ from urllib.error import URLError
 from urllib.parse import quote
 from urllib.request import Request, urlopen
 
+import lib_heos
+
 
 _host = "192.168.178.177"
 _port = 8080
@@ -54,12 +57,44 @@ def off() -> None:
     _command("PWSTANDBY")
 
 
+def _power_state() -> str:
+    """Return ON or STANDBY using Denon's control-protocol status query."""
+    try:
+        with socket.create_connection((_host, 23), timeout=_timeout) as connection:
+            connection.settimeout(_timeout)
+            connection.sendall(b"PW?\r")
+            with connection.makefile("r", encoding="ascii", newline="\r") as stream:
+                while line := stream.readline():
+                    response = line.strip()
+                    if response.startswith("PW"):
+                        state = response[2:]
+                        if state in {"ON", "STANDBY"}:
+                            return state
+    except OSError as error:
+        raise RuntimeError(f"Cannot query Denon power state: {error}") from error
+    raise RuntimeError("Denon did not return a valid power state")
+
+
 def next() -> None:
-    """Select the next preset or source."""
+    """Play the next HEOS favorite according to the receiver's power state."""
+    lib_heos.configure(_host, timeout=_timeout)
+    if _power_state() == "STANDBY":
+        lib_heos.play_favorite(1)
+        return
+    # Deliberately do nothing when the receiver is on but its current media is
+    # not one of the configured HEOS favorites.
+    lib_heos.next_favorite()
 
 
 def previous() -> None:
-    """Select the previous preset or source."""
+    """Play the previous HEOS favorite according to the receiver's power state."""
+    lib_heos.configure(_host, timeout=_timeout)
+    if _power_state() == "STANDBY":
+        lib_heos.play_favorite(1)
+        return
+    # Deliberately do nothing when the receiver is on but its current media is
+    # not one of the configured HEOS favorites.
+    lib_heos.previous_favorite()
 
 
 def volume_up() -> None:
@@ -74,12 +109,25 @@ def volume_down() -> None:
         _command("MVDOWN")
 
 
+def volume_mute() -> None:
+    """Mute the volume."""
+    _command("MUON")
+
+
 def main() -> int:
     """Run a receiver action from the command line."""
     parser = argparse.ArgumentParser(description="Control the Denon receiver")
     parser.add_argument(
         "action",
-        choices=("on", "off", "next", "previous", "volume-up", "volume-down"),
+        choices=(
+            "on",
+            "off",
+            "next",
+            "previous",
+            "volume-up",
+            "volume-down",
+            "volume-mute",
+        ),
     )
     parser.add_argument("--host", default=_host, help=f"receiver address (default: {_host})")
     parser.add_argument("--port", type=int, default=_port, help=f"HTTP port (default: {_port})")
@@ -116,10 +164,11 @@ def main() -> int:
         "previous": previous,
         "volume-up": volume_up,
         "volume-down": volume_down,
+        "volume-mute": volume_mute,
     }
     try:
         actions[args.action]()
-    except (OSError, URLError) as error:
+    except (OSError, URLError, RuntimeError, lib_heos.HeosError) as error:
         print(f"Denon {args.action} failed: {error}", file=sys.stderr)
         return 1
     return 0