feat: add application parameter to choose a custom microphone

ref: N25B-119

src/robot_interface/utils/microphone.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals  # So that `print` can print Unicode characters in names
 import logging
+import sys
 
 logger = logging.getLogger(__name__)
 
@@ -67,3 +68,53 @@ def choose_mic_default(audio):
         return audio.get_default_input_device_info()
     except IOError:
         return None
+
+
+def choose_mic_arguments(audio):
+    """
+    Get a microphone to use from command line arguments.
+
+    :param audio: An instance of PyAudio to use.
+    :type audio: pyaudio.PyAudio
+
+    :return: A dictionary from PyAudio containing information about the microphone to use, or None
+    if there is no microphone satisfied by the arguments.
+    :rtype: dict | None
+    """
+    microphone_name = None
+    for i, arg in enumerate(sys.argv):
+        if arg == "--microphone" and len(sys.argv) > i+1:
+            microphone_name = sys.argv[i+1].strip()
+        if arg.startswith("--microphone="):
+            microphone_name = arg[13:].strip()
+
+    if not microphone_name: return None
+
+    available_mics = list(get_microphones(audio))
+    for mic in available_mics:
+        if mic["name"] == microphone_name:
+            return mic
+
+    available_mic_names = [mic["name"] for mic in available_mics]
+    logger.warning("Microphone \"{}\" not found. Choose one of {}"
+                   .format(microphone_name, available_mic_names))
+
+    return None
+
+
+def choose_mic(audio):
+    """
+    Get a microphone to use. Firstly, tries to see if there's an application argument specifying the
+    microphone to use. If not, get the default microphone.
+
+    :param audio: An instance of PyAudio to use.
+    :type audio: pyaudio.PyAudio
+
+    :return: A dictionary from PyAudio containing information about the microphone to use, or None
+    if there is no microphone.
+    :rtype: dict | None
+    """
+    chosen_mic = choose_mic_arguments(audio)
+    if chosen_mic: return chosen_mic
+
+    return choose_mic_default(audio)