Wake word cleanup (#98652)

* Make arguments for async_pipeline_from_audio_stream keyword-only after hass

* Use a bytearray ring buffer

* Move generator outside

* Move stt stream generator outside

* Clean up execute

* Refactor VAD to use bytearray

* More tests

* Refactor chunk_samples to be more correct and robust

* Change AudioBuffer to use append instead of setitem

* Cleanup

---------

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

homeassistant/components/assist_pipeline/ring_buffer.py

@@ -0,0 +1,57 @@
+"""Implementation of a ring buffer using bytearray."""
+
+
+class RingBuffer:
+    """Basic ring buffer using a bytearray.
+
+    Not threadsafe.
+    """
+
+    def __init__(self, maxlen: int) -> None:
+        """Initialize empty buffer."""
+        self._buffer = bytearray(maxlen)
+        self._pos = 0
+        self._length = 0
+        self._maxlen = maxlen
+
+    @property
+    def maxlen(self) -> int:
+        """Return the maximum size of the buffer."""
+        return self._maxlen
+
+    @property
+    def pos(self) -> int:
+        """Return the current put position."""
+        return self._pos
+
+    def __len__(self) -> int:
+        """Return the length of data stored in the buffer."""
+        return self._length
+
+    def put(self, data: bytes) -> None:
+        """Put a chunk of data into the buffer, possibly wrapping around."""
+        data_len = len(data)
+        new_pos = self._pos + data_len
+        if new_pos >= self._maxlen:
+            # Split into two chunks
+            num_bytes_1 = self._maxlen - self._pos
+            num_bytes_2 = new_pos - self._maxlen
+
+            self._buffer[self._pos : self._maxlen] = data[:num_bytes_1]
+            self._buffer[:num_bytes_2] = data[num_bytes_1:]
+            new_pos = new_pos - self._maxlen
+        else:
+            # Entire chunk fits at current position
+            self._buffer[self._pos : self._pos + data_len] = data
+
+        self._pos = new_pos
+        self._length = min(self._maxlen, self._length + data_len)
+
+    def getvalue(self) -> bytes:
+        """Get bytes written to the buffer."""
+        if (self._pos + self._length) <= self._maxlen:
+            # Single chunk
+            return bytes(self._buffer[: self._length])
+
+        # Two chunks
+        return bytes(self._buffer[self._pos :] + self._buffer[: self._pos])