Reorganize stats (#9960)

* Reorganize stats

* Fix tests

frigate/stats/emitter.py

@@ -0,0 +1,61 @@
+"""Emit stats to listeners."""
+
+import json
+import logging
+import threading
+import time
+from multiprocessing.synchronize import Event as MpEvent
+
+from frigate.comms.inter_process import InterProcessRequestor
+from frigate.config import FrigateConfig
+from frigate.stats.util import stats_snapshot
+from frigate.types import StatsTrackingTypes
+
+logger = logging.getLogger(__name__)
+
+
+class StatsEmitter(threading.Thread):
+    def __init__(
+        self,
+        config: FrigateConfig,
+        stats_tracking: StatsTrackingTypes,
+        stop_event: MpEvent,
+    ):
+        threading.Thread.__init__(self)
+        self.name = "frigate_stats_emitter"
+        self.config = config
+        self.stats_tracking = stats_tracking
+        self.stop_event = stop_event
+        self.hwaccel_errors: list[str] = []
+        self.stats_history: list[dict[str, any]] = []
+
+        # create communication for stats
+        self.requestor = InterProcessRequestor()
+
+    def get_latest_stats(self) -> dict[str, any]:
+        """Get latest stats."""
+        if len(self.stats_history) > 0:
+            return self.stats_history[-1]
+        else:
+            stats = stats_snapshot(
+                self.config, self.stats_tracking, self.hwaccel_errors
+            )
+            self.stats_history.append(stats)
+            return stats
+
+    def get_stats_history(self) -> list[dict[str, any]]:
+        """Get stats history."""
+        return self.stats_history
+
+    def run(self) -> None:
+        time.sleep(10)
+        while not self.stop_event.wait(self.config.mqtt.stats_interval):
+            logger.debug("Starting stats collection")
+            stats = stats_snapshot(
+                self.config, self.stats_tracking, self.hwaccel_errors
+            )
+            self.stats_history.append(stats)
+            self.stats_history = self.stats_history[-10:]
+            self.requestor.send_data("stats", json.dumps(stats))
+            logger.debug("Finished stats collection")
+        logger.info("Exiting stats emitter...")