feat(api): add backend

routes and WebSockets

services/api/app/services/audio_service.py

@@ -0,0 +1,16 @@
+from datetime import datetime
+from app.repositories.audio_repository import AudioRepository
+from app.schemas.audio import AudioPoint
+
+
+class AudioService:
+    def __init__(self, repo: AudioRepository):
+        self.repo = repo
+
+    async def latest(self, limit: int) -> list[AudioPoint]:
+        rows = await self.repo.latest(limit)
+        return [AudioPoint.model_validate(r, from_attributes=True) for r in rows]
+
+    async def range(self, time_from: datetime, time_to: datetime) -> list[AudioPoint]:
+        rows = await self.repo.range(time_from, time_to)
+        return [AudioPoint.model_validate(r, from_attributes=True) for r in rows]

services/api/app/services/events_service.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from datetime import datetime
+from app.repositories.audio_repository import AudioRepository
+from app.schemas.events import LoudEvent
+
+
+class EventsService:
+    def __init__(self, repo: AudioRepository):
+        self.repo = repo
+
+    async def loud_events(
+        self,
+        threshold: float,
+        time_from: datetime | None,
+        time_to: datetime | None,
+        max_gap_sec: float = 1.0,
+    ) -> list[LoudEvent]:
+        samples = await self.repo.loud_samples(threshold, time_from, time_to)
+        if not samples:
+            return []
+
+        events: list[LoudEvent] = []
+        start = samples[0].time
+        end = samples[0].time
+        max_db = samples[0].rms_db
+        freq = samples[0].frequency_hz
+
+        for s in samples[1:]:
+            gap = (s.time - end).total_seconds()
+            if gap <= max_gap_sec:
+                end = s.time
+                if s.rms_db > max_db:
+                    max_db = s.rms_db
+            else:
+                events.append(
+                    LoudEvent(
+                        time=start,
+                        rms_db=round(float(max_db), 2),
+                        frequency_hz=int(freq),
+                        duration_sec=round((end - start).total_seconds(), 2),
+                    )
+                )
+                start, end, max_db, freq = s.time, s.time, s.rms_db, s.frequency_hz
+
+        events.append(
+            LoudEvent(
+                time=start,
+                rms_db=round(float(max_db), 2),
+                frequency_hz=int(freq),
+                duration_sec=round((end - start).total_seconds(), 2),
+            )
+        )
+        return events

services/api/app/services/stats_service.py

@@ -0,0 +1,35 @@
+from datetime import datetime, timedelta
+from app.repositories.audio_repository import AudioRepository
+from app.schemas.stats import StatsSummary
+
+_PERIODS = {
+    "10s": timedelta(seconds=10),
+    "1m": timedelta(minutes=1),
+    "1h": timedelta(hours=1),
+    "6h": timedelta(hours=6),
+    "24h": timedelta(hours=24),
+    "7d": timedelta(days=7),
+    "30d": timedelta(days=30),
+}
+
+
+class StatsService:
+    def __init__(self, repo: AudioRepository):
+        self.repo = repo
+
+    async def summary(self, period: str) -> StatsSummary:
+        if period not in _PERIODS:
+            raise ValueError(f"Unsupported period: {period}")
+
+        since = datetime.utcnow() - _PERIODS[period]
+        raw = await self.repo.summary_since(since)
+
+        total = raw["total_count"]
+        silence_percent = (raw["silence_count"] / total * 100.0) if total else 0.0
+
+        return StatsSummary(
+            avg_db=round(raw["avg_db"], 2),
+            max_db=round(raw["max_db"], 2),
+            dominant_freq=raw["dominant_freq"],
+            silence_percent=round(silence_percent, 2),
+        )