feat(api): add backend

routes and WebSockets

services/api/app/repositories/audio_repository.py

@@ -0,0 +1,74 @@
+from __future__ import annotations
+
+from datetime import datetime, timedelta
+from sqlalchemy import and_, func, select, text
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.audio_data import AudioData
+
+
+class AudioRepository:
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def latest(self, limit: int) -> list[AudioData]:
+        q = select(AudioData).order_by(AudioData.time.desc()).limit(limit)
+        res = await self.db.execute(q)
+        return list(res.scalars().all())
+
+    async def range(self, time_from: datetime, time_to: datetime) -> list[AudioData]:
+        q = (
+            select(AudioData)
+            .where(and_(AudioData.time >= time_from, AudioData.time <= time_to))
+            .order_by(AudioData.time.asc())
+        )
+        res = await self.db.execute(q)
+        return list(res.scalars().all())
+
+    async def loud_samples(
+        self,
+        threshold: float,
+        time_from: datetime | None,
+        time_to: datetime | None,
+    ) -> list[AudioData]:
+        cond = [AudioData.rms_db >= threshold]
+        if time_from:
+            cond.append(AudioData.time >= time_from)
+        if time_to:
+            cond.append(AudioData.time <= time_to)
+
+        q = select(AudioData).where(and_(*cond)).order_by(AudioData.time.asc())
+        res = await self.db.execute(q)
+        return list(res.scalars().all())
+
+    async def summary_since(self, since: datetime) -> dict:
+        q = select(
+            func.avg(AudioData.rms_db).label("avg_db"),
+            func.max(AudioData.rms_db).label("max_db"),
+            func.sum(func.case((AudioData.is_silence.is_(True), 1), else_=0)).label(
+                "silence_count"
+            ),
+            func.count().label("total_count"),
+        ).where(AudioData.time >= since)
+
+        res = await self.db.execute(q)
+        row = res.one()
+
+        # dominant freq excluding silence
+        fq = (
+            select(AudioData.frequency_hz, func.count().label("cnt"))
+            .where(and_(AudioData.time >= since, AudioData.is_silence.is_(False)))
+            .group_by(AudioData.frequency_hz)
+            .order_by(text("cnt DESC"))
+            .limit(1)
+        )
+        fres = await self.db.execute(fq)
+        frow = fres.first()
+
+        return {
+            "avg_db": float(row.avg_db or 0.0),
+            "max_db": float(row.max_db or 0.0),
+            "dominant_freq": int(frow[0]) if frow else 0,
+            "silence_count": int(row.silence_count or 0),
+            "total_count": int(row.total_count or 0),
+        }