second version

backend/app/routers/ev.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import date, datetime
 from typing import Annotated, Any
 
 import asyncpg
@@ -91,3 +91,88 @@ async def patch_ev_session(
         if row is None:
             raise HTTPException(status_code=404, detail="Session not found")
         return EvSessionPatchResponse(success=True, session_id=int(row["id"]))
+
+
+class ArrivalHourItem(BaseModel):
+    hour: int
+    confidence_pct: int
+    samples: int
+
+
+class ChargerTomorrowArrival(BaseModel):
+    tomorrow: list[ArrivalHourItem]
+
+
+class EvArrivalPredictionResponse(BaseModel):
+    insufficient_data: bool
+    tomorrow_date: str
+    chargers: dict[str, ChargerTomorrowArrival]
+
+
+@router.get("/arrival-prediction", response_model=EvArrivalPredictionResponse)
+async def get_ev_arrival_prediction(
+    site_id: int,
+    pool: Annotated[asyncpg.Pool, Depends(get_pg_pool)],
+) -> EvArrivalPredictionResponse:
+    """Top hodiny příjezdu z ems.fn_ev_expected_arrival; při <5 session celkem insufficient_data."""
+    async with pool.acquire() as conn:
+        site_ok = await conn.fetchval("SELECT EXISTS(SELECT 1 FROM ems.site WHERE id = $1)", site_id)
+        if not site_ok:
+            raise HTTPException(status_code=404, detail="Site not found")
+
+        n_sessions = int(
+            await conn.fetchval(
+                "SELECT COUNT(*)::int FROM ems.ev_session WHERE site_id = $1",
+                site_id,
+            )
+            or 0
+        )
+        insufficient = n_sessions < 5
+
+        tomorrow = await conn.fetchval(
+            """
+            SELECT (
+                CURRENT_TIMESTAMP AT TIME ZONE COALESCE(
+                    NULLIF(TRIM(timezone), ''),
+                    'Europe/Prague'
+                )
+            )::date + 1
+            FROM ems.site
+            WHERE id = $1
+            """,
+            site_id,
+        )
+        if tomorrow is None:
+            raise HTTPException(status_code=500, detail="Site date resolution failed")
+        tomorrow_d: date = tomorrow
+
+        chargers_rows = await conn.fetch(
+            "SELECT id, code FROM ems.asset_ev_charger WHERE site_id = $1 ORDER BY id",
+            site_id,
+        )
+
+        chargers: dict[str, ChargerTomorrowArrival] = {}
+        for ch in chargers_rows:
+            code = str(ch["code"])
+            preds = await conn.fetch(
+                "SELECT * FROM ems.fn_ev_expected_arrival($1, $2, $3::date)",
+                site_id,
+                ch["id"],
+                tomorrow_d,
+            )
+            chargers[code] = ChargerTomorrowArrival(
+                tomorrow=[
+                    ArrivalHourItem(
+                        hour=int(r["expected_hour"]),
+                        confidence_pct=int(r["confidence_pct"]),
+                        samples=int(r["sample_count"]),
+                    )
+                    for r in preds
+                ]
+            )
+
+    return EvArrivalPredictionResponse(
+        insufficient_data=insufficient,
+        tomorrow_date=tomorrow_d.isoformat(),
+        chargers=chargers,
+    )