feat(scada): add project monitoring replay

app/services/scada_raw.py

@@ -0,0 +1,66 @@
+"""Read-only chronological SCADA paging shared by REST and replay processing."""
+from __future__ import annotations
+
+import base64
+import hashlib
+import json
+import math
+from datetime import datetime
+
+from app.domain.schemas.scada import ScadaRawPage, ScadaRawReading
+from app.infra.db.timescaledb.repositories.scada import ScadaRepository
+
+
+def validate_window(start: datetime, end: datetime) -> None:
+    if start.tzinfo is None or end.tzinfo is None or start >= end:
+        raise ValueError("需要带时区、结束晚于开始的 SCADA 时间区间")
+
+
+def raw_reading(row: dict) -> ScadaRawReading:
+    value = row["monitored_value"]
+    invalid = value is not None and not math.isfinite(float(value))
+    return ScadaRawReading(
+        time=row["time"], device_id=row["device_id"],
+        monitored_value=None if invalid else value,
+        quality="invalid" if invalid else "missing" if value is None else "unvalidated",
+    )
+
+
+async def read_raw_page(
+    conn, *, project_id: str, device_ids: list[str], start: datetime,
+    end: datetime, limit: int = 500, cursor: str | None = None,
+    through: datetime | None = None,
+) -> ScadaRawPage:
+    validate_window(start, end)
+    ids = sorted(set(device_ids))
+    if not ids or len(ids) > 500 or not 1 <= limit <= 500:
+        raise ValueError("请选择 1 至 500 个设备，每页最多 500 条")
+    cap = min(through or end, end)
+    if cap.tzinfo is None or cap < start:
+        raise ValueError("模拟时间不在可读取区间内")
+    signature = hashlib.sha256(json.dumps(
+        [project_id, ids, start.isoformat(), end.isoformat()], separators=(",", ":")
+    ).encode()).hexdigest()
+    after = None
+    if cursor:
+        try:
+            data = json.loads(base64.urlsafe_b64decode(cursor.encode()))
+            frozen = datetime.fromisoformat(data["through"])
+            last = datetime.fromisoformat(data["time"])
+            if (data["query"] != signature or frozen.tzinfo is None or last.tzinfo is None
+                    or frozen > cap or not start <= last <= frozen or data["device"] not in ids):
+                raise ValueError()
+            cap, after = frozen, (last, data["device"])
+        except (ValueError, KeyError, TypeError, UnicodeError) as exc:
+            raise ValueError("SCADA 分页游标无效或查询范围已改变") from exc
+    rows = await ScadaRepository.get_raw_page(conn, ids, start, end, cap, limit + 1, after)
+    selected = rows[:limit]
+    next_cursor = None
+    if len(rows) > limit:
+        last = selected[-1]
+        next_cursor = base64.urlsafe_b64encode(json.dumps({
+            "query": signature, "through": cap.isoformat(),
+            "time": last["time"].isoformat(), "device": last["device_id"],
+        }, separators=(",", ":")).encode()).decode()
+    return ScadaRawPage(items=[raw_reading(row) for row in selected],
+                        next_cursor=next_cursor, scanned_through=cap)