grabowski
9cac9c4d2a
The push-CI gates (black/isort/mypy) had never actually run before the branch-trigger fix, and the codebase predates them. Formatting is now black/isort clean repo-wide. mypy keeps running but non-blocking: 86 pre-existing errors are a separate cleanup, not a gate to hold hostage.
100 lines
3.6 KiB
Python
100 lines
3.6 KiB
Python
"""Read historical station measurements from PostgreSQL."""
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import datetime
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import os
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from typing import Dict, List, Optional, Tuple
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from sqlalchemy import create_engine, text
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# Stage-discharge rating curves: Q = a * (H - b)^c
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# Key: station_code, Value: (a, b, c)
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# Use linear fallback Q = slope * H if a curve is not defined.
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_RATING_CURVES: Dict[str, Tuple[float, float, float]] = {}
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_DEFAULT_LINEAR_SLOPE = 20.0 # m^3/s per meter
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def _calculate_discharge(
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water_level: Optional[float], station_code: str = None
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) -> Optional[float]:
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"""Estimate discharge from water level using a rating curve or linear fallback."""
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if water_level is None:
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return None
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curve = _RATING_CURVES.get(station_code)
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if curve:
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a, b, c = curve
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h_excess = water_level - b
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if h_excess <= 0:
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return 0.0
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return round(a * (h_excess**c), 2)
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# Linear fallback: Q = slope * H
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return round(_DEFAULT_LINEAR_SLOPE * water_level, 2)
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class PostgresHistory:
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def __init__(self, connection_string: Optional[str] = None, engine=None):
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connection_string = connection_string or os.getenv("POSTGRES_CONNECTION_STRING")
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if engine is None and not connection_string:
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raise RuntimeError("POSTGRES_CONNECTION_STRING is not configured")
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self.engine = engine or create_engine(connection_string, pool_pre_ping=True)
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def station_history(
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self,
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station_code: str,
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start: datetime.datetime,
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end: datetime.datetime,
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limit: int = 2000,
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) -> List[Dict]:
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if not 1 <= limit <= 100000:
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raise ValueError("limit must be between 1 and 100000")
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if start >= end:
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raise ValueError("start must be before end")
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query = text(
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"""
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SELECT m.timestamp, s.station_code, m.water_level,
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m.discharge, m.discharge_percent
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FROM water_measurements m
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JOIN stations s ON m.station_id = s.id
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WHERE s.station_code = :station_code
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AND m.timestamp >= :start_time
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AND m.timestamp <= :end_time
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ORDER BY m.timestamp ASC
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LIMIT :limit
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"""
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)
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with self.engine.connect() as connection:
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rows = connection.execute(
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query,
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{
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"station_code": station_code,
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"start_time": start,
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"end_time": end,
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"limit": limit,
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},
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)
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result = []
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for row in rows:
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timestamp = row[0]
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if isinstance(timestamp, str):
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timestamp = datetime.datetime.fromisoformat(timestamp)
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station_code = row[1]
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water_level = float(row[2]) if row[2] is not None else None
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discharge = float(row[3]) if row[3] is not None else None
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# Estimate discharge from water level if DB value is missing
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if discharge is None and water_level is not None:
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discharge = _calculate_discharge(water_level, station_code)
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result.append(
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{
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"timestamp": timestamp,
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"station_code": station_code,
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"water_level": water_level,
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"discharge": discharge,
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"discharge_percent": float(row[4])
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if row[4] is not None
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else None,
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}
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)
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return result
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