core.py

"""
core.py

Implement get_location_properties(lat, lon) that:
- loads Survey of India shapefiles from `data/` (lazy loaded)
- performs point-in-polygon lookups (GeoPandas + Shapely)
- returns a small dict with required fields

NOTE: This is a minimal starter skeleton. Update attribute names depending on your SoI shapefile schemas.
"""

import geopandas as gpd
from shapely.geometry import Point
import os

# Update these to match your SoI filenames (place under data/)
SEISMIC_SHP = os.path.join("data", "soi_seismic_zones.shp")
WIND_SHP = os.path.join("data", "soi_wind_regions.shp")

# Lazy-loaded caches
_seismic_gdf = None
_wind_gdf = None

def _load_gdfs():
    global _seismic_gdf, _wind_gdf
    if _seismic_gdf is None:
        if not os.path.exists(SEISMIC_SHP):
            raise FileNotFoundError(
                f"Missing Survey-of-India seismic shapefile: {SEISMIC_SHP}\n"
                "Place SoI shapefile(s) in data/ or update core.py"
            )
        _seismic_gdf = gpd.read_file(SEISMIC_SHP)
    if _wind_gdf is None:
        if not os.path.exists(WIND_SHP):
            raise FileNotFoundError(
                f"Missing Survey-of-India wind shapefile: {WIND_SHP}\n"
                "Place SoI shapefile(s) in data/ or update core.py"
            )
        _wind_gdf = gpd.read_file(WIND_SHP)

def get_location_properties(lat: float, lon: float) -> dict:
    """
    Return properties for a given lat, lon.

    Output (minimum):
    {
      'lat': float,
      'lon': float,
      'seismic_zone': 'II'|'III'|'IV'|'V'|None,
      'basic_wind_speed': float|None,
      'notes': str
    }
    """
    _load_gdfs()
    pt = Point(lon, lat)  # (x=lon, y=lat)
    res = {"lat": lat, "lon": lon, "seismic_zone": None, "basic_wind_speed": None, "notes": ""}

    # seismic lookup
    try:
        if hasattr(_seismic_gdf, "sindex") and _seismic_gdf.sindex:
            candidate_idx = list(_seismic_gdf.sindex.query(pt))
            candidate = _seismic_gdf.iloc[candidate_idx] if candidate_idx else _seismic_gdf
        else:
            candidate = _seismic_gdf
        containing = candidate[candidate.contains(pt)]
        if not containing.empty:
            # Common field names: 'ZONE', 'zone', 'SeismicZ' etc. Adapt per file.
            for key in ("ZONE", "zone", "SeismicZone", "SeisZone", "SEIZONE"):
                if key in containing.columns:
                    res["seismic_zone"] = str(containing.iloc[0][key])
                    break
            # fallback: find string like II/III/IV/V
            if res["seismic_zone"] is None:
                for c in containing.columns:
                    val = containing.iloc[0][c]
                    if isinstance(val, str) and val.strip().upper() in {"II", "III", "IV", "V"}:
                        res["seismic_zone"] = val.strip().upper()
                        break
    except Exception as e:
        res["notes"] += f"Seismic lookup error: {e}. "

    # wind lookup
    try:
        if hasattr(_wind_gdf, "sindex") and _wind_gdf.sindex:
            candidate_idx = list(_wind_gdf.sindex.query(pt))
            candidate = _wind_gdf.iloc[candidate_idx] if candidate_idx else _wind_gdf
        else:
            candidate = _wind_gdf
        containing = candidate[candidate.contains(pt)]
        if not containing.empty:
            for key in ("Vb", "vb", "WIND_SPEED", "wind_speed", "BasicWind"):
                if key in containing.columns:
                    try:
                        res["basic_wind_speed"] = float(containing.iloc[0][key])
                        break
                    except Exception:
                        continue
            # fallback: try to coerce first numeric column
            if res["basic_wind_speed"] is None:
                for c in containing.columns:
                    try:
                        res["basic_wind_speed"] = float(containing.iloc[0][c])
                        break
                    except Exception:
                        continue
    except Exception as e:
        res["notes"] += f"Wind lookup error: {e}. "

    return res