"""FEMA NFHL flood zone lookup por lat/lng.

API publica: https://hazards.fema.gov/gis/nfhl/rest/services/public/NFHL/MapServer
Layer 28 = "S_FLD_HAZ_AR" (Special Flood Hazard Areas).

Sin key requerida. Sin rate limits estrictos.

Devuelve dict con:
    zone:    "X" / "X (shaded)" / "A" / "AE" / "AH" / "AO" / "V" / "VE" / etc.
    bfe:     Base Flood Elevation (ft) o None
    sfha:    bool - True si esta en Special Flood Hazard Area
    subtype: subzone description o None
"""

from __future__ import annotations

import requests

from .base import FetcherError, DEFAULT_TIMEOUT


FEMA_URL = "https://hazards.fema.gov/arcgis/rest/services/public/NFHL/MapServer/28/query"

# Zonas que son SFHA (Special Flood Hazard Area) segun FEMA
SFHA_ZONES = {"A", "AE", "AH", "AO", "AR", "A99", "V", "VE", "VO"}


def fetch_flood(lat: float, lng: float) -> dict:
    """Consulta FEMA NFHL para flood zone en (lat, lng).

    Si el punto NO esta en ninguna SFHA, FEMA devuelve features vacio
    y se interpreta como zona X (low risk, default outside SFHA).
    """
    if lat is None or lng is None:
        raise FetcherError("lat/lng requeridos")

    params = {
        "geometry": f"{lng},{lat}",      # FEMA usa lng,lat (x,y)
        "geometryType": "esriGeometryPoint",
        "inSR": "4326",                  # WGS84
        "spatialRel": "esriSpatialRelIntersects",
        "outFields": "FLD_ZONE,STATIC_BFE,ZONE_SUBTY",
        "returnGeometry": "false",
        "f": "json",
    }

    try:
        r = requests.get(FEMA_URL, params=params, timeout=DEFAULT_TIMEOUT)
        r.raise_for_status()
    except requests.RequestException as e:
        raise FetcherError(f"HTTP error: {e}") from e

    try:
        data = r.json()
    except ValueError as e:
        raise FetcherError(f"JSON parse error: {e}") from e

    # FEMA puede devolver "error" si la query es invalida
    if "error" in data:
        raise FetcherError(f"FEMA API error: {data['error']}")

    features = data.get("features", [])
    if not features:
        # Punto fuera de SFHA → low-risk zone X
        return {
            "zone": "X",
            "bfe": None,
            "sfha": False,
            "subtype": None,
            "source": "FEMA NFHL (outside SFHA)",
        }

    attrs = features[0].get("attributes", {}) or {}
    zone = (attrs.get("FLD_ZONE") or "unknown").strip()
    subtype = attrs.get("ZONE_SUBTY")

    # BFE: FEMA usa -9999 para "no aplica"
    bfe_raw = attrs.get("STATIC_BFE")
    bfe = bfe_raw if (bfe_raw is not None and bfe_raw != -9999) else None

    return {
        "zone": zone,
        "bfe": bfe,
        "sfha": zone in SFHA_ZONES,
        "subtype": subtype,
        "source": "FEMA NFHL",
    }