"""
KARST feature extractor for geological characteristics.
Single Responsibility: Extract karst-specific features.
"""
import geopandas as gpd
from typing import Dict, Any, Optional
from pathlib import Path
from .base import BaseFeatureExtractor


class KarstExtractor(BaseFeatureExtractor):
    """
    Extracts karst-related geological features.

    Features:
    - Karst presence/index
    - Bedrock permeability
    - Sinkhole density
    - Infiltration capacity (from IDPR data)
    - Aquifer characteristics
    """

    def __init__(
        self,
        idpr_data: Optional[Any] = None,
        karst_layer: Optional[Path] = None,
        **kwargs
    ):
        """
        Initialize karst extractor.

        Args:
            idpr_data: IDPR dataframe (infiltration vs runoff)
            karst_layer: Path to karst geological layer (shapefile/raster)
            **kwargs: Additional parameters
        """
        super().__init__(**kwargs)
        self.idpr_data = idpr_data
        self.karst_layer = karst_layer

    def extract(self, basin_gdf: gpd.GeoDataFrame) -> Dict[str, Any]:
        """
        Extract karst features from basin.

        Args:
            basin_gdf: GeoDataFrame with basin geometry

        Returns:
            Dictionary with karst features
        """
        if not self.validate_inputs(basin_gdf):
            raise ValueError("Invalid basin GeoDataFrame")

        features = {}

        # IDPR-based infiltration capacity
        if self.idpr_data is not None:
            features.update(self._extract_idpr_features(basin_gdf))

        # Karst geological features (placeholder)
        if self.karst_layer:
            features.update(self._extract_karst_geology(basin_gdf))

        return features

    def _extract_idpr_features(self, basin_gdf: gpd.GeoDataFrame) -> Dict[str, float]:
        """
        Extract IDPR (infiltration vs runoff tendency) features.

        IDPR developed by BRGM measures tendency toward infiltration or runoff.
        Higher values = more infiltration (karst behavior)
        """
        # This would involve spatial join with IDPR data
        # Placeholder implementation
        return {
            "idpr_mean": None,  # Mean IDPR value in basin
            "idpr_max": None,   # Max IDPR (most karst-prone areas)
            "infiltration_capacity": None  # Derived metric
        }

    def _extract_karst_geology(self, basin_gdf: gpd.GeoDataFrame) -> Dict[str, float]:
        """
        Extract karst geological characteristics.

        This would involve:
        - Intersecting with geological maps
        - Identifying karst lithology (limestone, dolomite)
        - Calculating karst area fraction
        """
        return {
            "karst_presence": None,      # Boolean or fraction
            "karst_area_fraction": None, # % of basin with karst
            "bedrock_permeability": None,# Estimated permeability
            "sinkhole_density": None     # Sinkholes per km²
        }

    def get_feature_names(self) -> list:
        """Get list of feature names."""
        return [
            "idpr_mean", "idpr_max", "infiltration_capacity",
            "karst_presence", "karst_area_fraction",
            "bedrock_permeability", "sinkhole_density"
        ]