from shapely import MultiPolygon, Polygon, Geometry, to_wkb, from_wkb
from sqlalchemy.types import TypeDecorator, LargeBinary


def convert_outage_geometry(event) -> MultiPolygon:
    assert event["polygons"]["type"] == "polygon"
    assert event["polygons"]["hasZ"] is False
    assert event["polygons"]["hasM"] is False
    polygon_list = []
    for ring in event["polygons"]["rings"]:
        polygon_list.append(Polygon(ring))
    return MultiPolygon(polygon_list)


class DBGeometry(TypeDecorator):
    impl = LargeBinary
    cache_ok = True

    def process_bind_param(self, value, dialect):
        if isinstance(value, Geometry):
            value = to_wkb(value)
        return value

    def process_result_value(self, value, dialect):
        if value is None:
            return value
        else:
            if not isinstance(value, Geometry):
                value = from_wkb(value)
            return value