import argparse
from collections import OrderedDict
import fiona
import shapely.geometry
from fiona.crs import CRS
from fiona.transform import transform_geom
from shapely.wkt import dumps

# data from https://www.naturalearthdata.com/downloads/50m-cultural-vectors/
ZIP_FILE = '/home/philipp/daten/GeoData/naturalearth/v5.1/ne_50m_admin_0_countries.zip'
LAYER_NAME = 'ne_50m_admin_0_countries'


def load_country(country_name: str):
    with fiona.open(f'zip://{ZIP_FILE}', layer=LAYER_NAME) as src:
        for feature in src:
            properties = feature['properties']
            if properties['NAME'] == country_name:
                return feature['geometry'], src.crs


def simplify_inner(country, crs):
    metric_crs = CRS.from_epsg(32632)  # Western Austria (UTM32)
    country = transform_geom(crs, metric_crs, country)
    country = shapely.geometry.shape(country)
    country = country.buffer(-5000)
    country = country.simplify(tolerance=5000)
    country = shapely.geometry.mapping(country)
    country = transform_geom(metric_crs, crs, country)
    return country


def save_country(country, crs, name, shapefile):
    schema = {
        'geometry': 'Polygon',
        'properties': OrderedDict([('name', 'str')])
    }
    with fiona.open(shapefile, 'w', crs=crs, schema=schema, driver='Shapefile') as c:
        feature = {
            'geometry': country,
            'properties': OrderedDict([('name', name)]),
        }
        c.write(feature)


def print_wkt(country):
    country = shapely.geometry.shape(country)
    print(dumps(country, rounding_precision=3))


def main(country_name: str, shapefile: str | None):
    country, crs = load_country(country_name)
    simplified_country = simplify_inner(country, crs)
    if shapefile:
        save_country(simplified_country, crs, country_name, shapefile)
    print_wkt(simplified_country)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Creates a simplified version of a country')
    parser.add_argument('--country', default='Austria', help='Country to simplify (e.g. Switzerland)')
    parser.add_argument('--shapefile', help='Write result to shape file with this name')
    args = parser.parse_args()
    main(args.country, args.shapefile)