#!/bin/python3

import argparse
import gpxpy
import gpxpy.gpx
import shapely
import pickle


def main(args):
    with open(args.polygon_file, 'rb') as f:
        area = pickle.load(f)

    with open(args.input_file, 'rb') as f:
        gpx = gpxpy.parse(f)

    gpx.waypoints = list(filter(lambda wp: area.contains(
        shapely.Point(wp.latitude, wp.longitude)), gpx.waypoints))

    with open(args.output_file, 'w') as f:
        f.write(gpx.to_xml())


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description="""
    Takes an input GPX file containing
    geocaches and filters out any waypoints outside a given area.
    """)
    parser.add_argument("input-file", help="Input GPX file")
    parser.add_argument("output-file", help="Output GPX file")
    parser.add_argument(
        "-p", "--polygon-file", help="File containing area's polygon",
        default="polygon.pickle")
    args = parser.parse_args()

    main(args)