#!/bin/python3

import osmapi
import shapely
import pickle
from os.path import exists


OSM_KOGGENLAND_ID = 161930
PICKLE_FILE = 'polygon.pickle'


def chunks(lst, n):
    """Yield successive n-sized chunks from lst."""
    for i in range(0, len(lst), n):
        yield lst[i:i + n]


def dump_polygon():
    osm_api = osmapi.OsmApi()
    koggenland = osm_api.RelationGet(OSM_KOGGENLAND_ID)
    ways = filter(lambda x: x['type'] == 'way', koggenland['member'])
    shell_ids = []

    for way in ways:
        way = osm_api.WayGet(way['ref'])
        node_ids = way['nd']
        if not shell_ids:
            shell_ids.append(node_ids[0])
        for node_id in node_ids[1:]:
            shell_ids.append(node_id)

    node_data = dict()
    for chunk in chunks(shell_ids, 100):
        node_data |= osm_api.NodesGet(chunk)

    shell = list()
    for shell_id in shell_ids:
        node = node_data[shell_id]
        shell.append((node['lat'], node['lon']))

    koggenland_polygon = shapely.Polygon(shell)
    with open(PICKLE_FILE, 'wb') as f:
        pickle.dump(koggenland_polygon, f)


def main():
    if not exists(PICKLE_FILE):
        print('Using OSM API to create polygon...')
        dump_polygon()
        print('Dumped polygon to file.')
    with open(PICKLE_FILE, 'rb') as f:
        area = pickle.load(f)
        print('Loaded polygon from file.')

    point_out = shapely.Point(52.68811, 4.91267)
    point_in = shapely.Point(52.69168, 4.91324)

    print('out', area.contains(point_out))
    print('in', area.contains(point_in))


if __name__ == '__main__':
    main()