import json
from shapely import Polygon
from shapely import Point
from pathlib import Path


def process_geojson(x, y, diff, expansion=False):
  selection_box = Polygon([[x + diff, y - diff],
                           [x - diff, y - diff],
                           [x - diff, y + diff],
                           [x + diff, y + diff]])
  geojson_file = Path('./data/collinear_clean 2.geojson').resolve()
  if not expansion:
    output_file = Path('./input_files/output_buildings.geojson').resolve()
  else:
    output_file = Path('./input_files/output_buildings_expanded.geojson').resolve()
  buildings_in_region = []

  with open(geojson_file, 'r') as file:
    city = json.load(file)
    buildings = city['features']

  for building in buildings:
    coordinates = building['geometry']['coordinates'][0]
    building_polygon = Polygon(coordinates)
    centroid = Point(building_polygon.centroid)

    if centroid.within(selection_box):
      buildings_in_region.append(building)

  output_region = {"type": "FeatureCollection",
                   "features": buildings_in_region}

  with open(output_file, 'w') as file:
    file.write(json.dumps(output_region, indent=2))

  return output_file