"""
Script to retrieve all Openstreetmap items matching a query and save
them as GPX Waypoints to a given output file in GPX format.
"""

__author__ = "fordprefect"
__date__ = "2020-03-2
__version__ = "0.1"

import gpxpy
import requests
import os
import sys
assert sys.version_info >= (3, 6), "At least Python 3.8 required due to fStrings. Replace all f\"…\" and comment this line to enable running in lower versions (but really, you should just update your Python version…)."

#####################################
######## configuration
#####################################

# search url of nominatim (don't change if you don't know what you are doing!)
url = "https://nominatim.openstreetmap.org/search/"

# search arguments, change query here
# for all supported keys see http://nominatim.org/release-docs/latest/api/Search/
args = {"q": "Wasserwanderplatz", "country": "Germany", "format": "json", "limit": 50}

# bounding box defined by two points [x1, y1, x2, y2]
use_boundingbox = True
boundingbox = [53.898, 11.338, 52.700, 14.332]

# output file name
gpxfilename = f"nominatimsearch_{args['q']}.gpx"

# OSM IDs to be ignored (used to find all matching items)
ignore_ids = []

# maximum number of search queries
maxsearchnums = 10

# verbosity
verbosity = 0

#####################################
######## end of configuration
#####################################

## initialize gpx file
if os.path.isfile(gpxfilename):
    # open file and parse
    if verbosity > 0: print(f"found file, extending")
    gpxfile = gpxpy.parse(open(gpxfilename, "r"))
else:
    if verbosity > 0: print("creating new file")
    gpxfile = gpxpy.gpx.GPX()

# search loop
for i in range(maxsearchnums):
    # fetch request
    if use_boundingbox:
        args["viewbox"] = ",".join(list(map(str, boundingbox)))
    if ignore_ids != []:
        args["exclude_place_ids"] = ",".join(list(map(str, ignore_ids)))
    r = requests.get(url + "?" + "&".join([f"{key}={args[key]}" for key in args]))

    if r.status_code != 200:
        if verbosity > 0: print(f"Query gone wrong: HTTP returned {r.status_code}")
        exit(1)

    # parse reply
    reply = r.json()
    assert isinstance(reply, list), "Unexpected type of reply: " + type(reply)
    if len(reply) == 0:
        if verbosity > 0: print(f"found {len(ignore_ids)} results in {i-1} iterations, finishing")
        break

    for point in reply:
        pid = point["place_id"]
        ignore_ids.append(pid)
        lat = point["lat"]
        lon = point["lon"]
        name = point["display_name"]
        gpxfile.waypoints.append(gpxpy.gpx.GPXWaypoint(latitude=lat, longitude=lon, name=name))

# save to disk
with open(gpxfilename, "w") as f:
    f.write(gpxfile.to_xml())
if verbosity > 0: print(f"GPX file written to {gpxfilename}")