#!/usr/bin/python
"""
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__ = "2020-03-26"
__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…)."

class OSMSearch():
    def __init__(self, args): 
        """
        TODO: write docstring
        """
        self.url = args.pop("url")
        self.maxsearchnums = args.pop("maxsearchnums")
        self.save_to_file = True if args["output"] == "disk" else False
        if self.save_to_file:
            self.gpxfilename = args.pop("outputfilename")
        self.print_xml = True if args["output"] == "print" else False
        self.use_boundingbox = args.pop("use_boundingbox")
        self.ignore_ids = args.pop("ignore_ids")
        if self.use_boundingbox:
            assert isinstance(list, args["boundingbox"])
            assert len(args["boundingbox"]) == 4
        else:
            args.pop("boundingbox")

        self.searchargs = args

        self.initialize_gpx_file()

        self.search()
        
        if self.save_to_file:
            self.save_to_disk()
        if self.print_xml:
            self.print_to_stdout()

    def initialize_gpx_file(self):
        if not self.save_to_file:
            self.gpxfile = gpxpy.gpx.GPX()
            return

        if os.path.isfile(self.gpxfilename):
            raise NotImplementedError("We don't know how to deal with existing files yet, sry")
            # TODO: file name collision? either:
            # 1) amend file
            #self.gpxfile = gpxpy.parse(open(gpxfilename, "r"))
            # 2) refuse to work
            # 3) alter file name
        else:
            self.gpxfile = gpxpy.gpx.GPX()

    def get_argstring(self):
        argstrings = []

        if self.use_boundingbox:
            argstring.append(",".join(list(map(str, self.searchargs["boundingbox"]))))
        if self.ignore_ids != []:
            argstrings.append(f"ignore_ids=" + ",".join(list(map(str, self.ignore_ids))))
        for arg in self.searchargs:
            argstrings.append(f"{arg}={self.searchargs[arg]}")

        return "?"+"&".join(argstrings)


    def search(self):
        """
        """

        for i in range(self.maxsearchnums):
            # fetch request
            r = requests.get(self.url + self.get_argstring())

            if r.status_code != 200:
                exit(1)

            # parse reply
            reply = r.json()
            assert isinstance(reply, list), "Unexpected type of reply: " + type(reply)
            if len(reply) == 0:
                break

            for point in reply:
                self.ignore_ids.append(point["place_id"])
                # TODO use better name than "display_name", maybe add more info to Waypoint
                self.gpxfile.waypoints.append(gpxpy.gpx.GPXWaypoint(latitude=point["lat"], longitude=point["lon"], name=point["display_name"]))

    def save_to_disk(self):
        with open(self.gpxfilename, "w") as f:
            f.write(self.gpxfile.to_xml())

    def print_to_stdout(self):
        print(self.gpxfile.to_xml())

default_args = {
    "q": "Camping",
    "format": "json",
    "limit": 50,
    "use_boundingbox": False,
    "boundingbox": [],
    "outputfilename": "test.gpx",
    "ignore_ids": [],
    "maxsearchnums": 10,
    "url": "https://nominatim.openstreetmap.org/search/",
    "output": "print",
}

if __name__ == "__main__":
    # cli invocation goes here
    # TODO: take user arguments and bring together with sensible defaults above
    OSMSearch(default_args)