#!/usr/bin/python3
# -*- coding: utf-8 -*-

import click
import sys
import functools
import xml.etree.ElementTree as ET
from lxml import etree
from datetime import datetime

@click.command()
@click.option("-f", help="file gpx to process", required=True)
@click.option("-o", help="outputfile", required=False)
@click.option("-op", help="operation to perform", default="INV", show_default=True )
def reapIt(f,op,o):
  tree = etree.parse(f)
  if op =="INV":
    inverse(tree)
  else:
    print("OP unknown") 
    sys.exit()

  if o is None:
      print((etree.tostring(tree, pretty_print=True)).decode('UTF-8'))
  else:
      tree.write(o, pretty_print=True)
      print('File written: ' + o)


def inverse(tree):
  s = tree.xpath('//trkpt')
  

  
  s = sorted(s,key=functools.cmp_to_key(timeComparator),reverse=True)

  #  print(s[0].xpath('time/text()')[0])
  #  print(s[-1].xpath('time/text()')[0])
  segs = tree.xpath('//trkseg')[0]
  segs.clear()
  
  for e in s:
    segs.append(e)
 


def timeComparator(trkpt1, trkpt2):
    d1 = datetime.fromisoformat(trkpt1.xpath('time/text()')[0].replace('Z','+00:00'))
    d2 = datetime.fromisoformat(trkpt2.xpath('time/text()')[0].replace('Z','+00:00'))
    return (int)((d1.timestamp()-d2.timestamp()))




if __name__ == '__main__':
    reapIt()