import xml.etree.ElementTree as etree
import datetime
from geopy.distance import geodesic
import re
import argparse

def extract(filename, tz, threshold, verbose):
	ns = {"kml": "http://www.opengis.net/kml/2.2"}

	outfile = filename.split(".")[0] + ".csv"
	tree = etree.parse(filename)
	root = tree.getroot()

	track1 = root.find("kml:Document/kml:Folder[@id='Tracks']/kml:Folder[@id='track 1']", ns)
	points = track1.find("kml:Folder[@id='track 1 points']", ns)
	placemarks = points.findall("kml:Placemark", ns)
	placemarks_count = len(placemarks)
	last_elevation = None
	last_coordinates = None
	last_timestamp = None
	first_timestamp = None
	distance = 0.0
	stop_time = 0
	elev_gain = 0
	elev_loss = 0
	
	if verbose:
		print(f"Processing {placemarks_count} points")

	with open(outfile, 'w') as csv_file:
		csv_file.write("TimeStamp,Elapsed Time (s),Distance (km),Speed (km/h),Elevation (m),Elev. gain (m),Elev. loss (m),Stop time (min)\n")

	for placemark in placemarks:
		timestamp = datetime.datetime.strptime(placemark.find("kml:TimeStamp/kml:when", ns).text, "%Y-%m-%dT%H:%M:%SZ").replace(tzinfo=datetime.timezone(datetime.timedelta(hours=0)))
		lng_lat_elev = placemark.find("kml:Point/kml:coordinates", ns).text.split(",")
		longitude = float(lng_lat_elev[0])
		latitude = float(lng_lat_elev[1])
		elevation = float(lng_lat_elev[2])

		if first_timestamp is None:
			first_timestamp = timestamp

		if last_coordinates is not None and last_timestamp is not None:
			delta_km = geodesic(last_coordinates, (latitude, longitude)).km
			time_spent = (timestamp - last_timestamp).total_seconds()
			speed = 3600 * delta_km / time_spent
			if speed < threshold:
				stop_time = stop_time + time_spent
			else:
				distance = distance + delta_km
				if last_elevation is not None:
					delta_elev = elevation - last_elevation
					if delta_elev >= 0:
						elev_gain += delta_elev
					else:
						elev_loss += delta_elev
			elapsed_time = timestamp - first_timestamp
			formatted_stop_time = (datetime.datetime(1,1,1) + datetime.timedelta(seconds=stop_time)).strftime("%H:%M:%S")
			formatted_elapsed_time = (datetime.datetime(1,1,1) + elapsed_time).strftime("%H:%M:%S")
			formatted_timestamp = timestamp.astimezone(datetime.timezone(datetime.timedelta(hours=tz))).strftime("%Y-%m-%d %H:%M:%S")
			line = "{},{},{:.3f},{:.1f},{},{:.0f},{:.0f},{}".format(formatted_timestamp, formatted_elapsed_time, distance, speed, elevation, elev_gain, elev_loss, formatted_stop_time)
			if verbose:
				print(line)

			with open(outfile, 'a+') as csv_file:
				csv_file.write(f"{line}\n")

		last_coordinates = (latitude, longitude)
		last_timestamp = timestamp
		last_elevation = elevation

	run_time = elapsed_time - datetime.timedelta(seconds=stop_time)
	avg_speed = distance / run_time.total_seconds() * 3600
	formatted_run_time = (datetime.datetime(1,1,1) + run_time).strftime("%H:%M:%S")
	line = "{},{},,{},,{:.2f}km,,+{:.0f}m{:.0f}m,{:.2f}km/h".format(formatted_elapsed_time, formatted_run_time, formatted_stop_time, distance, elev_gain, elev_loss, avg_speed)
	if verbose:
		print(line)

	with open(outfile, 'a+') as csv_file:
		csv_file.write("\ntime,run time,,stop time,,distance,,elev. gain-loss,avg. speed\n")
		csv_file.write(f"{line}\n")

	print(f"File {outfile} created.")

def get_options():
	parser = argparse.ArgumentParser(prog='SpeedTable by ClemRz', description='Extracts a CSV speed, elevation and distance table from a KML file.')
	parser.add_argument('filename', help='The path to the KML file')
	parser.add_argument('-tz', '--timezone', dest='timezone', default='0', help='The destination timezone')
	parser.add_argument('-th', '--threshold', dest='threshold', default='3', help='The speed threshold in km/h')
	parser.add_argument('-v', '--verbose', dest='verbose', help='Enables verbose output', action='store_true')
	return parser.parse_args()

def main():
	options = get_options()
	extract(options.filename, float(options.timezone), float(options.threshold), options.verbose)

if __name__ == '__main__':
	main()