#!/usr/bin/env python3
#################################################################
# Program is used for preparing DEM data                        #
# Author: Lv Xiaoran                                            #
# Created: October 2021                                         #
#################################################################

import os
import argparse
import numpy as np
import xml.etree.ElementTree as ET

######################################################################################
EXAMPLE = """example:
   get_boundingBox_from_kml.py   ssara_search_20211019042049.kml —delta_lat 0.5 —delta_lon 1.2
"""

def create_parser():
    parser = argparse.ArgumentParser(description='get boundingBox coordinates from SSARA kml file',
                                     formatter_class=argparse.RawTextHelpFormatter,
                                     epilog=EXAMPLE)

    parser.add_argument('file', nargs=1, type=str, help='ssara_search_kml file\n')
    parser.add_argument('--delta_lat', type=float, nargs=1, help='delta latitude to subtract/add from minimum/maximimum latitude [default 0]', default=[0.0])
    parser.add_argument('--delta_lon', nargs=1, type=float, help='delta longitude to subtract (add) from minimum (maximimum) longitude' ,default=[0.0])
    
    return parser

def cmd_line_parse(iargs=None):
    parser = create_parser()
    inps = parser.parse_args(args=iargs)  
    
    return inps

def process_kml(kml_file, delta_lat, delta_lon):
    """main code"""
    tree = ET.parse(kml_file)
    root = tree.getroot()

    # read lon/lat coordinate into latlon_store matrix
    lineStrings = tree.findall('.//{http://earth.google.com/kml/2.1}LineString')
    latlon_store = np.empty(shape=[0,2],dtype=float)
    for attributes in lineStrings:
        for subAttribute in attributes:
            if subAttribute.tag == '{http://earth.google.com/kml/2.1}coordinates':
                corners = subAttribute.text.split(' ')
                for corner in corners[0:-1]:
                    lon, lat, height = corner.split(',')
                    latlon_store = np.append(latlon_store,np.array([[float(lon), float(lat)]]),axis=0) 
    # select the max/min lat and lon
    lat_max = np.max(latlon_store[:,1])
    lat_min = np.min(latlon_store[:,1])

    lon_max = np.max(latlon_store[:,0])
    lon_min = np.min(latlon_store[:,0])

    # add the delta_lat/delta_lon
    lat_max2 = np.around((lat_max + delta_lat), 1)
    lat_min2 = np.around((lat_min - delta_lat), 1)

    lon_max2 = np.around((lon_max + delta_lon), 1)
    lon_min2 = np.around((lon_min - delta_lon), 1)

    return lat_min2, lat_max2, lon_min2, lon_max2

######################################################################################
def main(iargs=None):
    inps = cmd_line_parse(iargs)   
   
    kml_file = inps.file[0]
   
    delta_lat = inps.delta_lat[0] 
    delta_lon = inps.delta_lon[0]
 
    lat_min2, lat_max2, lon_min2, lon_max2 = process_kml(kml_file, delta_lat, delta_lon)

    str = 'SNWE: {} {} {} {}'.format(lat_min2, lat_max2, lon_min2, lon_max2)
    print(str)
    return str 
######################################################################################
if __name__ == '__main__':
    main()