#!/usr/bin/env python

# iss.py by Carl Monk (@ForToffee)
# https://github.com/ForToffee/ISSTracker
# updated for latest rpi - i2c - PA2EON.nl

import urllib.request 
import json
from time import sleep 
import unicornhat as UH
from pyorbital.orbital import Orbital
from datetime import datetime 
#from Adafruit_CharLCDPlate import Adafruit_CharLCDPlate
import lcddriver
from os import path

refresh = 15    #refresh time in secs

tle_url = "http://celestrak.com/NORAD/elements/stations.txt"
source_dir = path.dirname(path.realpath(__file__))
tle_filename = source_dir + "stations.txt"

feed_url = "https://api.wheretheiss.at/v1/satellites/25544"

#location = [0.710173,51.548189]	#tickfield centre, Southend on Sea
location = [5.37500,51.68750]	#JO21QQ
origin = [-20,-5]
deg_per_pixel = 22.5 #180/8

#lcd = Adafruit_CharLCDPlate()
lcd = lcddriver.lcd()

#retrieve and load the JSON data into a JSON object
def getJSON():
	try:
		jsonFeed = urllib.request.urlopen(feed_url)
		feedData = jsonFeed.read()
                #print(feedData)
		jsonFeed.close()
		data = json.loads(feedData)
		return data
	except urllib.request.HTTPError as e:
		print('HTTPError = ' + str(e.code))
	except urllib.error.URLError as e:
		print('URLError = ' + str(e.reason))
	except httplib.HTTPException as e:
		print('HTTPException')
	except Exception:
		import traceback
		print('generic exception: ' + traceback.format_exc())

	return []


#retrieve latest TLE file from web
def getTLEData():
	try:
		tle = urllib.request.urlopen(tle_url)
		with open(tle_filename, "wb") as local_file:
			local_file.write(tle.read())

	except urllib.error.HTTPError as e:
		print('HTTPError = ' + str(e.code))
		pass 
	except urllib.error.URLError as e:
		print('URLError = ' + str(e.reason))
		pass 
	except Exception:
		import traceback
		print('generic exception: ' + traceback.format_exc())
		pass 

#use this method to retrieve from web API
def parseISSDataFeed():
	data = getJSON()

	if len(data) == 0:
		return []

	lat = data['latitude']
	lng = data['longitude']
	alt = data['altitude']

	return [lng, lat, alt]

#
def parseISSTLEFile():
	orb = Orbital("iss (zarya)",tle_filename)
	utc_time = datetime.utcnow()
	return orb.get_lonlatalt(utc_time) + orb.get_observer_look(utc_time, location[0], location[1], 0)



#refresh the displayed pixels
#This subroutine  can be removed when used LCD only
#def drawISS(lng,lat):
#	lng = lng - origin[0]
#	lat = lat - origin[1]


#	x = abs(int((lng + 90) /22.5))
#	if x > 7:
#		x = 15 - x

#	y = abs(int(((lat * -1) +90) /22.5))

#	print('x-value: %i, y-value: %i' % (x, y))
#	UH.clear()
#	if (lng < -90) or (lng > 90):	#'behind earth
#		UH.set_pixel(x,y, 0, 0, 0xFF)
#		UH.brightness(0.2)
#	else:
#		UH.set_pixel(x,y, 0xFF, 0xFF, 0)
#		UH.brightness(0.4)

#	UH.show()

def updateLCD(data):
	if data[4] > 60:
		backlight = lcd.GREEN 
	elif data[4] > 10:
		backlight = lcd.YELLOW
	else:
		#backlight = lcd.ON
                backlight = lcd.backlight(1)

	lcd.lcd_clear()
	#lcd.lcd_message('lng:%.2f\nlat:%.2f' % (data[0],data[1]))
	lcd.lcd_display_string('lat:%.2f lng:%.2f' % (data[1],data[0]), 1)
        #lcd.backlight(backlight)
	#sleep(5)

	#lcd.lcd_clear()
	#lcd.lcd_message('alt:%.2f km' % (data[2]))
	lcd.lcd_display_string('alt:%.2f km' % (data[2]) ,2)
	#sleep(5)

	#lcd.lcd_clear()
	#lcd.lcd_message('azimuth:%.2f\nelevation:%.2f' % ( data[3], data[4]))
	lcd.lcd_display_string('az:%.2f el:%.2f' % ( data[3], data[4]), 3)
	sleep(5)


#main program

UH.rotation(90)
UH.set_pixel(0,0, 0xFF,0,0)
UH.show()
sleep(5)
#download latest TLE file 
getTLEData()

while True:
	#data = parseISSDataFeed()
	data = parseISSTLEFile()
    
	if len(data) > 0:
		print('long: %f, lat: %f, alt: %f, az:%f, elv:%f' % (data[0], data[1], data[2], data[3], data[4]))
		#Next line no need for LCD only
		#drawISS(data[0], data[1])
		updateLCD(data)
	else:
		print('no data')
		
	#sleep(refresh)