#!/usr/bin/python3

# thanks again to Adafruit for all their wonderful boards, libs and docs.
#
# docs:
# https://learn.adafruit.com/adafruit-mini-gps-pa1010d-module?view=all
#
# datasheet:
# https://cdn-learn.adafruit.com/assets/assets/000/084/295/original/CD_PA1010D_Datasheet_v.03.pdf

import time, board, busio, adafruit_gps, sys, argparse

sys.path.append('/import/home/ghz/repos/wxlib')
import wxlib as wx

i2c = board.I2C()
gps = adafruit_gps.GPS_GtopI2C(i2c)

# note this isn't /import/home, this is on the SD card
wx_dir = "/home/ghz/alt"

gps.send_command(b'PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0')
gps.send_command(b'PMTK220,100')

dat_fname = 'alt.dat'
time1 = time0 = time.monotonic()
alt_c = sat_c = vdop_c = hdop_c = pdop_c = cnt = 0

parser = argparse.ArgumentParser(description=u'Collect and average elevation data from a gps reciever, and then upload it somewhere.')
parser.add_argument('--debug', dest = 'debug', action = 'store_true', help = u'print intermittent data collection steps to console.')
args = parser.parse_args()

while True:
	time1 = time.monotonic()
	try:
		# apparently gps.update() can fail on us, from sth going on 4 lib functions down.
		gps_up_stat = gps.update()
	except KeyboardInterrupt:
		# this is not very likely, but whatever.
		print("keyboard interrupt. bailing.")
		exit()
	except:
		# warn. wait. bail.
		print("gps.update() error. prly from deep in the bowels of a lib somewere.")
		time.sleep(1.0) # wait a tic, mostly so we don't spam the console with infinite error messages when the data cable gets cut.
		continue # we haven't done anything yet, so just try again, time1 will take care of itself.

	if gps_up_stat:
		to = gps.timestamp_utc
		if gps.has_fix and to and to.tm_year and ((time1 - time0) > .1):
			time0 = time.monotonic()
			TS = "{}-{:02}-{:02}T{:02}:{:02}:{:02}Z".format(
				to.tm_year, to.tm_mon, to.tm_mday,
				to.tm_hour, to.tm_min, to.tm_sec)

			if args.debug:
				print(TS, end = "\t")
	
			alt = gps.altitude_m
			if alt is not None and args.debug:
				print(alt, "m", end = "\t")

			vdop = gps.vdop
			hdop = gps.hdop
			pdop = gps.pdop
			if (vdop and hdop and pdop) is not None and args.debug:
				print("{:.2f} vdop".format(vdop), end = "\t")
				print("{:.2f} hdop".format(hdop), end = "\t")
				print("{:.2f} pdop".format(pdop), end = "\t")

			# this has so far always returned 47.9 m
			if args.debug:
				geo_h = gps.height_geoid
				if geo_h is not None:
					print("{} m geoid height".format(geo_h), end = "\t")

			sats = gps.satellites
			if sats is not None and args.debug:
				print(sats, "sats")

			if (alt and sats and vdop and hdop and pdop) is not None:
				# experience (graphs) hath shewn that our worst data comes below these conditions. lose them.
				if (sats > 8.00 and pdop < 2.90 and hdop < 2.70 and vdop < 1.00):
					alt_c += alt
					sat_c += sats
					vdop_c += vdop
					hdop_c += hdop
					pdop_c += pdop
					cnt += 1
					if cnt >= 60:
						cts = time.strftime("%FT%TZ", time.gmtime())
						dat_s = "{}\t{:.2f} m\t{:.2f} vdop\t{:.2f} hdop \t{:.2f} pdop\t{:.2f} sats\n".format(
							cts, alt_c / cnt, vdop_c / cnt,
							hdop_c / cnt, pdop_c / cnt, sat_c / cnt)
						wx.write_out_dat_stamp_iso(cts, dat_fname, dat_s, wx_dir)
						if args.debug:
							print(dat_s)
						alt_c = sat_c = vdop_c = hdop_c = pdop_c = cnt = 0
	time.sleep(0.05)