#!/usr/bin/python3

#
# InfoEx <-> NRCS Auto Wx implementation
# Alexander Vasarab
# Wylark Mountaineering LLC
#
# Version 1.0.0
#
# This program fetches data from an NRCS SNOTEL site and pushes it to
# InfoEx using the new automated weather system implementation.
#
# It is designed to be run hourly, and it asks for the last three hours
# of data of each desired type, and selects the most recent one. This
# lends some resiliency to the process and helps ensure that we have a
# value to send, but it can lead to somewhat inconsistent/untruthful
# data if e.g. the HS is from the last hour but the tempPres is from two
# hours ago because the instrumentation had a hiccup. It's worth
# considering if this is a bug or a feature.
#
# For more information, see file: README
# For licensing, see file: LICENSE
#

import configparser
import csv
import datetime
import logging
import time
import zeep
import zeep.cache
import zeep.transports
from collections import OrderedDict
from ftplib import FTP
from optparse import OptionParser

log = logging.getLogger(__name__)
log.setLevel(logging.DEBUG)

try:
    from systemd.journal import JournalHandler
    log.addHandler(JournalHandler())
except:
    # fallback to syslog
    import logging.handlers
    log.addHandler(logging.handlers.SysLogHandler())

parser = OptionParser()
parser.add_option("--config", dest="config", metavar="FILE", help="location of config file")

(options, args) = parser.parse_args()

config = configparser.ConfigParser(allow_no_value=False)
config.read(options.config)

log.debug('STARTING UP')

wsdl = 'https://www.wcc.nrcs.usda.gov/awdbWebService/services?WSDL'

try:
    infoex = {
        'host': config['ftp']['host'],
        'uuid': config['ftp']['uuid'],
        'api_key': config['ftp']['api_key'],
        'location_uuid': config['wxsite']['location_uuid'],
        'wx_data': {}, # placeholder key, values to come later
        'csv_filename': config['wxsite']['csv_filename']
    }

    station_triplet = config['wxsite']['station_triplet']

    try:
        desired_data = config['wxsite']['desired_data'].split(',')
    except:
        # desired_data malformed or missing, setting default
        desired_data = [
                'TOBS', # AIR TEMPERATURE OBSERVED (degF)
                'SNWD', # SNOW DEPTH (in)
                'PREC'  # PRECIPITATION ACCUMULATION (in)
                ]
except KeyError as e:
    log.critical("%s not defined in %s" % (e, options.config))
    exit(1)
except Exception as exc:
    log.critical("Exception occurred in config parsing: '%s'" % (exc))
    exit(1)

# all sections/values present in config file, final sanity check
try:
    for key in config.sections():
        for subkey in config[key]:
            if not len(config[key][subkey]):
                raise ValueError;
except ValueError as exc:
    log.critical("Config value '%s.%s' is empty" % (key, subkey))
    exit(1)

# INFOEX FIELDS
#
# This won't earn style points in Python, but here we establish a couple
# of helpful mappings variables. The reason this is helpful is that the
# end result is simply an ordered set, the CSV file. But we still may
# want to manipulate the values arbitrarily before writing that file.
#
# Also note that the current Auto Wx InfoEx documentation shows these
# keys in a graphical table with the "index" beginning at 1, but here we
# are sanely indexing beginning at 0.
fmap = {}                           ; final_data     = [None] * 29
fmap['Location UUID'] = 0           ; final_data[0]  = infoex['location_uuid']
fmap['obDate'] = 1                  ; final_data[1]  = None
fmap['obTime'] = 2                  ; final_data[2]  = None
fmap['timeZone'] = 3                ; final_data[3]  = 'Pacific'
fmap['tempMaxHour'] = 4             ; final_data[4]  = None
fmap['tempMaxHourUnit'] = 5         ; final_data[5]  = 'F'
fmap['tempMinHour'] = 6             ; final_data[6]  = None
fmap['tempMinHourUnit'] = 7         ; final_data[7]  = 'F'
fmap['tempPres'] = 8                ; final_data[8]  = None
fmap['tempPresUnit'] = 9            ; final_data[9]  = 'F'
fmap['precipitationGauge'] = 10     ; final_data[10] = None
fmap['precipitationGaugeUnit'] = 11 ; final_data[11] = 'in'
fmap['windSpeedNum'] = 12           ; final_data[12] = None
fmap['windSpeedUnit'] = 13          ; final_data[13] = 'mph'
fmap['windDirectionNum'] = 14       ; final_data[14] = None
fmap['hS'] = 15                     ; final_data[15] = None
fmap['hsUnit'] = 16                 ; final_data[16] = 'in'
fmap['baro'] = 17                   ; final_data[17] = None
fmap['baroUnit'] = 18               ; final_data[18] = 'inHg'
fmap['rH'] = 19                     ; final_data[19] = None
fmap['windGustSpeedNum'] = 20       ; final_data[20] = None
fmap['windGustSpeedNumUnit'] = 21   ; final_data[21] = 'mph'
fmap['windGustDirNum'] = 22         ; final_data[22] = None
fmap['dewPoint'] = 23               ; final_data[23] = None
fmap['dewPointUnit'] = 24           ; final_data[24] = 'F'
fmap['hn24Auto'] = 25               ; final_data[25] = None
fmap['hn24AutoUnit'] = 26           ; final_data[26] = 'in'
fmap['hstAuto'] = 27                ; final_data[27] = None
fmap['hstAutoUnit'] = 28            ; final_data[28] = 'in'

# one final mapping, the NRCS fields that this program supports to
# their InfoEx counterpart
iemap = {}
iemap['PREC'] = 'precipitationGauge'
iemap['TOBS'] = 'tempPres'
iemap['SNWD'] = 'hS'

# floor time to nearest hour
dt = datetime.datetime.now()
end_date = dt - datetime.timedelta(minutes=dt.minute % 60,
                                   seconds=dt.second,
                                   microseconds=dt.microsecond)
begin_date = end_date - datetime.timedelta(hours=3)

transport = zeep.transports.Transport(cache=zeep.cache.SqliteCache())
client = zeep.Client(wsdl=wsdl, transport=transport)
time_all_elements = time.time()

log.debug("Getting %s data from %s to %s" % (str(desired_data),
    str(begin_date), str(end_date)))

for elementCd in desired_data:
    time_element = time.time()

    # get the last three hours of data for this elementCd
    tmp = client.service.getHourlyData(
            stationTriplets=[station_triplet],
            elementCd=elementCd,
            ordinal=1,
            beginDate=begin_date,
            endDate=end_date)

    log.info("Time to get elementCd '%s': %.3f sec" % (elementCd,
        time.time() - time_element))

    values = tmp[0]['values']

    # sort and isolate the most recent
    #
    # NOTE: we do this because sometimes there are gaps in hourly data
    #       in NRCS; yes, we may end up with slightly inaccurate data,
    #       so perhaps this decision will be re-evaluated in the future
    if values:
        ordered = sorted(values, key=lambda t: t['dateTime'], reverse=True)
        infoex['wx_data'][elementCd] = ordered[0]['value']
    else:
        infoex['wx_data'][elementCd] = None

log.info("Time to get all elementCds : %.3f sec" % (time.time() -
    time_all_elements))

log.debug("infoex[wx_data]: %s", str(infoex['wx_data']))

# Now we only need to add in what we want to change thanks to that
# abomination of a variable declaration earlier
final_data[fmap['Location UUID']] = infoex['location_uuid']
final_data[fmap['obDate']] = end_date.strftime('%m/%d/%Y')
final_data[fmap['obTime']] = end_date.strftime('%H:%M')

for elementCd in infoex['wx_data']:
    if elementCd not in iemap:
        log.warning("BAD KEY wx_data['%s']" % (elementCd))
        continue

    # CONSIDER: Casting every value to Float() -- need to investigate if
    #           any possible elementCds we may want are any other data
    #           type than float.
    #
    #           Another possibility is to query the API  with
    #           getStationElements and temporarily store the
    #           storedUnitCd. But that's pretty network-intensive and
    #           may not even be worth it if there's only e.g. one or two
    #           exceptions to any otherwise uniformly Float value set.
    final_data[fmap[iemap[elementCd]]] = infoex['wx_data'][elementCd]

log.debug("final_data: %s" % (str(final_data)))

with open(infoex['csv_filename'], 'w') as f:
    # The requirement is that empty values are represented in the CSV
    # file as "", csv.QUOTE_NONNUMERIC achieves that
    log.debug("writing CSV file '%s'" % (infoex['csv_filename']))
    writer = csv.writer(f, quoting=csv.QUOTE_NONNUMERIC)
    writer.writerow(final_data)
    f.close()

#with open(infoex['csv_filename'], 'rb') as f:
#    log.debug("uploading FTP file '%s'" % (infoex['host']))
#    ftp = FTP(infoex['host'], infoex['uuid'], infoex['api_key'])
#    ftp.storlines('STOR ' + infoex['csv_filename'], f)
#    ftp.close()
#    f.close()

log.debug('DONE')