import constants
import readdata
from sys import stdout
from datetime import timedelta
from time import sleep

from optparse import OptionParser

G5_IS_DEFAULT = True
DEFAULT_PAGE_COUNT = 2

parser = OptionParser()
parser.add_option("--g4", action="store_false", dest="g5", default=G5_IS_DEFAULT, help="use Dexcom G4 instead of Dexcom G5")
parser.add_option("--g5", action="store_true",  dest="g5", default=G5_IS_DEFAULT, help="use Dexcom G5 instead of Dexcom G4")

parser.add_option("-a", "--all",  action="store_const", dest="command", const="dump_everything", help="dump all available records")
parser.add_option("-p", "--poll", action="store_const", dest="command", const="poll",            help="poll for latest CGM record")

parser.add_option("-n", type="int", dest="num_records", default=DEFAULT_PAGE_COUNT, help="number of pages of CGM records to display")

(options, args) = parser.parse_args()

command = options.command or "dump_cgm"

def get_dexcom_reader():
        if options.g5:
                dd = readdata.DexcomG5.FindDevice()
                return readdata.DexcomG5(dd)
        else:
                dd = readdata.Dexcom.FindDevice()
                return readdata.Dexcom(dd)

dr = get_dexcom_reader()

def dump_everything():

#       record_types = ['METER_DATA', 'INSERTION_TIME', 'USER_EVENT_DATA', 'CAL_SET', 'SENSOR_DATA']

        unparseable = ['FIRMWARE_PARAMETER_DATA', 'RECEIVER_LOG_DATA', 'USER_SETTING_DATA', 'MAX_VALUE']
        parsed_to_xml = ['MANUFACTURING_DATA', 'PC_SOFTWARE_PARAMETER']
        skip = unparseable + parsed_to_xml
        record_types = filter(lambda v: not v in skip, constants.RECORD_TYPES)

        for t in record_types:
                print t + ":"
                for r in dr.ReadRecords(t):
                        print r

def dump_cgm():
        cgm_records = dr.ReadRecords('EGV_DATA', options.num_records)
        for cr in cgm_records:
                if not cr.display_only:
                        print cr

def recent(t):
        now = dr.ReadSystemTime()
        return t.system_time > now - timedelta(minutes=5)

def read_recent_egv_data():
        try:
                r = dr.ReadRecords('EGV_DATA', options.num_records)[-1]
                if recent(r) and not r.is_special and not r.display_only:
                        return r
                else:
                        return None
        except:
                return None

def format_times(now, stamp):
        diff = (stamp - now).total_seconds()
        operand = '-' if diff < 0 else '+' # should always be -
        return '%s %s %d' % (now.strftime('%s'), operand, abs(diff))

def poll():
        while True:
                r = read_recent_egv_data()
                if r is None:
                        sleep(10)
                else:
                        now = dr.ReadSystemTime()
                        print '%s: %s %s' % (format_times(now, r.system_time), r.glucose, r.trend_arrow)
                        stdout.flush()
                        next_reading = (r.system_time - now + timedelta(minutes=5, seconds=2)).total_seconds()
                        if (next_reading > 0):
                                sleep(next_reading)

{"dump_everything": dump_everything,
 "dump_cgm":        dump_cgm,
 "poll":            poll
}[command]()