#!/usr/local/bin/python2.7

import sys
import time
import signal
import optparse

try:
  import whisper
except ImportError:
  raise SystemExit('[ERROR] Please make sure whisper is installed properly')

_DROP_FUNCTIONS = {
    'zeroes': lambda x: x != 0,
    'nulls': lambda x: x is not None,
    'empty': lambda x: x != 0 and x is not None
}

# Ignore SIGPIPE
signal.signal(signal.SIGPIPE, signal.SIG_DFL)

now = int( time.time() )
yesterday = now - (60 * 60 * 24)

option_parser = optparse.OptionParser(usage='''%prog [options] path''')
option_parser.add_option('--from', default=yesterday, type='int', dest='_from',
  help=("Unix epoch time of the beginning of "
        "your requested interval (default: 24 hours ago)"))
option_parser.add_option('--until', default=now, type='int',
  help="Unix epoch time of the end of your requested interval (default: now)")
option_parser.add_option('--json', default=False, action='store_true',
  help="Output results in JSON form")
option_parser.add_option('--pretty', default=False, action='store_true',
  help="Show human-readable timestamps instead of unix times")
option_parser.add_option('--drop',
                         choices=list(_DROP_FUNCTIONS.keys()),
                         action='store',
                         help="Specify 'nulls' to drop all null values. \
Specify 'zeroes' to drop all zero values. \
Specify 'empty' to drop both null and zero values")

(options, args) = option_parser.parse_args()

if len(args) != 1:
  option_parser.print_help()
  sys.exit(1)

path = args[0]

from_time = int( options._from )
until_time = int( options.until )

try:
  data = whisper.fetch(path, from_time, until_time)
  if not data:
    raise SystemExit('No data in selected timerange')
  (timeInfo, values) = data
except (whisper.WhisperException, IOError) as exc:
  raise SystemExit('[ERROR] %s' % str(exc))

if options.drop:
  fcn = _DROP_FUNCTIONS.get(options.drop)
  values = [ x for x in values if fcn(x) ]

(start,end,step) = timeInfo

if options.json:
  values_json = str(values).replace('None','null')
  print('''{
    "start" : %d,
    "end" : %d,
    "step" : %d,
    "values" : %s
  }''' % (start,end,step,values_json))
  sys.exit(0)

t = start
for value in values:
  if options.pretty:
    timestr = time.ctime(t)
  else:
    timestr = str(t)
  if value is None:
    valuestr = "None"
  else:
    valuestr = "%f" % value
  print("%s\t%s" % (timestr,valuestr))
  t += step
