#!/usr/bin/env python

import ephem
import time
import os
import sys
from MmdDb import Db
from MmdLocation import Location

def createJavaArray (point_list, name):
  astring = '''var {0} = new Array (\n'''.format (name)
  astring = '{0}\tnew Array ('.format (astring)
  last = 'west'

  for point in point_list:
    if point[0][0] == '-':
      if last == 'east':
        astring = astring[:-1]
        astring = '{0}\n\t\t),\n\tnew Array ('.format (astring)
      last = 'west'
    else:
      last = 'east'
    astring = '{0}\n\t\tnew OpenLayers.LonLat ({1}, {2}).transform (from, to),'.format (astring, point[0], point[1])
  if astring[-1] == ',':
    astring = astring[:-1]
  astring = '{0}\n\t\t)\n\t);'.format (astring)
  return astring

def dms2degdec (lonlat):
  '''
  convert a position argument from Deg:Min:Sec.Frac to
  Deg.Frac and round the result to 5 decimal points
  '''

  parts = lonlat.split (':')
  if len (parts) != 3:
    return 0.0
  degrees = float (parts[0])
  fraction =  (float (parts[1]) * 60.0 + float (parts[2])) / 3600
  if parts[0][0] == '-':
    return round (degrees - fraction, 5)
  return round (degrees + fraction, 5)

class Satellite:

  def __init__ (self, location = False):
    self.name = 'RADIOSCAF-B/ARISSAT-1'
    self.tle_filename = '/usr/local/mmd/tles/current'
    self.db = Db ()
    self.initSatellite (location)
 
  def getCurrentSSP (self):
    ssp = self._loadCurrentSSP ()
    return ssp['timestamp'], ssp['longitude'], ssp['latitude']

  def getTrajectoryAsJavaArray (self, name, minutes = 180):
    astring = '''var {0} = new Array (\n'''.format (name)
    astring = '{0}\tnew Array ('.format (astring)
    last = 'west'
  
    for row in self._loadTrajectory (minutes):
      if str (row['longitude'])[0] == '-':
        if last == 'east':
          astring = astring[:-1]
          astring = '{0}\n\t\t),\n\tnew Array ('.format (astring)
        last = 'west'
      else:
        last = 'east'
      astring = '{0}\n\t\tnew OpenLayers.LonLat ({1}, {2}).transform (from, to),'.format (
        astring, row['longitude'], row['latitude'])
    if astring[-1] == ',':
      astring = astring[:-1]
    astring = '{0}\n\t\t)\n\t);'.format (astring)
    return astring


  def _loadTrajectory (self, minutes):
    return self.db.satelliteLoadTrajectory (time.strftime ('%s'), minutes)

  def _loadCurrentSSP (self):
    return self.db.satelliteLoadCurrentSSP (time.strftime ('%s'))

  def initSatellite (self, location = False):
    if not self._loadTLE ():
      return False
    if location:
      loc = location
    else:
      loc = Location ()

    sat = ephem.readtle (self._tle[0], self._tle[1], self._tle[2])
    obs = ephem.Observer ()
    obs.long, obs.lat, obs.elevation = loc.longitude, loc.latitude, loc.altitude
    sat.compute (obs)
    self.longitude = dms2degdec (sat.sublong.__str__ ())
    self.latitude = dms2degdec (sat.sublat.__str__ ())
    self.altitude = round (float (sat.elevation.__str__ ()), 1)

  def _computeTrajectory (self):
    '''
    computes 5 hours of future trajectory data, starting at the
    latest timestamp found in data base
    '''
    if not self._loadTLE ():
      return False

    sat = ephem.readtle (self._tle[0], self._tle[1], self._tle[2])
    graz = ephem.Observer ()
    graz.long, graz.lat, graz.elevation = 15.44226, 47.06576, 376

    latest = self.db.satelliteGetLatestSSP ()
    if latest:
      timestamp = int (latest['timestamp']) + 60
    else:
      timestamp = int (time.strftime ('%s')) + 60
    while timestamp % 60 != 0:
      timestamp += 1

    for i in range (60 * 5):
      graz.date = time.strftime ('%Y/%m/%d %H:%M:%S', time.gmtime (timestamp))
      sat.compute (graz)
      self.db.satelliteInsertNewSSP (timestamp, dms2degdec (sat.sublong.__str__ ()), dms2degdec (sat.sublat.__str__ ()))
      timestamp += 60
    return  True

  def _loadTLE (self):
    try:
      tle = open (self.tle_filename, 'r')
    except IOError:
      return False
    self._tle = []
    count = 0
    for line in tle.readlines ():
      self._tle.append (line)
      count += 1
    if count != 3:
      return False
    return True

  def cronJob (self):
    if self._updateTLEFile ():
      self._updateTrajectory ()
    return self._computeTrajectory ()

  def _updateTLEFile (self):
    return False

  def _updateTrajectory (self):
    self.db.satelliteDeleteObsoleteSSPs (time.strftime ('%s'))

  def getLatestSSP (self):
    return self.db.satelliteGetLatestSSP ()

if __name__ == "__main__":
  satellite = Satellite ()
  try:
    assert satellite.cronJob (), 'executing cronjob failed'
  except AssertionError as e:
    print 'Error: {0}'.format (e)
    sys.exit (1)
  sys.exit (0)

# vim: tw=0 ts=2
# EOF