#!/usr/bin/python3
#
# Version 2  
# 9 July 2013
#
# Modified to use xml format output from timegenie instead of text file
#
# Version 3
# 7 March 2014
#
# Added checks for unicode currency names
#
# Version 3.1
# 23 June 2014
#
# Added test for non-unicode strings to prevent a runtime warning
#

import sys
import urllib.request, urllib.parse, urllib.error
import os
import xml.etree.ElementTree as ET
import codecs
from datetime import datetime
from unidecode import unidecode

outstr = ''

outfile='/usr/share/units/currency.units'  

if len(sys.argv)==2 and sys.argv[1] != '--help' and sys.argv[1] != '-h':
  outfile = sys.argv[1]
elif len(sys.argv) != 1:
  sys.stderr.write('\nUsage: {0} [filename]\n\n'.format(sys.argv[0]))
  sys.stderr.write('Update currency information for \'units\' into the specified filename or if no\n')
  sys.stderr.write('filename is given, the default: \'{0}\'.\n'.format(outfile))
  sys.exit(1)

try:
# http://stackoverflow.com/questions/36600583/python-3-urllib-ignore-ssl-certificate-verification
  import ssl
  ctx = ssl.create_default_context()
  ctx.check_hostname = False
  ctx.verify_mode = ssl.CERT_NONE
  currencies = ET.parse(urllib.request.urlopen('https://rss.timegenie.com/forex.xml',context=ctx)).findall('data')
except IOError as exc:
  sys.stderr.write('Error connecting to currency server. {0}\n'.format(exc))
  sys.exit(1)

# print codes here

codes = [x.find('code').text for x in currencies]
names = [x.find('description').text for x in currencies]
values = [x.find('rate').text for x in currencies]

# Sometimes currency rates are missing from the xml file
# Delete such currencies

while True:
  try:
    none = values.index(None)
    sys.stderr.write('no rate for "%s" (%s)\n' % (names[none], codes[none]))
    del codes[none]
    del names[none]
    del values[none]
  except ValueError:
    break

# Precious metals are showing up with weird prices (per gram?)
# Delete them

metalcodes = ['XAG','XAU','XPD','XPT']
for i in range(len(metalcodes)):
  try:
    badind = codes.index(metalcodes[i])
    del codes[badind]
    del names[badind]
    del values[badind]
  except ValueError:
    break

names = [x.lower().replace(' ','') for x in names]

foundunicode=False
for i in range(len(names)):
  if names[i] == 'anguilla(ecd)':
    names[i] = 'eastcaribbeandollar'
  if isinstance(names[i],str):    # this test needed only for python2
    ascii = unidecode(names[i])
  else:
    ascii = names[i]
  if names[i] != ascii:
    if not foundunicode:
      foundunicode = True
      outstr += '# Unicode Currency Names\n\n!utf8\n'
    outstr += names[i] + ' ' *(23-len(names[i])) + ascii + '\n'
    names[i] = ascii
if foundunicode:
  outstr += '!endutf8\n\n'

outstr += '# ISO Currency Codes\n\n'

outstr += '\n'.join([x + ' '*20 + y for x,y in zip(codes,names)])

usd = codes.index('USD')
euro = codes.index('EUR')
usdval = values[usd] 

values = ['1|' + x +' euro' for x in values]
values[euro] = usdval + ' US$'

del names[usd]
del values[usd]

# print rates here

now = datetime.now()
outstr += '\n\n# Currency exchange rates from Time Genie (www.timegenie.com)\n'
outstr += '\n!message Currency exchange rates from www.timegenie.com on '+now.strftime('%Y-%m-%d')+'\n\n'

maxlen = max(list(map(len,names))) + 2
outstr += '\n'.join([x.ljust(maxlen) + y for x,y in zip(names, values)])


# precious metals prices

outstr += '\n\n# Precious metals prices from http://services.packetizer.com/spotprices/\n\n'

try:
  spotprices = ET.parse(urllib.request.urlopen('http://services.packetizer.com/spotprices/?f=xml'))
except IOError as exc:
  sys.stderr.write('Error connecting to spotprices server. {0}\n'.format(exc))
  sys.exit(1)

metals = ['gold','platinum','silver']

for metal in metals:
  outstr += '{0}    {1} US$/troyounce\n'.format((metal+'price').ljust(15), spotprices.find(metal).text)

try:
  if outfile == '-':
    info = codecs.lookup('utf8')
    outfile = codecs.StreamReaderWriter(sys.stdout, info.streamreader, info.streamwriter)
  else:    
    outfile = codecs.open(outfile,'w','utf8')
except IOError as exc:
  sys.stderr.write('Unable to write to output file. {0}\n'.format(exc))
  sys.exit(1)

outfile.write(outstr.replace('\n',os.linesep))

# In python3, open(outfile,mode='w',encoding='utf8') should work
# and then the explicit newline handling won't be needed