from chardet.universaldetector import UniversalDetector
import itertools
import os.path
import sys
import dbfUtils
import sys
from osgeo import osr
from urllib import urlencode
from urllib2 import urlopen
import json
import subprocess

if len(sys.argv) != 3:
    print "usage: python %s shp_file name" % sys.argv[0]
    sys.exit()
shp_file = sys.argv[1]
name = sys.argv[2]

dbf_file = shp_file[0:-4] + '.dbf'
prj_file = shp_file[0:-4] + '.prj'

shape_name = os.path.splitext(shp_file)[0]

def get_spatial_reference(shapefile):
    srs = osr.SpatialReference()
    shpfile = os.path.basename(shape_name)
    ret = srs.SetFromUserInput(prj_string)
    proj4 = srs.ExportToProj4()
    if not proj4:
        prj_file = open(shape_name +'.prj','r')
        prj_lines = prj_file.readlines()
        prj_file.close()
        for i in range(len(prj_lines)):
            prj_lines[i] = prj_string.rstrip( prj_lines[i] )
        srs = osr.SpatialReference()
        srs.ImportFromESRI(prj_lines)
        proj4 = srs.ExportToProj4()
        """
        if not proj4:
            #print 'Failed to convert prj of %s, giving up...' % shpfile
        else:
            #print 'Second try assuming ESRI wkt worked for %s!' % shpfile
        """
        srs.from_esri = True
    else:
        srs.from_esri = False
    srs.AutoIdentifyEPSG()
    return srs

def to_epsg(srs):
    if srs.IsGeographic():
        return srs.GetAuthorityCode('GEOGCS')
    else:
        c = srs.GetAuthorityCode('PROJCS')
        if c:
            return c
        else:
            try:
                return srs.GetAuthorityCode('GEOGCS')
            except:
                return None


srid = None

#Try detecting the SRID
if os.path.isfile(prj_file):
  prj_string = open(prj_file,'r').read()
  code = to_epsg(get_spatial_reference(shp_file))

  srid = code if code else None

try:
# Try to detect the encoding
    dbf = open(dbf_file.strip(), 'rb')
    db = dbfUtils.dbfreader(dbf)

    fnames = db.next()
    ftypes = db.next()

    # find string fields
    sfields = []
    for fno in range(len(fnames)):
      if ( ftypes[fno][0] == 'C' ) : sfields.append(fno)

    detector = UniversalDetector()

    # TODO: Make this a % of total table size and stop guessing correct values for guessing
    for row in itertools.islice(db, 1000):
      # Feed detector with concatenated string fields
      detector.feed( ''.join(row[fno] for fno in sfields) )
      if detector.done: break
    dbf.close()
    detector.close()
    encoding = detector.result["encoding"]
    confidence = detector.result["confidence"]
    if encoding=="ascii":
        encoding="LATIN1" # why not UTF8 here ?
    # There's problems detecting LATIN1 encodings, it detects KOI8-R instead of LATIN1
    if encoding=="KOI8-R":
        encoding="LATIN1"
    # Fix for #1336: since ISO-8859-2 is unlikely and UniversalDetector doesn't support ISO-8859-1, 
    # we'll fallback to ISO-8859-1 if confidence is not high
    if encoding=="ISO-8859-2" and confidence < 0.75:
        encoding="ISO-8859-1"
except Exception as err:
    encoding="None" # why not UTF8 here ?
    #sys.stderr.write(repr(err)+'\n')
    #sys.exit(1)

print "%s,%s,%s,%s" % (srid,encoding,shp_file,name)