"""

 This module houses the GeoIP object, a ctypes wrapper for the MaxMind GeoIP(R)

 C API (http://www.maxmind.com/app/c).  This is an alternative to the GPL

 licensed Python GeoIP interface provided by MaxMind.

 GeoIP(R) is a registered trademark of MaxMind, LLC of Boston, Massachusetts.

 For IP-based geolocation, this module requires the GeoLite Country and City

 datasets, in binary format (CSV will not work!).  The datasets may be 

 downloaded from MaxMind at http://www.maxmind.com/download/geoip/database/.

 Grab GeoIP.dat.gz and GeoLiteCity.dat.gz, and unzip them in the directory

 corresponding to settings.GEOIP_PATH.  See the GeoIP docstring and examples

 below for more details.

 TODO: Verify compatibility with Windows.

 Example:

 >>> from django.contrib.gis.utils import GeoIP

 >>> g = GeoIP()

 >>> g.country('google.com')

 {'country_code': 'US', 'country_name': 'United States'}

 >>> g.city('72.14.207.99')

 {'area_code': 650,

 'city': 'Mountain View',

 'country_code': 'US',

 'country_code3': 'USA',

 'country_name': 'United States',

 'dma_code': 807,

 'latitude': 37.419200897216797,

 'longitude': -122.05740356445312,

 'postal_code': '94043',

 'region': 'CA'}

 >>> g.lat_lon('salon.com')

 (37.789798736572266, -122.39420318603516)

 >>> g.lon_lat('uh.edu')

 (-95.415199279785156, 29.77549934387207) 

 >>> g.geos('24.124.1.80').wkt

 'POINT (-95.2087020874023438 39.0392990112304688)'

"""

import os, re

from ctypes import c_char_p, c_float, c_int, Structure, CDLL, POINTER

from ctypes.util import find_library

from django.conf import settings

if not settings._target: settings.configure()

# Creating the settings dictionary with any settings, if needed.

GEOIP_SETTINGS = dict((key, getattr(settings, key)) 

                      for key in ('GEOIP_PATH', 'GEOIP_LIBRARY_PATH', 'GEOIP_COUNTRY', 'GEOIP_CITY')

                      if hasattr(settings, key))

lib_path = GEOIP_SETTINGS.get('GEOIP_LIBRARY_PATH', None)

# GeoIP Exception class.

class GeoIPException(Exception): pass

# The shared library for the GeoIP C API.  May be downloaded

#  from http://www.maxmind.com/download/geoip/api/c/

if lib_path:

    lib_name = None

else:

    # TODO: Is this really the library name for Windows?

    lib_name = 'GeoIP'

# Getting the path to the GeoIP library.

if lib_name: lib_path = find_library(lib_name)

if lib_path is None: raise GeoIPException('Could not find the GeoIP library (tried "%s"). '

                                          'Try setting GEOIP_LIBRARY_PATH in your settings.' % lib_name)

lgeoip = CDLL(lib_path)

# Regular expressions for recognizing IP addresses and the GeoIP

# free database editions.

ipregex = re.compile(r'^(?P<w>\d\d?\d?)\.(?P<x>\d\d?\d?)\.(?P<y>\d\d?\d?)\.(?P<z>\d\d?\d?)$')

free_regex = re.compile(r'^GEO-\d{3}FREE')

lite_regex = re.compile(r'^GEO-\d{3}LITE')

#### GeoIP C Structure definitions ####

class GeoIPRecord(Structure):

    _fields_ = [('country_code', c_char_p),

                ('country_code3', c_char_p),

                ('country_name', c_char_p),

                ('region', c_char_p),

                ('city', c_char_p),

                ('postal_code', c_char_p),

                ('latitude', c_float),

                ('longitude', c_float),

                ('dma_code', c_int),

                ('area_code', c_int),

                ]

class GeoIPTag(Structure): pass

#### ctypes function prototypes ####

RECTYPE = POINTER(GeoIPRecord)

DBTYPE = POINTER(GeoIPTag)

# For retrieving records by name or address.

def record_output(func):

    func.restype = RECTYPE

    return func

rec_by_addr = record_output(lgeoip.GeoIP_record_by_addr)

rec_by_name = record_output(lgeoip.GeoIP_record_by_name)

# For opening up GeoIP databases.

geoip_open = lgeoip.GeoIP_open

geoip_open.restype = DBTYPE

# String output routines.

def string_output(func):

    func.restype = c_char_p

    return func

geoip_dbinfo = string_output(lgeoip.GeoIP_database_info)

cntry_code_by_addr = string_output(lgeoip.GeoIP_country_code_by_addr)

cntry_code_by_name = string_output(lgeoip.GeoIP_country_code_by_name)

cntry_name_by_addr = string_output(lgeoip.GeoIP_country_name_by_addr)

cntry_name_by_name = string_output(lgeoip.GeoIP_country_name_by_name)

#### GeoIP class ####

class GeoIP(object):

    # The flags for GeoIP memory caching.

    # GEOIP_STANDARD - read database from filesystem, uses least memory.

    #

    # GEOIP_MEMORY_CACHE - load database into memory, faster performance

    #        but uses more memory

    #

    # GEOIP_CHECK_CACHE - check for updated database.  If database has been updated,

    #        reload filehandle and/or memory cache.

    #

    # GEOIP_INDEX_CACHE - just cache

    #        the most frequently accessed index portion of the database, resulting

    #        in faster lookups than GEOIP_STANDARD, but less memory usage than

    #        GEOIP_MEMORY_CACHE - useful for larger databases such as

    #        GeoIP Organization and GeoIP City.  Note, for GeoIP Country, Region

    #        and Netspeed databases, GEOIP_INDEX_CACHE is equivalent to GEOIP_MEMORY_CACHE

    #

    GEOIP_STANDARD = 0

    GEOIP_MEMORY_CACHE = 1

    GEOIP_CHECK_CACHE = 2

    GEOIP_INDEX_CACHE = 4

    cache_options = dict((opt, None) for opt in (0, 1, 2, 4))

    def __init__(self, path=None, cache=0, country=None, city=None):

        """

        Initializes the GeoIP object, no parameters are required to use default

        settings.  Keyword arguments may be passed in to customize the locations

        of the GeoIP data sets.

        * path: Base directory to where GeoIP data is located or the full path

            to where the city or country data files (*.dat) are located.

            Assumes that both the city and country data sets are located in

            this directory; overrides the GEOIP_PATH settings attribute.

        * cache: The cache settings when opening up the GeoIP datasets,

            and may be an integer in (0, 1, 2, 4) corresponding to

            the GEOIP_STANDARD, GEOIP_MEMORY_CACHE, GEOIP_CHECK_CACHE,

            and GEOIP_INDEX_CACHE `GeoIPOptions` C API settings,

            respectively.  Defaults to 0, meaning that the data is read

            from the disk.

        * country: The name of the GeoIP country data file.  Defaults to

            'GeoIP.dat'; overrides the GEOIP_COUNTRY settings attribute.

        * city: The name of the GeoIP city data file.  Defaults to

            'GeoLiteCity.dat'; overrides the GEOIP_CITY settings attribute.

        """

        # Checking the given cache option.

        if cache in self.cache_options:

            self._cache = self.cache_options[cache]

        else:

            raise GeoIPException('Invalid caching option: %s' % cache)

        # Getting the GeoIP data path.

        if not path:

            path = GEOIP_SETTINGS.get('GEOIP_PATH', None)

            if not path: raise GeoIPException('GeoIP path must be provided via parameter or the GEOIP_PATH setting.')

        if not isinstance(path, basestring):

            raise TypeError('Invalid path type: %s' % type(path).__name__)

        cntry_ptr, city_ptr = (None, None)

        if os.path.isdir(path):

            # Getting the country and city files using the settings

            # dictionary.  If no settings are provided, default names

            # are assigned.

            country = os.path.join(path, country or GEOIP_SETTINGS.get('GEOIP_COUNTRY', 'GeoIP.dat'))

            city = os.path.join(path, city or GEOIP_SETTINGS.get('GEOIP_CITY', 'GeoLiteCity.dat'))

        elif os.path.isfile(path):

            # Otherwise, some detective work will be needed to figure

            # out whether the given database path is for the GeoIP country

            # or city databases.

            ptr = geoip_open(path, cache)

            info = geoip_dbinfo(ptr)

            if lite_regex.match(info):

                # GeoLite City database.

                city, city_ptr = path, ptr

            elif free_regex.match(info):

                # GeoIP Country database.

                country, cntry_ptr = path, ptr

            else:

                raise GeoIPException('Unable to recognize database edition: %s' % info)

        else:

            raise GeoIPException('GeoIP path must be a valid file or directory.')

        # `_init_db` does the dirty work.

        self._init_db(country, cache, '_country', cntry_ptr)

        self._init_db(city, cache, '_city', city_ptr)

    def _init_db(self, db_file, cache, attname, ptr=None):

        "Helper routine for setting GeoIP ctypes database properties."

        if ptr:

            # Pointer already retrieved.

            pass

        elif os.path.isfile(db_file or ''):

            ptr = geoip_open(db_file, cache)

        setattr(self, attname, ptr)

        setattr(self, '%s_file' % attname, db_file)

    def _check_query(self, query, country=False, city=False, city_or_country=False):

        "Helper routine for checking the query and database availability."

        # Making sure a string was passed in for the query.

        if not isinstance(query, basestring):

            raise TypeError('GeoIP query must be a string, not type %s' % type(query).__name__)

        # Extra checks for the existence of country and city databases.

        if city_or_country and self._country is None and self._city is None:

            raise GeoIPException('Invalid GeoIP country and city data files.')

        elif country and self._country is None:

            raise GeoIPException('Invalid GeoIP country data file: %s' % self._country_file)

        elif city and self._city is None:

            raise GeoIPException('Invalid GeoIP city data file: %s' % self._city_file)

    def city(self, query):

        """

        Returns a dictionary of city information for the given IP address or

        Fully Qualified Domain Name (FQDN).  Some information in the dictionary

        may be undefined (None).

        """

        self._check_query(query, city=True)

        if ipregex.match(query):

            # If an IP address was passed in

            ptr = rec_by_addr(self._city, c_char_p(query))

        else:

            # If a FQDN was passed in.

            ptr = rec_by_name(self._city, c_char_p(query))

        # Checking the pointer to the C structure, if valid pull out elements

        # into a dicionary and return.

        if bool(ptr):

            record = ptr.contents

            return dict((tup[0], getattr(record, tup[0])) for tup in record._fields_)

        else:

            return None

    def country_code(self, query):

        "Returns the country code for the given IP Address or FQDN."

        self._check_query(query, city_or_country=True)

        if self._country:

            if ipregex.match(query): return cntry_code_by_addr(self._country, query)

            else: return cntry_code_by_name(self._country, query)

        else:

            return self.city(query)['country_code']

    def country_name(self, query):

        "Returns the country name for the given IP Address or FQDN."

        self._check_query(query, city_or_country=True)

        if self._country:

            if ipregex.match(query): return cntry_name_by_addr(self._country, query)

            else: return cntry_name_by_name(self._country, query)

        else:

            return self.city(query)['country_name']

    def country(self, query):

        """

        Returns a dictonary with with the country code and name when given an 

        IP address or a Fully Qualified Domain Name (FQDN).  For example, both

        '24.124.1.80' and 'djangoproject.com' are valid parameters.

        """

        # Returning the country code and name

        return {'country_code' : self.country_code(query), 

                'country_name' : self.country_name(query),

                }

    #### Coordinate retrieval routines ####

    def coords(self, query, ordering=('longitude', 'latitude')):

        cdict = self.city(query)

        if cdict is None: return None

        else: return tuple(cdict[o] for o in ordering)

    def lon_lat(self, query):

        "Returns a tuple of the (longitude, latitude) for the given query."

        return self.coords(query)

    def lat_lon(self, query):

        "Returns a tuple of the (latitude, longitude) for the given query."

        return self.coords(query, ('latitude', 'longitude'))

    def geos(self, query):

        "Returns a GEOS Point object for the given query."

        ll = self.lon_lat(query)

        if ll:

            from django.contrib.gis.geos import Point

            return Point(ll, srid=4326)

        else:

            return None

    #### GeoIP Database Information Routines ####

    def country_info(self):

        "Returns information about the GeoIP country database."

        if self._country is None:

            ci = 'No GeoIP Country data in "%s"' % self._country_file

        else:

            ci = geoip_dbinfo(self._country)

        return ci

    country_info = property(country_info)

    def city_info(self):

        "Retuns information about the GeoIP city database."

        if self._city is None:

            ci = 'No GeoIP City data in "%s"' % self._city_file

        else:

            ci = geoip_dbinfo(self._city)

        return ci

    city_info = property(city_info)

    def info(self):

        "Returns information about all GeoIP databases in use."

        return 'Country:\n\t%s\nCity:\n\t%s' % (self.country_info, self.city_info)

    info = property(info)

    #### Methods for compatibility w/the GeoIP-Python API. ####

    @classmethod

    def open(cls, full_path, cache):

        return GeoIP(full_path, cache)

    def _rec_by_arg(self, arg):

        if self._city:

            return self.city(arg)

        else:

            return self.country(arg)

    region_by_addr = city

    region_by_name = city

    record_by_addr = _rec_by_arg

    record_by_name = _rec_by_arg

    country_code_by_addr = country_code

    country_code_by_name = country_code

    country_name_by_addr = country_name

    country_name_by_name = country_name