from django.contrib.gis.gdal.error import OGRException

#### OGRGeomType ####

class OGRGeomType(object):

    "Encapulates OGR Geometry Types."

    # Dictionary of acceptable OGRwkbGeometryType s and their string names.

    _types = {0 : 'Unknown',

              1 : 'Point',

              2 : 'LineString',

              3 : 'Polygon',

              4 : 'MultiPoint',

              5 : 'MultiLineString',

              6 : 'MultiPolygon',

              7 : 'GeometryCollection',

              100 : 'None',

              101 : 'LinearRing',

              }

    # Reverse type dictionary, keyed by lower-case of the name.

    _str_types = dict([(v.lower(), k) for k, v in _types.items()])

    def __init__(self, type_input):

        "Figures out the correct OGR Type based upon the input."

        if isinstance(type_input, OGRGeomType):

            num = type_input.num

        elif isinstance(type_input, basestring):

            num = self._str_types.get(type_input.lower(), None)

            if num is None:

                raise OGRException('Invalid OGR String Type "%s"' % type_input)

        elif isinstance(type_input, int):

            if not type_input in self._types:

                raise OGRException('Invalid OGR Integer Type: %d' % type_input)

            num = type_input

        else:

            raise TypeError('Invalid OGR input type given.')

        # Setting the OGR geometry type number.

        self.num = num

    def __str__(self):

        "Returns the value of the name property."

        return self.name

    def __eq__(self, other):

        """

        Does an equivalence test on the OGR type with the given

        other OGRGeomType, the short-hand string, or the integer.

        """

        if isinstance(other, OGRGeomType):

            return self.num == other.num

        elif isinstance(other, basestring):

            return self.name.lower() == other.lower()

        elif isinstance(other, int):

            return self.num == other

        else:

            return False

    def __ne__(self, other):

        return not (self == other)

    @property

    def name(self):

        "Returns a short-hand string form of the OGR Geometry type."

        return self._types[self.num]

    @property

    def django(self):

        "Returns the Django GeometryField for this OGR Type."

        s = self.name

        if s in ('Unknown', 'LinearRing', 'None'):

            return None

        else:

            return s + 'Field'