"""

 This module houses the Geometry Collection objects:

 GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon

"""

from ctypes import c_int, c_uint, byref

from types import TupleType, ListType

from django.contrib.gis.geos.base import GEOSGeometry

from django.contrib.gis.geos.error import GEOSException, GEOSIndexError

from django.contrib.gis.geos.geometries import Point, LineString, LinearRing, Polygon

from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR

from django.contrib.gis.geos.prototypes import create_collection, destroy_geom, geom_clone, geos_typeid, get_cs, get_geomn

class GeometryCollection(GEOSGeometry):

    _allowed = (Point, LineString, LinearRing, Polygon)

    _typeid = 7

    def __init__(self, *args, **kwargs):

        "Initializes a Geometry Collection from a sequence of Geometry objects."

        # Checking the arguments

        if not args:

            raise TypeError, 'Must provide at least one Geometry to initialize %s.' % self.__class__.__name__

        if len(args) == 1: 

            # If only one geometry provided or a list of geometries is provided

            #  in the first argument.

            if isinstance(args[0], (TupleType, ListType)):

                init_geoms = args[0]

            else:

                init_geoms = args

        else:

            init_geoms = args

        # Ensuring that only the permitted geometries are allowed in this collection

        if False in [isinstance(geom, self._allowed) for geom in init_geoms]:

            raise TypeError('Invalid Geometry type encountered in the arguments.')

        # Creating the geometry pointer array.

        ngeoms = len(init_geoms)

        geoms = get_pointer_arr(ngeoms)

        for i in xrange(ngeoms): geoms[i] = geom_clone(init_geoms[i].ptr)

        super(GeometryCollection, self).__init__(create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms)), **kwargs)

    def __getitem__(self, index):

        "Returns the Geometry from this Collection at the given index (0-based)."

        # Checking the index and returning the corresponding GEOS geometry.

        self._checkindex(index)

        return GEOSGeometry(geom_clone(get_geomn(self.ptr, index)), srid=self.srid)

    def __setitem__(self, index, geom):

        "Sets the Geometry at the specified index."

        self._checkindex(index)

        if not isinstance(geom, self._allowed):

            raise TypeError('Incompatible Geometry for collection.')

        ngeoms = len(self)

        geoms = get_pointer_arr(ngeoms)

        for i in xrange(ngeoms):

            if i == index:

                geoms[i] = geom_clone(geom.ptr)

            else:

                geoms[i] = geom_clone(get_geomn(self.ptr, i))

        # Creating a new collection, and destroying the contents of the previous poiner.

        prev_ptr = self.ptr

        srid = self.srid

        self._ptr = create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms))

        if srid: self.srid = srid

        destroy_geom(prev_ptr)

    def __iter__(self):

        "Iterates over each Geometry in the Collection."

        for i in xrange(len(self)):

            yield self.__getitem__(i)

    def __len__(self):

        "Returns the number of geometries in this Collection."

        return self.num_geom

    def _checkindex(self, index):

        "Checks the given geometry index."

        if index < 0 or index >= self.num_geom:

            raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index))

    @property

    def kml(self):

        "Returns the KML for this Geometry Collection."

        return '<MultiGeometry>%s</MultiGeometry>' % ''.join([g.kml for g in self])

    @property

    def tuple(self):

        "Returns a tuple of all the coordinates in this Geometry Collection"

        return tuple([g.tuple for g in self])

    coords = tuple

# MultiPoint, MultiLineString, and MultiPolygon class definitions.

class MultiPoint(GeometryCollection): 

    _allowed = Point

    _typeid = 4

class MultiLineString(GeometryCollection): 

    _allowed = (LineString, LinearRing)

    _typeid = 5

class MultiPolygon(GeometryCollection): 

    _allowed = Polygon

    _typeid = 6