"""

 This module houses the GEOSCoordSeq object, which is used internally

 by GEOSGeometry to house the actual coordinates of the Point,

 LineString, and LinearRing geometries.

"""

from ctypes import c_double, c_uint, byref

from types import ListType, TupleType

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

from django.contrib.gis.geos.libgeos import CS_PTR, HAS_NUMPY

from django.contrib.gis.geos.prototypes import cs_clone, cs_getdims, cs_getordinate, cs_getsize, cs_setordinate

if HAS_NUMPY: from numpy import ndarray

class GEOSCoordSeq(object):

    "The internal representation of a list of coordinates inside a Geometry."

    #### Python 'magic' routines ####

    def __init__(self, ptr, z=False):

        "Initializes from a GEOS pointer."

        if not isinstance(ptr, CS_PTR):

            raise TypeError('Coordinate sequence should initialize with a CS_PTR.')

        self._ptr = ptr

        self._z = z

    def __iter__(self):

        "Iterates over each point in the coordinate sequence."

        for i in xrange(self.size):

            yield self[i]

    def __len__(self):

        "Returns the number of points in the coordinate sequence."

        return int(self.size)

    def __str__(self):

        "Returns the string representation of the coordinate sequence."

        return str(self.tuple)

    def __getitem__(self, index):

        "Returns the coordinate sequence value at the given index."

        coords = [self.getX(index), self.getY(index)]

        if self.dims == 3 and self._z:

            coords.append(self.getZ(index))

        return tuple(coords)

    def __setitem__(self, index, value):

        "Sets the coordinate sequence value at the given index."

        # Checking the input value

        if isinstance(value, (ListType, TupleType)):

            pass

        elif HAS_NUMPY and isinstance(value, ndarray):

            pass

        else:

            raise TypeError('Must set coordinate with a sequence (list, tuple, or numpy array).')

        # Checking the dims of the input

        if self.dims == 3 and self._z:

            n_args = 3

            set_3d = True

        else:

            n_args = 2

            set_3d = False

        if len(value) != n_args:

            raise TypeError('Dimension of value does not match.')

        # Setting the X, Y, Z

        self.setX(index, value[0])

        self.setY(index, value[1])

        if set_3d: self.setZ(index, value[2])

    #### Internal Routines ####

    def _checkindex(self, index):

        "Checks the given index."

        sz = self.size

        if (sz < 1) or (index < 0) or (index >= sz):

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

    def _checkdim(self, dim):

        "Checks the given dimension."

        if dim < 0 or dim > 2:

            raise GEOSException('invalid ordinate dimension "%d"' % dim)

    @property

    def ptr(self):

        """

        Property for controlling access to coordinate sequence pointer,

        preventing attempted access to a NULL memory location.

        """

        if self._ptr: return self._ptr

        else: raise GEOSException('NULL coordinate sequence pointer encountered.')

    #### Ordinate getting and setting routines ####

    def getOrdinate(self, dimension, index):

        "Returns the value for the given dimension and index."

        self._checkindex(index)

        self._checkdim(dimension)

        return cs_getordinate(self.ptr, index, dimension, byref(c_double()))

    def setOrdinate(self, dimension, index, value):

        "Sets the value for the given dimension and index."

        self._checkindex(index)

        self._checkdim(dimension)

        cs_setordinate(self.ptr, index, dimension, value)

    def getX(self, index):

        "Get the X value at the index."

        return self.getOrdinate(0, index)

    def setX(self, index, value):

        "Set X with the value at the given index."

        self.setOrdinate(0, index, value)

    def getY(self, index):

        "Get the Y value at the given index."

        return self.getOrdinate(1, index)

    def setY(self, index, value):

        "Set Y with the value at the given index."

        self.setOrdinate(1, index, value)

    def getZ(self, index):

        "Get Z with the value at the given index."

        return self.getOrdinate(2, index)

    def setZ(self, index, value):

        "Set Z with the value at the given index."

        self.setOrdinate(2, index, value)

    ### Dimensions ###

    @property

    def size(self):

        "Returns the size of this coordinate sequence."

        return cs_getsize(self.ptr, byref(c_uint()))

    @property

    def dims(self):

        "Returns the dimensions of this coordinate sequence."

        return cs_getdims(self.ptr, byref(c_uint()))

    @property

    def hasz(self):

        """

        Returns whether this coordinate sequence is 3D.  This property value is

        inherited from the parent Geometry.

        """

        return self._z

    ### Other Methods ###

    def clone(self):

        "Clones this coordinate sequence."

        return GEOSCoordSeq(cs_clone(self.ptr), self.hasz)

    @property

    def kml(self):

        "Returns the KML representation for the coordinates."

        # Getting the substitution string depending on whether the coordinates have

        #  a Z dimension.

        if self.hasz: substr = '%s,%s,%s '

        else: substr = '%s,%s,0 '

        return '<coordinates>%s</coordinates>' % \

            ''.join([substr % self[i] for i in xrange(len(self))]).strip()

    @property

    def tuple(self):

        "Returns a tuple version of this coordinate sequence."

        n = self.size

        if n == 1: return self[0]

        else: return tuple([self[i] for i in xrange(n)])