"""

  This module contains the 'base' GEOSGeometry object -- all GEOS Geometries

  inherit from this object.

 """

 # Python, ctypes and types dependencies.

 import re

 from ctypes import addressof, byref, c_double, c_size_t

 # GEOS-related dependencies.

 from django.contrib.gis.geos.base import GEOSBase, ListMixin, gdal

 from django.contrib.gis.geos.coordseq import GEOSCoordSeq

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

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

 # All other functions in this module come from the ctypes 

 # prototypes module -- which handles all interaction with

 # the underlying GEOS library.

 from django.contrib.gis.geos import prototypes as capi

 from django.contrib.gis.geos import io

 # Regular expression for recognizing HEXEWKB and WKT.  A prophylactic measure

 # to prevent potentially malicious input from reaching the underlying C

 # library.  Not a substitute for good web security programming practices.

 hex_regex = re.compile(r'^[0-9A-F]+$', re.I)

 wkt_regex = re.compile(r'^(SRID=(?P<srid>\d+);)?(?P<wkt>(POINT|LINESTRING|LINEARRING|POLYGON|MULTIPOINT|MULTILINESTRING|MULTIPOLYGON|GEOMETRYCOLLECTION)[ACEGIMLONPSRUTY\d,\.\-\(\) ]+)$', re.I)

 class GEOSGeometry(GEOSBase, ListMixin):

     "A class that, generally, encapsulates a GEOS geometry."

     ptr_type = GEOM_PTR

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

     def __init__(self, geo_input, srid=None):

         """

         The base constructor for GEOS geometry objects, and may take the 

         following inputs:

          * strings: 

             - WKT

             - HEXEWKB (a PostGIS-specific canonical form)

             - GeoJSON (requires GDAL)

          * buffer: 

             - WKB

         The `srid` keyword is used to specify the Source Reference Identifier

         (SRID) number for this Geometry.  If not set, the SRID will be None.

         """ 

         if isinstance(geo_input, basestring):

             if isinstance(geo_input, unicode):

                 # Encoding to ASCII, WKT or HEXEWKB doesn't need any more.

                 geo_input = geo_input.encode('ascii')

             wkt_m = wkt_regex.match(geo_input)

             if wkt_m:

                 # Handling WKT input.

                 if wkt_m.group('srid'): srid = int(wkt_m.group('srid'))

                 g = io.wkt_r.read(wkt_m.group('wkt'))

             elif hex_regex.match(geo_input):

                 # Handling HEXEWKB input.

                 g = io.wkb_r.read(geo_input)

             elif gdal.GEOJSON and gdal.geometries.json_regex.match(geo_input):

                 # Handling GeoJSON input.

                 g = io.wkb_r.read(gdal.OGRGeometry(geo_input).wkb)

             else:

                 raise ValueError('String or unicode input unrecognized as WKT EWKT, and HEXEWKB.')

         elif isinstance(geo_input, GEOM_PTR):

             # When the input is a pointer to a geomtry (GEOM_PTR).

             g = geo_input

         elif isinstance(geo_input, buffer):

             # When the input is a buffer (WKB).

             g = io.wkb_r.read(geo_input)

         elif isinstance(geo_input, GEOSGeometry):

             g = capi.geom_clone(geo_input.ptr)

         else:

             # Invalid geometry type.

             raise TypeError('Improper geometry input type: %s' % str(type(geo_input)))

         if bool(g):

             # Setting the pointer object with a valid pointer.

             self.ptr = g

         else:

             raise GEOSException('Could not initialize GEOS Geometry with given input.')

         # Post-initialization setup.

         self._post_init(srid)

     def _post_init(self, srid):

         "Helper routine for performing post-initialization setup."

         # Setting the SRID, if given.

         if srid and isinstance(srid, int): self.srid = srid

         # Setting the class type (e.g., Point, Polygon, etc.)

         self.__class__ = GEOS_CLASSES[self.geom_typeid]

         # Setting the coordinate sequence for the geometry (will be None on 

         # geometries that do not have coordinate sequences)

         self._set_cs()

     def __del__(self):

         """

         Destroys this Geometry; in other words, frees the memory used by the

         GEOS C++ object.

         """

         if self._ptr: capi.destroy_geom(self._ptr)

     def __copy__(self):

         """

         Returns a clone because the copy of a GEOSGeometry may contain an

         invalid pointer location if the original is garbage collected.

         """

         return self.clone()

     def __deepcopy__(self, memodict):

         """

         The `deepcopy` routine is used by the `Node` class of django.utils.tree;

         thus, the protocol routine needs to be implemented to return correct 

         copies (clones) of these GEOS objects, which use C pointers.

         """

         return self.clone()

     def __str__(self):

         "WKT is used for the string representation."

         return self.wkt

     def __repr__(self):

         "Short-hand representation because WKT may be very large."

         return '<%s object at %s>' % (self.geom_type, hex(addressof(self.ptr)))

     # Pickling support

     def __getstate__(self):

         # The pickled state is simply a tuple of the WKB (in string form)

         # and the SRID.

         return str(self.wkb), self.srid

     def __setstate__(self, state):

         # Instantiating from the tuple state that was pickled.

         wkb, srid = state

         ptr = capi.from_wkb(wkb, len(wkb))

         if not ptr: raise GEOSException('Invalid Geometry loaded from pickled state.')

         self.ptr = ptr

         self._post_init(srid)

     # Comparison operators

     def __eq__(self, other):

         """

         Equivalence testing, a Geometry may be compared with another Geometry

         or a WKT representation.

         """

         if isinstance(other, basestring):

             return self.wkt == other

         elif isinstance(other, GEOSGeometry):

             return self.equals_exact(other)

         else:

             return False

     def __ne__(self, other):

         "The not equals operator."

         return not (self == other)

     ### Geometry set-like operations ###

     # Thanks to Sean Gillies for inspiration:

     #  http://lists.gispython.org/pipermail/community/2007-July/001034.html

     # g = g1 | g2

     def __or__(self, other):

         "Returns the union of this Geometry and the other."

         return self.union(other)

     # g = g1 & g2

     def __and__(self, other):

         "Returns the intersection of this Geometry and the other."

         return self.intersection(other)

     # g = g1 - g2

     def __sub__(self, other):

         "Return the difference this Geometry and the other."

         return self.difference(other)

     # g = g1 ^ g2

     def __xor__(self, other):

         "Return the symmetric difference of this Geometry and the other."

         return self.sym_difference(other)

     #### Coordinate Sequence Routines ####

     @property

     def has_cs(self):

         "Returns True if this Geometry has a coordinate sequence, False if not."

         # Only these geometries are allowed to have coordinate sequences.

         if isinstance(self, (Point, LineString, LinearRing)):

             return True

         else:

             return False

     def _set_cs(self):

         "Sets the coordinate sequence for this Geometry."

         if self.has_cs:

             self._cs = GEOSCoordSeq(capi.get_cs(self.ptr), self.hasz)

         else:

             self._cs = None

     @property

     def coord_seq(self):

         "Returns a clone of the coordinate sequence for this Geometry."

         if self.has_cs:

             return self._cs.clone()

     #### Geometry Info ####

     @property

     def geom_type(self):

         "Returns a string representing the Geometry type, e.g. 'Polygon'"

         return capi.geos_type(self.ptr)

     @property

     def geom_typeid(self):

         "Returns an integer representing the Geometry type."

         return capi.geos_typeid(self.ptr)

     @property

     def num_geom(self):

         "Returns the number of geometries in the Geometry."

         return capi.get_num_geoms(self.ptr)

     @property

     def num_coords(self):

         "Returns the number of coordinates in the Geometry."

         return capi.get_num_coords(self.ptr)

     @property

     def num_points(self):

         "Returns the number points, or coordinates, in the Geometry."

         return self.num_coords

     @property

     def dims(self):

         "Returns the dimension of this Geometry (0=point, 1=line, 2=surface)."

         return capi.get_dims(self.ptr)

     def normalize(self):

         "Converts this Geometry to normal form (or canonical form)."

         return capi.geos_normalize(self.ptr)

     #### Unary predicates ####

     @property

     def empty(self):

         """

         Returns a boolean indicating whether the set of points in this Geometry 

         are empty.

         """

         return capi.geos_isempty(self.ptr)

     @property

     def hasz(self):

         "Returns whether the geometry has a 3D dimension."

         return capi.geos_hasz(self.ptr)

     @property

     def ring(self):

         "Returns whether or not the geometry is a ring."

         return capi.geos_isring(self.ptr)

     @property

     def simple(self):

         "Returns false if the Geometry not simple."

         return capi.geos_issimple(self.ptr)

     @property

     def valid(self):

         "This property tests the validity of this Geometry."

         return capi.geos_isvalid(self.ptr)

     #### Binary predicates. ####

     def contains(self, other):

         "Returns true if other.within(this) returns true."

         return capi.geos_contains(self.ptr, other.ptr)

     def crosses(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries

         is T*T****** (for a point and a curve,a point and an area or a line and

         an area) 0******** (for two curves).

         """

         return capi.geos_crosses(self.ptr, other.ptr)

     def disjoint(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries

         is FF*FF****.

         """

         return capi.geos_disjoint(self.ptr, other.ptr)

     def equals(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries 

         is T*F**FFF*.

         """

         return capi.geos_equals(self.ptr, other.ptr)

     def equals_exact(self, other, tolerance=0):

         """

         Returns true if the two Geometries are exactly equal, up to a

         specified tolerance.

         """

         return capi.geos_equalsexact(self.ptr, other.ptr, float(tolerance))

     def intersects(self, other):

         "Returns true if disjoint returns false."

         return capi.geos_intersects(self.ptr, other.ptr)

     def overlaps(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries

         is T*T***T** (for two points or two surfaces) 1*T***T** (for two curves).

         """

         return capi.geos_overlaps(self.ptr, other.ptr)

     def relate_pattern(self, other, pattern):

         """

         Returns true if the elements in the DE-9IM intersection matrix for the

         two Geometries match the elements in pattern.

         """

         if not isinstance(pattern, basestring) or len(pattern) > 9:

             raise GEOSException('invalid intersection matrix pattern')

         return capi.geos_relatepattern(self.ptr, other.ptr, pattern)

     def touches(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries

         is FT*******, F**T***** or F***T****.

         """

         return capi.geos_touches(self.ptr, other.ptr)

     def within(self, other):

         """

         Returns true if the DE-9IM intersection matrix for the two Geometries

         is T*F**F***.

         """

         return capi.geos_within(self.ptr, other.ptr)

     #### SRID Routines ####

     def get_srid(self):

         "Gets the SRID for the geometry, returns None if no SRID is set."

         s = capi.geos_get_srid(self.ptr)

         if s == 0: return None

         else: return s

     def set_srid(self, srid):

         "Sets the SRID for the geometry."

         capi.geos_set_srid(self.ptr, srid)

     srid = property(get_srid, set_srid)

     #### Output Routines ####

     @property

     def ewkt(self):

         "Returns the EWKT (WKT + SRID) of the Geometry."

         if self.get_srid(): return 'SRID=%s;%s' % (self.srid, self.wkt)

         else: return self.wkt

     @property

     def wkt(self):

         "Returns the WKT (Well-Known Text) of the Geometry."

         return io.wkt_w.write(self.ptr)

     @property

     def hex(self):

         """

         Returns the HEX of the Geometry -- please note that the SRID is not

         included in this representation, because the GEOS C library uses

         -1 by default, even if the SRID is set.

         """

         # A possible faster, all-python, implementation: 

         #  str(self.wkb).encode('hex')

         return io.wkb_w.write_hex(self.ptr)

     @property

     def json(self):

         """

         Returns GeoJSON representation of this Geometry if GDAL 1.5+ 

         is installed.

         """

         if gdal.GEOJSON: return self.ogr.json

     geojson = json

     @property

     def wkb(self):

         "Returns the WKB of the Geometry as a buffer."

         return io.wkb_w.write(self.ptr)

     @property

     def kml(self):

         "Returns the KML representation of this Geometry."

         gtype = self.geom_type

         return '<%s>%s</%s>' % (gtype, self.coord_seq.kml, gtype)

     @property

     def prepared(self):

         """

         Returns a PreparedGeometry corresponding to this geometry -- it is

         optimized for the contains, intersects, and covers operations.

         """

         if GEOS_PREPARE: 

             return PreparedGeometry(self)

         else:

             raise GEOSException('GEOS 3.1+ required for prepared geometry support.')

     #### GDAL-specific output routines ####

     @property

     def ogr(self):

         "Returns the OGR Geometry for this Geometry."

         if gdal.HAS_GDAL:

             if self.srid:

                 return gdal.OGRGeometry(self.wkb, self.srid)

             else:

                 return gdal.OGRGeometry(self.wkb)

         else:

             return None

     @property

     def srs(self):

         "Returns the OSR SpatialReference for SRID of this Geometry."

         if gdal.HAS_GDAL and self.srid:

             return gdal.SpatialReference(self.srid)

         else:

             return None

     @property

     def crs(self):

         "Alias for `srs` property."

         return self.srs

     def transform(self, ct, clone=False):

         """

         Requires GDAL. Transforms the geometry according to the given 

         transformation object, which may be an integer SRID, and WKT or 

         PROJ.4 string. By default, the geometry is transformed in-place and 

         nothing is returned. However if the `clone` keyword is set, then this 

         geometry will not be modified and a transformed clone will be returned

         instead.

         """

         srid = self.srid

         if gdal.HAS_GDAL and srid:

             # Creating an OGR Geometry, which is then transformed.

             g = gdal.OGRGeometry(self.wkb, srid)

             g.transform(ct)

             # Getting a new GEOS pointer

             ptr = io.wkb_r.read(g.wkb)

             if clone: 

                 # User wants a cloned transformed geometry returned.

                 return GEOSGeometry(ptr, srid=g.srid)

             if ptr:

                 # Reassigning pointer, and performing post-initialization setup

                 # again due to the reassignment.

                 capi.destroy_geom(self.ptr)

                 self.ptr = ptr

                 self._post_init(g.srid)

             else:

                 raise GEOSException('Transformed WKB was invalid.')

     #### Topology Routines ####

     def _topology(self, gptr):

         "Helper routine to return Geometry from the given pointer."

         return GEOSGeometry(gptr, srid=self.srid)

     @property

     def boundary(self):

         "Returns the boundary as a newly allocated Geometry object."

         return self._topology(capi.geos_boundary(self.ptr))

     def buffer(self, width, quadsegs=8):

         """

         Returns a geometry that represents all points whose distance from this

         Geometry is less than or equal to distance. Calculations are in the

         Spatial Reference System of this Geometry. The optional third parameter sets

         the number of segment used to approximate a quarter circle (defaults to 8).

         (Text from PostGIS documentation at ch. 6.1.3)

         """

         return self._topology(capi.geos_buffer(self.ptr, width, quadsegs))

     @property

     def centroid(self):

         """

         The centroid is equal to the centroid of the set of component Geometries

         of highest dimension (since the lower-dimension geometries contribute zero

         "weight" to the centroid).

         """

         return self._topology(capi.geos_centroid(self.ptr))

     @property

     def convex_hull(self):

         """

         Returns the smallest convex Polygon that contains all the points 

         in the Geometry.

         """

         return self._topology(capi.geos_convexhull(self.ptr))

     def difference(self, other):

         """

         Returns a Geometry representing the points making up this Geometry

         that do not make up other.

         """

         return self._topology(capi.geos_difference(self.ptr, other.ptr))

     @property

     def envelope(self):

         "Return the envelope for this geometry (a polygon)."

         return self._topology(capi.geos_envelope(self.ptr))

     def intersection(self, other):

         "Returns a Geometry representing the points shared by this Geometry and other."

         return self._topology(capi.geos_intersection(self.ptr, other.ptr))

     @property

     def point_on_surface(self):

         "Computes an interior point of this Geometry."

         return self._topology(capi.geos_pointonsurface(self.ptr))

     def relate(self, other):

         "Returns the DE-9IM intersection matrix for this Geometry and the other."

         return capi.geos_relate(self.ptr, other.ptr)

     def simplify(self, tolerance=0.0, preserve_topology=False):

         """

         Returns the Geometry, simplified using the Douglas-Peucker algorithm

         to the specified tolerance (higher tolerance => less points).  If no

         tolerance provided, defaults to 0.

         By default, this function does not preserve topology - e.g. polygons can 

         be split, collapse to lines or disappear holes can be created or 

         disappear, and lines can cross. By specifying preserve_topology=True, 

         the result will have the same dimension and number of components as the 

         input. This is significantly slower.         

         """

         if preserve_topology:

             return self._topology(capi.geos_preservesimplify(self.ptr, tolerance))

         else:

             return self._topology(capi.geos_simplify(self.ptr, tolerance))

     def sym_difference(self, other):

         """

         Returns a set combining the points in this Geometry not in other,

         and the points in other not in this Geometry.

         """

         return self._topology(capi.geos_symdifference(self.ptr, other.ptr))

     def union(self, other):

         "Returns a Geometry representing all the points in this Geometry and other."

         return self._topology(capi.geos_union(self.ptr, other.ptr))

     #### Other Routines ####

     @property

     def area(self):

         "Returns the area of the Geometry."

         return capi.geos_area(self.ptr, byref(c_double()))

     def distance(self, other):

         """

         Returns the distance between the closest points on this Geometry

         and the other. Units will be in those of the coordinate system of

         the Geometry.

         """

         if not isinstance(other, GEOSGeometry): 

             raise TypeError('distance() works only on other GEOS Geometries.')

         return capi.geos_distance(self.ptr, other.ptr, byref(c_double()))

     @property

     def extent(self):

         """

         Returns the extent of this geometry as a 4-tuple, consisting of

         (xmin, ymin, xmax, ymax).

         """

         env = self.envelope

         if isinstance(env, Point):

             xmin, ymin = env.tuple

             xmax, ymax = xmin, ymin

         else:

             xmin, ymin = env[0][0]

             xmax, ymax = env[0][2]

         return (xmin, ymin, xmax, ymax)

     @property

     def length(self):

         """

         Returns the length of this Geometry (e.g., 0 for point, or the

         circumfrence of a Polygon).

         """

         return capi.geos_length(self.ptr, byref(c_double()))

     def clone(self):

         "Clones this Geometry."

         return GEOSGeometry(capi.geom_clone(self.ptr), srid=self.srid)

 # Class mapping dictionary.  Has to be at the end to avoid import 

 # conflicts with GEOSGeometry.

 from django.contrib.gis.geos.linestring import LineString, LinearRing

 from django.contrib.gis.geos.point import Point

 from django.contrib.gis.geos.polygon import Polygon

 from django.contrib.gis.geos.collections import GeometryCollection, MultiPoint, MultiLineString, MultiPolygon

 GEOS_CLASSES = {0 : Point,

                 1 : LineString,

                 2 : LinearRing,

                 3 : Polygon,

                 4 : MultiPoint,

                 5 : MultiLineString,

                 6 : MultiPolygon,

                 7 : GeometryCollection,

                 }

 # If supported, import the PreparedGeometry class.

 if GEOS_PREPARE:

     from django.contrib.gis.geos.prepared import PreparedGeometry