"""
 The OGRGeometry is a wrapper for using the OGR Geometry class
 (see http://www.gdal.org/classOGRGeometry.html).  OGRGeometry
 may be instantiated when reading geometries from OGR Data Sources
 (e.g. SHP files), or when given OGC WKT (a string).

 While the 'full' API is not present yet, the API is "pythonic" unlike
 the traditional and "next-generation" OGR Python bindings.  One major
 advantage OGR Geometries have over their GEOS counterparts is support
 for spatial reference systems and their transformation.

 Example:
  >>> from django.contrib.gis.gdal import OGRGeometry, OGRGeomType, SpatialReference
  >>> wkt1, wkt2 = 'POINT(-90 30)', 'POLYGON((0 0, 5 0, 5 5, 0 5)'
  >>> pnt = OGRGeometry(wkt1)
  >>> print(pnt)
  POINT (-90 30)
  >>> mpnt = OGRGeometry(OGRGeomType('MultiPoint'), SpatialReference('WGS84'))
  >>> mpnt.add(wkt1)
  >>> mpnt.add(wkt1)
  >>> print(mpnt)
  MULTIPOINT (-90 30,-90 30)
  >>> print(mpnt.srs.name)
  WGS 84
  >>> print(mpnt.srs.proj)
  +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
  >>> mpnt.transform_to(SpatialReference('NAD27'))
  >>> print(mpnt.proj)
  +proj=longlat +ellps=clrk66 +datum=NAD27 +no_defs
  >>> print(mpnt)
  MULTIPOINT (-89.999930378602485 29.999797886557641,-89.999930378602485 29.999797886557641)

  The OGRGeomType class is to make it easy to specify an OGR geometry type:
  >>> from django.contrib.gis.gdal import OGRGeomType
  >>> gt1 = OGRGeomType(3) # Using an integer for the type
  >>> gt2 = OGRGeomType('Polygon') # Using a string
  >>> gt3 = OGRGeomType('POLYGON') # It's case-insensitive
  >>> print(gt1 == 3, gt1 == 'Polygon') # Equivalence works w/non-OGRGeomType objects
  True True
"""
import sys
from binascii import a2b_hex, b2a_hex
from ctypes import byref, c_char_p, c_double, c_ubyte, c_void_p, string_at

from django.contrib.gis.gdal.base import GDALBase
from django.contrib.gis.gdal.envelope import Envelope, OGREnvelope
from django.contrib.gis.gdal.error import (
    GDALException, OGRIndexError, SRSException,
)
from django.contrib.gis.gdal.geomtype import OGRGeomType
from django.contrib.gis.gdal.prototypes import geom as capi, srs as srs_api
from django.contrib.gis.gdal.srs import CoordTransform, SpatialReference
from django.contrib.gis.geometry.regex import hex_regex, json_regex, wkt_regex
from django.utils import six
from django.utils.six.moves import range


# For more information, see the OGR C API source code:
#  http://www.gdal.org/ogr__api_8h.html
#
# The OGR_G_* routines are relevant here.
class OGRGeometry(GDALBase):
    "Generally encapsulates an OGR geometry."

    def __init__(self, geom_input, srs=None):
        "Initializes Geometry on either WKT or an OGR pointer as input."

        str_instance = isinstance(geom_input, six.string_types)

        # If HEX, unpack input to a binary buffer.
        if str_instance and hex_regex.match(geom_input):
            geom_input = six.memoryview(a2b_hex(geom_input.upper().encode()))
            str_instance = False

        # Constructing the geometry,
        if str_instance:
            wkt_m = wkt_regex.match(geom_input)
            json_m = json_regex.match(geom_input)
            if wkt_m:
                if wkt_m.group('srid'):
                    # If there's EWKT, set the SRS w/value of the SRID.
                    srs = int(wkt_m.group('srid'))
                if wkt_m.group('type').upper() == 'LINEARRING':
                    # OGR_G_CreateFromWkt doesn't work with LINEARRING WKT.
                    #  See http://trac.osgeo.org/gdal/ticket/1992.
                    g = capi.create_geom(OGRGeomType(wkt_m.group('type')).num)
                    capi.import_wkt(g, byref(c_char_p(wkt_m.group('wkt').encode())))
                else:
                    g = capi.from_wkt(byref(c_char_p(wkt_m.group('wkt').encode())), None, byref(c_void_p()))
            elif json_m:
                g = capi.from_json(geom_input.encode())
            else:
                # Seeing if the input is a valid short-hand string
                # (e.g., 'Point', 'POLYGON').
                OGRGeomType(geom_input)
                g = capi.create_geom(OGRGeomType(geom_input).num)
        elif isinstance(geom_input, six.memoryview):
            # WKB was passed in
            g = capi.from_wkb(bytes(geom_input), None, byref(c_void_p()), len(geom_input))
        elif isinstance(geom_input, OGRGeomType):
            # OGRGeomType was passed in, an empty geometry will be created.
            g = capi.create_geom(geom_input.num)
        elif isinstance(geom_input, self.ptr_type):
            # OGR pointer (c_void_p) was the input.
            g = geom_input
        else:
            raise GDALException('Invalid input type for OGR Geometry construction: %s' % type(geom_input))

        # Now checking the Geometry pointer before finishing initialization
        # by setting the pointer for the object.
        if not g:
            raise GDALException('Cannot create OGR Geometry from input: %s' % str(geom_input))
        self.ptr = g

        # Assigning the SpatialReference object to the geometry, if valid.
        if srs:
            self.srs = srs

        # Setting the class depending upon the OGR Geometry Type
        self.__class__ = GEO_CLASSES[self.geom_type.num]

    def __del__(self):
        "Deletes this Geometry."
        if self._ptr and capi:
            capi.destroy_geom(self._ptr)

    # Pickle routines
    def __getstate__(self):
        srs = self.srs
        if srs:
            srs = srs.wkt
        else:
            srs = None
        return bytes(self.wkb), srs

    def __setstate__(self, state):
        wkb, srs = state
        ptr = capi.from_wkb(wkb, None, byref(c_void_p()), len(wkb))
        if not ptr:
            raise GDALException('Invalid OGRGeometry loaded from pickled state.')
        self.ptr = ptr
        self.srs = srs

    @classmethod
    def from_bbox(cls, bbox):
        "Constructs a Polygon from a bounding box (4-tuple)."
        x0, y0, x1, y1 = bbox
        return OGRGeometry('POLYGON((%s %s, %s %s, %s %s, %s %s, %s %s))' % (
            x0, y0, x0, y1, x1, y1, x1, y0, x0, y0))

    # ### Geometry set-like operations ###
    # g = g1 | g2
    def __or__(self, other):
        "Returns the union of the two geometries."
        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)

    def __eq__(self, other):
        "Is this Geometry equal to the other?"
        if isinstance(other, OGRGeometry):
            return self.equals(other)
        else:
            return False

    def __ne__(self, other):
        "Tests for inequality."
        return not (self == other)

    def __str__(self):
        "WKT is used for the string representation."
        return self.wkt

    # #### Geometry Properties ####
    @property
    def dimension(self):
        "Returns 0 for points, 1 for lines, and 2 for surfaces."
        return capi.get_dims(self.ptr)

    def _get_coord_dim(self):
        "Returns the coordinate dimension of the Geometry."
        return capi.get_coord_dim(self.ptr)

    def _set_coord_dim(self, dim):
        "Sets the coordinate dimension of this Geometry."
        if dim not in (2, 3):
            raise ValueError('Geometry dimension must be either 2 or 3')
        capi.set_coord_dim(self.ptr, dim)

    coord_dim = property(_get_coord_dim, _set_coord_dim)

    @property
    def geom_count(self):
        "The number of elements in this Geometry."
        return capi.get_geom_count(self.ptr)

    @property
    def point_count(self):
        "Returns the number of Points in this Geometry."
        return capi.get_point_count(self.ptr)

    @property
    def num_points(self):
        "Alias for `point_count` (same name method in GEOS API.)"
        return self.point_count

    @property
    def num_coords(self):
        "Alais for `point_count`."
        return self.point_count

    @property
    def geom_type(self):
        "Returns the Type for this Geometry."
        return OGRGeomType(capi.get_geom_type(self.ptr))

    @property
    def geom_name(self):
        "Returns the Name of this Geometry."
        return capi.get_geom_name(self.ptr)

    @property
    def area(self):
        "Returns the area for a LinearRing, Polygon, or MultiPolygon; 0 otherwise."
        return capi.get_area(self.ptr)

    @property
    def envelope(self):
        "Returns the envelope for this Geometry."
        # TODO: Fix Envelope() for Point geometries.
        return Envelope(capi.get_envelope(self.ptr, byref(OGREnvelope())))

    @property
    def extent(self):
        "Returns the envelope as a 4-tuple, instead of as an Envelope object."
        return self.envelope.tuple

    # #### SpatialReference-related Properties ####

    # The SRS property
    def _get_srs(self):
        "Returns the Spatial Reference for this Geometry."
        try:
            srs_ptr = capi.get_geom_srs(self.ptr)
            return SpatialReference(srs_api.clone_srs(srs_ptr))
        except SRSException:
            return None

    def _set_srs(self, srs):
        "Sets the SpatialReference for this geometry."
        # Do not have to clone the `SpatialReference` object pointer because
        # when it is assigned to this `OGRGeometry` it's internal OGR
        # reference count is incremented, and will likewise be released
        # (decremented) when this geometry's destructor is called.
        if isinstance(srs, SpatialReference):
            srs_ptr = srs.ptr
        elif isinstance(srs, six.integer_types + six.string_types):
            sr = SpatialReference(srs)
            srs_ptr = sr.ptr
        else:
            raise TypeError('Cannot assign spatial reference with object of type: %s' % type(srs))
        capi.assign_srs(self.ptr, srs_ptr)

    srs = property(_get_srs, _set_srs)

    # The SRID property
    def _get_srid(self):
        srs = self.srs
        if srs:
            return srs.srid
        return None

    def _set_srid(self, srid):
        if isinstance(srid, six.integer_types):
            self.srs = srid
        else:
            raise TypeError('SRID must be set with an integer.')

    srid = property(_get_srid, _set_srid)

    # #### Output Methods ####
    @property
    def geos(self):
        "Returns a GEOSGeometry object from this OGRGeometry."
        from django.contrib.gis.geos import GEOSGeometry
        return GEOSGeometry(self.wkb, self.srid)

    @property
    def gml(self):
        "Returns the GML representation of the Geometry."
        return capi.to_gml(self.ptr)

    @property
    def hex(self):
        "Returns the hexadecimal representation of the WKB (a string)."
        return b2a_hex(self.wkb).upper()

    @property
    def json(self):
        """
        Returns the GeoJSON representation of this Geometry.
        """
        return capi.to_json(self.ptr)
    geojson = json

    @property
    def kml(self):
        "Returns the KML representation of the Geometry."
        return capi.to_kml(self.ptr, None)

    @property
    def wkb_size(self):
        "Returns the size of the WKB buffer."
        return capi.get_wkbsize(self.ptr)

    @property
    def wkb(self):
        "Returns the WKB representation of the Geometry."
        if sys.byteorder == 'little':
            byteorder = 1  # wkbNDR (from ogr_core.h)
        else:
            byteorder = 0  # wkbXDR
        sz = self.wkb_size
        # Creating the unsigned character buffer, and passing it in by reference.
        buf = (c_ubyte * sz)()
        capi.to_wkb(self.ptr, byteorder, byref(buf))
        # Returning a buffer of the string at the pointer.
        return six.memoryview(string_at(buf, sz))

    @property
    def wkt(self):
        "Returns the WKT representation of the Geometry."