from ctypes import c_char_p, c_int, c_size_t, c_uint, POINTER

from django.contrib.gis.geos.libgeos import lgeos, CS_PTR, GEOM_PTR

from django.contrib.gis.geos.prototypes.errcheck import \

    check_geom, check_minus_one, check_sized_string, check_string, check_zero

### ctypes generation functions ###

def bin_constructor(func):

    "Generates a prototype for binary construction (HEX, WKB) GEOS routines."

    func.argtypes = [c_char_p, c_size_t]

    func.restype = GEOM_PTR

    func.errcheck = check_geom

    return func

# HEX & WKB output

def bin_output(func):

    "Generates a prototype for the routines that return a a sized string."

    func.argtypes = [GEOM_PTR, POINTER(c_size_t)]

    func.errcheck = check_sized_string

    return func

def geom_output(func, argtypes):

    "For GEOS routines that return a geometry."

    if argtypes: func.argtypes = argtypes

    func.restype = GEOM_PTR

    func.errcheck = check_geom

    return func

def geom_index(func):

    "For GEOS routines that return geometries from an index."

    return geom_output(func, [GEOM_PTR, c_int])

def int_from_geom(func, zero=False):

    "Argument is a geometry, return type is an integer."

    func.argtypes = [GEOM_PTR]

    func.restype = c_int

    if zero: 

        func.errcheck = check_zero

    else:

        func.errcheck = check_minus_one

    return func

def string_from_geom(func):

    "Argument is a Geometry, return type is a string."

    # We do _not_ specify an argument type because we want just an

    # address returned from the function.

    func.argtypes = [GEOM_PTR]

    func.errcheck = check_string

    return func

### ctypes prototypes ###

# TODO: Tell all users to use GEOS 3.0.0, instead of the release 

#  candidates, and use the new Reader and Writer APIs (e.g.,

#  GEOSWKT[Reader|Writer], GEOSWKB[Reader|Writer]).  A good time

#  to do this will be when Refractions releases a Windows PostGIS

#  installer using GEOS 3.0.0.

# Creation routines from WKB, HEX, WKT

from_hex = bin_constructor(lgeos.GEOSGeomFromHEX_buf)

from_wkb = bin_constructor(lgeos.GEOSGeomFromWKB_buf)

from_wkt = geom_output(lgeos.GEOSGeomFromWKT, [c_char_p])

# Output routines

to_hex = bin_output(lgeos.GEOSGeomToHEX_buf)

to_wkb = bin_output(lgeos.GEOSGeomToWKB_buf)

to_wkt = string_from_geom(lgeos.GEOSGeomToWKT)

# The GEOS geometry type, typeid, num_coordites and number of geometries

geos_normalize = int_from_geom(lgeos.GEOSNormalize)

geos_type = string_from_geom(lgeos.GEOSGeomType)

geos_typeid = int_from_geom(lgeos.GEOSGeomTypeId)

get_dims = int_from_geom(lgeos.GEOSGeom_getDimensions, zero=True)

get_num_coords = int_from_geom(lgeos.GEOSGetNumCoordinates)

get_num_geoms = int_from_geom(lgeos.GEOSGetNumGeometries)

# Geometry creation factories

create_point = geom_output(lgeos.GEOSGeom_createPoint, [CS_PTR])

create_linestring = geom_output(lgeos.GEOSGeom_createLineString, [CS_PTR]) 

create_linearring = geom_output(lgeos.GEOSGeom_createLinearRing, [CS_PTR])

# Polygon and collection creation routines are special and will not

# have their argument types defined.

create_polygon = geom_output(lgeos.GEOSGeom_createPolygon, None)

create_collection = geom_output(lgeos.GEOSGeom_createCollection, None)

# Ring routines

get_extring = geom_output(lgeos.GEOSGetExteriorRing, [GEOM_PTR])

get_intring = geom_index(lgeos.GEOSGetInteriorRingN)

get_nrings = int_from_geom(lgeos.GEOSGetNumInteriorRings)

# Collection Routines

get_geomn = geom_index(lgeos.GEOSGetGeometryN)

# Cloning

geom_clone = lgeos.GEOSGeom_clone

geom_clone.argtypes = [GEOM_PTR]

geom_clone.restype = GEOM_PTR

# Destruction routine.

destroy_geom = lgeos.GEOSGeom_destroy

destroy_geom.argtypes = [GEOM_PTR]

destroy_geom.restype = None

# SRID routines

geos_get_srid = lgeos.GEOSGetSRID

geos_get_srid.argtypes = [GEOM_PTR]

geos_get_srid.restype = c_int

geos_set_srid = lgeos.GEOSSetSRID

geos_set_srid.argtypes = [GEOM_PTR, c_int]

geos_set_srid.restype = None