from ctypes import c_double, c_int, c_uint, POINTER

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

from django.contrib.gis.geos.prototypes.errcheck import last_arg_byref, GEOSException

## Error-checking routines specific to coordinate sequences. ##

def check_cs_ptr(result, func, cargs):

    "Error checking on routines that return Geometries."

    if not result:

        raise GEOSException('Error encountered checking Coordinate Sequence returned from GEOS C function "%s".' % func.__name__)

    return result

def check_cs_op(result, func, cargs):

    "Checks the status code of a coordinate sequence operation."

    if result == 0:

        raise GEOSException('Could not set value on coordinate sequence')

    else:

        return result

def check_cs_get(result, func, cargs):

    "Checking the coordinate sequence retrieval."

    check_cs_op(result, func, cargs)

    # Object in by reference, return its value.

    return last_arg_byref(cargs)

## Coordinate sequence prototype generation functions. ##

def cs_int(func):

    "For coordinate sequence routines that return an integer."

    func.argtypes = [CS_PTR, POINTER(c_uint)]

    func.restype = c_int

    func.errcheck = check_cs_get

    return func

def cs_operation(func, ordinate=False, get=False):

    "For coordinate sequence operations."

    if get:

        # Get routines get double parameter passed-in by reference.

        func.errcheck = check_cs_get

        dbl_param = POINTER(c_double)

    else:

        func.errcheck = check_cs_op

        dbl_param = c_double

    if ordinate:

        # Get/Set ordinate routines have an extra uint parameter.

        func.argtypes = [CS_PTR, c_uint, c_uint, dbl_param]

    else:

        func.argtypes = [CS_PTR, c_uint, dbl_param]

    func.restype = c_int

    return func

def cs_output(func, argtypes):

    "For routines that return a coordinate sequence."

    func.argtypes = argtypes

    func.restype = CS_PTR

    func.errcheck = check_cs_ptr

    return func

## Coordinate Sequence ctypes prototypes ##

# Coordinate Sequence constructors & cloning.

cs_clone = cs_output(lgeos.GEOSCoordSeq_clone, [CS_PTR])

create_cs = cs_output(lgeos.GEOSCoordSeq_create, [c_uint, c_uint])

get_cs = cs_output(lgeos.GEOSGeom_getCoordSeq, [GEOM_PTR])

# Getting, setting ordinate

cs_getordinate = cs_operation(lgeos.GEOSCoordSeq_getOrdinate, ordinate=True, get=True)

cs_setordinate = cs_operation(lgeos.GEOSCoordSeq_setOrdinate, ordinate=True)

# For getting, x, y, z

cs_getx = cs_operation(lgeos.GEOSCoordSeq_getX, get=True)

cs_gety = cs_operation(lgeos.GEOSCoordSeq_getY, get=True)

cs_getz = cs_operation(lgeos.GEOSCoordSeq_getZ, get=True)

# For setting, x, y, z

cs_setx = cs_operation(lgeos.GEOSCoordSeq_setX)

cs_sety = cs_operation(lgeos.GEOSCoordSeq_setY)

cs_setz = cs_operation(lgeos.GEOSCoordSeq_setZ)

# These routines return size & dimensions.

cs_getsize = cs_int(lgeos.GEOSCoordSeq_getSize)

cs_getdims = cs_int(lgeos.GEOSCoordSeq_getDimensions)