"""ctypes single-value "parameter" arguments (e.g. byref)
"""
REGISTRY_NAME = 'ctypeparameter'
import ctypes, _ctypes

from OpenGL import constants, constant
from OpenGL.arrays import formathandler
import operator

c = ctypes.c_float(0)
ParamaterType = ctypes.byref(c).__class__
del c

class CtypesParameterHandler( formathandler.FormatHandler ):
	"""Ctypes Paramater-type-specific data-type handler for OpenGL"""
	isOutput = True
	HANDLED_TYPES = (ParamaterType, _ctypes._SimpleCData)
	def from_param( cls, value, typeCode=None ):
		if isinstance( value, ParamaterType ):
			return value 
		else:
			return ctypes.byref( value )
	from_param = voidDataPointer = classmethod( from_param )
	def dataPointer( cls, value ):
		if isinstance( value, ParamaterType ):
			return value 
		else:
			return ctypes.addressof( value )
	dataPointer = classmethod( dataPointer )
	def zeros( self, dims, typeCode ):
		"""Return Numpy array of zeros in given size"""
		type = GL_TYPE_TO_ARRAY_MAPPING[ typeCode ]
		for dim in dims:
			type *= dim 
		return type() # should expicitly set to 0s
	def ones( self, dims, typeCode='d' ):
		"""Return numpy array of ones in given size"""
		raise NotImplementedError( """Haven't got a good ones implementation yet""" )
##		type = GL_TYPE_TO_ARRAY_MAPPING[ typeCode ]
##		for dim in dims:
##			type *= dim 
##		return type() # should expicitly set to 0s
	def arrayToGLType( self, value ):
		"""Given a value, guess OpenGL type of the corresponding pointer"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		result = ARRAY_TO_GL_TYPE_MAPPING.get( value._type_ )
		if result is not None:
			return result
		raise TypeError(
			"""Don't know GL type for array of type %r, known types: %s\nvalue:%s"""%(
				value._type_, ARRAY_TO_GL_TYPE_MAPPING.keys(), value,
			)
		)
	def arraySize( self, value, typeCode = None ):
		"""Given a data-value, calculate dimensions for the array"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		dims = 1
		for base in self.types( value ):
			length = getattr( base, '_length_', None)
			if length is not None:
				dims *= length
		return dims 
	def arrayByteCount( self, value, typeCode = None ):
		"""Given a data-value, calculate number of bytes required to represent"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		return ctypes.sizeof( value )
	def types( self, value ):
		"""Produce iterable producing all composite types"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		dimObject = value
		while dimObject is not None:
			yield dimObject
			dimObject = getattr( dimObject, '_type_', None )
			if isinstance( dimObject, (str,unicode)):
				dimObject = None 
	def dims( self, value ):
		"""Produce iterable of all dimensions"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		for base in self.types( value ):
			length = getattr( base, '_length_', None)
			if length is not None:
				yield length
	def asArray( self, value, typeCode=None ):
		"""Convert given value to an array value of given typeCode"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		return ctypes.byref( value )
	def unitSize( self, value, typeCode=None ):
		"""Determine unit size of an array (if possible)"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		return tuple(self.dims(value))[-1]
	def dimensions( self, value, typeCode=None ):
		"""Determine dimensions of the passed array value (if possible)"""
		if isinstance( value, ParamaterType ):
			value = value._obj
		return tuple( self.dims(value) )


ARRAY_TO_GL_TYPE_MAPPING = {
	constants.GLdouble: constants.GL_DOUBLE,
	constants.GLfloat: constants.GL_FLOAT,
	constants.GLint: constants.GL_INT,
	constants.GLuint: constants.GL_UNSIGNED_INT,
	constants.GLshort: constants.GL_SHORT,
	constants.GLushort: constants.GL_UNSIGNED_SHORT,
		
	constants.GLchar: constants.GL_CHAR,
	constants.GLbyte: constants.GL_BYTE,
	constants.GLubyte: constants.GL_UNSIGNED_BYTE,
}
GL_TYPE_TO_ARRAY_MAPPING = {
	constants.GL_DOUBLE: constants.GLdouble,
	constants.GL_FLOAT: constants.GLfloat,
	constants.GL_INT: constants.GLint,
	constants.GL_UNSIGNED_INT: constants.GLuint,
	constants.GL_SHORT: constants.GLshort,
	constants.GL_UNSIGNED_SHORT: constants.GLushort,
		
	constants.GL_CHAR: constants.GLchar,
	constants.GL_BYTE: constants.GLbyte,
	constants.GL_UNSIGNED_BYTE: constants.GLubyte,
}
