import types
import weakref

from .lock import allocate_lock
from .error import CDefError, VerificationError, VerificationMissing

# type qualifiers
Q_CONST    = 0x01
Q_RESTRICT = 0x02
Q_VOLATILE = 0x04

def qualify(quals, replace_with):
    if quals & Q_CONST:
        replace_with = ' const ' + replace_with.lstrip()
    if quals & Q_VOLATILE:
        replace_with = ' volatile ' + replace_with.lstrip()
    if quals & Q_RESTRICT:
        # It seems that __restrict is supported by gcc and msvc.
        # If you hit some different compiler, add a #define in
        # _cffi_include.h for it (and in its copies, documented there)
        replace_with = ' __restrict ' + replace_with.lstrip()
    return replace_with


class BaseTypeByIdentity(object):
    is_array_type = False
    is_raw_function = False

    def get_c_name(self, replace_with='', context='a C file', quals=0):
        result = self.c_name_with_marker
        assert result.count('&') == 1
        # some logic duplication with ffi.getctype()... :-(
        replace_with = replace_with.strip()
        if replace_with:
            if replace_with.startswith('*') and '&[' in result:
                replace_with = '(%s)' % replace_with
            elif not replace_with[0] in '[(':
                replace_with = ' ' + replace_with
        replace_with = qualify(quals, replace_with)
        result = result.replace('&', replace_with)
        if '$' in result:
            raise VerificationError(
                "cannot generate '%s' in %s: unknown type name"
                % (self._get_c_name(), context))
        return result

    def _get_c_name(self):
        return self.c_name_with_marker.replace('&', '')

    def has_c_name(self):
        return '$' not in self._get_c_name()

    def is_integer_type(self):
        return False

    def get_cached_btype(self, ffi, finishlist, can_delay=False):
        try:
            BType = ffi._cached_btypes[self]
        except KeyError:
            BType = self.build_backend_type(ffi, finishlist)
            BType2 = ffi._cached_btypes.setdefault(self, BType)
            assert BType2 is BType
        return BType

    def __repr__(self):
        return '<%s>' % (self._get_c_name(),)

    def _get_items(self):
        return [(name, getattr(self, name)) for name in self._attrs_]


class BaseType(BaseTypeByIdentity):

    def __eq__(self, other):
        return (self.__class__ == other.__class__ and
                self._get_items() == other._get_items())

    def __ne__(self, other):
        return not self == other

    def __hash__(self):
        return hash((self.__class__, tuple(self._get_items())))


class VoidType(BaseType):
    _attrs_ = ()

    def __init__(self):
        self.c_name_with_marker = 'void&'

    def build_backend_type(self, ffi, finishlist):
        return global_cache(self, ffi, 'new_void_type')

void_type = VoidType()


class BasePrimitiveType(BaseType):
    def is_complex_type(self):
        return False


class PrimitiveType(BasePrimitiveType):
    _attrs_ = ('name',)

    ALL_PRIMITIVE_TYPES = {
        'char':               'c',
        'short':              'i',
        'int':                'i',
        'long':               'i',
        'long long':          'i',
        'signed char':        'i',
        'unsigned char':      'i',
        'unsigned short':     'i',
        'unsigned int':       'i',
        'unsigned long':      'i',
        'unsigned long long': 'i',
        'float':              'f',
        'double':             'f',
        'long double':        'f',
        'float _Complex':     'j',
        'double _Complex':    'j',
        '_Bool':              'i',
        # the following types are not primitive in the C sense
        'wchar_t':            'c',
        'char16_t':           'c',
        'char32_t':           'c',
        'int8_t':             'i',
        'uint8_t':            'i',
        'int16_t':            'i',
        'uint16_t':           'i',
        'int32_t':            'i',
        'uint32_t':           'i',
        'int64_t':            'i',
        'uint64_t':           'i',
        'int_least8_t':       'i',
        'uint_least8_t':      'i',
        'int_least16_t':      'i',
        'uint_least16_t':     'i',
        'int_least32_t':      'i',
        'uint_least32_t':     'i',
        'int_least64_t':      'i',
        'uint_least64_t':     'i',
        'int_fast8_t':        'i',
        'uint_fast8_t':       'i',
        'int_fast16_t':       'i',
        'uint_fast16_t':      'i',
        'int_fast32_t':       'i',
        'uint_fast32_t':      'i',
        'int_fast64_t':       'i',
        'uint_fast64_t':      'i',
        'intptr_t':           'i',
        'uintptr_t':          'i',
        'intmax_t':           'i',
        'uintmax_t':          'i',
        'ptrdiff_t':          'i',
        'size_t':             'i',
        'ssize_t':            'i',
        }

    def __init__(self, name):
        assert name in self.ALL_PRIMITIVE_TYPES
        self.name = name
        self.c_name_with_marker = name + '&'

    def is_char_type(self):
        return self.ALL_PRIMITIVE_TYPES[self.name] == 'c'
    def is_integer_type(self):
        return self.ALL_PRIMITIVE_TYPES[self.name] == 'i'
    def is_float_type(self):
        return self.ALL_PRIMITIVE_TYPES[self.name] == 'f'
    def is_complex_type(self):
        return self.ALL_PRIMITIVE_TYPES[self.name] == 'j'

    def build_backend_type(self, ffi, finishlist):
        return global_cache(self, ffi, 'new_primitive_type', self.name)


class UnknownIntegerType(BasePrimitiveType):
    _attrs_ = ('name',)

    def __init__(self, name):
        self.name = name
        self.c_name_with_marker = name + '&'

    def is_integer_type(self):
        return True

    def build_backend_type(self, ffi, finishlist):
        raise NotImplementedError("integer type '%s' can only be used after "
                                  "compilation" % self.name)

class UnknownFloatType(BasePrimitiveType):
    _attrs_ = ('name', )

    def __init__(self, name):
        self.name = name
        self.c_name_with_marker = name + '&'

    def build_backend_type(self, ffi, finishlist):
        raise NotImplementedError("float type '%s' can only be used after "
                                  "compilation" % self.name)


class BaseFunctionType(BaseType):
    _attrs_ = ('args', 'result', 'ellipsis', 'abi')

    def __init__(self, args, result, ellipsis, abi=None):
        self.args = args
        self.result = result
        self.ellipsis = ellipsis
        self.abi = abi
        #
        reprargs = [arg._get_c_name() for arg in self.args]
        if self.ellipsis:
            reprargs.append('...')
        reprargs = reprargs or ['void']
        replace_with = self._base_pattern % (', '.join(reprargs),)
        if abi is not None:
            replace_with = replace_with[:1] + abi + ' ' + replace_with[1:]
        self.c_name_with_marker = (
            self.result.c_name_with_marker.replace('&', replace_with))


class RawFunctionType(BaseFunctionType):
    # Corresponds to a C type like 'int(int)', which is the C type of
    # a function, but not a pointer-to-function.  The backend has no
    # notion of such a type; it's used temporarily by parsing.
    _base_pattern = '(&)(%s)'
    is_raw_function = True

    def build_backend_type(self, ffi, finishlist):
        raise CDefError("cannot render the type %r: it is a function "
                        "type, not a pointer-to-function type" % (self,))

    def as_function_pointer(self):
        return FunctionPtrType(self.args, self.result, self.ellipsis, self.abi)


class FunctionPtrType(BaseFunctionType):
    _base_pattern = '(*&)(%s)'

    def build_backend_type(self, ffi, finishlist):
        result = self.result.get_cached_btype(ffi, finishlist)
        args = []
        for tp in self.args:
            args.append(tp.get_cached_btype(ffi, finishlist))
        abi_args = ()
        if self.abi == "__stdcall":
            if not self.ellipsis:    # __stdcall ignored for variadic funcs
                try:
                    abi_args = (ffi._backend.FFI_STDCALL,)
                except AttributeError:
                    pass
        return global_cache(self, ffi, 'new_function_type',
                            tuple(args), result, self.ellipsis, *abi_args)

    def as_raw_function(self):
        return RawFunctionType(self.args, self.result, self.ellipsis, self.abi)


class PointerType(BaseType):
    _attrs_ = ('totype', 'quals')

    def __init__(self, totype, quals=0):
        self.totype = totype
        self.quals = quals
        extra = qualify(quals, " *&")
        if totype.is_array_type:
            extra = "(%s)" % (extra.lstrip(),)
        self.c_name_with_marker = totype.c_name_with_marker.replace('&', extra)

    def build_backend_type(self, ffi, finishlist):
        BItem = self.totype.get_cached_btype(ffi, finishlist, can_delay=True)
        return global_cache(self, ffi, 'new_pointer_type', BItem)

voidp_type = PointerType(void_type)

def ConstPointerType(totype):
    return PointerType(totype, Q_CONST)

const_voidp_type = ConstPointerType(void_type)


class NamedPointerType(PointerType):
    _attrs_ = ('totype', 'name')

    def __init__(self, totype, name, quals=0):
        PointerType.__init__(self, totype, quals)
        self.name = name
        self.c_name_with_marker = name + '&'


class ArrayType(BaseType):
    _attrs_ = ('item', 'length')
    is_array_type = True

    def __init__(self, item, length):
        self.item = item
        self.length = length
        #
        if length is None:
            brackets = '&[]'
        elif length == '...':
            brackets = '&[/*...*/]'
        else:
            brackets = '&[%s]' % length
        self.c_name_with_marker = (
            self.item.c_name_with_marker.replace('&', brackets))

    def length_is_unknown(self):
        return isinstance(self.length, str)

    def resolve_length(self, newlength):
        return ArrayType(self.item, newlength)

    def build_backend_type(self, ffi, finishlist):
        if self.length_is_unknown():
            raise CDefError("cannot render the type %r: unknown length" %
                            (self,))
        self.item.get_cached_btype(ffi, finishlist)   # force the item BType
        BPtrItem = PointerType(self.item).get_cached_btype(ffi, finishlist)
        return global_cache(self, ffi, 'new_array_type', BPtrItem, self.length)

char_array_type = ArrayType(PrimitiveType('char'), None)


class StructOrUnionOrEnum(BaseTypeByIdentity):
    _attrs_ = ('name',)
    forcename = None

    def build_c_name_with_marker(self):
        name = self.forcename or '%s %s' % (self.kind, self.name)
        self.c_name_with_marker = name + '&'

    def force_the_name(self, forcename):
        self.forcename = forcename
        self.build_c_name_with_marker()

    def get_official_name(self):
        assert self.c_name_with_marker.endswith('&')
        return self.c_name_with_marker[:-1]


class StructOrUnion(StructOrUnionOrEnum):
    fixedlayout = None