from rpython.rtyper.lltypesystem import rffi, lltype
from rpython.rlib.rarithmetic import widen
from pypy.module.cpyext.api import (
    cpython_api, generic_cpy_call, CANNOT_FAIL, Py_ssize_t,
    PyVarObject, size_t, slot_function, cts,
    Py_TPFLAGS_HEAPTYPE, Py_LT, Py_LE, Py_EQ, Py_NE, Py_GT,
    Py_GE, CONST_STRING, FILEP, fwrite, c_only, PY_SSIZE_T_MAX)
from pypy.module.cpyext.pyobject import (
    PyObject, PyObjectP, from_ref, incref, decref,
    get_typedescr, hack_for_result_often_existing_obj)
from pypy.module.cpyext.pyerrors import PyErr_NoMemory, PyErr_BadInternalCall
from pypy.objspace.std.bytesobject import invoke_bytes_method
from pypy.interpreter.error import OperationError, oefmt
from pypy.interpreter.executioncontext import ExecutionContext
import pypy.module.__builtin__.operation as operation


@cpython_api([size_t], rffi.VOIDP)
def PyObject_Malloc(space, size):
    # returns non-zero-initialized memory, like CPython
    return lltype.malloc(rffi.VOIDP.TO, size,
                         flavor='raw',
                         add_memory_pressure=True)

@cpython_api([size_t, size_t], rffi.VOIDP)
def PyObject_Calloc(space, nelem, elsize):
    if elsize != 0 and nelem > PY_SSIZE_T_MAX / elsize:
        return lltype.nullptr(rffi.VOIDP.TO)
    return lltype.malloc(rffi.VOIDP.TO, nelem * elsize,
                         flavor='raw', zero=True,
                         add_memory_pressure=True)

realloc = rffi.llexternal('realloc', [rffi.VOIDP, rffi.SIZE_T], rffi.VOIDP)

@cpython_api([rffi.VOIDP, size_t], rffi.VOIDP)
def PyObject_Realloc(space, ptr, size):
    if not lltype.cast_ptr_to_int(ptr):
        return lltype.malloc(rffi.VOIDP.TO, size,
                         flavor='raw',
                         add_memory_pressure=True)
    # XXX FIXME
    return realloc(ptr, size)

@c_only([rffi.VOIDP], lltype.Void)
def _PyPy_Free(ptr):
    lltype.free(ptr, flavor='raw')

@c_only([Py_ssize_t], rffi.VOIDP)
def _PyPy_Malloc(size):
    # XXX: the malloc inside BaseCpyTypedescr.allocate and
    # typeobject.type_alloc specify zero=True, so this is why we use it also
    # here. However, CPython does a simple non-initialized malloc, so we
    # should investigate whether we can remove zero=True as well
    return lltype.malloc(rffi.VOIDP.TO, size,
                         flavor='raw', zero=True,
                         add_memory_pressure=True)


def _dealloc(space, obj):
    # This frees an object after its refcount dropped to zero, so we
    # assert that it is really zero here.
    assert obj.c_ob_refcnt == 0
    pto = obj.c_ob_type
    obj_voidp = rffi.cast(rffi.VOIDP, obj)
    try:
        generic_cpy_call(space, pto.c_tp_free, obj_voidp)
    finally:
        if widen(pto.c_tp_flags) & Py_TPFLAGS_HEAPTYPE:
            decref(space, rffi.cast(PyObject, pto))

@cpython_api([PyObject], PyObjectP, error=CANNOT_FAIL)
def _PyObject_GetDictPtr(space, op):
    return lltype.nullptr(PyObjectP.TO)

@cpython_api([PyObject], rffi.INT_real, error=-1)
def PyObject_IsTrue(space, w_obj):
    return space.is_true(w_obj)

@cpython_api([PyObject], rffi.INT_real, error=-1)
def PyObject_Not(space, w_obj):
    return not space.is_true(w_obj)

@cpython_api([PyObject, PyObject], PyObject, result_is_ll=True)
def PyObject_GetAttr(space, w_obj, w_name):
    """Retrieve an attribute named attr_name from object o. Returns the attribute
    value on success, or NULL on failure.  This is the equivalent of the Python
    expression o.attr_name."""
    w_res = space.getattr(w_obj, w_name)
    return hack_for_result_often_existing_obj(space, w_res)

@cpython_api([PyObject, CONST_STRING], PyObject, result_is_ll=True)
def PyObject_GetAttrString(space, w_obj, name_ptr):
    """Retrieve an attribute named attr_name from object o. Returns the attribute
    value on success, or NULL on failure. This is the equivalent of the Python
    expression o.attr_name."""
    name = rffi.charp2str(name_ptr)
    w_res = space.getattr(w_obj, space.newtext(name))
    return hack_for_result_often_existing_obj(space, w_res)

@cpython_api([PyObject, PyObject], rffi.INT_real, error=CANNOT_FAIL)
def PyObject_HasAttr(space, w_obj, w_name):
    try:
        w_res = operation.hasattr(space, w_obj, w_name)
        return space.is_true(w_res)
    except OperationError:
        return 0

@cpython_api([PyObject, CONST_STRING], rffi.INT_real, error=CANNOT_FAIL)
def PyObject_HasAttrString(space, w_obj, name_ptr):
    try:
        name = rffi.charp2str(name_ptr)
        w_res = operation.hasattr(space, w_obj, space.newtext(name))
        return space.is_true(w_res)
    except OperationError:
        return 0

@cpython_api([PyObject, PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_SetAttr(space, w_obj, w_name, value):
    if value:
        w_value = from_ref(space, value)
        operation.setattr(space, w_obj, w_name, w_value)
    else:
        space.delattr(w_obj, w_name)
    return 0

@cpython_api([PyObject, CONST_STRING, PyObject], rffi.INT_real, error=-1)
def PyObject_SetAttrString(space, w_obj, name_ptr, value):
    w_name = space.newtext(rffi.charp2str(name_ptr))
    if value:
        w_value = from_ref(space, value)
        operation.setattr(space, w_obj, w_name, w_value)
    else:
        space.delattr(w_obj, w_name)
    return 0

@cpython_api([PyObject], lltype.Void)
def PyObject_ClearWeakRefs(space, w_object):
    w_object.clear_all_weakrefs()

@cpython_api([PyObject], Py_ssize_t, error=-1)
def PyObject_Size(space, w_obj):
    return space.len_w(w_obj)

@cpython_api([PyObject], rffi.INT_real, error=CANNOT_FAIL)
def PyCallable_Check(space, w_obj):
    """Determine if the object o is callable.  Return 1 if the object is callable
    and 0 otherwise.  This function always succeeds."""
    return int(space.is_true(space.callable(w_obj)))

@cpython_api([PyObject, PyObject], PyObject, result_is_ll=True)
def PyObject_GetItem(space, w_obj, w_key):
    """Return element of o corresponding to the object key or NULL on failure.
    This is the equivalent of the Python expression o[key]."""
    w_res = space.getitem(w_obj, w_key)
    return hack_for_result_often_existing_obj(space, w_res)

@cpython_api([PyObject, PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_SetItem(space, w_obj, w_key, w_value):
    """Map the object key to the value v.  Returns -1 on failure.  This is the
    equivalent of the Python statement o[key] = v."""
    space.setitem(w_obj, w_key, w_value)
    return 0

@cpython_api([PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_DelItem(space, w_obj, w_key):
    """Delete the mapping for key from o.  Returns -1 on failure. This is the
    equivalent of the Python statement del o[key]."""
    space.delitem(w_obj, w_key)
    return 0

@cpython_api([PyObject], PyObject)
def PyObject_Type(space, w_obj):
    """When o is non-NULL, returns a type object corresponding to the object type
    of object o. On failure, raises SystemError and returns NULL.  This
    is equivalent to the Python expression type(o). This function increments the
    reference count of the return value. There's really no reason to use this
    function instead of the common expression o->ob_type, which returns a
    pointer of type PyTypeObject*, except when the incremented reference
    count is needed."""
    return space.type(w_obj)

@cpython_api([PyObject], PyObject)
def PyObject_Str(space, w_obj):
    if w_obj is None:
        return space.newtext("<NULL>")
    return space.str(w_obj)

@cts.decl("PyObject * PyObject_Bytes(PyObject *v)")
def PyObject_Bytes(space, w_obj):
    from pypy.module.cpyext.bytesobject import PyBytes_FromObject
    if w_obj is None:
        return space.newbytes("<NULL>")
    if space.type(w_obj) is space.w_bytes:
        return w_obj
    w_result = invoke_bytes_method(space, w_obj)
    if w_result is not None:
        return w_result
    return PyBytes_FromObject(space, w_obj)

@cpython_api([PyObject], PyObject)
def PyObject_Repr(space, w_obj):
    """Compute a string representation of object o.  Returns the string
    representation on success, NULL on failure.  This is the equivalent of the
    Python expression repr(o).  Called by the repr() built-in function and
    by reverse quotes."""
    if w_obj is None:
        return space.newtext("<NULL>")
    return space.repr(w_obj)

@cpython_api([PyObject, PyObject], PyObject)
def PyObject_Format(space, w_obj, w_format_spec):
    if w_format_spec is None:
        w_format_spec = space.newtext('')
    # issue 3404: handle PyObject_Format(type('a'), '')
    if (space.isinstance_w(w_format_spec, space.w_unicode) and
                space.len_w(w_format_spec) == 0):
        return space.unicode_from_object(w_obj)
    w_ret = space.call_method(w_obj, '__format__', w_format_spec)
    if space.isinstance_w(w_format_spec, space.w_unicode):
        return space.unicode_from_object(w_ret)
    return w_ret

@cpython_api([PyObject], PyObject)
def PyObject_ASCII(space, w_obj):
    r"""As PyObject_Repr(), compute a string representation of object
    o, but escape the non-ASCII characters in the string returned by
    PyObject_Repr() with \x, \u or \U escapes.  This generates a
    string similar to that returned by PyObject_Repr() in Python 2.
    Called by the ascii() built-in function."""
    return operation.ascii(space, w_obj)

@cpython_api([PyObject], PyObject)
def PyObject_Unicode(space, w_obj):
    """Compute a Unicode string representation of object o.  Returns the Unicode
    string representation on success, NULL on failure. This is the equivalent of
    the Python expression unicode(o).  Called by the unicode() built-in
    function."""
    if w_obj is None:
        return space.newutf8("<NULL>", 6)
    return space.call_function(space.w_unicode, w_obj)

@cpython_api([PyObject, PyObject, rffi.INT_real], PyObject)
def PyObject_RichCompare(space, w_o1, w_o2, opid_int):
    """Compare the values of o1 and o2 using the operation specified by opid,
    which must be one of Py_LT, Py_LE, Py_EQ,
    Py_NE, Py_GT, or Py_GE, corresponding to <,
    <=, ==, !=, >, or >= respectively. This is the equivalent of
    the Python expression o1 op o2, where op is the operator corresponding
    to opid. Returns the value of the comparison on success, or NULL on failure."""
    opid = rffi.cast(lltype.Signed, opid_int)
    if opid == Py_LT: return space.lt(w_o1, w_o2)
    if opid == Py_LE: return space.le(w_o1, w_o2)
    if opid == Py_EQ: return space.eq(w_o1, w_o2)
    if opid == Py_NE: return space.ne(w_o1, w_o2)
    if opid == Py_GT: return space.gt(w_o1, w_o2)
    if opid == Py_GE: return space.ge(w_o1, w_o2)
    PyErr_BadInternalCall(space)

@cpython_api([PyObject, PyObject, rffi.INT_real], rffi.INT_real, error=-1)
def PyObject_RichCompareBool(space, w_o1, w_o2, opid_int):
    """Compare the values of o1 and o2 using the operation specified by opid,
    which must be one of Py_LT, Py_LE, Py_EQ,
    Py_NE, Py_GT, or Py_GE, corresponding to <,
    <=, ==, !=, >, or >= respectively. Returns -1 on error,
    0 if the result is false, 1 otherwise. This is the equivalent of the
    Python expression o1 op o2, where op is the operator corresponding to
    opid."""
    # Quick result when objects are the same.
    # Guarantees that identity implies equality.
    if space.is_w(w_o1, w_o2):
        opid = rffi.cast(lltype.Signed, opid_int)
        if opid == Py_EQ:
            return 1
        if opid == Py_NE:
            return 0
    w_res = PyObject_RichCompare(space, w_o1, w_o2, opid_int)
    return int(space.is_true(w_res))

@cpython_api([PyObject], PyObject, result_is_ll=True)
def PyObject_SelfIter(space, ref):
    """Undocumented function, this is what CPython does."""
    incref(space, ref)
    return ref

@cpython_api([PyObject, PyObject], PyObject)
def PyObject_GenericGetAttr(space, w_obj, w_name):
    """Generic attribute getter function that is meant to be put into a type
    object's tp_getattro slot.  It looks for a descriptor in the dictionary
    of classes in the object's MRO as well as an attribute in the object's
    __dict__ (if present).  As outlined in descriptors, data
    descriptors take preference over instance attributes, while non-data
    descriptors don't.  Otherwise, an AttributeError is raised."""
    from pypy.objspace.descroperation import object_getattribute
    w_descr = object_getattribute(space)
    return space.get_and_call_function(w_descr, w_obj, w_name)

@cpython_api([PyObject, PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_GenericSetAttr(space, w_obj, w_name, w_value):
    """Generic attribute setter function that is meant to be put into a type
    object's tp_setattro slot.  It looks for a data descriptor in the
    dictionary of classes in the object's MRO, and if found it takes preference
    over setting the attribute in the instance dictionary. Otherwise, the
    attribute is set in the object's __dict__ (if present).  Otherwise,
    an AttributeError is raised and -1 is returned."""
    from pypy.objspace.descroperation import object_setattr, object_delattr
    if w_value is not None:
        w_descr = object_setattr(space)
        space.get_and_call_function(w_descr, w_obj, w_name, w_value)
    else:
        w_descr = object_delattr(space)
        space.get_and_call_function(w_descr, w_obj, w_name)
    return 0

@cpython_api([PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_IsInstance(space, w_inst, w_cls):
    """Returns 1 if inst is an instance of the class cls or a subclass of
    cls, or 0 if not.  On error, returns -1 and sets an exception.  If
    cls is a type object rather than a class object, PyObject_IsInstance()
    returns 1 if inst is of type cls.  If cls is a tuple, the check will
    be done against every entry in cls. The result will be 1 when at least one
    of the checks returns 1, otherwise it will be 0. If inst is not a class
    instance and cls is neither a type object, nor a class object, nor a
    tuple, inst must have a __class__ attribute --- the class relationship
    of the value of that attribute with cls will be used to determine the result
    of this function."""
    from pypy.module.__builtin__.abstractinst import abstract_isinstance_w
    return abstract_isinstance_w(space, w_inst, w_cls, allow_override=True)

@cpython_api([PyObject, PyObject], rffi.INT_real, error=-1)
def PyObject_IsSubclass(space, w_derived, w_cls):
    """Returns 1 if the class derived is identical to or derived from the class
    cls, otherwise returns 0.  In case of an error, returns -1. If cls
    is a tuple, the check will be done against every entry in cls. The result will
    be 1 when at least one of the checks returns 1, otherwise it will be
    0. If either derived or cls is not an actual class object (or tuple),
    this function uses the generic algorithm described above."""
    from pypy.module.__builtin__.abstractinst import abstract_issubclass_w
    return abstract_issubclass_w(space, w_derived, w_cls, allow_override=True)

@cpython_api([PyObject], rffi.INT_real, error=-1)
def PyObject_AsFileDescriptor(space, w_obj):
    """Derives a file descriptor from a Python object.  If the object is an
    integer or long integer, its value is returned.  If not, the object's
    fileno() method is called if it exists; the method must return an integer or
    long integer, which is returned as the file descriptor value.  Returns -1 on
    failure."""
    try:
        fd = space.int_w(w_obj)
    except OperationError:
        try:
            w_meth = space.getattr(w_obj, space.newtext('fileno'))
        except OperationError:
            raise oefmt(space.w_TypeError,
                        "argument must be an int, or have a fileno() method.")
        else:
            w_fd = space.call_function(w_meth)
            fd = space.int_w(w_fd)

    if fd < 0:
        raise oefmt(space.w_ValueError,
                    "file descriptor cannot be a negative integer")

    return rffi.cast(rffi.INT_real, fd)


@cpython_api([PyObject], lltype.Signed, error=-1)
def PyObject_Hash(space, pyobj):
    """
    Compute and return the hash value of an object o.  On failure, return -1.
    This is the equivalent of the Python expression hash(o)."""

    from pypy.module.cpyext.typeobject import py_type_ready
    py_type_ready(space, pyobj.c_ob_type)
    w_obj = from_ref(space, pyobj)
    return space.hash_w(w_obj)

@cpython_api([PyObject, rffi.DOUBLE], lltype.Signed, error=-1)
def _Py_HashDouble(space, w_obj, v):
    """Specific function for double, in CPython this uses the value of v
    except for nans
    """
    from pypy.objspace.std.floatobject import float_hash
    return space.int_w(float_hash(space, w_obj, v))

@cpython_api([PyObject], lltype.Signed, error=-1)
def PyObject_HashNotImplemented(space, o):
    """Set a TypeError indicating that type(o) is not hashable and return -1.
    This function receives special treatment when stored in a tp_hash slot,
    allowing a type to explicitly indicate to the interpreter that it is not
    hashable.
    """
    raise oefmt(space.w_TypeError, "unhashable type")

@cpython_api([PyObject], PyObject)
def PyObject_Dir(space, w_o):
    """This is equivalent to the Python expression dir(o), returning a (possibly
    empty) list of strings appropriate for the object argument, or NULL if there
    was an error.  If the argument is NULL, this is like the Python dir(),
    returning the names of the current locals; in this case, if no execution frame
    is active then NULL is returned but PyErr_Occurred() will return false."""
    return space.call_function(space.builtin.get('dir'), w_o)

# Also in include/object.h
Py_PRINT_RAW = 1 # No string quotes etc.

@cpython_api([PyObject, FILEP, rffi.INT_real], rffi.INT_real, error=-1)
def PyObject_Print(space, pyobj, fp, flags):
    """Print an object o, on file fp.  Returns -1 on error.  The flags argument
    is used to enable certain printing options.  The only option currently
    supported is Py_PRINT_RAW; if given, the str() of the object is written
    instead of the repr()."""
    if not pyobj:
        w_str = space.newtext("<nil>")
    else:
        w_obj = from_ref(space, pyobj)
        if rffi.cast(lltype.Signed, flags) & Py_PRINT_RAW:
            w_str = space.str(w_obj)
        else:
            w_str = space.repr(w_obj)

    count = space.len_w(w_str)
    data = space.text_w(w_str)
    with rffi.scoped_nonmovingbuffer(data) as buf:
        fwrite(buf, 1, count, fp)
    return 0

@cts.decl("""
    Py_ssize_t PyObject_LengthHint(PyObject *o, Py_ssize_t defaultvalue)""",
    error=-1)
def PyObject_LengthHint(space, w_o, defaultvalue):
    return space.length_hint(w_o, defaultvalue)

@cpython_api([lltype.Signed], lltype.Void)
def _PyPyGC_AddMemoryPressure(space, report):
    from rpython.rlib import rgc
    rgc.add_memory_pressure(report)


ExecutionContext.cpyext_recursive_repr = None

@cpython_api([PyObject], rffi.INT_real, error=-1)
def Py_ReprEnter(space, w_obj):
    ec = space.getexecutioncontext()
    d = ec.cpyext_recursive_repr
    if d is None:
        d = ec.cpyext_recursive_repr = {}
    if w_obj in d:
        return 1
    d[w_obj] = None
    return 0

@cpython_api([PyObject], lltype.Void)
def Py_ReprLeave(space, w_obj):
    ec = space.getexecutioncontext()
    d = ec.cpyext_recursive_repr
    if d is not None:
        try:
            del d[w_obj]
        except KeyError:
            pass

@cpython_api([PyObject, rffi.VOIDP], PyObject)
def PyObject_GenericGetDict(space, w_obj, context):
    from pypy.interpreter.typedef import descr_get_dict
    return descr_get_dict(space, w_obj)

@cpython_api([PyObject, PyObject, rffi.VOIDP], rffi.INT_real, error=-1)
def PyObject_GenericSetDict(space, w_obj, w_value, context):
    from pypy.interpreter.typedef import descr_set_dict
    if w_value is None:
        raise oefmt(space.w_TypeError, "cannot delete __dict__")
    descr_set_dict(space, w_obj, w_value)
    return 0

@cpython_api([], rffi.INT_real, error=CANNOT_FAIL)
def PyGC_IsEnabled(space):
    import gc
    return int(gc.isenabled())

@cpython_api([], rffi.INT_real, error=CANNOT_FAIL)
def PyGC_Disable(space):
    import gc
    ret = int(gc.isenabled())
    gc.disable()
    return ret

@cpython_api([], rffi.INT_real, error=CANNOT_FAIL)
def PyGC_Enable(space):
    import gc
    ret = int(gc.isenabled())
    gc.enable()
    return ret

@cpython_api([PyObject], rffi.INT_real, error=CANNOT_FAIL)
def PyObject_GC_IsTracked(space, w_obj):
    """All objects in PyPy are tracked, this will always return 1
    """
    return 1

@cpython_api([PyObject], rffi.INT_real, error=CANNOT_FAIL)
def PyObject_GC_IsFinalized(space, w_obj):
    """For now, always return 0
    """
    return 0

@cpython_api([PyObject, PyObject], rffi.INT_real, error=-1)
def Py_Is(space, w_obj1, w_obj2):
    res = space.is_w(w_obj1, w_obj2)
    return int(res)

@cpython_api([], rffi.INT_real, error = -1)
def PyGC_Collect(space):
    import gc
    gc.collect()
    return 0