# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial

"""
enum_sig.py

Enumerate all signatures of a class.

This module separates the enumeration process from the formatting.
It is not easy to adhere to this protocol, but in the end, it paid off
by producing a lot of clarity.
"""

import inspect
import sys
import types
import typing
from shibokensupport.signature import get_signature as get_sig
from shibokensupport.signature.layout import create_signature
from enum import Enum


"""
PYSIDE-1599: Making sure that pyi files always are tested.

A new problem popped up when supporting true properties:
When there exists an item named "property", then we cannot use
the builtin `property` as decorator, but need to prefix it with "builtins".

We scan for such a name in a class, and if there should a property be
declared in the same class, we use `builtins.property` in the class and
all sub-classes. The same consideration holds for "overload".
"""

_normal_functions = (types.BuiltinFunctionType, types.FunctionType)
if hasattr(sys, "pypy_version_info"):
    # In PyPy, there are more types because our builtin functions
    # are created differently in C++ and not in PyPy.
    _normal_functions += (type(get_sig),)


def signal_check(thing):
    return thing and type(thing) in (Signal, SignalInstance)


class ExactEnumerator(object):
    """
    ExactEnumerator enumerates all signatures in a module as they are.

    This class is used for generating complete listings of all signatures.
    An appropriate formatter should be supplied, if printable output
    is desired.
    """

    def __init__(self, formatter, result_type=dict):
        global EnumMeta, Signal, SignalInstance
        try:
            # Lazy import
            from PySide6.QtCore import Qt, Signal, SignalInstance
            EnumMeta = type(Qt.Key)
        except ImportError:
            EnumMeta = Signal = SignalInstance = None

        self.fmt = formatter
        self.result_type = result_type
        self.fmt.level = 0
        self.fmt.is_method = self.is_method
        self.collision_candidates = {"property", "overload"}

    def is_method(self):
        """
        Is this function a method?
        We check if it is a simple function.
        """
        tp = type(self.func)
        return tp not in _normal_functions

    def section(self):
        if hasattr(self.fmt, "section"):
            self.fmt.section()

    def module(self, mod_name):
        __import__(mod_name)
        self.fmt.mod_name = mod_name
        with self.fmt.module(mod_name):
            module = sys.modules[mod_name]
            members = inspect.getmembers(module, inspect.isclass)
            functions = inspect.getmembers(module, inspect.isroutine)
            ret = self.result_type()
            self.fmt.class_name = None
            for class_name, klass in members:
                self.collision_track = set()
                ret.update(self.klass(class_name, klass))
            if len(members):
                self.section()
            for func_name, func in functions:
                ret.update(self.function(func_name, func))
            if len(functions):
                self.section()
            return ret

    def klass(self, class_name, klass):
        ret = self.result_type()
        if ("._") in class_name:
            # This happens when introspecting enum.Enum etc. Python 3.8.8 does not
            # like this, but we want to remove that, anyway.
            return ret
        if "<" in class_name:
            # This is happening in QtQuick for some reason:
            ## class std::shared_ptr<QQuickItemGrabResult >:
            # We simply skip over this class.
            return ret
        bases_list = []
        for base in klass.__bases__:
            name = base.__qualname__
            if name not in ("object", "property", "type"):
                name = base.__module__ + "." + name
            bases_list.append(name)
        bases_str = ', '.join(bases_list)
        class_str = f"{class_name}({bases_str})"
        # class_members = inspect.getmembers(klass)
        # gives us also the inherited things.
        class_members = sorted(list(klass.__dict__.items()))
        subclasses = []
        functions = []
        enums = []
        properties = []
        signals = []
        attributes = {}

        for thing_name, thing in class_members:
            if signal_check(thing):
                signals.append((thing_name, thing))
            elif inspect.isclass(thing):
                subclass_name = ".".join((class_name, thing_name))
                subclasses.append((subclass_name, thing))
            elif inspect.isroutine(thing):
                func_name = thing_name.split(".")[0]   # remove ".overload"
                functions.append((func_name, thing))
            elif type(type(thing)) is EnumMeta:
                # take the real enum name, not what is in the dict
                if not thing_name.startswith("_"):
                    enums.append((thing_name, type(thing).__qualname__, thing))
            elif isinstance(thing, property):
                properties.append((thing_name, thing))
            # Support attributes that have PySide types as values,
            # but we skip the 'staticMetaObject' that needs
            # to be defined at a QObject level.
            elif "PySide" in str(type(thing)) and "QMetaObject" not in str(type(thing)):
                if class_name not in attributes:
                    attributes[class_name] = {}
                attributes[class_name][thing_name] = thing

            if thing_name in self.collision_candidates:
                self.collision_track.add(thing_name)

        init_signature = getattr(klass, "__signature__", None)
        new_enum = sys.pyside63_option_python_enum
        # PYSIDE-2752: Enums without values will not have a constructor, so
        # we set the init_signature to None, to avoid having an empty pyi
        # entry, like:
        #    class QCborTag(enum.IntEnum):
        #  or
        #    class BeginFrameFlag(enum.Flag):
        if isinstance(klass, type(Enum)):
            init_signature = None
        # sort by class then enum value
        enums.sort(key=lambda tup: (tup[1], tup[2].value if new_enum else tup[2]))

        # We want to handle functions and properties together.
        func_prop = sorted(functions + properties, key=lambda tup: tup[0])

        # find out how many functions create a signature
        sigs = list(_ for _ in functions if get_sig(_[1]))
        self.fmt.have_body = bool(subclasses or sigs or properties or enums or  # noqa W:504
                                  init_signature or signals or attributes)

        with self.fmt.klass(class_name, class_str):
            self.fmt.level += 1
            self.fmt.class_name = class_name
            if hasattr(self.fmt, "enum"):
                # this is an optional feature
                if len(enums):
                    self.section()
                for enum_name, enum_class_name, value in enums:
                    with self.fmt.enum(enum_class_name, enum_name,
                                       value.value if new_enum else value):
                        pass
            if hasattr(self.fmt, "signal"):
                # this is an optional feature
                if len(signals):
                    self.section()
                for signal_name, signal in signals:
                    sig_class = type(signal)
                    sig_class_name = f"{sig_class.__qualname__}"
                    sig_str = str(signal)
                    with self.fmt.signal(sig_class_name, signal_name, sig_str):
                        pass
            if hasattr(self.fmt, "attribute"):
                if len(attributes):
                    self.section()
                for class_name, attrs in attributes.items():
                    for attr_name, attr_value in attrs.items():
                        with self.fmt.attribute(attr_name, attr_value):
                            pass
            if len(subclasses):
                self.section()
            for subclass_name, subclass in subclasses:
                save = self.collision_track.copy()
                ret.update(self.klass(subclass_name, subclass))
                self.collision_track = save
                self.fmt.class_name = class_name
            if len(subclasses):
                self.section()
            ret.update(self.function("__init__", klass))
            for func_name, func in func_prop:
                if func_name != "__init__":
                    if isinstance(func, property):
                        ret.update(self.fproperty(func_name, func))
                    else:
                        ret.update(self.function(func_name, func))
            self.fmt.level -= 1
            if len(func_prop):
                self.section()
        return ret

    @staticmethod
    def get_signature(func):
        return get_sig(func)

    def function(self, func_name, func, decorator=None):
        self.func = func    # for is_method()
        ret = self.result_type()
        if decorator in self.collision_track:
            decorator = f"builtins.{decorator}"
        signature = self.get_signature(func, decorator)
        if signature is not None:
            with self.fmt.function(func_name, signature, decorator) as key:
                ret[key] = signature
        del self.func
        return ret

    def fproperty(self, prop_name, prop):
        ret = self.function(prop_name, prop.fget, type(prop).__qualname__)
        if prop.fset:
            ret.update(self.function(prop_name, prop.fset, f"{prop_name}.setter"))
        if prop.fdel:
            ret.update(self.function(prop_name, prop.fdel, f"{prop_name}.deleter"))
        return ret


def stringify(signature):
    if isinstance(signature, list):
        # remove duplicates which still sometimes occour:
        ret = set(stringify(sig) for sig in signature)
        return sorted(ret) if len(ret) > 1 else list(ret)[0]
    return tuple(str(pv) for pv in signature.parameters.values())


class SimplifyingEnumerator(ExactEnumerator):
    """
    SimplifyingEnumerator enumerates all signatures in a module filtered.

    There are no default values, no variable
    names and no self parameter. Only types are present after simplification.
    The functions 'next' resp. '__next__' are removed
    to make the output identical for Python 2 and 3.
    An appropriate formatter should be supplied, if printable output
    is desired.
    """

    def function(self, func_name, func):
        ret = self.result_type()
        signature = get_sig(func, 'existence')
        sig = stringify(signature) if signature is not None else None
        if sig is not None and func_name not in ("next", "__next__", "__div__"):
            with self.fmt.function(func_name, sig) as key:
                ret[key] = sig
        return ret


class HintingEnumerator(ExactEnumerator):
    """
    HintingEnumerator enumerates all signatures in a module slightly changed.

    This class is used for generating complete listings of all signatures for
    hinting stubs. Only default values are replaced by "...".
    """

    def __init__(self, *args, **kwds):
        super().__init__(*args, **kwds)
        # We need to provide default signatures for class properties.
        cls_param = inspect.Parameter("cls", inspect._POSITIONAL_OR_KEYWORD)
        set_param = inspect.Parameter("arg_1", inspect._POSITIONAL_OR_KEYWORD, annotation=object)
        self.getter_sig = inspect.Signature([cls_param], return_annotation=object)
        self.setter_sig = inspect.Signature([cls_param, set_param])
        self.deleter_sig = inspect.Signature([cls_param])

    def get_signature(self, func, decorator=None):
        # Class properties don't have signature support (yet).
        # In that case, produce a fake one.
        sig = get_sig(func, "hintingstub")
        if not sig:
            if decorator:
                if decorator.endswith(".setter"):
                    sig = self.setter_sig
                elif decorator.endswith(".deleter"):
                    sig = self.deleter_sig
                else:
                    sig = self.getter_sig
        return sig
