"""Methods to add arguments based on class/method/function signatures."""

import dataclasses
import inspect
import re
from argparse import SUPPRESS
from contextlib import suppress
from typing import Any, Callable, List, Optional, Set, Tuple, Type, Union

from ._actions import _ActionConfigLoad
from ._common import get_class_instantiator, is_dataclass_like, is_subclass
from ._optionals import get_doc_short_description, pydantic_support
from ._parameter_resolvers import (
    ParamData,
    get_parameter_origins,
    get_signature_parameters,
)
from ._typehints import (
    ActionTypeHint,
    LazyInitBaseClass,
    callable_instances,
    is_optional,
)
from ._util import LoggerProperty, get_import_path, get_private_kwargs, iter_to_set_str
from .typing import register_pydantic_type

__all__ = [
    "compose_dataclasses",
    "SignatureArguments",
]


kinds = inspect._ParameterKind
inspect_empty = inspect._empty


class SignatureArguments(LoggerProperty):
    """Methods to add arguments based on signatures to an ArgumentParser instance."""

    def add_class_arguments(
        self,
        theclass: Type,
        nested_key: Optional[str] = None,
        as_group: bool = True,
        as_positional: bool = False,
        default: Optional[LazyInitBaseClass] = None,
        skip: Optional[Set[Union[str, int]]] = None,
        instantiate: bool = True,
        fail_untyped: bool = True,
        sub_configs: bool = False,
        **kwargs,
    ) -> List[str]:
        """Adds arguments from a class based on its type hints and docstrings.

        Note: Keyword arguments without at least one valid type are ignored.

        Args:
            theclass: Class from which to add arguments.
            nested_key: Key for nested namespace.
            as_group: Whether arguments should be added to a new argument group.
            as_positional: Whether to add required parameters as positional arguments.
            default: Default value used to override parameter defaults. Must be lazy_instance.
            skip: Names of parameters or number of positionals that should be skipped.
            instantiate: Whether the class group should be instantiated by :code:`instantiate_classes`.
            fail_untyped: Whether to raise exception if a required parameter does not have a type.
            sub_configs: Whether subclass type hints should be loadable from inner config file.

        Returns:
            The list of arguments added.

        Raises:
            ValueError: When not given a class.
            ValueError: When there are required parameters without at least one valid type.
        """
        if not inspect.isclass(theclass):
            raise ValueError(f'Expected "theclass" parameter to be a class type, got: {theclass}.')
        if default and not (isinstance(default, LazyInitBaseClass) and isinstance(default, theclass)):
            raise ValueError(f'Expected "default" parameter to be a lazy instance of the class, got: {default}.')
        linked_targets = get_private_kwargs(kwargs, linked_targets=None)

        added_args = self._add_signature_arguments(
            theclass,
            None,
            nested_key,
            as_group,
            as_positional,
            skip,
            fail_untyped,
            sub_configs=sub_configs,
            instantiate=instantiate,
            linked_targets=linked_targets,
        )

        if default:
            skip = skip or set()
            prefix = nested_key + "." if nested_key else ""
            defaults = default.lazy_get_init_args()
            if defaults:
                defaults = {prefix + k: v for k, v in defaults.items() if k not in skip}
                self.set_defaults(**defaults)  # type: ignore

        return added_args

    def add_method_arguments(
        self,
        theclass: Type,
        themethod: str,
        nested_key: Optional[str] = None,
        as_group: bool = True,
        as_positional: bool = False,
        skip: Optional[Set[Union[str, int]]] = None,
        fail_untyped: bool = True,
        sub_configs: bool = False,
    ) -> List[str]:
        """Adds arguments from a class based on its type hints and docstrings.

        Note: Keyword arguments without at least one valid type are ignored.

        Args:
            theclass: Class which includes the method.
            themethod: Name of the method for which to add arguments.
            nested_key: Key for nested namespace.
            as_group: Whether arguments should be added to a new argument group.
            as_positional: Whether to add required parameters as positional arguments.
            skip: Names of parameters or number of positionals that should be skipped.
            fail_untyped: Whether to raise exception if a required parameter does not have a type.
            sub_configs: Whether subclass type hints should be loadable from inner config file.

        Returns:
            The list of arguments added.

        Raises:
            ValueError: When not given a class or the name of a method of the class.
            ValueError: When there are required parameters without at least one valid type.
        """
        if not inspect.isclass(theclass):
            raise ValueError('Expected "theclass" argument to be a class object.')
        if not hasattr(theclass, themethod) or not callable(getattr(theclass, themethod)):
            raise ValueError('Expected "themethod" argument to be a callable member of the class.')

        return self._add_signature_arguments(
            theclass,
            themethod,
            nested_key,
            as_group,
            as_positional,
            skip,
            fail_untyped,
            sub_configs=sub_configs,
        )

    def add_function_arguments(
        self,
        function: Callable,
        nested_key: Optional[str] = None,
        as_group: bool = True,
        as_positional: bool = False,
        skip: Optional[Set[Union[str, int]]] = None,
        fail_untyped: bool = True,
        sub_configs: bool = False,
    ) -> List[str]:
        """Adds arguments from a function based on its type hints and docstrings.

        Note: Keyword arguments without at least one valid type are ignored.

        Args:
            function: Function from which to add arguments.
            nested_key: Key for nested namespace.
            as_group: Whether arguments should be added to a new argument group.
            as_positional: Whether to add required parameters as positional arguments.
            skip: Names of parameters or number of positionals that should be skipped.
            fail_untyped: Whether to raise exception if a required parameter does not have a type.
            sub_configs: Whether subclass type hints should be loadable from inner config file.

        Returns:
            The list of arguments added.

        Raises:
            ValueError: When not given a callable.
            ValueError: When there are required parameters without at least one valid type.
        """
        if not callable(function):
            raise ValueError('Expected "function" argument to be a callable object.')

        method_name = None
        if hasattr(function, "__class__") and callable_instances(function.__class__):
            function = function.__class__
            method_name = "__call__"

        return self._add_signature_arguments(
            function,
            method_name,
            nested_key,
            as_group,
            as_positional,
            skip,
            fail_untyped,
            sub_configs=sub_configs,
        )

    def _add_signature_arguments(
        self,
        function_or_class,
        method_name,
        nested_key: Optional[str],
        as_group: bool = True,
        as_positional: bool = False,
        skip: Optional[Set[Union[str, int]]] = None,
        fail_untyped: bool = True,
        sub_configs: bool = False,
        instantiate: bool = True,
        linked_targets: Optional[Set[str]] = None,
    ) -> List[str]:
        """Adds arguments from parameters of objects based on signatures and docstrings.

        Args:
            function_or_class: Object from which to add arguments.
            method_name: Class method from which to add arguments.
            nested_key: Key for nested namespace.
            as_group: Whether arguments should be added to a new argument group.
            as_positional: Whether to add required parameters as positional arguments.
            skip: Names of parameters or number of positionals that should be skipped.
            fail_untyped: Whether to raise exception if a required parameter does not have a type.
            sub_configs: Whether subclass type hints should be loadable from inner config file.
            instantiate: Whether the class group should be instantiated by :code:`instantiate_classes`.

        Returns:
            The list of arguments added.

        Raises:
            ValueError: When there are required parameters without at least one valid type.
        """
        params = get_signature_parameters(function_or_class, method_name, logger=self.logger)

        skip_positionals = [s for s in (skip or []) if isinstance(s, int)]
        if skip_positionals:
            if len(skip_positionals) > 1 or any(p <= 0 for p in skip_positionals):
                raise ValueError(f"Unexpected number of positionals to skip: {skip_positionals}")
            names = {p.name for p in params[: skip_positionals[0]]}
            params = params[skip_positionals[0] :]
            self.logger.debug(
                f"Skipping parameters {names} because {skip_positionals[0]} positionals requested to be skipped."
            )

        ## Create group if requested ##
        doc_group = get_doc_short_description(function_or_class, method_name, logger=self.logger)
        component = getattr(function_or_class, method_name) if method_name else function_or_class
        group = self._create_group_if_requested(
            component,
            nested_key,
            as_group,
            doc_group,
            config_load=len(params) > 0,
            instantiate=instantiate,
        )

        ## Add parameter arguments ##
        added_args: List[str] = []
        for param in params:
            self._add_signature_parameter(
                group,
                nested_key,
                param,
                added_args,
                skip={s for s in (skip or []) if isinstance(s, str)},
                fail_untyped=fail_untyped,
                sub_configs=sub_configs,
                linked_targets=linked_targets,
                as_positional=as_positional,
            )

        return added_args

    def _add_signature_parameter(
        self,
        group,
        nested_key: Optional[str],
        param,
        added_args: List[str],
        skip: Optional[Set[str]] = None,
        fail_untyped: bool = True,
        as_positional: bool = False,
        sub_configs: bool = False,
        instantiate: bool = True,
        linked_targets: Optional[Set[str]] = None,
        default: Any = inspect_empty,
        **kwargs,
    ):
        name = param.name
        kind = param.kind
        annotation = param.annotation
        if default == inspect_empty:
            default = param.default
            if default == inspect_empty and is_optional(annotation):
                default = None
        is_required = default == inspect_empty
        src = get_parameter_origins(param.component, param.parent)
        skip_message = f'Skipping parameter "{name}" from "{src}" because of: '
        if not fail_untyped and annotation == inspect_empty:
            annotation = Any
            default = None if is_required else default
            is_required = False
        if is_required and linked_targets is not None and name in linked_targets:
            default = None
            is_required = False
        if (
            kind in {kinds.VAR_POSITIONAL, kinds.VAR_KEYWORD}
            or (not is_required and name[0] == "_")
            or (annotation == inspect_empty and not is_required and default is None)
        ):
            return
        elif skip and name in skip:
            self.logger.debug(skip_message + "Parameter requested to be skipped.")
            return
        if is_factory_class(default):
            default = param.parent.__dataclass_fields__[name].default_factory()
        if annotation == inspect_empty and not is_required:
            annotation = type(default)
        if "help" not in kwargs:
            kwargs["help"] = param.doc
        if not is_required:
            kwargs["default"] = default
            if default is None and not is_optional(annotation, object):
                annotation = Optional[annotation]
        elif not as_positional:
            kwargs["required"] = True
        is_subclass_typehint = False
        is_dataclass_like_typehint = is_dataclass_like(annotation)
        dest = (nested_key + "." if nested_key else "") + name
        args = [dest if is_required and as_positional else "--" + dest]
        if param.origin:
            group_name = "; ".join(str(o) for o in param.origin)
            if group_name in group.parser.groups:
                group = group.parser.groups[group_name]
            else:
                group = group.parser.add_argument_group(
                    f"Conditional arguments [origins: {group_name}]",
                    name=group_name,
                )
        if (
            annotation in {str, int, float, bool}
            or is_subclass(annotation, (str, int, float))
            or is_dataclass_like_typehint
        ):
            kwargs["type"] = annotation
            register_pydantic_type(annotation)
        elif annotation != inspect_empty:
            try:
                is_subclass_typehint = ActionTypeHint.is_subclass_typehint(annotation, all_subtypes=False)
                kwargs["type"] = annotation
                sub_add_kwargs: dict = {"fail_untyped": fail_untyped, "sub_configs": sub_configs}
                if is_subclass_typehint:
                    prefix = f"{name}.init_args."
                    subclass_skip = {s[len(prefix) :] for s in skip or [] if s.startswith(prefix)}
                    sub_add_kwargs["skip"] = subclass_skip
                else:
                    register_pydantic_type(annotation)
                args = ActionTypeHint.prepare_add_argument(
                    args=args,
                    kwargs=kwargs,
                    enable_path=is_subclass_typehint and sub_configs,
                    container=group,
                    logger=self.logger,
                    sub_add_kwargs=sub_add_kwargs,
                )
            except ValueError as ex:
                self.logger.debug(skip_message + str(ex))
        if "type" in kwargs or "action" in kwargs:
            sub_add_kwargs = {
                "fail_untyped": fail_untyped,
                "sub_configs": sub_configs,
                "instantiate": instantiate,
            }
            if is_dataclass_like_typehint:
                kwargs.update(sub_add_kwargs)
            action = group.add_argument(*args, **kwargs)
            action.sub_add_kwargs = sub_add_kwargs
            if is_subclass_typehint and len(subclass_skip) > 0:
                action.sub_add_kwargs["skip"] = subclass_skip
            added_args.append(dest)
        elif is_required and fail_untyped:
            raise ValueError(
                "With fail_untyped=True, all mandatory parameters must have a supported"
                f" type. Parameter '{name}' from '{src}' does not specify a type."
            )

    def add_dataclass_arguments(
        self,
        theclass: Type,
        nested_key: str,
        default: Optional[Union[Type, dict]] = None,
        as_group: bool = True,
        fail_untyped: bool = True,
        **kwargs,
    ) -> List[str]:
        """Adds arguments from a dataclass based on its field types and docstrings.

        Args:
            theclass: Class from which to add arguments.
            nested_key: Key for nested namespace.
            default: Value for defaults. Must be instance of or kwargs for theclass.
            as_group: Whether arguments should be added to a new argument group.
            fail_untyped: Whether to raise exception if a required parameter does not have a type.

        Returns:
            The list of arguments added.

        Raises:
            ValueError: When not given a dataclass.
            ValueError: When default is not instance of or kwargs for theclass.
        """
        if not is_dataclass_like(theclass):
            raise ValueError(f'Expected "theclass" argument to be a dataclass-like, given {theclass}')

        doc_group = get_doc_short_description(theclass, logger=self.logger)
        for key in ["help", "title"]:
            if key in kwargs and kwargs[key] is not None:
                doc_group = kwargs.pop(key)
        group = self._create_group_if_requested(theclass, nested_key, as_group, doc_group, config_load_type=theclass)

        defaults = {}
        if default is not None:
            if isinstance(default, dict):
                with suppress(TypeError):
                    default = theclass(**default)
            if not isinstance(default, theclass):
                raise ValueError(
                    f'Expected "default" argument to be an instance of "{theclass.__name__}" '
                    f"or its kwargs dict, given {default}"
                )
            defaults = dataclass_to_dict(default)

        added_args: List[str] = []
        param_kwargs = {k: v for k, v in kwargs.items() if k == "sub_configs"}
        for param in get_signature_parameters(theclass, None, logger=self.logger):
            self._add_signature_parameter(
                group,
                nested_key,
                param,
                added_args,
                fail_untyped=fail_untyped,
                default=defaults.get(param.name, inspect_empty),
                **param_kwargs,
            )

        return added_args

    def add_subclass_arguments(
        self,
        baseclass: Union[Type, Tuple[Type, ...]],
        nested_key: str,
        as_group: bool = True,
        skip: Optional[Set[str]] = None,
        instantiate: bool = True,
        required: bool = False,
        metavar: str = "CONFIG | CLASS_PATH_OR_NAME | .INIT_ARG_NAME VALUE",
        help: str = (
            'One or more arguments specifying "class_path" and "init_args" for any subclass of %(baseclass_name)s.'
        ),
        **kwargs,
    ):
        """Adds arguments to allow specifying any subclass of the given base class.

        This adds an argument that requires a dictionary with a "class_path"
        entry which must be a import dot notation expression. Optionally any
        init arguments for the class can be given in the "init_args" entry.
        Since subclasses can have different init arguments, the help does not
        show the details of the arguments of the base class. Instead a help
        argument is added that will print the details for a given class path.

        Args:
            baseclass: Base class or classes to use to check subclasses.
            nested_key: Key for nested namespace.
            as_group: Whether arguments should be added to a new argument group.
            skip: Names of parameters that should be skipped.
            required: Whether the argument group is required.
            metavar: Variable string to show in the argument's help.
            help: Description of argument to show in the help.
            **kwargs: Additional parameters like in add_class_arguments.

        Raises:
            ValueError: When given an invalid base class.
        """
        if is_dataclass_like(baseclass):
            raise ValueError("Not allowed for dataclass-like classes.")
        if type(baseclass) is not tuple:
            baseclass = (baseclass,)  # type: ignore
        if not all(inspect.isclass(c) for c in baseclass):
            raise ValueError('Expected "baseclass" argument to be a class or a tuple of classes.')

        doc_group = None
        if len(baseclass) == 1:  # type: ignore
            doc_group = get_doc_short_description(baseclass[0], logger=self.logger)
        group = self._create_group_if_requested(
            baseclass,
            nested_key,
            as_group,
            doc_group,
            config_load=False,
            required=required,
            instantiate=False,
        )

        added_args: List[str] = []
        if skip is not None:
            skip = {f"{nested_key}.init_args." + s for s in skip}
        param = ParamData(name=nested_key, annotation=Union[baseclass], component=baseclass)
        str_baseclass = iter_to_set_str(get_import_path(x) for x in baseclass)
        kwargs.update(
            {
                "metavar": metavar,
                "help": (help % {"baseclass_name": str_baseclass}),
            }
        )
        if "default" not in kwargs:
            kwargs["default"] = SUPPRESS
        self._add_signature_parameter(
            group, None, param, added_args, skip, sub_configs=True, instantiate=instantiate, **kwargs
        )

    def _create_group_if_requested(
        self,
        obj,
        nested_key,
        as_group,
        doc_group,
        config_load=True,
        config_load_type=None,
        required=False,
        instantiate=True,
    ):
        if required:
            if nested_key is None:
                raise ValueError("A nested_key is mandatory to make required.")
            self.required_args.add(nested_key)

        group = self
        if as_group:
            if doc_group is None:
                if isinstance(obj, tuple) and len(obj) == 1:
                    doc_group = str(obj[0])
                else:
                    doc_group = str(obj)
            name = obj.__name__ if nested_key is None else nested_key
            group = self.add_argument_group(strip_title(doc_group), name=name)
            if config_load and nested_key is not None:
                group.add_argument("--" + nested_key, action=_ActionConfigLoad(basetype=config_load_type))
            if inspect.isclass(obj) and nested_key is not None and instantiate:
                group.dest = nested_key
                group.group_class = obj
                group.instantiate_class = group_instantiate_class
        return group


def group_instantiate_class(group, cfg):
    try:
        value, parent, key = cfg.get_value_and_parent(group.dest)
    except KeyError:
        value = {}
        parent = cfg
        key = group.dest
    instantiator_fn = get_class_instantiator()
    parent[key] = instantiator_fn(group.group_class, **value)


def strip_title(value):
    if value is not None:
        value = re.sub(r"\.$", "", value.strip())
    return value


def is_factory_class(value):
    return value.__class__ == dataclasses._HAS_DEFAULT_FACTORY_CLASS


def dataclass_to_dict(value) -> dict:
    if pydantic_support:
        from pydantic import BaseModel  # pylint: disable=no-name-in-module

        if isinstance(value, BaseModel):
            return value.dict()
    if isinstance(value, LazyInitBaseClass):
        return value.lazy_get_init_data().as_dict()
    return dataclasses.asdict(value)


def compose_dataclasses(*args):
    """Returns a dataclass inheriting all given dataclasses and properly handling __post_init__."""

    @dataclasses.dataclass
    class ComposedDataclass(*args):
        def __post_init__(self):
            for arg in args:
                if hasattr(arg, "__post_init__"):
                    arg.__post_init__(self)

    return ComposedDataclass
