# (c) 2017 Ansible By Red Hat
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

from __future__ import annotations

import collections.abc as c

from ansible.playbook import Play
from ansible.playbook.block import Block
from ansible.playbook.role import Role
from ansible.playbook.task import Task
from ansible._internal._templating._engine import TemplateEngine
from ansible.utils.display import Display

display = Display()


def get_reserved_names(include_private: bool = True) -> set[str]:
    """ this function returns the list of reserved names associated with play objects"""

    public = set(TemplateEngine().environment.globals.keys())
    private = set()

    # FIXME: find a way to 'not hardcode', possibly need role deps/includes
    class_list = [Play, Role, Block, Task]

    for aclass in class_list:
        # build ordered list to loop over and dict with attributes
        for name, attr in aclass.fattributes.items():
            if attr.private:
                private.add(name)
            else:
                public.add(name)

    # local_action is implicit with action
    if 'action' in public:
        public.add('local_action')

    # loop implies with_
    # FIXME: remove after with_ is not only deprecated but removed
    if 'loop' in private or 'loop' in public:
        public.add('with_')

    if include_private:
        result = public.union(private)
    else:
        result = public

    result.discard('gather_subset')

    return result


def warn_if_reserved(myvars: c.Iterable[str], additional: c.Iterable[str] | None = None) -> None:
    """Issue a warning for any variable which conflicts with an internally reserved name."""
    if additional is None:
        reserved = _RESERVED_NAMES
    else:
        reserved = _RESERVED_NAMES.union(additional)

    varnames = set(myvars)
    varnames.discard('vars')  # we add this one internally, so safe to ignore

    if conflicts := varnames.intersection(reserved):
        # Ensure the varname used for obj is the tagged one from myvars and not the untagged one from reserved.
        # This can occur because tags do not affect value equality, and intersection can return values from either the left or right side.
        for varname in (name for name in myvars if name in conflicts):
            display.warning(f'Found variable using reserved name {varname!r}.', obj=varname)


def is_reserved_name(name: str) -> bool:
    return name in _RESERVED_NAMES


_RESERVED_NAMES = frozenset(get_reserved_names())