predicates.py

from typing import Any, Union

from django.contrib.auth.models import User
from django.db.models import Q
from django.utils.timezone import localdate, localtime

from rules import predicate

from aleksis.apps.chronos.models import Event, ExtraLesson, LessonEvent, LessonPeriod
from aleksis.apps.cursus.models import Course
from aleksis.core.models import Group, Person
from aleksis.core.util.core_helpers import get_site_preferences
from aleksis.core.util.predicates import check_object_permission

from ..models import Documentation, PersonalNote


@predicate
def is_none(user: User, obj: Any) -> bool:
    """Predicate that checks if the provided object is None-like."""
    return not bool(obj)


@predicate
def is_lesson_teacher(user: User, obj: Union[LessonPeriod, Event, ExtraLesson]) -> bool:
    """Predicate for teachers of a lesson.

    Checks whether the person linked to the user is a teacher in the register object.
    If the register object is a lesson period and has a substitution linked,
    this will **only** check if the person is one of the substitution teachers.
    """
    if obj:
        return user.person in obj.get_teachers().all()
    return False


@predicate
def is_lesson_original_teacher(user: User, obj: Union[LessonPeriod, Event, ExtraLesson]) -> bool:
    """Predicate for teachers of a lesson.

    Checks whether the person linked to the user is a teacher in the register object.
    If the register object is a lesson period and has a substitution linked,
    this will **also** check if the person is one of the substitution teachers.
    """
    if obj:
        if isinstance(obj, LessonPeriod) and user.person in obj.lesson.teachers.all():
            return True
        return user.person in obj.get_teachers().all()
    return False


@predicate
def is_lesson_participant(user: User, obj: LessonPeriod) -> bool:
    """Predicate for participants of a lesson.

    Checks whether the person linked to the user is a member in
    the groups linked to the given LessonPeriod.
    """
    if hasattr(obj, "lesson") or hasattr(obj, "groups"):
        for group in obj.get_groups().all():
            if user.person in list(group.members.all()):
                return True
    return False


@predicate
def is_lesson_parent_group_owner(user: User, obj: LessonPeriod) -> bool:
    """
    Predicate for parent group owners of a lesson.

    Checks whether the person linked to the user is the owner of
    any parent groups of any groups of the given LessonPeriods lesson.
    """
    if hasattr(obj, "lesson") or hasattr(obj, "groups"):
        for group in obj.get_groups().all():
            for parent_group in group.parent_groups.all():
                if user.person in list(parent_group.owners.all()):
                    return True
    return False


@predicate
def is_group_owner(user: User, obj: Union[Group, Person]) -> bool:
    """Predicate for group owners of a given group.

    Checks whether the person linked to the user is the owner of the given group.
    If there isn't provided a group, it will return `False`.
    """
    if isinstance(obj, Group) and user.person in obj.owners.all():
        return True

    return False


@predicate
def is_person_group_owner(user: User, obj: Person) -> bool:
    """
    Predicate for group owners of any group.

    Checks whether the person linked to the user is
    the owner of any group of the given person.
    """
    if obj:
        for group in use_prefetched(obj, "member_of"):
            if user.person in use_prefetched(group, "owners"):
                return True
        return False
    return False


def use_prefetched(obj, attr):
    prefetched_attr = f"{attr}_prefetched"
    if hasattr(obj, prefetched_attr):
        return getattr(obj, prefetched_attr)
    return getattr(obj, attr).all()


@predicate
def is_person_primary_group_owner(user: User, obj: Person) -> bool:
    """
    Predicate for group owners of the person's primary group.

    Checks whether the person linked to the user is
    the owner of the primary group of the given person.
    """
    if obj.primary_group:
        return user.person in use_prefetched(obj.primary_group, "owners")
    return False


def has_person_group_object_perm(perm: str):
    """Predicate builder for permissions on a set of member groups.

    Checks whether a user has a permission on any group of a person.
    """
    name = f"has_person_group_object_perm:{perm}"

    @predicate(name)
    def fn(user: User, obj: Person) -> bool:
        groups = use_prefetched(obj, "member_of")
        return any(check_object_permission(user, perm, group, checker_obj=obj) for group in groups)

    return fn


@predicate
def is_group_member(user: User, obj: Union[Group, Person]) -> bool:
    """Predicate for group membership.

    Checks whether the person linked to the user is a member of the given group.
    If there isn't provided a group, it will return `False`.
    """
    if isinstance(obj, Group) and user.person in obj.members.all():
        return True

    return False


def has_lesson_group_object_perm(perm: str):
    """Predicate builder for permissions on lesson groups.

    Checks whether a user has a permission on any group of a LessonPeriod.
    """
    name = f"has_lesson_group_object_perm:{perm}"

    @predicate(name)
    def fn(user: User, obj: LessonPeriod) -> bool:
        if hasattr(obj, "lesson"):
            groups = obj.lesson.groups.all()
            for group in groups:
                if check_object_permission(user, perm, group, checker_obj=obj):
                    return True
        return False

    return fn


def has_personal_note_group_perm(perm: str):
    """Predicate builder for permissions on personal notes.

    Checks whether a user has a permission on any group of a person of a PersonalNote.
    """
    name = f"has_personal_note_person_or_group_perm:{perm}"

    @predicate(name)
    def fn(user: User, obj: PersonalNote) -> bool:
        if hasattr(obj, "person"):
            groups = obj.person.member_of.all()
            for group in groups:
                if check_object_permission(user, perm, group, checker_obj=obj):
                    return True
        return False

    return fn


@predicate
def is_own_personal_note(user: User, obj: PersonalNote) -> bool:
    """Predicate for users referred to in a personal note.

    Checks whether the user referred to in a PersonalNote is the active user.
    """
    if hasattr(obj, "person") and obj.person is user.person:
        return True
    return False


@predicate
def is_parent_group_owner(user: User, obj: Group) -> bool:
    """Predicate which checks whether the user is the owner of any parent group of the group."""
    if hasattr(obj, "parent_groups"):
        for parent_group in use_prefetched(obj, "parent_groups"):
            if user.person in use_prefetched(parent_group, "owners"):
                return True
    return False


@predicate
def is_personal_note_lesson_teacher(user: User, obj: PersonalNote) -> bool:
    """Predicate for teachers of a register object linked to a personal note.

    Checks whether the person linked to the user is a teacher
    in the register object linked to the personal note.
    If the register object is a lesson period and has a substitution linked,
    this will **only** check if the person is one of the substitution teachers.
    """
    if hasattr(obj, "register_object"):
        return user.person in obj.register_object.get_teachers().all()
    return False


@predicate
def is_personal_note_lesson_original_teacher(user: User, obj: PersonalNote) -> bool:
    """Predicate for teachers of a register object linked to a personal note.

    Checks whether the person linked to the user is a teacher
    in the register object linked to the personal note.
    If the register object is a lesson period and has a substitution linked,
    this will **also** check if the person is one of the substitution teachers.
    """
    if hasattr(obj, "register_object"):
        if (
            isinstance(obj.register_object, LessonPeriod)
            and user.person in obj.lesson_period.lesson.teachers.all()
        ):
            return True

        return user.person in obj.register_object.get_teachers().all()
    return False


@predicate
def is_personal_note_lesson_parent_group_owner(user: User, obj: PersonalNote) -> bool:
    """
    Predicate for parent group owners of a lesson referred to in the lesson of a personal note.

    Checks whether the person linked to the user is the owner of
    any parent groups of any groups of the given LessonPeriod lesson of the given PersonalNote.
    If so, also checks whether the person linked to the personal note actually is a member of this
    parent group.
    """
    if hasattr(obj, "register_object"):
        for group in obj.register_object.get_groups().all():
            for parent_group in group.parent_groups.all():
                if user.person in use_prefetched(
                    parent_group, "owners"
                ) and obj.person in use_prefetched(parent_group, "members"):
                    return True
    return False


@predicate
def is_teacher(user: User, obj: Person) -> bool:
    """Predicate which checks if the provided object is a teacher."""
    return user.person.is_teacher


@predicate
def is_group_role_assignment_group_owner(user: User, obj: Union[Group, Person]) -> bool:
    """Predicate for group owners of a group role assignment.

    Checks whether the person linked to the user is the owner of the groups
    linked to the given group role assignment.
    If there isn't provided a group role assignment, it will return `False`.
    """
    if obj:
        for group in obj.groups.all():
            if user.person in list(group.owners.all()):
                return True
    return False


@predicate
def is_owner_of_any_group(user: User, obj):
    """Predicate which checks if the person is group owner of any group."""
    return Group.objects.filter(owners=user.person).exists()


@predicate
def is_course_teacher(user: User, obj: Course):
    """Predicate for teachers of a course.

    Checks whether the person linked to the user is a teacher in the course.
    """
    if obj:
        return user.person in obj.teachers.all()
    return False


@predicate
def is_lesson_event_teacher(user: User, obj: LessonEvent):
    """Predicate for teachers of a lesson event.

    Checks whether the person linked to the user is a teacher in the lesson event.
    """
    if obj:
        return user.person in obj.all_teachers
    return False


@predicate
def is_course_member(user: User, obj: Course):
    """Predicate for members of a course.

    Checks whether the person linked to the user is a member in the course.
    """
    if obj:
        for g in obj.groups.all():
            if user.person in g.members.all():
                return True
    return False


@predicate
def is_course_group_owner(user: User, obj: Course):
    """Predicate for group owners of a course.

    Checks whether the person linked to the user is a owner of any group
    (or their respective parent groups) linked to the course.
    """
    if obj:
        for g in obj.groups.all():
            if user.person in g.owners.all():
                return True
            for pg in g.parent_groups.all():
                if user.person in pg.owners.all():
                    return True
    return False


@predicate
def is_lesson_event_member(user: User, obj: LessonEvent):
    """Predicate for members of a lesson event.

    Checks whether the person linked to the user is a member in the lesson event,
    or a members of the course, if the lesson event has one.
    """
    if obj:
        for g in obj.groups.all():
            if user.person in g.members.all():
                return True

    return False


@predicate
def is_lesson_event_group_owner(user: User, obj: LessonEvent):
    """Predicate for group owners of a lesson event.

    Checks whether the person linked to the user is a owner of any group
    (or their respective parent groups) linked to the lesson event,
    or a owner of any group linked to the course, if the lesson event has one.
    """
    if obj:
        for g in obj.groups.all():
            if user.person in g.owners.all():
                return True
            for pg in g.parent_groups.all():
                if user.person in pg.owners.all():
                    return True
    return False


@predicate
def is_documentation_teacher(user: User, obj: Documentation):
    """Predicate for teachers of a documentation.

    Checks whether the person linked to the user is a teacher in the documentation.
    """
    if obj:
        if not str(obj.pk).startswith("DUMMY") and hasattr(obj, "teachers"):
            teachers = obj.teachers
        elif obj.amends.amends:
            teachers = obj.amends.teachers if obj.amends.teachers else obj.amends.amends.teachers
        else:
            teachers = obj.amends.teachers
        return user.person in teachers.all()
    return False


@predicate
def can_view_documentation(user: User, obj: Documentation):
    """Predicate which checks if the user is allowed to view a documentation."""
    if obj:
        if is_documentation_teacher(user, obj):
            return True
        if obj.amends:
            return (
                is_lesson_event_teacher(user, obj.amends)
                | is_lesson_event_member(user, obj.amends)
                | is_lesson_event_group_owner(user, obj.amends)
            )
        if obj.course:
            return is_course_teacher(user, obj.course)
    return False


@predicate
def can_view_any_documentation(user: User):
    """Predicate which checks if the user is allowed to view any documentation."""
    allowed_lesson_events = LessonEvent.objects.related_to_person(user.person)

    return Documentation.objects.filter(
        Q(teachers=user.person)
        | Q(amends__in=allowed_lesson_events)
        | Q(course__teachers=user.person)
    ).exists()


@predicate
def can_edit_documentation(user: User, obj: Documentation):
    """Predicate which checks if the user is allowed to edit or delete a documentation."""
    if obj:
        if is_documentation_teacher(user, obj):
            return True
        if obj.amends:
            return is_lesson_event_teacher(user, obj.amends) | is_lesson_event_group_owner(
                user, obj.amends
            )
    return False


@predicate
def is_in_allowed_time_range(user: User, obj: Documentation):
    """Predicate which checks if the documentation is in the allowed time range for editing."""
    if obj and (
        get_site_preferences()["alsijil__allow_edit_future_documentations"] == "all"
        or (
            get_site_preferences()["alsijil__allow_edit_future_documentations"] == "current_day"
            and obj.datetime_start.date() <= localdate()
        )
        or (
            get_site_preferences()["alsijil__allow_edit_future_documentations"] == "current_time"
            and obj.datetime_start <= localtime()
        )
    ):
        return True
    return False