from rest_framework.permissions import BasePermission
from apps.chat.models.chat import ChatRoom, ChatMessage


class IsRoomParticipant(BasePermission):
    """
    Ensures that only authorized participants (individual user or member of a participating institution)
    can view room messages, send messages, or receive read receipts.
    """
    def has_permission(self, request, view):
        return bool(request.user and request.user.is_authenticated and request.user.is_active)

    def has_object_permission(self, request, view, obj):
        if not request.user or not request.user.is_authenticated:
            return False

        if getattr(request.user, 'is_super_admin', False) or getattr(request.user, 'is_regional_admin', False):
            return True

        room = obj if isinstance(obj, ChatRoom) else getattr(obj, 'room', None)
        if not room:
            return False

        return room.is_participant(request.user)