db/schema/0400_perm.sql

create type public.perm_mode as enum ('-', 'r', 'w');

create table public.perm
  ( id               int              not null primary key generated always as identity
  , uid              human_uuid.huid  not null unique default human_uuid.huid()
  , owner_user       int              not null references public.usr(id)
  , owner_group      int              not null references public.grp(id)
  , owner_user_mode  public.perm_mode not null
  , owner_group_mode public.perm_mode not null
  , everyone_mode    public.perm_mode not null
  , path             text             not null unique
  );

do language plpgsql $$
declare
  root int;
  admins int;
begin
  root := (public.usr_root()).id;
  admins := (public.grp_admins()).id;

  insert into public.perm
    (path, owner_user, owner_group, owner_user_mode, owner_group_mode, everyone_mode)
  values
    ('/communities/', root, admins, 'w', 'w', 'r')
  , ('/users/', root, admins, 'w', 'w', 'w')
  , ('/groups/', root, admins, 'w', 'w', 'w')
  ;
end;
$$;

create function do_insert_usr_perm() returns trigger language plpgsql as $$
declare
  admins int;
begin
  admins := (public.grp_admins()).id;

  insert into public.perm
    (path, owner_user, owner_group, owner_user_mode, owner_group_mode, everyone_mode)
  values
    ('/users/' || human_uuid.huid_to_string(NEW.uid) || '/tag', NEW.id, admins, 'w', 'w', 'r')
  , ('/users/' || human_uuid.huid_to_string(NEW.uid) || '/email', NEW.id, admins, 'w', 'w', '-')
  , ('/users/' || human_uuid.huid_to_string(NEW.uid) || '/deleted', NEW.id, admins, 'w', 'w', '-')
  , ('/users/' || human_uuid.huid_to_string(NEW.uid) || '/password', NEW.id, admins, 'w', 'w', '-')
  ;

  return new;
end;
$$;

create trigger insert_usr_perm
after insert on public.usr
for each row execute function do_insert_usr_perm();

create function do_insert_grp_perm() returns trigger language plpgsql as $$
begin
  insert into public.perm
    (path, owner_user, owner_group, owner_user_mode, owner_group_mode, everyone_mode)
  values
    ('/groups/' || human_uuid.huid_to_string(NEW.uid) || '/members', (public.get_acting_usr()).id, NEW.id, 'w', 'w', '-')
  , ('/groups/' || human_uuid.huid_to_string(NEW.uid) || '/tag', (public.get_acting_usr()).id, NEW.id, 'w', 'w', 'r')
  ;

  return new;
end;
$$;

create trigger insert_grp_perm
after insert on public.grp
for each row
execute function do_insert_grp_perm();

create function do_insert_community_perm() returns trigger language plpgsql as $$
begin
  -- TODO: insert some default community groups, use community_XX_admin as group owner

  insert into public.perm
    (path, owner_user, owner_group, owner_user_mode, owner_group_mode, everyone_mode)
  values
    ('/communities/' || human_uuid.huid_to_string(NEW.uid) || '/posts', (public.get_acting_usr()).id, NEW.id, 'w', 'w', 'r')
  , ('/communities/' || human_uuid.huid_to_string(NEW.uid) || '/tag', (public.get_acting_usr()).id, NEW.id, 'w', 'w', 'r')
  , ('/communities/' || human_uuid.huid_to_string(NEW.uid) || '/deleted', (public.get_acting_usr()).id, NEW.id, 'w', 'w', '-')
  ;

  return new;
end;
$$;

create trigger insert_community_perm
after insert on public.community
for each row
execute function do_insert_community_perm();

select audit( 'public'
            , 'perm'
            , array[ row('owner_user', 'int')
                   , row('owner_group', 'int')
                   , row('owner_user_mode', 'public.perm_mode')
                   , row('owner_group_mode', 'public.perm_mode')
                   , row('everyone_mode', 'public.perm_mode')
                   ] :: audited_column[]
            , soft_delete => false
            );

select immutable( 'public'
                , 'perm'
                , array[ 'id'
                       , 'uid'
                       , 'path'
                       ]
                );