#  Copyright 2021 Northern.tech AS
#  This file is part of CFEngine 3 - written and maintained by Northern.tech AS.
#  This program 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; version 3.
#  This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA
# To the extent this program is licensed as part of the Enterprise
# versions of Cfengine, the applicable Commercial Open Source License
# (COSL) may apply to this file if you as a licensee so wish it. See
# included file COSL.txt.
#+begin_src prep
#@ ```
#@ echo "MATCHING before region" > /tmp/example_select_region.txt
#@ echo "BEGIN" >> /tmp/example_select_region.txt
#@ echo "MATCHING inside region" >> /tmp/example_select_region.txt
#@ echo "END" >> /tmp/example_select_region.txt
#@ echo "MATCHING after region" >> /tmp/example_select_region.txt
#@ ```
#+end_src
#+begin_src cfengine3
bundle agent main
# @brief Demonstrate how edit_line can operate within a region of a file
{
  vars:
    "file" string => "/tmp/example_select_region.txt";

  files:
    "$(file)"
      comment => "We want to delete any lines that begin with the string
                  MATCHING inside the region described by regular expressions
                  matching the beginning and end of the region.",
      create => "true",
      edit_line => delete_inside_region("^MATCHING.*", "^BEGIN.*", "^END.*");

  reports:
    "$(file)" printfile => cat($(this.promiser));
}

########################################################
bundle edit_line delete_inside_region(line_reg, begin_reg, end_reg)
# @brief Delete lines matching `line_reg` when found within the expected region starting with `begin_reg` and `end_reg`
{
  delete_lines:
    "$(line_reg)" select_region => between($(begin_reg), $(end_reg));
}

body select_region between(start, end)
# @brief Select a region exclusively between regular expressions `start` and `end`.
{
  select_start => "$(start)";
  select_end => "$(end)";
@if minimum_version(3.10)
  select_end_match_eof => "false";
@endif
}

body printfile cat(file)
# @brief Report the contents of a file
# @param file The full path of the file to report
{
  file_to_print => "$(file)";
  number_of_lines => "inf";
}

#+end_src
#+begin_src example_output
#@ ```
#@ R: /tmp/example_select_region.txt
#@ R: MATCHING before region
#@ R: BEGIN
#@ R: END
#@ R: MATCHING after region
#@ ```
#+end_src
