#!/bin/bash
# Output DOT file representing package dependencies
#
#   Copyright (C) 2014-2023 Ryan Specialty, LLC.
#
#   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, either version 3 of the License, or
#   (at your option) any later version.
#
#   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, see <http://www.gnu.org/licenses/>.
##


relpath()
{
  while read p; do
    if [[ ! "$p" =~ \.\. ]]; then
      echo "$p"
    else
      sed 's|[^/]\+/\.\./|/|' | relpath
    fi
  done
}


undepify()
{
  sed 's|^\(\./\)\?\(.*\)\.dep:|/\2 |'
}


dotify()
{
  echo 'digraph {'

  local from to
  while read -r from to; do
    printf '"%s" -> "%s";\n' "$from" "$to"
  done

  echo '}'
}


main()
{
  local root="${1?Missing project root}"

  cd "$root"

  find . -name '*.dep' | while read -r depfile; do
    # Absolute paths can be output verbatim
    grep -H '^/' "$depfile"

    # Relative paths need processing
    local dir=$( dirname "$depfile" | sed 's|^\./|/|' )
    grep -Hv '^/' "$depfile" \
      | sed "s|:|:$dir/|"
  done \
    | grep -v '\$$' \
    | relpath \
    | undepify \
    | dotify
}

main "$@"