#!/bin/bash

# pfilter 1.0 by Martin Aspeli <optilude@gmx.net>

# Filter for Gentoo Linux (www.gentoo.org)'s Portage system, allowing you to
# select which packages from an emerge -p you wish to update. Takes output
# from emerge -p as its standard input, prints list of selected packages.

# Suggested use: # emerge -up world | pfilter | xargs emerge -u

# This will do an emerge -up world, then allow you to deselect any of the
# packages about to be installed (using dialog) and then do an emerge -u on
# those packages. Note that if you deselect a package which is a dependency
# of a selected package, it will still be installed.

# read from standard input and make items suitable for passing to dialog's
# checklist as checklist options.

select_packages=1

get_checklist_items () {
  # Read input and break portage --pretend output into package and info
  local line=""
 
  # Read lines
  while read line ; do

   # ... find its parts: \1 = the status characters, \2 = name of package
   # \3 = optionally version of installed package
   
   if test "${select_packages}" = "1" ; then
     echo "${line}" | grep "^\[ebuild " | \
      sed 's/^\[ebuild \([^]]*\)] \([^[:space:]]*\)[[:space:]]\?\(.*\)$/\2 \"\1\3\" on/'
   else
     echo "${line}" | grep "^\[ebuild " | \
      sed 's/^\[ebuild \([^]]*\)] \([^[:space:]]*\)[[:space:]]\?\(.*\)$/\2 \"\1\3\" off/'   
   fi
  done
}

# display checklist (using dialog) of all the ebuilds given as command line
# options (output from get_checklist_items).
display_checklist () {
  if test "${1}" = "" ; then
   return 1   
  fi
      
  # Display the checklist dialogue
  eval "dialog --title 'Portage ebuild filter' --separate-output \
            --checklist  'Select packages to install:' 0 0 0 ${@} 2>&1" || \
      exit 1
}

# format ebuilds output by display_checklist by removing version info and
# double quotes.
format_ebuilds () {
  for package in ${@} ; do
   # print leading =
   echo "=${package}"
  done
}

print_help () {
  echo "Usage: emerge -p [packages] | pfilter [options]"
  echo
  echo "Options:"
  echo "  -d        Deselect packages by default"
  echo "  -h        Display this message"
  echo
}

init () {
  select_packages=0
      
  while getopts "d" opt ; do
   case "${opt}" in
     d)
      select_packages=0
      ;;
     *)
      print_help && exit 1
      ;;
   esac
  done
}

init ${@}

# get the filtered packages from the checklist
packages=$(display_checklist $(get_checklist_items))

# if any selected, print them
test "${packages}" != "" && format_ebuilds ${packages} || exit 1