#!/bin/sh

# 2019, Joost van Baal-Ilić
# This code is in the public domain, no copyright is claimed


# copy from:
# $Id: apt-is 105635 2019-08-19 10:34:27Z joostvb $


#
# apt-is - test status of packages
#
# usage:
#  apt-is action package
#
# examples:
#
#  $ apt-is available uruk
#  true
#
#  $ apt-is installed caspar
#  false
#
#  apt-is installed $pkg && do stuff
#
#  if `apt-is missing $module`; then pip cargo pear install blah; fi
#

case "$1" in
  installed)
    if dpkg -s "$2" 2>/dev/null | grep Status | grep -q installed
    then
      echo true
    else
      echo false
      exit 1
    fi
  ;;
  available)
    if apt-cache show "$2" >/dev/null 2>&1
    then
      echo true
    else
      echo false
      exit 1
    fi
  ;;
  missing)
    # candidate for installing from non-debian non-apt sources: not installed, not available
    if dpkg -s "$2" 2>/dev/null | grep Status | grep -q installed
    then
      echo false
      exit 1
    elif apt-cache show "$2" >/dev/null 2>&1
    then
      echo false
      exit 1
    else
      echo true
    fi
    ;;
  *)
    echo "$0: usage: apt-is {available|installed|missing} <package>"
esac

exit 0