#!/bin/bash

set -eu
# set -x
set -o pipefail

use_rpm=False
use_deb=False
use_brew=False
rpm_packages=""
deb_packages=""
brew_packages=""

function usage
{
    retval="$1"
    case "$retval" in
        0)
            ;;
        1)
            exec 1>&2
            ;;
        *)
            echo "$0: Internal error: argument to usage must be 0 or 1" 1>&2
            exit 1
            ;;
    esac
    echo "$0 --force-rpm --force-deb --force-brew --rpm-packages --deb-packages --brew-packages"
    echo "If you do not give --force-rpm, --force-deb or --force-brew, this script will guess which to use"
    echo
    echo "Example:"
    echo "    $0 --rpm-packages 'coreutils sharutils' --deb-packages 'coreutils sharutils' --brew-packages ''"
    echo
    echo "Note that package names commonly differ from rpm to deb systems"
    exit "$retval"
}

while [ "$#" -ge 1 ]
do
    case "$1" in
        --force-rpm)
            use_rpm=True
            ;;
        --force-deb)
            use_deb=True
            ;;
        --force-brew)
            use_brew=True
            ;;
        --rpm-packages)
            rpm_packages="$2"
            shift
            ;;
        --deb-packages)
            deb_packages="$2"
            shift
            ;;
        --brew-packages)
            brew_packages="$2"
            shift
            ;;
        --help|-h)
            usage 0
            ;;
        *)
            echo "$0: Unrecognized option: $1" 1>&2
            usage 1
            ;;
    esac
    shift
done

case "$use_rpm-$use_deb-$use_brew" in
	True*True)
		echo "$0: Only specify zero or one of --force-rpm, --force-deb and --force-brew" 1>&2
		exit 1
		;;
esac

case "$use_rpm-$use_deb-$use_brew" in
	False-False-False)
		# Neither rpm, deb nor brew forced - try to guess
		if type -p rpm > /dev/null 2>&1
		then
			use_rpm=True
		fi

		if type -p apt-get > /dev/null 2>&1
		then
			use_deb=True
		fi

		if type -p brew > /dev/null 2>&1
		then
			use_brew=True
		fi
esac

function rpm_all_found
{
    # shellcheck disable=SC2048
    for package in $*
    do
        # FIXME: This might not be the correct way to test if an rpm is already installed
        if rpm -q "$package" > /dev/null 2>&1
        then
            continue
        else
            # We didn't find one - return negative-logic false
            return 1
        fi
    done
    # We found them all - return negative-logic true
    return 0
}

function deb_all_found
{
    # shellcheck disable=SC2048
    for package in $*
    do
        # See https://stackoverflow.com/questions/1298066/check-if-a-package-is-installed-and-then-install-it-if-its-not

        # These don't work
        # if dpkg -p "$package" > /dev/null 2>&1
        # if dpkg -s "$package" > /dev/null 2>&1
        # if dpkg-query -l "$package" > /dev/null 2>&1
        # if dpkg-query -p "$package" > /dev/null 2>&1
        if dpkg-query -s "$package" 2> /dev/null | grep '^Status: ' | tr ' ' '\n' | grep -Fqx installed
        then
            continue
        else
            # We didn't find one - return negative-logic false
            return 1
        fi
    done
    # We found them all - return negative-logic true
    return 0
}

function brew_all_found
{
	# We don't really need this - brew does not run as root.  But it might be a little faster - not sure really.

    # shellcheck disable=SC2048
    for package in $*
    do
        # See https://apple.stackexchange.com/questions/284379/with-homebrew-how-to-check-if-a-software-package-is-installed

        if brew list "$package" > /dev/null 2>&1
        then
            continue
        else
            # We didn't find one - return negative-logic false
            return 1
        fi
    done
    # We found them all - return negative-logic true
    return 0
}

function deb_install_packages
{
    # shellcheck disable=SC2048,SC2086
    sudo apt-get install -y $*
}

function rpm_install_packages
{
    # shellcheck disable=SC2048,SC2086
    sudo yum install -y $*
}

function brew_install_packages
{
    # shellcheck disable=SC2048,SC2086
    brew install $*
}


case "$use_rpm-$use_deb-$use_brew" in
	True*True)
		echo "$0: Internal error: \$use_rpm-\$use_deb-\$use_brew has a strange value: $use_rpm-$use_deb-$use_brew" 1>&2
		exit 1
		;;
	False-False-False)
		echo "$0: Internal error: \$use_rpm, \$use_deb and \$use_brew are all False" 1>&2
		exit 1
		;;
	True-*-*)
		if rpm_all_found "$rpm_packages"
		then
			echo "$0: All rpm packages found, nothing to do" 1>&2
			exit 0
		else
			rpm_install_packages "$rpm_packages"
		fi
		;;
    *-True-*)
		# shellcheck disable=SC2086
		if deb_all_found $deb_packages
		then
			echo "$0: All deb packages found, nothing to do" 1>&2
			exit 0
		else
			# shellcheck disable=SC2086
			deb_install_packages $deb_packages
		fi
        ;;
    *-*-True)
		# shellcheck disable=SC2086
		if brew_all_found $brew_packages
		then
			echo "$0: All brew packages found, nothing to do" 1>&2
			exit 0
		else
			# shellcheck disable=SC2086
			brew_install_packages $brew_packages
		fi
        ;;
    *)
        echo "$0: Internal error: \$use_rpm has a strange value: $use_rpm" 1>&2
        exit 1
        ;;
esac