#!/bin/bash

PKGS=""
PINS=""

get_depends()
{
        apt-cache show $1/jessie-backports 2>/dev/null | grep -e Depends -e PreDepends \
                | awk -F'Depends:' '{print $2}' | tr ',' '\n' | grep \(.*\) | awk -F' ' '{print $1}'
}

exists_in_bpo()
{
        if apt-cache show $1/jessie-backports 2>/dev/null >/dev/null; then
                return 0
        else
                return 1
        fi
}

get_version_in_bpo()
{
        apt-cache show $1/jessie-backports | grep ^Version: | awk -F' ' '{print $2}'
}

eval_check_loop()
{
        if grep ^${1}$ <<< "$PKGS" >/dev/null ; then
                return 1
        fi
        PKGS="$(echo "$PKGS" ; echo $1)"
}

pinn_check_loop()
{
        if grep ^${1}$ <<< "$PINS" >/dev/null ; then
                return 1
        fi
        PINS="$(echo "$PINS" ; echo $1)"
}

generate_pinning()
{
        name=$1
        if ! pinn_check_loop $name ; then
                return
        fi
        version=$(get_version_in_bpo $name)
        echo -e "Package: $name\nPin: version $version\nPin-Priority: 1002\n"
}


eval()
{
        package=$1
        if ! eval_check_loop $package ; then
                return
        fi
        for i in $(get_depends $package)
        do
                if ! exists_in_bpo $i ; then
                        continue
                fi

                generate_pinning $i
                eval $i
        done
}

generate_pinning keystone
eval keystone