#!/bin/bash
# Copyright (C) 2014 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

distro-name() {
    if [[ -f /etc/fedora-release ]]; then
        echo fedora
    elif [[ -e /etc/os-release ]]; then
        sed -rn 's/^ID=(.*)/\1/p' /etc/os-release
    else
        echo "unknown distro"
        return 1
    fi
}

distro-name-ver() {
    echo `distro-name``debian-archive`
}

debian-archive() {
    isdeb || return 0
    local archive
    local policy="${1:-$(apt-cache policy)}"
    # a = archive
    # n = codename
    # o = origin
    # c = component (licensing component)
    # l = label (Debian{,-Security,-Updates})
    { for archive in stable testing unstable; do
          # print priority + archive name. priority is in
          # the previous line after finding the archive.
          read -rd '' expression <<EOF ||:
/o=Debian,a=$archive,.*l=Debian,c=main/{x;s/^ *([-0-9]+).*/\1 $archive/p;q};h
EOF
          echo "$policy" | sed -rn "$expression"
      done
    } | sort -rn | head -n1 | grep -oE "\w+$"
}


isdebian-testing() {
    [[ $(debian-archive) == testing ]]
}
# I only do testing or stable.
isdebian-stable() {
    [[ $(debian-archive) == stable ]]
}

debian-codename() {
    isdeb || return 0
    local policy="$(apt-cache policy)"
    archive=$(debian-archive "$policy")
    echo "$policy" | sed -rn "s/^.*a=$archive,n=([a-z]+).*/\1/p;T;q"
}
isfedora() {
    [[ $(distro-name) == fedora ]]
}
isdebian() {
    [[ $(distro-name) == debian ]]
}
isarch() {
    [[ $(distro-name) == arch ]]
}
# is debian/apt based
isdeb() { command -v apt-get &>/dev/null; }
isubuntu() {
    [[ $(distro-name) == ubuntu ]]
}