#!/usr/bin/env bash

# Copyright 2023 Red Hat, Inc. All rights reserved.
#
# 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.

# NOTE(tonyb): set and shopts are done after CLI parsing for brevity.

function usage {
    echo "$(basename $0): -d [device] -g [vg name] -v [volume spec]"
    echo "      [device]: The device path to use as the Physical Volume: eg /dev/sdb"
    echo "     [vg name]: The name for the new Volume Group: eg main"
    echo " [volume spec]: A colon ':' separated specification for a volume to create."
    echo "                This contains 3 parts"
    echo "          <name>: The Logical Volume name: eg afscache"
    echo "          <size>: The size (in extents) for the Logical Volume: eg 50%VG"
    echo "   <mount point>: The mount point for the volume: eg /var/cache/afscache"
    echo ""
    echo "NOTE: This script doesn't need to know the full size of the volume"
    echo ""
    echo "Example invocation:"
    echo "# $(basename $0) -d /dev/sdb -g main -v afscache:50%VG:/var/cache/openafs -v proxycache:50%VG:/var/cache/apache2"
}

declare -a VOLUMES=()

while [ $# -gt 0 ] ; do
    case "$1" in
    -d|--device)
        PV_DEVICE="${2}"
        shift 1
    ;;
    -g|--group)
        VOLUME_GROUP="${2}"
        shift 1
    ;;
    -v|--volume)
        VOLUMES+=("${2}")
        shift 1
    ;;
    --help)
        usage
        exit 0
    ;;
    *)
        echo "Unkown arg: '$1'"
        echo ""
        usage
        exit 1
    ;;
    esac
    shift 1
done

if [ -z "${PV_DEVICE}" ] ; then
    echo "You need to specify a device.    Aborting"
    usage
    exit 1
fi

if [ -z "${VOLUME_GROUP}" ] ; then
    echo "You need to specify a volume group name.    Aborting"
    usage
    exit 1
fi

if [ -z "${VOLUMES[*]}" ] ; then
    echo "You need to specify at least one volume.    Aborting"
    usage
    exit 1
fi

if [ "$(id -u)" -ne 0 ] ; then
    echo "You need to have root permissions for this script to run.    Aborting."
    echo ""
    usage
    exit 1
fi

# Sanity check that we don't break anything that already has an fs.
if blkid | grep -q $PV_DEVICE ; then
    echo "$PV_DEVICE appears in blkid.   Aborting."
    blkid
    exit 1
fi

# NOTE: This isn't expected to install any packages but just in case let us
# list the script requirements here
apt-get update && apt-get install -y e2fsprogs lvm2 parted perl

set -xeuo pipefail

parted --script $PV_DEVICE mklabel msdos mkpart primary 0% 100% set 1 lvm on
partprobe -s $PV_DEVICE
pvcreate ${PV_DEVICE}1
vgcreate ${VOLUME_GROUP} ${PV_DEVICE}1

for vol_spec in "${VOLUMES[@]}"; do
    IFS=:
    set -- $vol_spec
    VOLUME_NAME="$1"
    VOLUME_SIZE="$2"
    VOLUME_MOUNT="$3"
    VOLUME_DEVICE="/dev/${VOLUME_GROUP}/${VOLUME_NAME}"

    lvcreate -l "${VOLUME_SIZE}" -n $VOLUME_NAME ${VOLUME_GROUP}
    mkfs.ext4 -m 0 -j -L $VOLUME_NAME ${VOLUME_DEVICE}
    tune2fs -i 0 -c 0 ${VOLUME_DEVICE}

    # Remove existing fstab entries for this device.
    # TODO(tonyb): Should this be a pre-check and error rather than silently cleaning it up
    #              We could also add a flag to do this eg '--fstab-cleanup' or '--permissive'.
    #              This applies to othre scripts in this dir
    perl -nle "m,${VOLUME_DEVICE}, || print" -i /etc/fstab

    if [ ! -d "$VOLUME_MOUNT" ] ; then
        mkdir -p "$VOLUME_MOUNT"
    fi

    echo "${VOLUME_DEVICE}  ${VOLUME_MOUNT}  ext4  errors=remount-ro,barrier=0  0  2" >> /etc/fstab
done

exit 0