#!/bin/bash

ME=$(basename $0);

set -o pipefail;

function show_help()
{
    usage_banner;
    cat <<EOF

Usage:  $ME [-h] [-t FSTYPE] DEVICE

Prepare DEVICE to be used in volumes.
DEVICE is the special file corresponding to the
device (e.g /dev/sdXX).

General:
  -t FSTYPE                 Prepare DEVICE using FSTYPE filesystem.
                            Supported filesystems are ext3/ext4/xfs
                            (Default is ext4/ext3)

Miscellaneous:
  -h                        display this help and exit

Example:
  $ME /dev/sdb
  $ME -t xfs /dev/sdb
EOF
}


function usage_banner()
{
    echo "Gluster Storage Virtual Appliance, Version 1.2."
}

function fail()
{
    echo "$ME: FATAL: $@"
    exit 1;
}


function main()
{
    # Parse command line arguments.
    while getopts :ht: OPT; do
	case "$OPT" in
	    h)
		show_help
		exit 0
		;;
	    t)
		fstype=$OPTARG
		case $fstype in
		    ext3 | ext4 | xfs)
			;;
		    *)
			echo "unknown fstype $fstype"
			show_help
			exit 1
			;;
		esac
		;;
	    \?)
                # getopts issues an error message
		echo "Invalid option: -$OPTARG"
		show_help
		exit 1
		;;
	    :)
		echo "Option -$OPTARG requires an argument."
		show_help
		exit 1
		;;
	esac
    done

    # Remove the switches we parsed above.
    shift `expr $OPTIND - 1`

    # We want only one non-option argument.
    if [ $# -ne 1 ]; then
	show_help
	exit 1
    fi

    if [ -z "$fstype" ]; then
	if [ -x /sbin/mkfs.ext4 ]; then
	    fstype=ext4
	elif [ -x /sbin/mkfs.ext3 ]; then
	    fstype=ext3
	else
	    fail "neither ext4 nor ext3 support available (or mkfs tools not present)"
	fi
    fi

    set -e;

    devblk="$1";
    blk=$(echo $1 | cut -f3 -d/);
    mnt="/export/$blk";

    [ -e $mnt ] || mkdir -p $mnt

    [ -b $devblk ] || fail "$devblk is not a valid block device";

    [ -d $mnt ] || fail "$mnt is not a directory";

    grep -wq $blk /proc/partitions || fail "$blk is not detected in /proc/partitions";

    blkid -c /dev/null | grep -q "^$devblk:" && fail "$devblk is already formatted";

    grep -q " $mnt " /proc/mounts && fail "$mnt already has a mount";
    grep -q " $mnt/" /proc/mounts && fail "$mnt has a submount";

    grep -q " $mnt " /etc/fstab && fail "$mnt already has an entry in fstab";

    grep -wq "$devblk" /etc/fstab && fail "$devblk already has an entry in fstab";

    if [ ! -x /sbin/mkfs.$fstype ]; then
	fail "no $fstype support available"
    fi

    case $fstype in
	ext3 | ext4)
	    /sbin/mkfs.$fstype -I 512 $devblk;
	    ;;
	xfs)
	    /sbin/mkfs.$fstype -i size=512 $devblk
	    ;;
    esac

    uuid=$(blkid -c /dev/null -o value $devblk | head -1); #sed -n 's/ID_FS_UUID=//p');

    grep -wq "$uuid" /etc/fstab && fail "$uuid already has an entry in fstab";

    case $fstype in
	ext3 | ext4)
	    echo "UUID=$uuid $mnt $fstype defaults,user_xattr 0 2" >> /etc/fstab || fail "Failed to update fstab";
	    ;;
	*)
	    echo "UUID=$uuid $mnt $fstype defaults 0 2" >> /etc/fstab || fail "Failed to update fstab";
	    ;;
    esac

    mount -v $mnt || fail "mounting $devblk on $mnt failed";

cat <<EOF

================================================================================
Completed mounting and setting up fstab for $devblk on $mnt

You may now expand existing volumes or create new volumes with commands like:

  sh# gluster volume create VOLNAME $(hostname):$mnt/SUBDIR" ...

  or

  sh# gluster volume add-brick VOLNAME $(hostname):$mnt/SUBDIR ...

Please refer documentation at http://www.gluster.com/community/documentation/
for the exact syntax and reference.

================================================================================
EOF
}


main "$@";