#!/bin/bash
#
# esata
# Version: __appVersion__
#
# Add, remove, mount, and unmount external SATA drives

BASEDEV=/dev/sdc
PARTITION=2
MNT=/media/esata
# ----
DEV=${BASEDEV}${PARTITION}
DELAY=5

error_exit() {
    echo "$0: $1" >&2
    exit 1
}

have_root() {
    [ $(whoami) == "root" ] && return 0 || return 1
}

scsi_dev() {
    local d=$(basename "$BASEDEV")
    ls /sys/block/$d/device/scsi_disk | 2>/dev/null \
	sed -e "s/^\([0-9a-f]*\):.*$/\1/"
}

registered() {
    if [ -b "$BASEDEV" ]; then
	[ -n "$VERBOSE" ] && echo "registered"
	return 0
    else
	[ -n "$VERBOSE" ] && echo "not registered"
	return 1
    fi
}

partitioned() {
    if [ -b "$DEV" ]; then
	[ -n "$VERBOSE" ] && echo "partitioned"
	return 0
    else
	[ -n "$VERBOSE" ] && echo "not partitioned"
	return 1
    fi
}

mounted() {
    if mount | grep -q "$MNT"; then
	[ -n "$VERBOSE" ] && echo "mounted"
	return 0
    else
	[ -n "$VERBOSE" ] && echo "not mounted"
	return 1
    fi
}

doregister() {
    have_root || error_exit "need root privileges to register device"
    registered && return 0
    [ -n "$VERBOSE" ] && echo "register SATA device"
    scsiadd -a $(scsi_dev) 0 0 0 >/dev/null || return 1
    sleep $DELAY
    registered || return 1
    [ -n "$VERBOSE" ] && echo "register ok"
    return 0
}

domount() {
    have_root || error_exit "need root privileges to mount device"
    mounted && return 0
    doregister || return 1
    partitioned || return 1
    [ -n "$VERBOSE" ] && echo "mount SATA $DEV"
    mkdir -p "$MNT" || return 1
    mount "$DEV" "$MNT" || return 1
    [ -n "$VERBOSE" ] && echo "mount ok"
    return 0
}

dounregister() {
    have_root || error_exit "need root privileges to unregister device"
    registered || return 0
    [ -n "$VERBOSE" ] && echo "unregister SATA device"
    scsiadd -r $(scsi_dev) 0 0 0 >/dev/null || return 1
    sleep $DELAY
    registered && return 1
    [ -n "$VERBOSE" ] && echo "unregister ok"
    return 0
}

doumount() {
    if mounted; then
	have_root || error_exit "need root privileges to unmount device"
	[ -n "$VERBOSE" ] && echo "unmount SATA $DEV"
	umount "$MNT" || return 1
	mounted && return 1
	[ -n "$VERBOSE" ] && echo "unmount ok"
    fi
    dounregister || return 1
    return 0
}

# MAIN

unset VERBOSE
if [ "$1" = "-v" ]; then
    VERBOSE=1
    shift
fi
if [ "$1" = "mount" ]; then
    if domount; then
	echo "esata mounted on $MNT"
    else
	echo "$0: cannot mount esata" >&2
	dounregister
    fi
elif [ "$1" = "umount" -o "$1" = "unmount" ]; then
    if doumount; then
	echo "esata is unmounted"
    else
	error_exit "cannot unmount esata"
    fi
elif [ "$1" = "register" ]; then
    if doregister; then
	echo "esata drive registered as $BASEDEV"
	partitioned || echo "WARNING: drive is not partitioned"
    else
	error_exit "cannot register esata"
    fi
elif [ "$1" = "status" ]; then
    if mounted; then
	echo "esata mounted on $MNT"
    elif registered; then
	echo "esata registered as $BASEDEV but not mounted"
	partitioned || echo "WARNING: drive is not partitioned"
    else
	echo "esata is unregistered"
    fi
    #mount | grep "$DEV"
    #scsiadd -p | grep "scsi1"
else
    echo "usage: $0 [-v] <mount|umount|register|status>"
fi
exit 0