#! /bin/bash

# @file   update_install
# @author Nat Goodspeed
# @date   2013-01-09
# @brief  Update the containing Second Life application bundle to the version in
#         the specified tarball.
# 
#         This bash implementation is derived from the previous linux-updater.bin
#         application.
# 
# $LicenseInfo:firstyear=2013&license=viewerlgpl$
# Copyright (c) 2013, Linden Research, Inc.
# $/LicenseInfo$

tarball="$1"                        # the file to install
markerfile="$2"                     # create this file on failure
mandatory="$3"                      # what to write to markerfile on failure

function log {
    # our log file will be open as stderr -- but until we set up that
    # redirection, logging to stderr is better than nothing
    echo "$*" 1>&2
}

function status {
    log "$@"
    # Prefix with '#' so xmenity will recognize it as a status message
    echo "#$*"
}

function fail {
    # Log the message
    log "$@"
    # tell subsequent viewer things went south
    echo "$mandatory" > "$markerfile"
    # add boilerplate
    local msg="An error occurred while updating Second Life:
$*
Please download the latest viewer from www.secondlife.com."
    # Restate test from xmenity to detect whether we can use zenity or must
    # fall back to xmessage
    zenpath="$(which zenity)"
    if [ -n "$zenpath" -a -x "$zenpath" ]
    then "$zenpath" --error --title "Second Life Viewer Updater" \
                    --width=320 --height=120 --text="$msg"
    else xmessage -buttons -OK:2 -center "$msg"
    fi
    exit 1
}

function sudo_mv {
    # If we have write permission to both parent directories, shouldn't need
    # sudo.
    if [ -w "$(dirname "$1")" -a -w "$(dirname "$2")" ]
    then mv "$1" "$2" || fail "Couldn't move $1 to $2"
    else # use one of the likely sudo programs
         sudo="$(which gksudo)"
         if [ -z "$sudo" ]
         then sudo="$(which kdesu)"
         fi
         if [ -z "$sudo" ]
         then # couldn't find either one, just try it anyway
              mv "$1" "$2" || fail "Couldn't move $1 to $2"
         else # even with sudo, could fail, e.g. different filesystems
              "$sudo" mv "$1" "$2" || fail "Couldn't move $1 to $2"
         fi
    fi
}

# empty array
cleanups=()

function cleanup {
    # wacky bash syntax for appending to array
    cleanups[${#cleanups[*]}]="$*"
}

function onexit {
    for action in "${cleanups[@]}"
    do # don't quote, support actions consisting of multiple words
       $action
    done
}

trap 'onexit' EXIT

mydir="$(dirname "$0")"
# We happen to know that the viewer specifies a marker-file pathname within
# the logs directory.
logsdir="$(dirname "$markerfile")"
logname="$logsdir/updater.log"

# move aside old updater.log; we're about to create a new one
[ -f "$logname" ] && mv "$logname" "$logname.old"

# Set up redirections for this script such that stderr is logged, while
# special stdout messages drive our UI, as described in xmenity.
exec 2> "$logname" | "$mydir/xmenity"
# Piping to xmenity requires that we end with a line consisting of the string
# "100" to terminate zenity progress bar.
cleanup echo 100

# Rather than setting up a special pipeline to timestamp every line of stderr,
# produce header lines into log file indicating timestamp and the arguments
# with which we were invoked.
date 1>&2
log "$0 $*"

# Log every command we execute, along with any stderr it might produce
set -x

status 'Installing Second Life...'

# Creating tempdir under /tmp means it's possible that tempdir is on a
# different filesystem than INSTALL_DIR. One is tempted to create tempdir on a
# path derived from `dirname INSTALL_DIR`, but then we might need to add
# another sudo prompt to create it.
tempdir="/tmp/$(basename "$0").$$"
tempinstall="$tempdir/install"
mkdir -p "$tempinstall" || fail "Couldn't create $tempinstall"
cleanup rm -rf "$tempdir"

# If we already knew the name of the tarball's top-level directory, we could
# just move that when all was said and done. Since we don't, untarring to the
# 'install' subdir with --strip 1 effectively renames that top-level
# directory.
tar --strip 1 -xjf "$tarball" -C "$tempinstall" || fail "Untar command failed"

INSTALL_DIR="$(cd "$mydir/.." ; pwd)"

# Considering we're launched from a subdirectory of INSTALL_DIR, would be
# surprising if it did NOT already exist...
if [ -f "$INSTALL_DIR" ]
then backup="$INSTALL_DIR.backup"
     backupn=1
     while [ -f "$backup" ]
     do backup="$INSTALL_DIR.backup.$backupn"
        ((backupn += 1))
     done
     sudo_mv "$INSTALL_DIR" "$backup"
fi
# We unpacked the tarball into tempinstall. Move that.
sudo_mv "$tempinstall" "$INSTALL_DIR"

rm -f "$tarball"

# launch the updated viewer
"$INSTALL_DIR/secondlife" &