#!/bin/bash
#
# RunWM - this is a script used to launch window managers
#
#

WM_CHOICE=
KNOW_WM="no"

if [ -n "$1" ] ; then
    case "$1" in
    --afterstep | --AfterStep | \
    --windowmaker | --wmaker | --WindowMaker | \
    --fvwm95 | --Fvwm95 | \
    --fvwmMWM | --fvwmmwm | \
    --MWM | --Mwm | --mwm )
	KNOW_WM="yes"
	WM_CHOICE=$1
	shift
	;;
    --help)
	echo "Usage: $0 [window_manager] where window_manager can be"
	echo "  --AfterStep     start Afterstep"
	echo "  --WindowMaker   start WindowMaker"
	echo "  --Fvwm95        start Fvwm2 with '95 interface"
	echo "  --FvwmMWM       start Fvwm2 with MWM interface"
	echo
	exit 0
	;;
    *)
	KNOW_WM="no"
	WM_CHOICE=
	;;
    esac
fi

# Now, some braindead window managers don't know how to pass arguments to another
# wm when doing a Restart... (fvwm2 is one of them)

if [ -z "$WM_CHOICE" ] ; then
    #try to see if we are called funny names...
    case "$0" in 
	*RunWM.Fvwm95)
	    WM_CHOICE="--Fvwm95"
	    KNOW_WM="yes"
	    ;;
	*RunWM.MWM)
	    WM_CHOICE="--FvwmMWM"
	    KNOW_WM="yes"
	    ;;
	*RunWM.AfterStep)
	    WM_CHOICE="--AfterStep"
	    KNOW_WM="yes"
	    ;;
	*RunWM.WindowMaker)
	    WM_CHOICE="--WindowMaker"
	    KNOW_WM="yes"
	    ;;
    esac
fi

if [ "$KNOW_WM" = "no" ] ; then
    if [ -f $HOME/.wm_style ] ; then
	WM_CHOICE="--$(cat $HOME/.wm_style)"
    else
	WM_CHOICE="--Fvwm95"
    fi
fi

############### FUNCTIONS FOR WINDOW MANAGERS ############################
#
###
#

function Start_Fvwm95 () {
    local RCFILE
    local FVWMOPTIONS
    local FVWMVER
    # first, find an M4-enabled config file (such as 
    # the one from AnotherLevel) for fvwm2 or fvwm95.
    RCFILE=""
    for tryfile in "$HOME/.fvwm2rc.m4" \
		   "/etc/X11/AnotherLevel/fvwm2rc.m4"; do
	if [ -f "$tryfile" ]; then
	    RCFILE="$tryfile"
	    break
	fi
    done

    # if it really exists, use it; if not, fvwm2 or fvwm95 will
    # automagically look for a config file in the regular places.
    if [ -n "$RCFILE" ]; then
	FVWMOPTIONS="-cmd 'FvwmM4 -debug $RCFILE'"
    else
	FVWMOPTIONS=""
    fi

    # TheNextLevel is supposed to work with both fvwm95 and fvwm2
    for FVWMVER in 2 95 95-2; do
	if [ -n "$(type -path fvwm${FVWMVER})" ]; then
	    env > "$HOME"/Xrootenv.0
	    # if this works, we stop here
	    eval "exec fvwm${FVWMVER} ${FVWMOPTIONS}" > "$HOME"/.FVWM${FVWMVER}-errors 2>&1
	fi
    done
    cat >&2 <<EOF
 WARNING: You selected Fvwm2 as your window manager, but your installation
 does not appear to be functional. The executable /usr/bin/fvwm2 was 
 not found on your system.
EOF
    echo "RESUMING with TWM..." >&2
    xvt &
    eval "exec twm" > $HOME/.TWM-errors 2>&1
}

#
###
#

function Start_AfterStep () {
# we have to start up afterstep
  if [ -x /usr/bin/afterstep ] ; then
    mkdir -p $HOME/GNUstep/Library/AfterStep
    wmconfig --output=afterstep --directories  2>/dev/null
    env > "$HOME"/Xrootenv.0
    # if this works, we stop here
    eval "exec /usr/bin/afterstep" > "$HOME"/.AfterStep-errors 2>&1
  else
    cat <<EOF
 WARNING: You selected AfterStep as your window manager, but your installation
 of AfterStep does not appear to be functional. Either /usr/bin/afterstep
 was not found or /usr/share/afterstep directory is incomplete.
EOF
  fi
    echo "RESUMING with Fvwm2 (95 look)" >&2
    Start_Fvwm95
}

#
###
#

function Start_WindowMaker () {
  if [ -x /usr/bin/wmaker.inst -a -d /usr/share/WindowMaker ] ; then
    [ -d $HOME/GNUstep ] || /usr/bin/wmaker.inst --batch
    env > "$HOME"/Xrootenv.0
    eval "exec /usr/bin/wmaker" > "$HOME"/.WindowMaker-errors 2>&1
  else
    cat <<EOF
 WARNING: You selected WindowMaker as your window manager, but your
 installation of WindowMaker does not appear to be functional. Either
 /usr/bin/wmaker was not found or /usr/share/WindowMaker directory
 is missing.
EOF
  fi
    echo "RESUMING with Fvwm2 (95 look)" >&2
    Start_Fvwm95
}

#
###
#

# there is not really any difference between this and the previous one
# but we stay prepared... :-)
function Start_MWM () {
    Start_Fvwm95 $*
}

##############################################################################

################### THE REAL WORK IS DNE HERE ################################
case "$WM_CHOICE" in
    --afterstep | --AfterStep)
	echo "AfterStep" > $HOME/.wm_style
	Start_AfterStep
	exit 0;
	;;
    --windowmaker | --wmaker | --WindowMaker)
	echo "WindowMaker" > $HOME/.wm_style
	Start_WindowMaker
	exit 0;
	;;
    --fvwm95 | --Fvwm95)
	echo "Fvwm95" > $HOME/.wm_style
	Start_Fvwm95
	exit 0
	;;
    --MWM | --Mwm | --mwm | \
    --FvwmMWM | --fvwmmwm)
	echo "MWM" > $HOME/.wm_style
	Start_MWM
	exit 0;
	;;
    *)
	echo "This window manager ($WM_CHOICE) is unknown to me."
	$0 --help
	exit -1
	;;
esac

if [ "$KNOWN_WM" = "yes" ] ; then
cat <<EOF

    The window manager you have requested ($WM_CHOICE) could not be started.
EOF
else
cat <<EOF

    The default window manager ($WM_CHOICE) could not be started. You have
    selected this window manager in your $HOME/.wm_style file or it was
    selected as the default window manager by the system administrator.
EOF
fi
cat <<EOF
    Check your settings and try again.
EOF

exit -1;
################# This is it #########################