#!/bin/bash
#
#   CDM: The Console Display Manager
#
#   Copyright (C) 2009-2011, Daniel J Griffiths <ghost1227@archlinux.us>
#   Thanks to:
#
#       Andrwe          beta-testing and submitting the fix for the all
#                       important X incrementation function
#       brisbin33       code cleanup
#       tigrmesh        finding a critical issue with the gnome-session handler
#       Profjim         several incredibly useful patches
#       lambchops468    consolekit and hibernation patches
#       CasperVector    Massive rearchitecturing and code sanisation
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#   
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#   
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#   MA 02110-1301, USA.

name=$(basename "$0")
longname='Console Display Manager'
ver='0.6'

trap '' SIGINT SIGTSTP
source /etc/init.d/functions.sh

# Exit functions.

exitnormal() { exit 0; }
exiterror() { sleep 1; exit 1; }

# Source cdm configurations.

if [[ -n "$1" ]]; then
	if [[ -f "$HOME/.cdmrc" ]]
	then
		source "$1"
	else
		eerror "$self: config file \`$1' does not exist."
		exiterror
	fi
elif [[ -f "$HOME/.cdmrc" ]]; then
	source "$HOME/.cdmrc"
elif [[ -f /etc/cdmrc ]]; then
	source /etc/cdmrc
fi

# Default options.

dialogrc=${dialogrc:-}
countfrom=${countfrom:-0}
binlist=${binlist:-()}
namelist=${namelist:-()}
xtty=${xtty:-7}
locktty=${locktty:-no}
display=${display:-0}
consolekit=${consolekit:-yes}
cktimeout=${cktimeout:-30}
serverargs=${serverargs:-'-nolisten tcp'}

# Offer all available sessions in /etc/X11/Sessions,
# if binlist if not explicitly set in cdmrc.

if [[ "${#binlist[@]}" == 0 ]]; then
	binlist=($(ls /etc/X11/Sessions))
	flaglist=($(sed 's/[[:digit:]]\+/X/g' <<< ${!flaglist[*]}))
	namelist=(${binlist[@]^})
fi

# Generate the main menu.
menu=()
for ((count=0; count<${#namelist[@]}; count++)); do
	menu=("${menu[@]}" "$((count+countfrom))" "${namelist[${count}]}")
done

# Override dialog display if only one option is available.
if [[ "$count" == 1 ]]; then
	binindex=0
else
	# Display selection dialog.
	binindex=$(
		DIALOGRC="$dialogrc" dialog --colors --stdout \
		--backtitle "${longname} v${ver}" \
		--ok-label ' Select ' --cancel-label ' Exit ' \
		--menu 'Select session' 0 0 0 "${menu[@]}"
	)
	if [[ $? != 0 ]]; then
		clear
		exitnormal
	fi
fi

# Run $bin according to its flag.
let binindex-=countfrom
bin="${binlist[${binindex}]}"
case ${flaglist[$binindex]} in
	# *C*onsole programs.
	[Cc])
		clear
		# If $bin is a login shell, it might `exec' cdm again, causing an endless
		# loop. To solve this problem, export $CDM_SPAWN when `exec'ing $bin and
		# only let the shell automatically `exec' cdm when $CDM_SPAWN is not set.
		# See also the example shell profile file shipped with this cdm package.
		CDM_SPAWN=$$ exec $bin
		;;

	# *X* programs.
	[Xx])
		clear

		# If X is already running and locktty=yes, activate it,
		# otherwise increment.
		if $(yesno locktty); then
			# Activate existing X session.
			if xdpyinfo -display ":$display.0" &> /dev/null; then
				chvt "$((display+xtty))"
				exitnormal
			fi
		else
			# Get the first empty display.
			display=0
			while [[ "$display" < 7 ]]; do
				if dpyinfo=$(xdpyinfo -display ":$display.0" 2>&1 1>/dev/null) ||
					# Display is in use by another user.
					[[ "$dpyinfo" == 'No protocol specified'* ]]
				then
					let display+=1
				else
					break
				fi
			done
		fi
		serverargs=":${display} $serverargs vt$((xtty+display))"

		$(yesno consolekit) && launchflags="-c -t $cktimeout"
		if ! eval cdm-xlaunch $launchflags -- $bin -- $serverargs; then
			ewarn "$self: \`cdm-xlaunch' exited unsuccessfully."
			exiterror
		fi
		;;

	*)
		eerror "$self: unknown flag: \`${flaglist[$binindex]}'."
		exiterror
		;;
esac