#!/bin/sh

# startx configuration file.

# Copyright (C) 2011-2013  Simon Ruderich
#
# 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 3 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, see <http://www.gnu.org/licenses/>.


# Some systems don't set the LANG environment variable when starting xinitrc,
# this causes problems for rxvt-unicode-256color which fails to display UTF-8
# characters correctly when LANG is missing and for notify.py which also needs
# LANG set (for Python's decode() function). Therefore load my general shell
# environment which also includes $LANG.
if test -f "$HOME/.shell/env"; then
    # Debug function used in ~/.shell/env.
    source_debug() {
        # Do nothing.
        :
    }

    . "$HOME/.shell/env"
fi


installed() {
    type "$1" >/dev/null 2>&1
}
error() {
    if installed xmessage; then
        xmessage "$@" &
    else
        # Log message to a file which is displayed by my Zsh setup on startup.
        printf '%s\n' "$*" >>"$HOME/.xinitrc.errors"
    fi
}
# Save PID of the most recently started background process. Used to terminate
# them when logging out to prevent unused background processes. On some
# systems this is only necessary for some programs (like ssh-agent), haven't
# yet figured out why.
save_background_pid() {
    background_pids="$background_pids $!"
}
background_pids=


# Options, can be modified in ~/.xinitrc.local. To disable a boolean option
# set it to an empty value.
#
# Default to use a background image.
set_background=yes
# Default to display a warning if `xautolock` is not available.
screen_lock_force=yes
# Lock screen after x minutes of inactivity, requires `xautolock` to be
# installed.
screen_lock_time=3
# Locker program to lock the screen, used below with `xautolock`.
screen_locker=xtrlock

# Load settings for the local system.
if test -f "$HOME/.xinitrc.local"; then
    . "$HOME/.xinitrc.local"
fi


# Start ssh-agent if no agent is running and we have private keys, thanks to
# http://code.haskell.org/XMonadContrib/scripts/xinitrc (read on 2011-06-19).
if test -z "$SSH_AGENT_PID" \
        && test -x /usr/bin/ssh-agent \
        && test -f "$HOME/.ssh/id_rsa"; then
    # -s to force bourne shell output. This file is a bourne shell script even
    # if the environment might suggest otherwise.
    eval `/usr/bin/ssh-agent -s` >/dev/null
fi

# Use a black background for the root window.
xsetroot -solid black

# Force English keyboard layout.
if installed setxkbmap; then
    setxkbmap us
fi

# Use the Caps lock as Ctrl because it's easier to reach and very useful for
# all programs. Caps lock is removed completely. Thanks to
# http://snarfed.org/space/switch%20control%20and%20caps%20lock
if xmodmap | grep -E '^lock.*Caps_Lock' >/dev/null; then
    xmodmap -e 'remove Lock = Caps_Lock'
    xmodmap -e 'remove Control = Control_L'
    xmodmap -e 'keysym Caps_Lock = Control_L'
    xmodmap -e 'add Control = Control_L'
fi
# Move grave and tilde next to left shift key. This setting may only be
# necessary because of my German keyboard which I use with English settings.
xmodmap -e 'keycode 94 = grave asciitilde'

# Disable annoying audio bell. Thanks to Sebastian Rachuj.
xset b off

# Change the background if available.
if test -f "$HOME/.background" && test -n "$set_background"; then
    if installed hsetroot; then
        hsetroot -full "$HOME/.background"
    elif installed feh; then
        feh --bg-scale "$HOME/.background"
        # Remove the unnecessary ~/.fehbg file created by `feh`. I don't want
        # to restore the background, I just run `feh` on each startx run.
        # --no-fehbg is only available in recent feh releases.
        rm -f "$HOME/.fehbg"
    fi
fi

# Display timed reminders and recheck the file for changes every minute (-z1).
if installed remind && test -f "$HOME/.reminders"; then
    remind -z1 -k'.shell/bin/notify.py %s &' "$HOME/.reminders" &
    save_background_pid
fi

# Set color temperature of display according to time of day.
if installed redshift; then
    redshift -l 49.9:10.9 -t 5500:4500 >/dev/null &
fi

# Automatically lock the screen after x minutes of inactivity if `xautolock`
# is available. Warn if locker wasn't found.
if installed xautolock; then
    if installed "$screen_locker"; then
        xautolock -secure -time "$screen_lock_time" -locker "$screen_locker" &
    else
        error "Locker '$screen_locker' not installed. Auto lock won't work!"
    fi
elif test -n "$screen_lock_force"; then
    error "'xautolock' not found. Auto lock won't work!"
fi


# XMonad doesn't start a terminal emulator on its own, start one when I login.
(urxvt || rxvt || xterm) &

# Start window manager.
xmonad


# Cleanup.
#
# Kill ssh-agent to prevent unused background processes.
if test -x /usr/bin/ssh-agent; then
    /usr/bin/ssh-agent -k >/dev/null
    # No `eval` necessary, we terminate anyway.
fi
# Kill remaining background processes.
kill $background_pids