#!/bin/sh

# Copyright (c) 2000-2002 Timothy M. King (tmk@lordzork.com)
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the 
# Software is furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in 
# all copies or substantial portions of the Software. 
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL 
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
# DEALINGS IN THE SOFTWARE.

PATH=$PATH:/usr/bin:/usr/local/bin:/usr/X11R6/bin

img_apps="qiv xli xv wmsetbg Esetroot display xsetbg"

display_full_cmd="display -geometry 800x600 -window root"
display_tile_cmd="display -window root"
display_center_cmd="display -backdrop -window root"
display_default_cmd="$display_center_cmd"

Esetroot_full_cmd="Esetroot -scale"
Esetroot_tile_cmd="Esetroot"
Esetroot_center_cmd="Esetroot -c"
Esetroot_default_cmd="$Esetroot_center_cmd"

wmsetbg_full_cmd="wmsetbg -s -S"
wmsetbg_tile_cmd="wmsetbg -t"
wmsetbg_center_cmd="wmsetbg -e"
wmsetbg_default_cmd="$wmsetbg_center_cmd"

qiv_full_cmd="qiv --root_s"
qiv_tile_cmd="qiv --root_t"
qiv_center_cmd="qiv --root"
qiv_default_cmd="$qiv_center_cmd"

xv_full_cmd="xv -max -smooth -root -quit"
xv_tile_cmd="xv -root -quit"
xv_center_cmd="xv -rmode 5 -root -quit"
xv_default_cmd="$xv_center_cmd"

xli_full_cmd="xli -fullscreen -onroot -quiet"
xli_tile_cmd="xli -onroot -quiet"
xli_center_cmd="xli -center -onroot quiet"
xli_default_cmd="$xli_center_cmd"

xsetbg_full_cmd="xsetbg -fillscreen"
xsetbg_tile_cmd="xsetbg"
xsetbg_center_cmd="xsetbg -center"
xsetbg_default_cmd="$xsetbg_center_cmd"

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

me=${0##*/}
version=2.1
copyright="(c) 2000-$(date +%Y) by Timothy M. King (http://lordzork.com/)"
config=$HOME/.bsetbgrc
last_cmd_file=$HOME/.bsetbg_last_cmd
refresh_cmd=xrefresh
p=$me:

quit() 
{
	[ "$1" ] && rc=$1 && shift 1
	[ "$*" ] && echo -e $*
	exit ${rc:-0}
}

bool() 
{
	case $1 in
		[yY][eE][sS]|1|[yY]|[tT][rR][uU][eE]|[oO][nN]) : ;;
		*) return 1 ;;
	esac
}

check_exe_in_path() 
{
	if [ -z "$1" ]; then
    		return 1
	elif [ -x "$(which $1 2>/dev/null)" ]; then
    		return 0
	elif [ -x "$(type $1 2>/dev/null)" ]; then
    		return 0
	else
    		return 1
	fi
}

help_msg() 
{
	cat <<EOF
$me $version $copyright

  -center <file>           center an image on the desktop
  -tile <file>             tile an image on the desktop
  -full <file>             stretch an image to fill the desktop
  -exec <args> <file>      specify an external command to execute
  
  -post <string>           arguments to be passed to the post-command
  -debug                   prints commands without executing them
EOF

	# this is extremely lame, but probably more portable than grep -E   
	bsetroot_help=$(bsetroot -help  2>&1| grep -v "^bsetroot" | grep -v "^  -help")
	case $bsetroot_help in
   		BaseDisplay*)	echo ;;
		*-gradient*)	echo "$bsetroot_help"
	esac

	cat <<EOF
  -generate <string>       generate a config file
  -help                    this message
  -version                 output version information
EOF
	quit ${1:-0}
}

get_apps() 
{
	for a in $img_apps; do
    		if check_exe_in_path $a; then
			eval center_cmd=\$$a\_center_cmd
			eval full_cmd=\$$a\_full_cmd
			eval tile_cmd=\$$a\_tile_cmd
			eval default_cmd=\$$a\_default_cmd
			return 0
		else
			if [ "$not_found" ]; then
				not_found="$not_found $a"
			else
				not_found=$a
			fi
		fi
	done
	return 1
}

do_generate() 
{
	echo -e "# created by $me $version on $(date)\n#"
	echo -e "# seting NO_EXEC to a boolean value (eg true/false) will cause $me"
	echo -e "# to never modify the root window\n#"
	echo -e "#NO_EXEC=\n#"
	echo -e "# POST_COMMAND can be set to a command that will be run run every time"
	echo -e "# $me sets the root image\n#"
	echo -e "#POST_COMMAND=\n#"
	echo -e "# if LOG_LAST_CMD is set (boolean), bsetbg will keep a log of the last"
	echo -e "# two successful commands.\n#"
	echo -e "#LOG_LAST_CMD=\n#"
	echo -e "# the LOGFILE specifies the file that bsetbg uses when LOG_LAST_CMD"
	echo -e "# is defined. this defaults to ~/.bsetbg_last_cmd .\n#"
	echo -e "#LOGFILE=\n#"
	echo -e "# the following are default configuration values for the most popular image"
	echo -e "# programs. See the man page of the respective application for more info.\n" 

	[ "$*" ] && img_apps="$*"

	for a in $img_apps; do
    		if check_exe_in_path $a; then
			if ! bool $have_match; then
				q='\"'
				[ "$(eval echo \$$a\_center_cmd)" ] &&
				eval echo CENTER=$q\$$a\_center_cmd$q &&
			
				[ "$(eval echo \$$a\_full_cmd)" ] &&
				eval echo FULL=$q\$$a\_full_cmd$q &&
			
				[ "$(eval echo \$$a\_tile_cmd)" ] &&
				eval echo TILE=$q\$$a\_tile_cmd$q &&
			
				[ "$(eval echo \$$a\_default_cmd)" ] &&
				eval echo -e DEFAULT=$q\$$a\_default_cmd$q \\\\n &&
			
				have_match=1
			else
				[ "$(eval echo \$$a\_center_cmd)" ] && 
				eval echo \\#CENTER=$q\$$a\_center_cmd$q
			
				[ "$(eval echo \$$a\_full_cmd)" ] &&
				eval echo \\#FULL=$q\$$a\_full_cmd$q
			
				[ "$(eval echo \$$a\_tile_cmd)" ] &&
				eval echo \\#TILE=$q\$$a\_tile_cmd$q
			
				[ "$(eval echo \$$a\_default_cmd)" ] &&
				eval echo -e \\#DEFAULT=$q\$$a\_default_cmd$q \\\\n
			fi
		fi
	done
	quit 0
}

do_bsetroot() 
{
	if check_exe_in_path bsetroot; then
		read_config

		$debug bsetroot $* 2>/dev/null; rc=$?
		
		if [ "$rc" -gt 0 ]; then
			help_msg $rc
		else
			log_cmd bsetroot $*; $refresh_cmd 2>/dev/null
		fi
	else
    		quit 1 "couldn't find bsetroot in $PATH"
	fi
}

do_standard() 
{
	[ -z "$1" ] && help_msg 1

	bool $noconfig || read_config

	get_img_command $1
	check_img_command $do_this

	case $# in
    		1) file="$1" ;;
		*) file="$2"
	esac

	if [ -f "$file" ]; then
    		exec_img_command $do_this $file 
	else
    		quit 1 "$file does not exist"
	fi
} 

do_exec() 
{
	[ "$#" -lt 3 ] && help_msg 3

	bool $noconfig || read_config
    
	# check to see if -*c, -*f, or -*t were spcified, if so
	# assume the last argument is a filename
	b_arg=$(eval echo \$$(( $# - 1 )) )
	app=$1

	case $b_arg in
    		-c|*-center|c|-t|*-tile*|t|-f|*-full|f)
			eval file=\$$#
			f_args="$b_arg $file"
	esac

	# put the rest of the arguments into the varialbe $e_args
	while [ "$*" ]; do
    		for a in "$*"; do
    			case $1 in
				$b_arg|$file) : ;;
				*) e_args="$e_args "$1""
			esac
			shift 1
    		done
	done

	# with $f_args defined, check for image and do things normally
	if [ "$f_args" ]; then
		[ ! -f "$file" ] && quit 1 "$file does not exist"
	
		if check_img_command $e_args; then
    			do_this="$e_args"
    		else
			read_config
    			get_img_command $f_args
			check_img_command $do_this
			echo "$p couldn't find '$app' in path, using $type command instead"
    		fi
	# without $f_args, run the command blindly if it's in $PATH
	elif check_exe_in_path $e_args; then
    		do_this="$e_args"
	else
    		quit 1 "$p unable to run the following command: $e_args"
	fi

	exec_img_command $do_this $file
}    

get_img_command() 
{
	case $1 in
		*-full|-f|f)	type=full; do_this="$full_cmd" ;;
		*-tile|-t|t)	type=tile; do_this="$tile_cmd" ;;
		*-center|-c|c)	type=center; do_this="$center_cmd" ;;
		*)		type=default; do_this="$default_cmd"
	esac
}

check_img_command() 
{
	if check_exe_in_path $1; then
    		do_this="$*"
		rc=0
	elif get_apps; then
    		get_img_command $*
		rc=1
	else
		quit 1 "$p couldn't find a suitable image program. tried the following:\\n
		$(for a in $not_found; do echo "    $a\\n"; done)"
	fi

	if [ "$rc" -gt 0 -a -z "$e_args" ] && bool $read_config; then
    		echo "$p couldn't find a suitable $type command in $config"
	fi

    return $rc
}

exec_img_command() 
{
	unset rc
	command=$*

	if [ "$debug" ]; then
    		$debug $command
	else
    		$command >/dev/null 2>&1; rc=$?
	fi

	if [ "$rc" -gt 0 ]; then
    		echo "$p '$command' exited with status $rc"
		get_apps
		noconfig=1
		parse_args ${f_args:-$my_args}
		echo "$p using '$command' as $type"
		$debug $command >/dev/null 2>&1; rc=$?
		[ "$rc" =  0 ] && log_cmd $do_this $file && $refresh_cmd 2>/dev/null
	else
    		log_cmd $do_this $file; xrefresh 2>/dev/null
	fi
	return $rc
}

log_cmd() 
{
	bool $LOG_LAST_CMD || return 1
	[ "$debug" ] && return 1
	echo -e "$prev_cmd\n$*" >$last_cmd_file
	return $?
}

read_config() 
{
	[ -f $config ] || return 1

	if bool $read_config; then
		unset read_config
	else
		read_config=1
	fi

	. $HOME/.bsetbgrc 2>/dev/null
	check_no_exec

	full_cmd=$FULL
	center_cmd=$CENTER
	tile_cmd=$TILE
	default_cmd=$CENTER
	last_cmd_file=${LOGFILE:-$last_cmd_file}
    
	bool $LOG_LAST_CMD && prev_cmd=$(tail -n 1 $last_cmd_file 2>/dev/null)    
}

check_no_exec() 
{
	bool $NO_EXEC && 
	quit 0 "$p no_exec mode. the root window will not be modified."
}

post_command() 
{
	if [ -n "$POST_COMMAND" -a "$rc" -le 0 ]; then
		if [ -n "$debug" ]; then
			$debug "running post_command: $POST_COMMAND $post_args"
		else
			post_command_output=$($POST_COMMAND $post_args 2>&1); erc=$?
			if [ "$erc" -gt 0 ]; then
				echo "$p post-command '$POST_COMMAND $post_args' exited with status $erc"
				[ -n "$post_command_output" ] &&
					echo "$POST_COMMAND $post_args: $post_command_output"
			fi
		fi
	fi
}

add_arg() 
{
	[ "$1" ] || return 1
	if [ "$args" ]; then
    		args="$args $1"
	else
    		args=$1
	fi
}  

add_post_arg() 
{
	[ -z "$1" ] && return 1
	if [ "$post_args" ]; then
		post_args="$post_args $1"
	else
		post_args=$1
	fi
}

check_cmd() 
{
	if [ -z "$command" ]; then
		command=${2:-$1}; eval ${3:-${2:-$1}}=1
	elif bool $do_post; then
		add_post_arg ${1}
	else
		finished=1
	fi 
}

parse_args() 
{
	case $1 in
    		-d|*-debug|d)
			unset refresh_cmd; debug=echo\ $me\_debug: ;;

		-p|-*-post|p)			
			unset finished do_standard do_exec; do_post=1 ;;
				
		-c|*-center|c|-t|*-tile*|t|-f|*-full|f)
			case $command in
				do_standard|do_generate|do_bsetroot)
					finished=1 ;;
				do_exec)
					if ! bool $got_fcmd; then
						add_arg $1 args; got_fcmd=1
					else
						finished=1
					fi ;;
				*)	
					add_arg $1; do_standard=1; command=do_standard
			esac ;;		
		
		-a|*-app|a|-e|*-exec|e)
			check_cmd "do_exec" ;;
		
		-mod|-gradient|-solid|-display)
			check_cmd "do_bsetroot" && add_arg $1 ;;

		-g|*-generate*|g)
			check_cmd $1 "do_generate" ;;
		
		-v|*-version|v)
			[ -z "$command" ] && quit 0 $me $version $copyright ;;
		
		-h|*-help|h)
			[ -z "$command" ] && help_msg ;;
		
		*)	
			bool $finished && return 1		

			case $1 in -*)
				bool $do_exec || bool $do_bsetroot || bool $do_post || help_msg 1
			esac
		
			if bool $do_standard || bool $do_exec || bool $do_bsetroot || bool $do_generate; then
				add_arg $1
			elif bool $do_post; then
				add_post_arg $1
			else
				add_arg $1; command=do_standard; finished=1
			fi
	esac
}

[ -z "$*" ] && help_msg 1

my_args=$*

for arg in "$@"; do
	parse_args "$arg"
	shift 1
done

[ "$debug" ] && echo

$command $args
post_command $rc

quit $rc