#!/bin/sh

#  cfg_update.sh 0.0.1, (c) 2008 by Patrick Boylan
#
#  You can modify, redistribute, and pretty much do whatever you want
#  with this script under the terms of the GNU General Public License,
#  Version 2, or the new one if you prefer.  If you didn't get a copy of
#  the GNU GPL with this program, look in /usr/share/common-licenses/ on
#  Debian-based systems, or http://gnu.org/licenses/gpl-2.0.txt .  If
#  the URL should fail for some reason, they have a search engine.
#
#  This script was written to address a minor pet peeve of mine, with
#  relation to updating Lynx.  The install-cfg.sh script [part of the
#  Lynx sources] will preserve your old settings by appending them to
#  the new lynx.cfg .  This is good, but then they're out of context.
#  It could also cause problems for some, because the *last* occurrence
#  of a given setting will take precedence, so if you change something
#  in the body of the file, another, conflicting item appended to the
#  end may still override it.
#
#  This script [tries to] interleave your old settings with the relevant
#  comments in the new file.  `Orphaned' settings are still appended to
#  the end, if it can't find a proper context for them.
#
#  However, this IS NOT a drop-in replacement for install-cfg.sh , which
#  accepts different command-line options, does some filtering for dead
#  URLs [mine doesn't], and plays nicely with the makefile [wrt the
#  HELPFILE setting in particular].


#  CHANGES:
#     0.0.1 * I think it works, but please let me know if it doesn't...
#
#             Lynxcookie-sneaking(a)sneakEmail,com
#             [but fix the (a) and the comma first]


nom="$(basename "$0")"
tmp1="cfg_update_tmp"

how2 () {
echo "
Usage: $nom /path/to/old/lynx.cfg ./new/lynx.cfg [output file | dir]

   Import settings from your old lynx.cfg file to a newer one.

   If no output path is specified, a file named \`lynx.cfg[.N]' will be
   created in the current directory.  The script *will_not* overwrite
   any existing file unless explicitly told to do so.  A number will be
   appended to the name if a file named \`lynx.cfg' already exists in
   the specified location [and if an output directory, not filename
   is specified].

   Any pathname may be relative or absolute, but the output directory
   must already exist.

   You should use the unmodified lynx.cfg included in the Lynx sources
   as your \`/path/to/new/lynx.cfg', because the updated one will already
   have your old settings appended to it.  That one can be used as your
   \`/path/to/old/lynx.cfg' though [because it already has your old
   settings appended to it].
"
}

if [ "$1" = "" ] || [ "$1" = "-h" ] || [ "$1" = "-help" ] || [ "$1" = "--help" ]
then
	how2
	exit 0
fi

if [ -f "$1" ]
then
	old_cfg="$1"
else
	echo "\nError: \`$1' is not a file."
	how2
	exit 1
fi

if [ -f "$2" ]
then
	new_cfg="$2"
else
	echo "\nError: \`$2' is not a file."
	how2
	exit 1
fi
#  Some half-hearted idiot-proofing.


if [ "$3" = "" ]
then
	out_cfg="`pwd`"
else
	out_cfg="$3"
fi

if [ -e "$out_cfg" ]
then
	if [ -f "$out_cfg" ]
	then
		echo "Replacing \`$out_cfg'..."

	elif [ -d "$out_cfg" ]
	then
		out_cfg="$out_cfg/lynx.cfg"
		tmp_cfg="$out_cfg"
		num=0

		while [ -e "$tmp_cfg" ]
		do
			tmp_cfg="${out_cfg}.$num"
			num=$(($num + 1))
		done
		out_cfg="$tmp_cfg"

		echo "Output to file \`$out_cfg'...'"
	else
		echo "\nError: \`$out_cfg' exists, and is not a regular file."
		how2
		exit 1
	fi

elif [ ! -d "$(dirname "$out_cfg")" ]
then
	echo "\nError: Parent directory must exist!"
	how2
	exit 1
else
	echo "Output to file \`$out_cfg'...'"
fi
#  Not so half-hearted I guess...


old_cfg="$(cat "$old_cfg" | grep "^[ 	]*[A-Za-z]")"
#  Extract active configuration lines from old lynx.cfg .

if [ "$old_cfg" = "" ]
then
	echo "\`$1' has no settings to save!"
	exit
else
	echo "Loaded settings from \`$1'..."
fi


oldIFS="$IFS"
IFS='
'
seek_cfg=''
for line in $old_cfg
do
	seek_cfg="$seek_cfg$(echo $line | cut --delimiter=':' --fields=1)\n"
	#  Extract only the variable, not its definition.
done
seek_cfg="$(echo -n "$seek_cfg" | sort -u)"
#  Remove duplicates; they'll only slow you down later.

grep_cfg="$(echo -n "$seek_cfg" | tr '\n' '|')"
IFS="$oldIFS"


tmp1="$(dirname "$out_cfg")/$tmp1"
tmp2="$tmp1"
num=0
while [ -e "$tmp2" ]
do
	tmp2="${tmp1}.$num"
	num=$(($num + 1))
	#  Make sure the temp directory does not already
	#  exist, because it will be deleted later.
done
tmp1="$tmp2"
mkdir "$tmp1"

echo "Using temp directory \`$tmp1'..."


echo "Splitting \`$new_cfg' on blank lines..."
csplit --quiet --digits=6 --prefix="$tmp1/cfg" "$new_cfg" '/^$/' '{*}'


echo "Matching old settings to new sections...\n"

for phile in $(find "$tmp1" -type f | sort -r)
do
	this_cfg="$(cat "$phile")"
	if [ "$(echo "$this_cfg" | grep "^[# 	]*[A-Za-z]" | \
		egrep "$grep_cfg")" != "" ]
	then
		for sought in $seek_cfg
		do
			if [ "$(echo "$this_cfg" | grep "^[#]*$sought:")" != "" ]
			then
				echo "Found  $sought"

				echo "$old_cfg" | grep "^[ 	]*$sought" \
				>> "$phile"

				#  Drop this item from your search
				#  lists, because it's been found.
				#
				old_cfg="$(echo -n "$old_cfg" | \
					grep -v "^[ 	]*$sought")"
				seek_cfg="$(echo -n "$seek_cfg" | \
					grep -v "^$sought$")"
				grep_cfg="$(echo -n "$seek_cfg" | \
					tr '|' '\n' | \
					grep -v "^$sought$")"
				grep_cfg="$(echo -n "$seek_cfg" | tr '\n' '|')"
			fi
		done
	fi
done

cat $(find "$tmp1" -type f | sort) > "$out_cfg"

echo "\nRemoving temp-files, \`$tmp1'."
rm -rf "$tmp1"

if [ "$(echo -n "$old_cfg")" != "" ]
then
	{
	echo
	echo "## The following lines were saved from your previous configuration:"
	echo "#"
	echo "$old_cfg"
	} >> "$out_cfg"

	echo "\n...Had a few pieces left over (orphaned settings)..."
	echo "\n$old_cfg"
	echo "\nAppended to end of file."
fi

echo "Done."

#  Also dedicated to the memory of Cheetah the cat, but I don't want
#  to go all sentimental about it here.  I think I'm getting better at
#  writing these things without her.