#!/usr/bin/env bash
#----------------------------------------------------------------------

CMD="$0 $@"

SCRIPT_NAME=$(basename $0)

printusage(){
	echo "Usage:"
	echo "  $SCRIPT_NAME [OPTIONS] [[INPUT] OUTPUT]"
}

printhelp(){
	echo "Generate docs from latex package/class"
	echo
	printusage
	echo
	echo "Options:"
	echo "  -h | --help         Show this message and exit"
	echo "  -p | --prefix PREFIX"
	echo "                      Set the doc comment PREFIX (default: \"%\")"
	echo "  -s | --strip        Strip docs out"
	echo "  -n | --no-msg       Don't add the \"generated with\" message to output"
	echo
	echo "This will:"
	echo "  - read the INPUT"
	echo "  - keep lines starting with \\def\\<module-name>@[A-Z]\\+"
	echo "  - keep lines starting with '%%'"
	echo "  - %%%%% Text -> \\subsection{Text}"
	echo "  - %%%% Text -> \\section{Text}"
	echo "  - %% >> code -> \\begin{verbatim}code\\end{verbatim}"
	echo "  - write the result to OUTPUT"
	echo
	echo "If no OUTPUT is given $SCRIPT_NAME will write to stdout. If no INPUT"
	echo "is given $SCRIPT_NAME will read stdin."
	echo
	echo "PREFIX can replace the second \"%\" in the above patterns to make it"
	echo "possible to integrate multiple layers of documentation in one file"
	echo "and to integrate them in various ways, for example, in the photobook"
	echo "document class documentation \"M\" prefix is used to indicate"
	echo "meta-command docs, this enables us to document them in the relevant"
	echo "location (i.e. at the implementation) in source but move the docs to"
	echo "a unified location in docs, effectively decoupling the source and doc"
	echo "structure when needed."
	echo
	echo "Strip mode is the reverse of of the default, it will strip out docs"
	echo "and empty lines, keeping only the actual code and code comments."
	echo
	echo "NOTE: stripping will not remove non-doc comments."
	echo "NOTE: the idea of keeping latex docs in a latex file is far simpler"
	echo "      than all the stuff crammed into .dtx, at least for my needs:"
	echo "          - keep the code readable"
	echo "          - keep the docs readable"
	echo "      in both the repo and in installed form, so .dtx is not used."
}

# Usage: printmsg TEXT
printmsg(){
	# print message...
	if [ -z $NO_MSG ] ; then 
		echo "%----------------------------------------------------------------------"
		echo "% $1 file generated by:" 
		echo "%    $CMD"
		echo "% NOTE: multiple messages indicate multiple runs."
		echo "%----------------------------------------------------------------------"
	fi
}



#----------------------------------------------------------------------
# Args and defaults...

PREFIX=%

while true ; do
	case $1 in
		-h|--help)
			printhelp
			exit
			;;
		-p|--prefix)
			PREFIX=$2
			shift 2
			continue
			;;
		-s|--strip)
			STRIP_DOC=1
			shift
			continue
			;;
		-n|--no-msg)
			NO_MSG=1
			shift
			continue
			;;

		# handle unknown options...
		-*|--*)
			echo "Error: unknown option: \"$1\"" >&2
			exit
			;;

		# non-flag, option parsing done...
		*)
			break
			;;
	esac
done

INPUT=${1:-/dev/stdin}

OUTPUT=${2:-/dev/stdout}


# generate the module name...
MODULE=$(basename "$INPUT")
MODULE=${MODULE/.*/}


#----------------------------------------------------------------------
# do the work...

# make docs...
if [ -z $STRIP_DOC ] ; then
	printmsg "Documentation" \
		> "$OUTPUT"
	cat "$INPUT" \
		| grep -E '(^%'$PREFIX'|^\\edef\\'$MODULE'@[A-Z][A-Z]+)' \
		| sed \
			-e 's/^\(\\edef\\\)'$MODULE'@/%'$PREFIX'\1/' \
			-e 's/%'$PREFIX'%%%% \(.*\)/%'$PREFIX'\\subsubsection{\1}\\label{subsubsec:\1}/' \
			-e 's/%'$PREFIX'%%% \(.*\)/%'$PREFIX'\\subsection{\1}\\label{subsec:\1}/' \
			-e 's/%'$PREFIX'%% \(.*\)/%'$PREFIX'\\section{\1}\\label{sec:\1}/' \
			-e 's/%'$PREFIX'\s\+>>\s\+\(.*\)/%'$PREFIX'\\begin{verbatim} \1 \\end{verbatim}/' \
		| cut -c 3- - \
		>> "$OUTPUT"

# make stripped code...
else
	printmsg "Stripped code" \
		> "$OUTPUT"
	cat "$INPUT" \
		| grep -Ev '%'$PREFIX'' \
		| grep -Ev '^(\s*%)?\s*$' \
		>> "$OUTPUT"
fi



#----------------------------------------------------------------------
#                                            vim:set ts=4 sw=4 nowrap :