#!/usr/bin/env bash

# Receivers, filters, writers are called "modules" in this script
print_modhelp()
{
	local ggo="$1"

	$GENGETOPT --show-detailed-help \
		--set-version "" \
		--set-package "" \
		< "$ggo" | awk 'BEGIN {
			have_purpose=0
			have_usage=0
		} {
			if (!have_purpose) {
				if ($0 ~ /^ *$/)
					next
				printf(" (%s):", $0)
				have_purpose=1
				next
			}
			if (!have_usage) {
				if ($0 ~ /^Usage: /) {
					have_usage=1
				}
				next
			}
			print $0
		}'
}

make_help()
{
	local target="$1" module ggo

	ggo="$GGO_DIR/$1.ggo"
	$GENGETOPT --show-detailed-help \
		--set-version "$VERSION" \
		--set-package "para_$1" \
		< "$ggo"

	if [[ "$target" == 'recv' || "$target" == 'audiod' ]]; then
		for module in $RECEIVERS; do
			ggo="$GGO_DIR/${module}_recv.ggo"
			[[ ! -f "$ggo" ]] && continue
			printf "\nOptions for the $module receiver"
			print_modhelp "$ggo"
		done
	fi
	if [[ "$target" == 'filter' || "$target" == 'audiod' ]]; then
		for module in $FILTERS; do
			ggo="$GGO_DIR/${module}_filter.ggo"
			[[ ! -f "$ggo" ]] && continue
			printf "\nOptions for the $module filter"
			print_modhelp "$ggo"
		done
	fi
	if [[ "$target" == 'write' || "$target" == 'audiod' ]]; then
		for module in $WRITERS; do
			ggo="$GGO_DIR/${module}_write.ggo"
			[[ ! -f "$ggo" ]] && continue
			printf "\nOptions for the $module writer"
			print_modhelp "$ggo"
		done
	fi
}

set -u

(($# != 1)) && exit 1

# These must be set by the caller (make or help2man)
export COMMAND_LISTS FILTERS GENGETOPT GGO_DIR HELP2MAN HELP2MAN_DIR \
	RECEIVERS VERSION WRITERS

# If either --version or --help-xxx was given, we are being called by help2man
if [[ "$1" == "--version" ]]; then
	echo "$VERSION"
	exit $?
fi
if [[ "$1" =~ --help- ]]; then
	make_help "${1#--help-}"
	exit $?
fi

# Called by make, run help2man
output_file="$1"
target="${output_file##*/para_}"
target="${target%.*}" # server, audiod, filter, ...
link="$HELP2MAN_DIR/para_$target"

cl_opts=
for cl in $COMMAND_LISTS; do
	cl_opts+=" --include $cl"
done

# Create a symlink para_$target, pointing to this script. This hack is
# necessary because help2man always includes the name of the executable in its
# output.
ln -sf "$PWD/$0" "$link"

# This will call us again twice, with either --help-$target or --version given.
$HELP2MAN --no-info --help-option "--help-$target" $cl_opts \
	"$link" > "$output_file"
if (($? != 0)); then
	rm -f "$output_file"
	exit 1
fi