#!/bin/sh
#
# /usr/local/bin/localwebgalleryupdate
# Copyright 2008 Jonas Smedegaard <dr@jones.dk>
#
# $Id: localwebgallerydaemon,v 1.1 2008-03-18 23:22:03 jonas Exp $
#
# (Re)generate web gallery whenever source directory changes
#
# TODO: Implement options:
#   --help
#   --sourcedir
#   --targetdir
#   --run-once
#   --now
#   --verbose
#   --debug
#   --init (create targetdir if missing, fail if exists and non-empty)
#
# TODO: implement ask() and the following options:
#   --reset (purge output dir -- use with --init to always build from scratch)
#   --force
#
# TODO: Support more gallery engines
#
# TODO: Support overriding defaults in rc-file
#

set -e
#set -bm

# Defaults options
SOURCEDIR="$HOME/public_media"
TARGETDIR="$HOME/public_html/gallery"
GENERATOR="lazygal"
THEME="image-index"

# Use defaults if not overridden
sourcedir="${1:-$SOURCEDIR}"
targetdir="${2:-$TARGETDIR}"

PRG=$(basename "$0")

# Required external programs
EXTPRG="/usr/bin/fileschanged"
case $GENERATOR in
    lazygal)
    	EXTPRG="$EXTPRG /usr/bin/$GENERATOR"
	;;
esac

showhelp() {
	cat <<EOF
Usage:   $PRG [ SOURCEDIR ] [ TARGETDIR ]

Defaults:
    SOURCEDIR:  $SOURCEDIR
    TARGETDIR:  $TARGETDIR

Examples:
    $PRG ~/my/images /var/www/gallery &
    daemon -u me -n gallery-me -- $PRG ~/my/images /var/www/gallery
EOF
}

exit1()	{
	echo >&2 "Error: $1"
	echo >&2 "Exiting..."
	exit 1
}

lazygal_opts="--quiet --check-all-dirs --clean-destination ${THEME:+--theme $THEME}"

# Sanity checks
[ -d "$sourcedir" ] || exit1 "Source directory \"$sourcedir\" is not a directory"
[ -d "$targetdir" ] || exit1 "Target directory \"$targetdir\" is not a directory"
for prg in $EXTPRG; do
	[ -x "$prg" ] || exit1 "Required program \"$prg\" not installed"
done

updategallery() {
	onemoretime=yes
	trap 'onemoretime=yes' USR1
	while [ -n "$onemoretime" ]; do
		onemoretime=
		case "$GENERATOR" in
		    lazygal)
			lazygal $lazygal_opts -o "$targetdir" "$sourcedir"
			;;
		esac
		sleep 10
	done
}

pid=
fileschanged -r -s created,changed,deleted "$sourcedir" | while read file; do

	# Ignore hidden files (used for temporary files by rsync)
	case "$file" in
	    .*)
		continue
		;;
	esac

	# Invoke update if not active or telling to take another spin fails
	if [ -z "$progress" ] || ! kill -USR1 $(jobs -p) 2>/dev/null; then
		progress=yes
		updategallery &
	fi
done

exit 0