# Functions used for interactive installation of new changes to running system
# vim: ft=sh

dodiff() {
	if [ -d "$2" ]; then
		# If we just copying some file to directory
		OUT=$2/$(basename "$1")
	else
		OUT=$2
	fi
	if ! [ -f "$OUT" ]; then
		echo "Not installed: $1 => $OUT"
		read -p "Install? (Y/n) "
		if [[ $REPLY =~ ^[Yy]?$ ]]; then
			doinst "$1" "$OUT"
		fi
		return
	fi
	if cmp "$1" "$OUT" >/dev/null; then
		echo "No difference detected: $OUT"
		return
	fi
	vimdiff "$1" "$OUT"
}

checkdiff() {
	# Iterate trough source directory but ignore any git repositories
	# Note that it's design decision to not iterate trough target directory.
	if [ -d "$1" ]; then
		# This is check if we have correct inst command basically. If it is
		# directory than it have to have trailing slash to ensure that no
		# additional directory is created.
		if ! echo "$1" | grep -qE '/$'; then
			echo ERROR: Directory without trailing slash detected: $1
			exit 1
		fi
		# Got trough all files ignoring git repositories
		for f in `find "$1" \( -type d -exec test -e '{}'/.git \; \) -prune -o -type f -print`; do
			F="${f#$1}"
			dodiff "$1/$F" "$2/$F"
		done
		# Check if we have all directories ignoring those in git repositories
		for d in `find "$1" -type d -print -exec test -e '{}'/.git \; -prune`; do
			D="${d#$1}"
			if [ ! -d "$2/$D" ]; then
				echo "Directory not installed: $1/$D => $2/$D"
				read -p "Install? (Y/n) "
				if [[ $REPLY =~ ^[Yy]?$ ]]; then
					doinst "$1/$D/" "$2/$D"
				fi
			fi
		done
		# Now checkout git repositories
		for g in `find "$1" -type d -exec test -e '{}'/.git \; -print -prune`; do
			G="${g#$1}"
			PREV="$(pwd)"
			cd "$2/$G"
			# Check if we have any change at all
			if git --work-tree=. diff --exit-code -s; then
				echo "No difference detected in git: $2/$G"
			else
				echo "Checkout of git repository: $2/$G"
				# Checkout all files to HEAD
				git --work-tree=. checkout -f HEAD
				# Update all submodules
				git --work-tree=. submodule update
			fi
			cd "$PREV"
		done
	else
		dodiff "$1" "$2"
	fi
}

# Managing two git trees with master has small inconvenience that git allows only
# single branch checkout in all work trees, so as it sets now git will execute all
# commands not on deployed tree but on tree in this repository, so we need specify
# work tree on command line every time we want target deployed work tree.
doinst() {
	echo rsync -rlpt $1 $2
	rsync -rlpt $1 $2
	# Now edit all .git files in target directory
	for g in `find "$2" -name '.git' -type f`; do
		if ! grep -q "gitdir: " "$g"; then
			continue # Probably not a git repository or who knows.
		fi
		echo "Pointing git repository $g to this repository"
		echo gitdir: $PWD/.git`sed "s/^gitdir: [./]*git//" "$g"` > "$g"
	done
}

inst() {
	if [ -e "$2" ]; then
		# If output exists, execute diff instead
		checkdiff $1 $2
		return
	fi
	doinst $1 $2
}