{ postgresql_15, postgresql_16, writeScriptBin, ... }:

let
	newPostgres = postgresql_16;
	oldPostgres = postgresql_15;
in writeScriptBin "upgrade-pg-cluster" ''
	set -eux
	systemctl stop postgresql

	export NEWDATA="/var/lib/postgresql/${newPostgres.psqlSchema}"
	export NEWBIN="${newPostgres}/bin"

	export OLDDATA="/var/lib/postgresql/${oldPostgres.psqlSchema}"
	export OLDBIN="${oldPostgres}/bin"

	install -d -m 0700 -o postgres -g postgres "$NEWDATA"
	cd "$NEWDATA"
	sudo -u postgres "$NEWBIN/initdb" -D "$NEWDATA"

	sudo -u postgres "$NEWBIN/pg_upgrade" \
	    --old-datadir "$OLDDATA" --new-datadir "$NEWDATA" \
	    --old-bindir "$OLDBIN" --new-bindir "$NEWBIN" \
	    "$@"
''