defmodule HAHandler.PGSQL.Watcher do
	use GenServer
	require Logger

	def start_link(opts) do
		GenServer.start_link(__MODULE__, opts)
	end

	@impl true
	def init(opts) do
		# Starts a Postgrex child but does not means the connection was
		# successful.
		# TODO: set dbconnections backoff and connect hooks
		# See https://github.com/elixir-ecto/db_connection/blob/master/lib/db_connection.ex#L343
		{:ok, pid} = Postgrex.start_link(opts)

		state = %{
			backend: pid,
			hostname: Keyword.get(opts, :hostname)
		}

		{:ok, state}
	end

	@impl true
	def handle_call({:execute, query, params}, _from, %{backend: backend} = state) do
		{:reply, Postgrex.query(backend, query, params), state}
	end
end