apply_var.lua

local log = require "resources.functions.log".apply_var

function apply_global_var(str, t)
	return (string.gsub(str, "$${.-}", function(key)
		key = string.sub(key, 4, -2)
		local var = t and t[key] or freeswitch.getGlobalVariable(key)
		if not var then
			log.warningf("unknown global variable: %s", key)
		end
		return var or ''
	end))
end

function apply_session_var(str, t)
	return (string.gsub(str, "${.-}", function(key)
		key = string.sub(key, 3, -2)
		local var = t and t[key] or freeswitch.getGlobalVariable(key)
		return var or ''
	end))
end

function apply_var(str, t)
	local str = apply_global_var(str, t)
	if session then
		str = apply_session_var(str, t)
	end
	return str
end

-- usage 
--   apply_global_var('$${hold_music}')
--
--   dofile( apply_global_var('$${script_dir}/foo.lua') )
--
-- apply_global_var('$${storage_dir}/$${domain}',{
--   domain = 'my_domain';
-- })