Mapping number to text in Axis Y



I am new in grafana, and We are starting to monitoring every device of our network,

and in UPS section We are trying to make alerts about UPS states like UPS online, UPS on Battery, UPS in Bypass and so on, for make that We are using singlestat making a value mapping (state number 3 is UPS Online)

but actually singlestat doesnot have the option to configure or set alert to email, so for this reason We are using graph, but in the graph We havenot the option for make a value mapping in the Axis Y, to convert the number 3 on online text (for example), and When We get an alert We only get the status, so We only get the number, How We can do the value mapping in the Y Axis?, or How we can make that the alert of a number can be a text of a state?