namu | Write code , Without code | Translation library

Using this piece of code in html.slim view file to change ending of a name from e to ai, and it works fine:

@provider_user.name.split.map {|w| (w.end_with?('e') ? (w.chomp(w[w.length - 1]) + 'ai') : w) }.join(" ")

And using this pease for multiple options:

@provider_user.name.split.map {|w| (w.end_with?('e') ? (w.chomp(w[w.length - 1]) + 'ai') : (w.end_with?('d') ? (w.chomp(w[w.length - 1]) + 'i') : (w.end_with?('as') ? (w.chomp(w[w.length - 1]) + 'u') : w))) }.join(" ")

All good when only last string needs to be changed, like name = namai, namd = nami .

However for (w.end_with?('as') ? (w.chomp(w[w.length - 1]) + 'u') i get namas = namau, instead of namas = namu .

Guess it is due to length - 1 which makes a replacement of last string only.

How can it be adjusted to replace more that last string?