#compdef mdo

local environ e cmd cpp
local -a _comp_priv_prefix
local -A opt_args

zstyle -a ":completion:${curcontext}:" environ environ

for e in "${environ[@]}"
do local -x "$e"
done

cmd="$words[1]"
cpp='_comp_priv_prefix=( $cmd -n ${(kv)opt_args[(I)-u]} )'
_arguments -s -S -A '-*' : \
  '-u+[run command as specified user]: :_users' \
  '-i[keep the calling user]' \
  "*:: :{ $cpp; _normal }"