#!/usr/bin/env expect

log_user 0
set prompt {/@}
set cmd [lindex $argv 0]

# start bash with no startup files for clean env
spawn env INPUTRC=/dev/null PS1=$prompt bash --norc
expect $prompt

# set some readline variables for consistent completion output
send "bind 'set show-all-if-ambiguous on'\r"
expect $prompt
send "bind 'set bell-style none'\r"
expect $prompt
send "bind 'set completion-query-items -1'\r"
expect $prompt
send "bind 'set page-completions off'\r"
expect $prompt
send "bind 'set completion-display-width 0'\r"
expect $prompt

# run the completion
send "$cmd\t $prompt"
expect {
   # multiple matches, printed on separate lines, followed by prompt
   -re "^$cmd\r\n(.*)\r\n$prompt$cmd" { puts $expect_out(1,string) }
   # single match, completed in-place
   -re "^($cmd\[^ \]*)  $prompt" { puts $expect_out(1,string) }
   # single match, completed in-place, nospace
   -re "^($cmd\[^ \]+) $prompt"  { puts $expect_out(1,string) }
   # no match
   -re "^$cmd $prompt" { exit }
}