# This function performs host completion based on ssh's known_hosts files,
# defaulting to standard host completion if they don't exist.
#
_known_hosts()
{
	local cur ocur user suffix aliases global_kh user_kh hosts
	local -a kh config

	COMPREPLY=()
	cur=${COMP_WORDS[COMP_CWORD]}
	ocur=$cur

	[ "$1" = -a ] || [ "$2" = -a ] && aliases='yes'
	[ "$1" = -c ] || [ "$2" = -c ] && suffix=':'
	[[ $cur == *@* ]] && user=${cur%@*}@ && cur=${cur#*@}
	kh=()

	# ssh config files
	[ -r /etc/ssh/ssh_config ] && config[0]=/etc/ssh/ssh_config
	[ -r ~/.ssh/config ]	   && config[1]=~/.ssh/config

	if [ ${#config[@]} -gt 0 ]; then
	    # expand path (if present) to global known hosts file
	    global_kh=$( eval echo $( sed -ne 's/^[Gg][Ll][Oo][Bb][Aa][Ll][Kk][Nn][Oo][Ww][Nn][Hh][Oo][Ss][Tt][Ss][Ff][Ii][Ll][Ee]['$'\t '']*\(.*\)$/\1/p' ${config[@]} ) )
	    # expand path (if present) to user known hosts file
	    user_kh=$( eval echo $( sed -ne 's/^[Uu][Ss][Ee][Rr][Kk][Nn][Oo][Ww][Nn][Hh][Oo][Ss][Tt][Ss][Ff][Ii][Ll][Ee]['$'\t '']*\(.*\)$/\1/p' ${config[@]} ) )
	fi

	# choose which global known hosts file to use
	if [ -r "$global_kh" ]; then
	    kh=( "$global_kh" )
	else
	    [ -r /etc/known_hosts ]    && kh[0]=/etc/known_hosts
	    [ -r /etc/known_hosts2 ]   && kh[1]=/etc/known_hosts2
	fi

	# choose which user known hosts file to use
	if [ -r "$user_kh" ]; then
	    kh=( ${kh[@]} "$user_kh" )
	else
	    [ -r ~/.ssh/known_hosts ]  && kh=( ${kh[@]} ~/.ssh/known_hosts )
	    [ -r ~/.ssh/known_hosts2 ] && kh=( ${kh[@]} ~/.ssh/known_hosts2 )
	fi

	# If we have known_hosts files to use
	if [ ${#kh[@]} -gt 0 ]; then
	    # Escape slashes and dots in paths for awk
	    cur=${cur//\//\\\/}
	    cur=${cur//\./\\\.}

	    if [[ "$cur" == [0-9]*.* ]]; then
		# Digits followed by a dot - just search for that
		cur="^$cur.*"
	    elif [[ "$cur" == [0-9]* ]]; then
		# Digits followed by no dot - search for digits followed
		# by a dot
		cur="^$cur.*\."
	    elif [ -z "$cur" ]; then
		# A blank - search for a dot or an alpha character
		cur="[a-z.]"
	    else
		cur="^$cur"
	    fi

	    # FS needs to look for a comma separated list
	    COMPREPLY=( $( awk 'BEGIN {FS=","}
				{for (i=1; i<=2; ++i) { \
				       gsub(" .*$", "", $i); \
				       if ($i ~ /'$cur'/) {print $i} \
				}}' ${kh[@]} ) )

	    # append any available aliases from config files
	    if [ ${#config[@]} -gt 0 ] && [ -n "$aliases" ]; then
		hosts=$( compgen -W "$( echo $( sed -ne "s/^[Hh][Oo][Ss][Tt]["$'\t '"]*\([^*?]*\)$/\1/p" ${config[@]} ) )" -- $ocur )
		COMPREPLY=( ${COMPREPLY[@]} $hosts )
	    fi

	    # apply suffix
	    for (( i=0; i < ${#COMPREPLY[@]}; i++ )); do
		COMPREPLY[i]=$user${COMPREPLY[i]}$suffix
	    done
	else
	    # Just do normal hostname completion
	    COMPREPLY=( $( compgen -A hostname -S "$suffix" -- $cur ) )
	fi

	return 0
}
complete -F _known_hosts traceroute ping fping telnet host nslookup rsh \
			 rlogin ftp

# ssh(1) completion
#
_ssh()
{
	local cur prev
	local -a config

	COMPREPLY=()
	cur=${COMP_WORDS[COMP_CWORD]}
	prev=${COMP_WORDS[COMP_CWORD-1]}

	case "$prev" in
	-*c)
	    COMPREPLY=( $( compgen -W 'blowfish 3des 3des-cbc blowfish-cbc \
			   arcfour cast128-cbc' -- $cur ) )
	    ;;
	-*l)
	    COMPREPLY=( $( compgen -u -- $cur ) )
	    ;;
	*)
	    _known_hosts -a

	    [ $COMP_CWORD -eq 1 ] || \
		COMPREPLY=( ${COMPREPLY[@]} $( compgen -c -- $cur ) )
	esac

	return 0
}
shopt -u hostcomplete && complete -F _ssh ssh slogin sftp