#!/usr/bin/env zsh
# Forward a local port to a server via SSH tunnel.

setopt LOCAL_OPTIONS ERR_RETURN NO_UNSET PIPE_FAIL

zmodload zsh/zutil
local -a o_help=()
local -a o_lport=()
local -a o_rport=()
zparseopts -D -K -- h=o_help -help=o_help -local-port:=o_lport -remote-port:=o_rport
if [[ ${#o_help} -ne 0 || ! -v 1 || ${#o_lport} -ne 2 || ${#o_rport} -ne 2 ]]; then
    local ret=$(( ${#o_help} ^ 1 ))
    print -u $(( 1 + ${ret} )) "usage: ${0} [-h|--help]" \
          "--local-port <PORT> --remote-port <PORT> <HOST>"
    return ${ret}
fi
local host=${1}
local lport=${o_lport[2]}
local rport=${o_rport[2]}

print -P "%F{12}Forwarding local port%f %F{13}${lport}%f %F{12}over SSH tunnel" \
      "to%f" "%F{13}${host}%f %F{12}port%f %F{13}${rport}%f %F{12}…%f"
ssh -R ${rport}:"[::1]":${lport} -N -T ${host}