#!/bin/bash
# Copyright 2017 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Other
### serve from a remote workstation

## usage: fx serve-remote [--no-serve] HOSTNAME [REMOTE-PATH]
##
## HOSTNAME     the hostname of the workstation you want to serve from
## REMOTE-PATH  defaults to ~/fuchsia. The path on the to FUCHSIA_DIR on the workstation.
##
##  --no-serve  only tunnel, do not start a package server

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?
fx-config-read

serve=true
host=""
dir=""
while [[ $# -ne 0 ]]; do
  case "$1" in
  --help|-h)
      fx-command-help
      exit 0
      ;;
  --no-serve)
    serve=false
    ;;
  -*)
    fx-error "Unknown flag: $1"
    fx-command-help
    exit 1
    ;;
  *)
    if [[ -z "${host}" ]]; then
      host="$1"
    elif [[ -z "${dir}" ]]; then
      dir="$1"
    else
      fx-error "unexpected argument: '$1'"
      exit 1
    fi
    ;;
  esac
  shift
done

if [[ -z "${host}" ]]; then
  fx-error "HOSTNAME must be specified"
  fx-command-help
  exit 1
fi

if "${serve}"; then
  if [[ -z "${dir}" ]]; then
    if ssh "$host" ls \~/fuchsia/.jiri_root/bin/fx > /dev/null; then
      dir="~/fuchsia"
    else
      fx-error "failed to find ~/fuchsia on $host, please specify REMOTE-DIR"
      fx-command-help
      exit 1
    fi
  fi
fi

target_addr=$(get-fuchsia-device-addr)
if [[ $? -ne 0 || -z "${target_addr}" ]]; then
  fx-error "unable to discover device. Is the target up?"
  exit 1
fi

echo "Using remote ${host}:${dir}"
echo "Using target device $(get-device-name)"

# First we need to check if we already have a control master for the
# host, if we do, we might already have the forwards and so we don't
# need to worry about tearing down:
if ! ssh -O check "${host}" > /dev/null 2>&1; then
  # If we didn't have a control master, and the device already has 8022
  # bound, then there's a good chance there's a stale sshd instance
  # running from another device or another session that will block the
  # forward, so we'll check for that and speculatively attempt to clean
  # it up. Unfortunately this means authing twice, but it's likely the
  # best we can do for now.
  if ssh "${host}" 'ss -ln | grep :8022' > /dev/null; then
    ssh "${host}" 'pkill -u $USER sshd'
    ssh "${host}" -O exit > /dev/null 2>&1
  fi
fi

args=(
  -6 # We want ipv6 binds for the port forwards
  -L "\*:8083:localhost:8083" # requests to the package server address locally go to the workstation
  -R "8022:[${target_addr}]:22" # requests from the workstaiton to ssh to localhost:8022 will make it to the target
  -R "2345:[${target_addr}]:2345" # requests from the workstation to the debug agent on localhost will make it to the target
  -o ExitOnForwardFailure=yes
  "${host}"
)

# If the user requested serving, then we'll check to see if there's a
# server already running and kill it, this prevents most cases where
# signal propagation seems to sometimes not make it to "pm".
if "${serve}" && ssh "${args[@]}" 'ss -ln | grep :8083' > /dev/null; then
  ssh "${args[@]}" 'pkill -u $USER pm'
fi

if "${serve}"; then
  # Starts a package server
  args+=(
    "-tt" # explicitly force a pty, for HUP'ing on the remote
    "cd ${dir} && ./.jiri_root/bin/fx set-device '[::1]:8022' && ./.jiri_root/bin/fx serve-updates"
  )
else
  # Starts nothing, just goes to sleep
  args+=("-nNT")
fi

exec ssh  "${args[@]}"