#!/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=Device management
### start a remote interactive shell in the target device

## usage: fx shell [-h|--help] [--check | [<ssh flags>] <command>]
##
## Creates an SSH connection with a device and executes a command.
##
## Arguments:
##   -h|--help    Print out this message.
##   --check      Diagnose SSH keys and show relevant information about SSH keys
##                and the target device and exit.
##   <ssh flags>  Flags and command are passed to SSH as is. Consult SSH help
##                for a list of available flags.

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

check=false
case $1 in
  --check)
    check=true
    shift
    ;;
  -h|--help)
    fx-command-help
    exit 0
    ;;
esac

${FUCHSIA_DIR}/tools/ssh-keys/gen-ssh-keys.sh || exit $?

if $check; then
  privkey="$(get-ssh-privkey)"

  has_error=false

  # private key doesn't exist, should not happen because of gen-ssh-keys.sh above
  if [[ ! -f "${privkey}" ]]; then
    fx-error "Unexpected error: Private key does not exist: ${privkey}"
    exit 1
  fi

  pubkey="$(ssh-keygen -y -f "${privkey}")" || exit $?

  # ignore stderr in case the authkeys file doesn't exist, as we will attempt
  # to create it below.
  authkeys="$(get-ssh-authkeys 2>/dev/null)"

  # auth key doesn't exist
  if [[ ! -f "${authkeys}" ]]; then
    has_error=true
    fx-warn "Authorized keys file does not exist, attempting to create it: ${authkeys}"
    echo "${pubkey}" > "${authkeys}"
    echo "ok, created ${authkeys}"
  fi

  if ! grep -q "$pubkey" "$authkeys"; then
    has_error=true
    fx-warn "Authorized keys file does not contain your Fuchsia public key, attempting to fix: ${authkeys}"
    echo "${pubkey}" >> "${authkeys}"
    echo "ok, fixed ${authkeys}"
  fi

  fx-config-read

  conffile="${FUCHSIA_BUILD_DIR}/ssh-keys/ssh_config"
  if [[ ! -f "${conffile}" ]] || ! grep -q "IdentityFile\s*$privkey" "$conffile"; then
    has_error=true
    fx-warn "ssh_config file doesn't exist or does not contain the correct private key, attempting to fix: ${conffile}"
    fx build --no-zircon ssh-keys/ssh_config
    if [[ $? -ne 0 || ! -f "${conffile}" ]] || ! grep -q "IdentityFile\s*$privkey" "$conffile"; then
      fx-error "Unexpected error, cannot regenerate ssh_config: ${conffile}"
      exit 1
    fi
    echo "ok, created ${conffile}"
  fi

  # ignore stderr in case device-finder is not built yet
  deviceaddr="$(get-fuchsia-device-addr 2>/dev/null)"
  deviceport="$(get-device-ssh-port 2>/dev/null)"
  echo "Device address: ${deviceaddr:-"unknown"}"
  echo "Device SSH port: ${deviceport:-"default"}"
  echo "SSH config: ${conffile}"
  echo "SSH private key file: ${privkey}"
  echo "SSH authorized keys file: ${authkeys}"
  echo

  if $has_error; then
    fx-warn "Some issues were found and fixed. Please look above for more information"
  else
    echo "SSH configuration is in good shape, no issues detected"
  fi

  exit 0
fi

args=()
device_port="$(get-device-ssh-port)" || exit $?
if [[ -n "${device_port}" ]]; then
  args+=( "-p" "${device_port}" )
fi
device_addr="$(get-fuchsia-device-addr)" || exit $?
if [[ -z "${device_addr}" ]]; then
  # Error output is provided to stderr by get-fuchsia-device-addr
  exit 1
fi
args+=( "${device_addr}" )

args+=( "$@" )
# Note: I know there are people who don't like the host-key message, but DO NOT
# apply -q here, it silences error messages and makes network and configuration
# failures much harder to diagnose when helping people. The control master will
# mean you only get one per TCP socket, which is once per newly booted host.
# It's not a huge burden compared to end user support.
fx-command-run ssh "${args[@]}"
status=$?

# FX_CALLER is not empty if this script was executed via fx-command-run/exec
# and we only want to show this hint message when the user executes 'fx shell'
# directly.
if [[ -z "${FX_CALLER}" && $status -eq 255 ]]; then
  echo "Hint: use 'fx shell --check' to diagnose SSH configuration issues."
fi
exit $status