#!/bin/bash
# Copyright 2018 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=Software delivery
### start the update server and attach to a running fuchsia device
## usage: fx serve-updates [-v] [-l host[:port]]
##   -l host:port for "pm serve" to listen on
##   --no-auto-config do not configure this host as a package server on the device
##   -v verbose (do not suppress `pm serve` output)

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

function usage {
  fx-command-help serve-updates
}

fx-standard-switches "$@"
set -- "${FX_ARGV[@]}"

port="8083"
serve_flags=()
verbose=false
auto_config=true
while (($#)); do
  case "$1" in
    -l)
      shift
      port="${1##*:}"
      serve_flags+=(-l "$1")
      ;;
    --no-auto-config)
      auto_config=false
      ;;
    -v|--verbose)
      verbose=true
      ;;
    *)
      echo "Unrecognized option: $1"
      usage
      exit 1
      ;;
  esac
  shift
done

if fx-is-bringup; then
  fx-error "$0 is not supported in the bringup build configuration, as there are no package features in bringup."
  exit 1
fi

if [[ "${verbose}" != true ]]; then
  serve_flags+=("-q")
fi

pm_srv_pid=
cleanup() {
  if [[ -n "${pm_srv_pid}" ]]; then
    if kill -0 "${pm_srv_pid}" 2> /dev/null; then
      kill -TERM "${pm_srv_pid}" 2> /dev/null
      wait "${pm_srv_pid}" 2> /dev/null
    fi
  fi
}
trap cleanup EXIT

log() {
  # This format matches bootserver so that `fx serve` ui is easier to read.
  echo "$(date '+%Y-%m-%d %H:%M:%S') [serve-updates] $@"
}

# In any multi-homing scenario (two target interfaces, or two host interfaces),
# the resolve process can return different results at different times. As such
# we pin the address here, and let the ssh check loop below perform a clear
# whenever it is in the "discovery" state. This stabilizes the "connection"
# under multi-homed conditions.
serve_updates_target_addr=""
target-addr() {
  if [[ -z "${serve_updates_target_addr}" ]]; then
    serve_updates_target_addr="$(get-device-addr-resource)"
    if [[ -n "${serve_updates_target_addr}" && -n "$(get-device-ssh-port)" ]]; then
      serve_updates_target_addr="${serve_updates_target_addr}:$(get-device-ssh-port)"
    fi
  fi

  if [[ -n "$serve_updates_target_addr" ]]; then
    echo "$serve_updates_target_addr"
    return 0
  fi

  return 1
}

clear-target-addr() {
  serve_updates_target_addr=""
}

with-pinned-target() {
  # Ensure we pin in the running shell before making a subshell. We also want
  # to make sure we get an address at all.
  if ! target-addr > /dev/null; then
    return 1
  fi

  (
    export FUCHSIA_DEVICE_NAME="$(target-addr)"
    "$@"
  )
}

if [[ "${auto_config}" == false ]]; then
  log "Flag '--no-auto-config' used, automatic device configuration disabled."
  log "Use 'fx -d DEVICE add-update-source --port ${port}' to reconfigure devices as needed, since it is not persistent accross reboots."
  log "Serving packages on port ${port}..."
  exec "${FUCHSIA_BUILD_DIR}/host_x64/pm" serve -repo "${FUCHSIA_BUILD_DIR}/amber-files" "${serve_flags[@]}"
fi

if [[ -z "${pm_srv_pid}" ]]; then
  # The use of host_x64/ is deliberate over tools/.
  "${FUCHSIA_BUILD_DIR}/host_x64/pm" serve -repo "${FUCHSIA_BUILD_DIR}/amber-files" "${serve_flags[@]}" &
  pm_srv_pid=$!
fi

# Allow a little slack for pm serve to startup, that way the first kill -0 will catch a dead server
sleep 0.1
if ! kill -0 "${pm_srv_pid}" 2> /dev/null; then
  log "Server died, exiting"
  wait
  exit $?
fi

log "Discovery..."

# State is used to prevent too much output
state="discover"
while true; do
  if ! kill -0 "${pm_srv_pid}" 2> /dev/null; then
    log "Server died, exiting"
    pm_srv_pid=
    exit 1
  fi

  if [[ "$state" == "discover" ]]; then
    # While we're still trying to connect to the device, clear the target
    # address state so we re-resolve.
    clear-target-addr
    with-pinned-target fx-command-run shell exit 2>/dev/null
    ping_result=$?
  else
    with-pinned-target fx-command-run shell -O check > /dev/null 2>&1
    ping_result=$?
  fi

  if [[ "$state" == "discover" && "$ping_result" == 0 ]]; then
    log "Device up"
    state="config"
  fi

  if [[ "$state" == "config" ]]; then
    log "Registering devhost as update source"
    if with-pinned-target fx-command-run add-update-source --port "${port}"; then
      log "Ready to push packages!"
      # Log the uptime so that it is clear(er) from fx serve if the device rebooted.
      # The tr is present as the output sometimes contains spurious control characters.
      clock=$(with-pinned-target fx-command-run shell clock --monotonic)
      if [[ -n ${clock} ]]; then
        uptime=$(echo $clock | tr '[[:cntrl:]]' ' ' )
        log "Target uptime: $(( $uptime / 1000000000 ))"
        state="ready"
      else
        log "Device lost while checking uptime"
        state="discover"
      fi
    else
      log "Device lost while configuring update source"
      state="discover"
    fi
  fi

  if [[ "$state" == "ready" ]]; then
    if [[ "$ping_result" != 0 ]]; then
      log "Device lost"
      state="discover"
    else
      sleep 1
    fi
  fi
done

# See EXIT trap above for cleanup that occurs