#!/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 [-v] [-l host[:port]] [-c version] [--no-auto-config] [--name NAME]
##
##   -l port            port that "fx serve" will listen on
##   --no-auto-config   do not configure this host as a package server on the device
##   --name NAME        Name the generated update source config NAME.
##   --[no-]persist     enable or disable persistence of repository metadata. Disabled
##                      by default.
##   -v                 verbose mode, shows info and debug messages from "ffx repository serve"
##   -C|--clean         clean the package repository first. This flag is only
##                      valid if the incremental package publishing is enabled.
##
## This command supports:
##  - incremental package publishing. If enabled, it will auto-publish packages as they
##    are created or modified.
##  - foreground repository serving. If enabled, the repository server and device registration
##    flows will be ran as a foreground process.
##
## To enable incremental package serving, run "fx --enable=incremental serve ..."
## To enable foreground repository serving, run "fx --enable=foreground_repo_server serve ..."

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

function usage {
  fx-command-help serve
}

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

port=""
verbose=false
auto_config=true
clean_first=false
source_name=""
persist="--no-persist"
while (($#)); do
  case "$1" in
    -l)
      port="${2##*:}"
      shift
      ;;
    --name)
      source_name="$2"
      shift
      ;;
    --no-persist)
      ;;
    --persist)
      persist="--persist"
      ;;
    --no-auto-config)
      auto_config=false
      ;;
    -v|--verbose)
      verbose=true
      ;;
    -C|--clean)
      clean_first=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

sunset_resolutions() {
  fx-error "Please consider switching to foreground serving via ffx, and report"
  fx-error "any blocking issues at your earliest convenience."
  fx-error "To serve repositories, please pick between the following two options:"
  fx-error ""
  fx-error "1. Disable pm and switch to ffx foreground server (aka supported):"
  fx-error ""
  fx-error "   Ensure your shell does *not* export the environment variable"
  fx-error "   FUCHSIA_DISABLED_foreground_repo_server"
  fx-error ""
  fx-error "   $ ffx config remove repository.server.mode"
  fx-error "   $ ffx config remove repository.server.enabled"
  fx-error "   $ ffx doctor --restart-daemon"
  fx-error ""
  fx-error "   Then restart \"fx serve\""
  fx-error ""
  fx-error "2. Strongly discouraged, this option is going away at the end"
  fx-error "   of 2024Q2: Ensure your shell *does* export the following"
  fx-error "   environment variable wherever you use fx and ffx."
  fx-error ""
  fx-error "   $ export FUCHSIA_DISABLED_foreground_repo_server=1"
  fx-error ""
  fx-error "   Enable the ffx background server:"
  fx-error ""
  fx-error "   $ ffx config remove repository.server.mode"
  fx-error "   $ ffx config set repository.server.enabled true"
  fx-error "   $ ffx doctor --restart-daemon"
  fx-error ""
  fx-error "In both cases, please note that an already running foreground server is"
  fx-error "not always detected correctly. Consider running the following commands"
  fx-error "in case of problems:"
  fx-error ""
  fx-error "$ ffx config remove repository.server.listen"
  fx-error "$ ffx doctor --restart-daemon"
  fx-error ""
  fx-error "Finally, if you are using a remote workflow like \`fx serve-remote\` or"
  fx-error "\`funnel\` you may need to do these commands on your local and remote"
  fx-error "computers."
  fx-error ""
  exit 1
}

# Determine which server is configured.
server_mode="$(package-server-mode)"
err=$?
if [[ "${err}" -ne 0 ]]; then
  exit 1
fi

# pm is no longer supported
if [[ "${server_mode}" = "pm" ]] ; then
  fx-error "Invoking pm via fx serve is no longer supported. Additionally,"
  fx-error "the pm is slated for removal, targeted for 2024 Q2."
  sunset_resolutions
fi

package_tool_pid=
ffx_server_started=
foreground_repo_server_pid=
cleanup() {
  if [[ -n "${package_tool_pid}" ]]; then
    if kill -0 "${package_tool_pid}" 2> /dev/null; then
      kill -TERM "${package_tool_pid}" 2> /dev/null
      wait "${package_tool_pid}" 2> /dev/null
    fi
  fi
  if [[ -n "${foreground_repo_server_pid}" ]]; then
    if kill -0 "${foreground_repo_server_pid}" 2> /dev/null; then
      kill -TERM "${foreground_repo_server_pid}" 2> /dev/null
      wait "${foreground_repo_server_pid}" 2> /dev/null
    fi
  fi
  if [[ ! -z "${ffx_server_started}" ]]; then
    ffx-stop-server
  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] $@"
}

# 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-fuchsia-device-port)" ]]; then
      serve_updates_target_addr="${serve_updates_target_addr}:$(get-fuchsia-device-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="$(target-addr)"
    "$@"
  )
}

repo_dir="${FUCHSIA_BUILD_DIR}/amber-files"

if is_feature_enabled "incremental" || is_feature_enabled "incremental_new"; then
  # macOS in particular has a low default for number of open file descriptors
  # per process, which is prohibitive for higher job counts. Here we raise
  # the number of allowed file descriptors per process if it appears to be
  # low in order to avoid failures due to the limit. See `getrlimit(2)` for
  # more information.
  if [[ $(ulimit -n) -lt 1000 ]]; then
    ulimit -n 32768
  fi

  if $clean_first; then
    $verbose && echo -n >&2 "Cleaning the package repository..."
    if [[ -d "${repo_dir}" ]]; then
      rm -Rf "${repo_dir}"
    fi
    $verbose && echo >&2 "done"
  fi

  if [[
      ! -e "${repo_dir}/keys/snapshot.json" ||
      ! -e "${repo_dir}/keys/targets.json" ||
      ! -e "${repo_dir}/keys/timestamp.json" ||
      ! -e "${repo_dir}/repository/1.root.json" ||
      ! -e "${repo_dir}/repository/root.json"
  ]]; then
    echo >&2 "Preparing the package repository..."

    fx-command-run build build/images/updates:prepare_publish
    if [[ $? -ne 0 ]]; then
      exit $?
    fi

    echo >&2 "done"
  fi
else
  if $clean_first; then
    fx-error "Flag '-C' or '--clean' can only be used if the incremental feature is enabled"
    exit 1
  fi
fi

# Default the port to 8083 if it is unset.
if is_feature_enabled "foreground_repo_server"; then
  if [[ -z "${port}" ]]; then
    port="8083"
  fi
fi

if [[ "$(ffx-repository-server-enabled)" == "true" ]]; then
  if is_feature_enabled "foreground_repo_server"; then
    fx-error "Both ffx foreground and background serving are enabled. This is mutually incompatible."
  else
    fx-error "Starting an ffx background server from \"fx serve\" is no longer supported,"
    fx-error "preceding the upcoming removal of background serving at the end of 2024Q2."
  fi
  sunset_resolutions
fi

# Error out if we can't start a package server.
check-if-we-can-start-package-server "${server_mode}" "" "${port}"
err=$?
if [[ "${err}" -ne 0 ]]; then
  exit 1
fi

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}..."
  log "Repository is being served in the background by ffx"
  exit 0
fi

if is_feature_enabled "incremental" || is_feature_enabled "incremental_new"; then
  fx-info "Incremental package auto-publishing is enabled for ffx."
  package_tool_flags=(
    --watch
    --package-list "all_package_manifests.list"
    --trusted-root "${repo_dir}/repository/9.root.json"
    --ignore-missing-packages
    --time-versioning
  )
  package_tool_args=( repository publish "${repo_dir}" "${package_tool_flags[@]}" )

  # Check for erroneously running instances of package-tool
  package_tool_pids=$(pgrep -f "package-tool repository publish $(fx-command-run get-build-dir)/amber-files --watch")
  if [[ -n $package_tool_pids ]]; then
    fx-info "Incremental auto-publisher for this build config is/are already running under pid(s): $(echo $package_tool_pids)"
    fx-info "This is likely a side effect from a previous run. Restarting."
    kill -TERM $package_tool_pids
  fi

  # the manifest list file has relative paths and package manifest watcher looks for them
  # from PWD, so the command needs to be executed in "$FUCHSIA_BUILD_DIR"
  if [[ "${verbose}" == true ]]; then
    cd "${FUCHSIA_BUILD_DIR}" && fx-command-exec host-tool package-tool "${package_tool_args[@]}" &
  else
    cd "${FUCHSIA_BUILD_DIR}" && fx-command-exec host-tool package-tool "${package_tool_args[@]}" >/dev/null &
  fi
  package_tool_pid=$!
fi

# Check if device is set via fx set-device before the discovery loop is started
device_name="$(get-device-name 2>/dev/null)"
if [[ -z "${device_name}" ]]; then
  fx-warn ""
  fx-warn "No default device set. If 'fx serve' gets stuck on"
  fx-warn "\"Discovery...\" you can set a default device by running"
  fx-warn "'fx list-devices' to get a list of devices, and then running"
  fx-warn "'fx set-device'."
  fx-warn "\n"
else
  fx-info ""
  fx-info "Default device set: ${device_name}"
  fx-info "\n"
fi

# Make sure the ssh config is present and has the expected private key
check-ssh-config

log "Discovery..."

# State is used to prevent too much output
state="discover"

# Keep track if we reported any discovery failures
reported_discovery_failed=0

# exponential backoff in seconds.
backoff=1
while true; do
  if [[ "${state}" == "discover" ]]; then
    # While we're still trying to connect to the device, clear the target
    # address state so we re-resolve.
    clear-target-addr
    with-pinned-target fx-command-run shell exit 2>/dev/null
    ping_result=$?

    if [[ "${ping_result}" == 0 ]]; then
      log "Device up"
      reported_discovery_failed=0
      backoff=1
      state="config"
    elif [[ "${reported_discovery_failed}" == 0 ]]; then
      reported_discovery_failed=1

      # Log if we don't know the device's address yet, or if we don't have a device configured.
      device_addr="$(get-fuchsia-device-addr 2>/dev/null)"
      if [[ -z "${device_addr}" ]]; then
        device_name="$(get-device-name 2>/dev/null)"
        if [[ -n "${device_name}" ]]; then
          log "Trying to resolve '${device_name}'..."
        else
          log "Either no device or multiple devices are discoverable. Run 'fx list-devices' and if necessary run 'fx set-device'."
        fi
      else
        log "Trying to connect to ${device_addr}..."
      fi
    fi

    if [[ "${ping_result}" != 0 ]]; then
      sleep "${backoff}"
      backoff=$(( $backoff * 2 ))
      if [[ "${backoff}" -gt 10 ]]; then
        backoff=10
      fi
    fi
  else
    with-pinned-target fx-command-run shell -O check > /dev/null 2>&1
    ping_result=$?
  fi

  if [[ "${state}" == "config" ]]; then
    log "Registering devhost as update source"

    if is_feature_enabled "foreground_repo_server"; then
      ffx_flags=( --config repository.foreground.enabled=true )
      if [[ "${verbose}" == true ]]; then
        ffx_flags+=( -v )
      fi

      if [[ -z "${source_name}" ]]; then
        source_name="$(ffx-default-repository-name)"
      fi

      # Start repository server in foreground, wait until it
      # voluntarily exits
      fx-command-run ffx ${ffx_flags[@]} repository serve \
        --address [::]:${port} \
        --repository "${source_name}" \
        --repo-path "${repo_dir}" \
        --alias "fuchsia.com" \
        --alias "chromium.org"

      exit 0
    else
      add_update_source_args=( "${persist}" --port "${port}" --server-mode "${server_mode}" )
      if [[ ! -z "${source_name}" ]]; then
        add_update_source_args+=( --name "${source_name}" )
      fi

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

  if [[ "${state}" == "ready" ]]; then
    if [[ "${ping_result}" != 0 ]]; then
      log "Device lost"

      # Ensure foreground repo session stops before spinning another.
      if [[ -n "${foreground_repo_server_pid}" ]]; then
        if kill -0 "${foreground_repo_server_pid}" 2> /dev/null; then
          kill -TERM "${foreground_repo_server_pid}" 2> /dev/null
          wait "${foreground_repo_server_pid}" 2> /dev/null
        fi
        foreground_repo_server_pid=
      fi

      state="discover"
    else
      sleep 1
    fi
  fi
done

# See EXIT trap above for cleanup that occurs