#!/bin/sh

# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This scripts performs update of stateful partition directories useful for
# dev_mode.

# in order to support developers going from older images with the old shflags
# we'll check for both new shflags and old shflags
if [ -f /usr/share/misc/shflags ] ; then
  . /usr/share/misc/shflags
elif [ -f /usr/lib/shflags ] ; then
  . /usr/lib/shflags
else
  echo >&2 "$0 Unable to source shflags"
  exit 1
fi

# Constants for states.
CLEAN_STATE="clean"
OLD_STATE="old"
RESET_STATE="reset"

LSB_RELEASE="/etc/lsb-release"
STATEFUL_DIR="/mnt/stateful_partition"
UPDATE_STATE_FILE=".update_available"

DEFINE_string stateful_change "${OLD_STATE}" \
  "The state of the new stateful partition - used in update testing."

FLAGS "$@" || exit 1

# Die on error.
set -e

remove_quotes() {
  echo "$1" | sed -e "s/^'//; s/'$//"
}

update_dev_image () {
  local base_update_url devserver_url
  if [ -n "${FLAGS_ARGV}" ]; then
    base_update_url=$(remove_quotes "${FLAGS_ARGV}")
  else
    if [ -f "${STATEFUL_DIR}${LSB_RELEASE}" ]; then
      devserver_url=$(grep CHROMEOS_DEVSERVER ${STATEFUL_DIR}${LSB_RELEASE} |
          cut -f 2 -d '=')
    fi
    if [ -z "${devserver_url}" ]; then
      devserver_url=$(grep CHROMEOS_DEVSERVER ${LSB_RELEASE} | cut -f 2 -d '=')
    fi
    # Sanity check.
    if [ -z "${devserver_url}" ]; then
      echo >&2 "No CHROMEOS_DEVSERVER URL found in lsb-release file"
      exit 1
    fi
    # Devserver URL should never contain "/update"
    devserver_url=$(echo ${devserver_url} | sed -e 's#/update##')
    base_update_url="${devserver_url}/static"
  fi

  local stateful_update_url="${base_update_url}/stateful.tgz"
  echo >&2 "Downloading stateful payload from ${stateful_update_url}"
  # Download and unzip directories onto the stateful partition.
  eval "wget -qS -T 300 -O - \"${stateful_update_url}\"" |
      tar --ignore-command-error --overwrite --directory=${STATEFUL_DIR} -xz
  echo >&2 "Successfully downloaded update"

  if [ ! -d "${STATEFUL_DIR}/var_new" ] ||
      [ ! -d "${STATEFUL_DIR}/dev_image_new" ]; then
    echo >&2 "Missing var or dev_image in stateful payload."
    return 1
  fi
}

reset_state () {
  echo >&2 "Resetting stateful update state."
  rm -f "${STATEFUL_DIR}/${UPDATE_STATE_FILE}"
  rm -rf "${STATEFUL_DIR}/var_new"
  rm -rf "${STATEFUL_DIR}/dev_image_new"
}

update_old_state () {
  echo >&2 "Performing standard stateful update."
  echo -n "" > "${STATEFUL_DIR}/${UPDATE_STATE_FILE}"
}

update_clean_state () {
  echo >&2 "Restoring state to factory_install with dev_image."
  echo -n "clobber" > "${STATEFUL_DIR}/${UPDATE_STATE_FILE}"
}

main () {
  if [ "${FLAGS_stateful_change}" = "${RESET_STATE}" ]; then
    reset_state
  elif update_dev_image; then
    if [ "${FLAGS_stateful_change}" = "${OLD_STATE}" ]; then
      update_old_state
    elif [ "${FLAGS_stateful_change}" = "${CLEAN_STATE}" ]; then
      update_clean_state
    else
      echo >&2 "Invalid state given to stateful update.  Aborting..."
      return 1
    fi
  else
    return 1
  fi
}

main $@