#!/usr/bin/env python
# Copyright 2016 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.

# Note: This is a py2/3 compatible file.

from __future__ import print_function

import argparse
import errno
import os
import re
import subprocess
import time
import tempfile

import json

import fw_update
import ecusb.tiny_servo_common as c
from ecusb import tiny_servod

class ServoUpdaterException(Exception):
  """Raised on exceptions generated by servo_updater."""

BOARD_C2D2 = 'c2d2'
BOARD_SERVO_MICRO = 'servo_micro'
BOARD_SERVO_V4 = 'servo_v4'
BOARD_SERVO_V4P1 = 'servo_v4p1'
BOARD_SWEETBERRY = 'sweetberry'

DEFAULT_BOARD = BOARD_SERVO_V4

# These lists are to facilitate exposing choices in the command-line tool
# below.
BOARDS = [BOARD_C2D2, BOARD_SERVO_MICRO, BOARD_SERVO_V4, BOARD_SERVO_V4P1,
          BOARD_SWEETBERRY]

# Servo firmware bundles four channels of firmware. We need to make sure the
# user does not request a non-existing channel, so keep the lists around to
# guard on command-line usage.

DEFAULT_CHANNEL = STABLE_CHANNEL = 'stable'

PREV_CHANNEL = 'prev'

# The ordering here matters. From left to right it's the channel that the user
# is most likely to be running. This is used to inform and warn the user if
# there are issues. e.g. if the all channels are the same, we want to let the
# user know they are running the 'stable' version before letting them know they
# are running 'dev' or even 'alpah' which (while true) might cause confusion.

CHANNELS = [DEFAULT_CHANNEL, PREV_CHANNEL, 'dev', 'alpha']

DEFAULT_BASE_PATH = '/usr/'
TEST_IMAGE_BASE_PATH = '/usr/local/'

COMMON_PATH = 'share/servo_updater'

FIRMWARE_DIR = "firmware/"
CONFIGS_DIR = "configs/"

RETRIES_COUNT = 10
RETRIES_DELAY = 1

def do_with_retries(func, *args):
  """
  Call function passed as argument and check if no error happened.
  If exception was raised by function,
  it will be retried up to RETRIES_COUNT times.

  Args:
    func: function that will be called
    args: arguments passed to 'func'

  Returns:
    If call to function was successful, its result will be returned.
    If retries count was exceeded, exception will be raised.
  """

  retry = 0
  while retry < RETRIES_COUNT:
    try:
      return func(*args)
    except Exception as e:
      print("Retrying function %s: %s" % (func.__name__, e))
      retry = retry + 1
      time.sleep(RETRIES_DELAY)
      continue

  raise Exception("'{}' failed after {} retries".format(func.__name__, RETRIES_COUNT))

def flash(brdfile, serialno, binfile):
  """
  Call fw_update to upload to updater USB endpoint.

  Args:
    brdfile:  path to board configuration file
    serialno: device serial number
    binfile:  firmware file
  """

  p = fw_update.Supdate()
  p.load_board(brdfile)
  p.connect_usb(serialname=serialno)
  p.load_file(binfile)

  # Start transfer and erase.
  p.start()
  # Upload the bin file
  print("Uploading %s" % binfile)
  p.write_file()

  # Finalize
  print("Done. Finalizing.")
  p.stop()

def flash2(vidpid, serialno, binfile):
  """
  Call fw update via usb_updater2 commandline.

  Args:
    vidpid:   vendor id and product id of device
    serialno: device serial number (optional)
    binfile:  firmware file
  """

  tool = 'usb_updater2'
  cmd = "%s -d %s" % (tool, vidpid)
  if serialno:
    cmd += " -S %s" % serialno
  cmd += " -n"
  cmd += " %s" % binfile

  print(cmd)
  help_cmd = '%s --help' % tool
  with open('/dev/null') as devnull:
    valid_check = subprocess.call(help_cmd.split(), stdout=devnull,
                                  stderr=devnull)
  if valid_check:
    raise ServoUpdaterException('%s exit with res = %d. Make sure the tool '
                                'is available on the device.' % (help_cmd,
                                                                 valid_check))
  res = subprocess.call(cmd.split())

  if res in (0, 1, 2):
    return res
  else:
    raise ServoUpdaterException("%s exit with res = %d" % (cmd, res))

def select(tinys, region):
  """
  Ensure the servo is in the expected ro/rw region.
  This function jumps to the required region and verify if jump was
  successful by executing 'sysinfo' command and reading current region.
  If response was not received or region is invalid, exception is raised.

  Args:
    tinys:  TinyServod object
    region: region to jump to, only "rw" and "ro" is allowed
  """

  if region not in ["rw", "ro"]:
    raise Exception("Region must be ro or rw")

  if region is "ro":
    cmd = "reboot"
  else:
    cmd = "sysjump %s" % region

  tinys.pty._issue_cmd(cmd)

  tinys.close()
  time.sleep(2)
  tinys.reinitialize()

  res = tinys.pty._issue_cmd_get_results("sysinfo", ["Copy:[\s]+(RO|RW)"])
  current_region = res[0][1].lower()
  if current_region != region:
    raise Exception("Invalid region: %s/%s" % (current_region, region))

def do_version(tinys):
  """Check version via ec console 'pty'.

  Args:
    tinys: TinyServod object

  Returns:
    detected version number

  Commands are:
  # > version
  # ...
  # Build:   tigertail_v1.1.6749-74d1a312e
  """
  cmd = '\r\nversion\r\n'
  regex = 'Build:\s+(\S+)[\r\n]+'

  results = tinys.pty._issue_cmd_get_results(cmd, [regex])[0]

  return results[1].strip(' \t\r\n\0')

def do_updater_version(tinys):
  """Check whether this uses python updater or c++ updater

  Args:
    tinys: TinyServod object

  Returns:
    updater version number. 2 or 6.
  """
  vers = do_version(tinys)

  # Servo versions below 58 are from servo-9040.B. Versions starting with _v2
  # are newer than anything _v1, no need to check the exact number. Updater
  # version is not directly queryable.
  if re.search('_v[2-9]\.\d', vers):
    return 6
  m = re.search('_v1\.1\.(\d\d\d\d)', vers)
  if m:
    version_number = int(m.group(1))
    if version_number < 5800:
      return 2
    else:
      return 6
  raise ServoUpdaterException(
      "Can't determine updater target from vers: [%s]" % vers)

def _extract_version(boardname, binfile):
  """Find the version string from |binfile|.

  Args:
    boardname: the name of the board, eg. "servo_micro"
    binfile: path to the binary to search

  Returns:
    the version string.
  """
  if boardname is None:
    # cannot extract the version if the name is None
    return None
  rawstrings = subprocess.check_output(
      ['cbfstool', binfile, 'read', '-r', 'RO_FRID', '-f', '/dev/stdout'],
      **c.get_subprocess_args())
  m = re.match(r'%s_v\S+' % boardname, rawstrings)
  if m:
    newvers = m.group(0).strip(' \t\r\n\0')
  else:
    raise ServoUpdaterException("Can't find version from file: %s." % binfile)

  return newvers

def get_firmware_channel(bname, version):
  """Find out which channel |version| for |bname| came from.

  Args:
    bname: board name
    version: current version string

  Returns:
    one of the channel names if |version| came from one of those, or None
  """
  for channel in CHANNELS:
    # Pass |bname| as cname to find the board specific file, and pass None as
    # fname to ensure the default directory is searched
    _, _, vers = get_files_and_version(bname, None, channel=channel)
    if version == vers:
      return channel
  # None of the channels matched. This firmware is currently unknown.
  return None

def get_files_and_version(cname, fname=None, channel=DEFAULT_CHANNEL):
  """Select config and firmware binary files.

  This checks default file names and paths.
  In: /usr/share/servo_updater/[firmware|configs]
  check for board.json, board.bin

  Args:
    cname: board name, or config name. eg. "servo_v4" or "servo_v4.json"
    fname: firmware binary name. Can be None to try default.
    channel: the channel requested for servo firmware. See |CHANNELS| above.

  Returns:
    cname, fname, version: validated filenames selected from the path.
  """
  for p in (DEFAULT_BASE_PATH, TEST_IMAGE_BASE_PATH):
    updater_path = os.path.join(p, COMMON_PATH)
    if os.path.exists(updater_path):
      break
  else:
    raise ServoUpdaterException('servo_updater/ dir not found in known spots.')

  firmware_path = os.path.join(updater_path, FIRMWARE_DIR)
  configs_path = os.path.join(updater_path, CONFIGS_DIR)

  for p in (firmware_path, configs_path):
    if not os.path.exists(p):
      raise ServoUpdaterException('Could not find required path %r' % p)

  if not os.path.isfile(cname):
    # If not an existing file, try checking on the default path.
    newname = os.path.join(configs_path, cname)
    if os.path.isfile(newname):
      cname = newname
    else:
      # Try appending ".json" to convert board name to config file.
      cname = newname + ".json"
    if not os.path.isfile(cname):
      raise ServoUpdaterException("Can't find config file: %s." % cname)

  # Always retrieve the boardname
  with open(cname) as data_file:
    data = json.load(data_file)
  boardname = data['board']

  if not fname:
    # If no |fname| supplied, look for the default locations with the board
    # and channel requested.
    binary_file = '%s.%s.bin' % (boardname, channel)
    newname = os.path.join(firmware_path, binary_file)
    if os.path.isfile(newname):
      fname = newname
    else:
      raise ServoUpdaterException("Can't find firmware binary: %s." %
                                  binary_file)
  elif not os.path.isfile(fname):
    # If a name is specified but not found, try the default path.
    newname = os.path.join(firmware_path, fname)
    if os.path.isfile(newname):
      fname = newname
    else:
      raise ServoUpdaterException("Can't find file: %s." % fname)

  # Lastly, retrieve the version as well for decision making, debug, and
  # informational purposes.
  binvers = _extract_version(boardname, fname)

  return cname, fname, binvers

def main():
  parser = argparse.ArgumentParser(description="Image a servo device")
  parser.add_argument('-p', '--print', dest='print_only', action='store_true',
                      default=False,
                      help='only print available firmware for board/channel')
  parser.add_argument('-s', '--serialno', type=str,
                      help="serial number to program", default=None)
  parser.add_argument('-b', '--board', type=str,
                      help="Board configuration json file",
                      default=DEFAULT_BOARD, choices=BOARDS)
  parser.add_argument('-c', '--channel', type=str,
                      help="Firmware channel to use",
                      default=DEFAULT_CHANNEL, choices=CHANNELS)
  parser.add_argument('-f', '--file', type=str,
                      help="Complete ec.bin file", default=None)
  parser.add_argument('--force', action="store_true",
                      help="Update even if version match", default=False)
  parser.add_argument('-v', '--verbose', action="store_true",
                      help="Chatty output")
  parser.add_argument('-r', '--reboot', action="store_true",
                      help="Always reboot, even after probe.")

  args = parser.parse_args()

  brdfile, binfile, newvers = get_files_and_version(args.board, args.file,
                                                    args.channel)

  # If the user only cares about the information then just print it here,
  # and exit.
  if args.print_only:
    output = ('board: %s\n'
              'channel: %s\n'
              'firmware: %s') % (args.board, args.channel, newvers)
    print(output)
    return

  serialno = args.serialno

  with open(brdfile) as data_file:
      data = json.load(data_file)
  vid, pid = int(data['vid'], 0), int(data['pid'], 0)
  vidpid = "%04x:%04x" % (vid, pid)
  iface = int(data['console'], 0)
  boardname = data['board']

  # Make sure device is up.
  print("===== Waiting for USB device =====")
  c.wait_for_usb(vidpid, serialname=serialno)
  # We need a tiny_servod to query some information. Set it up first.
  tinys = tiny_servod.TinyServod(vid, pid, iface, serialno, args.verbose)

  if not args.force:
    vers = do_version(tinys)
    print("Current %s version is   %s" % (boardname, vers))
    print("Available %s version is %s" % (boardname, newvers))

    if newvers == vers:
      print("No version update needed")
      if args.reboot:
        select(tinys, 'ro')
      return
    else:
      print("Updating to recommended version.")

  # Make sure the servo MCU is in RO
  print("===== Jumping to RO =====")
  do_with_retries(select, tinys, 'ro')

  print("===== Flashing RW =====")
  vers = do_with_retries(do_updater_version, tinys)
  # To make sure that the tiny_servod here does not interfere with other
  # processes, close it out.
  tinys.close()

  if vers == 2:
    flash(brdfile, serialno, binfile)
  elif vers == 6:
    flash2(vidpid, serialno, binfile)
  else:
    raise ServoUpdaterException("Can't detect updater version")

  # Make sure device is up.
  c.wait_for_usb(vidpid, serialname=serialno)
  # After we have made sure that it's back/available, reconnect the tiny servod.
  tinys.reinitialize()

  # Make sure the servo MCU is in RW
  print("===== Jumping to RW =====")
  do_with_retries(select, tinys, 'rw')

  print("===== Flashing RO =====")
  vers = do_with_retries(do_updater_version, tinys)

  if vers == 2:
    flash(brdfile, serialno, binfile)
  elif vers == 6:
    flash2(vidpid, serialno, binfile)
  else:
    raise ServoUpdaterException("Can't detect updater version")

  # Make sure the servo MCU is in RO
  print("===== Rebooting =====")
  do_with_retries(select, tinys, 'ro')

  print("===== Finished =====")

if __name__ == "__main__":
  main()
