# Copyright 2018 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.

import contextlib
import logging

from autotest_lib.server import autotest
from autotest_lib.server.cros import tradefed_constants as constants


class ChromeLogin(object):
    """Context manager to handle Chrome login state."""

    def need_reboot(self, hard_reboot=False):
        """Marks state as "dirty" - reboot needed during/after test."""
        logging.info('Will reboot DUT when Chrome stops.')
        self._need_reboot = True
        if hard_reboot and self._host.servo:
            self._hard_reboot_on_failure = True

    def __init__(self, host, board=None, dont_override_profile=False,
                 enable_default_apps=False):
        """Initializes the ChromeLogin object.

        @param board: optional parameter to extend timeout for login for slow
                      DUTs. Used in particular for virtual machines.
        @param dont_override_profile: reuses the existing test profile if any
        @param enable_default_apps: enables default apps (like Files app)
        """
        self._host = host
        self._timeout = constants.LOGIN_BOARD_TIMEOUT.get(
            board, constants.LOGIN_DEFAULT_TIMEOUT)
        self._dont_override_profile = dont_override_profile
        self._enable_default_apps = enable_default_apps
        self._need_reboot = False
        self._hard_reboot_on_failure = False

    def _cmd_builder(self, verbose=False):
        """Gets remote command to start browser with ARC enabled."""
        # If autotest is not installed on the host, as with moblab at times,
        # getting the autodir will raise an exception.
        cmd = autotest.Autotest.get_installed_autodir(self._host)
        cmd += '/bin/autologin.py --arc'
        if self._dont_override_profile:
            logging.info('Starting Chrome with a possibly reused profile.')
            cmd += ' --dont_override_profile'
        else:
            logging.info('Starting Chrome with a fresh profile.')
        if self._enable_default_apps:
            logging.info('Using --enable_default_apps to start Chrome.')
            cmd += ' --enable_default_apps'
        if not verbose:
            cmd += ' > /dev/null 2>&1'
        return cmd

    def _login(self, timeout=None, raise_exception=False, verbose=False):
        """Logs into Chrome."""
        try:
            # We used to call cheets_StartAndroid, but it is a little faster to
            # call a script on the DUT. This also saves CPU time on the server.
            self._host.run(
                self._cmd_builder(verbose=verbose),
                ignore_status=False,
                verbose=verbose,
                timeout=timeout)

            # Sanity check if Android has really started. When autotest client
            # installed on the DUT was partially broken, the command may succeed
            # without actually logging into Chrome/Android. See b/129382439.
            ret = self._host.run('android-sh -c "ls /data/misc/adb"',
                ignore_status=True, timeout=9)
            if ret.exit_status != 0:
                logging.error('autologin.py succeeded but Android not running. '
                    'Let us try reinstalling Autotest.')
                raise autotest.AutodirNotFoundError()
            return True
        except autotest.AutodirNotFoundError:
            # Autotest is not installed (can happen on moblab after image
            # install). Run dummy_Pass to foce autotest install, before trying
            # to login again.
            logging.warning(
                'Autotest not installed, forcing install using dummy_Pass...')
            try:
                autotest.Autotest(self._host).run_timed_test(
                    'dummy_Pass',
                    timeout=2 * timeout,
                    check_client_result=True)
                self._host.run(
                    self._cmd_builder(),
                    ignore_status=False,
                    verbose=verbose,
                    timeout=timeout)
                return True
            except:
                # We were unable to start the browser/Android. Maybe we can
                # salvage the DUT by rebooting. This can hide some failures.
                self._reboot()
                if raise_exception:
                    raise
        except:
            # We were unable to start the browser/Android. Maybe we can
            # salvage the DUT by rebooting. This can hide some failures.
            self._reboot()
            if raise_exception:
                raise
        return False

    def enter(self):
        """Logs into Chrome with retry."""
        timeout = self._timeout
        logging.info('Ensure Android is running (timeout=%d)...', timeout)
        if not self._login(timeout=timeout):
            timeout *= 2
            # The DUT reboots after unsuccessful login, try with more time.
            logging.info('Retrying failed login (timeout=%d)...', timeout)
            self._login(timeout=timeout, raise_exception=True, verbose=True)

    def exit(self):
        """On exit restart the browser or reboot the machine."""
        if not self._need_reboot:
            try:
                self._restart()
            except:
                logging.error('Restarting browser has failed.')
                self.need_reboot()
        if self._need_reboot:
            self._reboot()

    def _restart(self):
        """Restart Chrome browser."""
        # We clean up /tmp (which is memory backed) from crashes and
        # other files. A reboot would have cleaned /tmp as well.
        # TODO(ihf): Remove "start ui" which is a nicety to non-ARC tests (i.e.
        # now we wait on login screen, but login() above will 'stop ui' again
        # before launching Chrome with ARC enabled).
        logging.info('Skipping reboot, restarting browser.')
        script = 'stop ui'
        script += '&& find /tmp/ -mindepth 1 -delete '
        script += '&& start ui'
        self._host.run(script, ignore_status=False, verbose=False, timeout=120)

    def _reboot(self):
        """Reboot the machine."""
        if self._hard_reboot_on_failure:
            logging.info('Powering OFF the DUT: %s', self._host)
            self._host.servo.get_power_state_controller().power_off()
            logging.info('Powering ON the DUT: %s', self._host)
            self._host.servo.get_power_state_controller().power_on()
        else:
            logging.info('Rebooting...')
            self._host.reboot()


@contextlib.contextmanager
def login_chrome(hosts, **kwargs):
    """Returns Chrome log-in context manager for multiple hosts. """
    # TODO(pwang): Chromelogin takes 10+ seconds for it to successfully
    #              enter. Parallelize if this becomes a bottleneck.
    instances = [ChromeLogin(host, **kwargs) for host in hosts]
    for instance in instances:
        instance.enter()
    yield instances
    for instance in instances:
        instance.exit()