# Copyright (c) 2017 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 datetime
import logging
import os
import re
import time

from autotest_lib.client.bin import utils
from autotest_lib.client.common_lib import error
from autotest_lib.server.cros import stress
from autotest_lib.server.cros.faft.firmware_test import FirmwareTest

class firmware_EmmcWriteLoad(FirmwareTest):
    """
    Runs chromeos-install repeatedly while monitoring dmesg output for EMMC
    timeout errors.

    This test requires a USB disk plugged-in, which contains a Chrome OS test
    image (built by "build_image test"). On runtime, this test first switches
    DUT to developer mode. When dev_boot_usb=0, pressing Ctrl-U on developer
    screen should not boot the USB disk. When dev_boot_usb=1, pressing Ctrl-U
    should boot the USB disk.

    The length of time in minutes should be specified by the parameter
    -a 'minutes_to_run=240'
    """
    version = 1

    INSTALL_COMMAND = '/usr/sbin/chromeos-install --yes'
    ERROR_MESSAGE_REGEX = re.compile(
            r'mmc[0-9]+: Timeout waiting for hardware interrupt', re.MULTILINE)

    def initialize(self, host, cmdline_args, ec_wp=None):
        """Initialize the test"""
        dict_args = utils.args_to_dict(cmdline_args)
        self.minutes_to_run = int(dict_args.get('minutes_to_run', 5))
        super(firmware_EmmcWriteLoad, self).initialize(
            host, cmdline_args, ec_wp=ec_wp)

        self.switcher.setup_mode('dev')
        # Use the USB key for Ctrl-U dev boot, not recovery.
        self.setup_usbkey(usbkey=True, host=False, used_for_recovery=False)

        self.original_dev_boot_usb = self.faft_client.system.get_dev_boot_usb()
        logging.info('Original dev_boot_usb value: %s',
                     str(self.original_dev_boot_usb))


    def read_dmesg(self, filename):
        """Put the contents of 'dmesg -cT' into the given file.

        @param filename: The file to write 'dmesg -cT' into.
        """
        with open(filename, 'w') as f:
            self._client.run('dmesg -cT', stdout_tee=f)

        return utils.read_file(filename)

    def check_for_emmc_error(self, dmesg):
        """Check the current dmesg output for the specified error message regex.

        @param dmesg: Contents of the dmesg buffer.

        @return True if error found.
        """
        for line in dmesg.splitlines():
            if self.ERROR_MESSAGE_REGEX.search(line):
                return True

        return False

    def install_chrome_os(self):
        """Runs the install command. """
        self.faft_client.system.run_shell_command(self.INSTALL_COMMAND)

    def poll_for_emmc_error(self, dmesg_file, poll_seconds=20):
        """Continuously polls the contents of dmesg for the emmc failure message

        @param dmesg_file: Contents of the dmesg buffer.
        @param poll_seconds: Time to wait before checking dmesg again.

        @return True if error found.
        """
        end_time = datetime.datetime.now() + \
                   datetime.timedelta(minutes=self.minutes_to_run)

        while datetime.datetime.now() <= end_time:
            dmesg = self.read_dmesg(dmesg_file)
            contains_error = self.check_for_emmc_error(dmesg)

            if contains_error:
                raise error.TestFail('eMMC error found. Dmesg output: %s' %
                                     dmesg)
            time.sleep(poll_seconds)

    def cleanup(self):
        """Cleanup the test"""
        try:
            self.ensure_dev_internal_boot(self.original_dev_boot_usb)
        except Exception as e:
            logging.error("Caught exception: %s", str(e))
        super(firmware_EmmcWriteLoad, self).cleanup()

    def run_once(self):
        """Main test logic"""
        self.faft_client.system.set_dev_boot_usb(1)
        self.switcher.simple_reboot()
        self.switcher.bypass_dev_boot_usb()
        self.switcher.wait_for_client()

        logging.info('Expected USB boot, set dev_boot_usb to the original.')
        self.check_state((self.checkers.dev_boot_usb_checker, (True, True),
                          'Device not booted from USB image properly.'))
        stressor = stress.ControlledStressor(self.install_chrome_os)

        dmesg_filename = os.path.join(self.resultsdir, 'dmesg')

        logging.info('===== Starting OS install loop. =====')
        logging.info('===== Running install for %s minutes. =====',
                     self.minutes_to_run)
        stressor.start()

        self.poll_for_emmc_error(dmesg_file=dmesg_filename)

        logging.info('Stopping install loop.')
        # Usually takes a little over 3 minutes to install so make sure we
        # wait long enough for a install iteration to complete.
        stressor.stop(timeout=300)

        logging.info("Installing OS one more time.")
        # Installing OS one more time to ensure DUT is left in a good state
        self.install_chrome_os()