#!/usr/bin/python
#
# Copyright (c) 2014 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 as datetime_base
import logging
from datetime import datetime

import common

from autotest_lib.client.common_lib import global_config
from autotest_lib.client.common_lib import host_states
from autotest_lib.client.common_lib import time_utils
from autotest_lib.server import utils
from autotest_lib.server.cros.dynamic_suite import reporting_utils
from autotest_lib.server.lib import status_history

CONFIG = global_config.global_config


class BoardNotAvailableError(utils.TestLabException):
    """Raised when a board is not available in the lab."""


class NotEnoughDutsError(utils.TestLabException):
    """Rasied when the lab doesn't have the minimum number of duts."""

    _BUG_URL_PREFIX = CONFIG.get_config_value('BUG_REPORTING',
                                              'tracker_url')

    def __init__(self, board, pool, num_available, num_required, hosts):
        """Initialize instance.

        Please pass arguments by keyword.

        @param board: Name of board.
        @param pool: Name of pool.
        @param num_available: Number of available hosts.
        @param num_required: Number of hosts required.
        @param hosts: Sequence of Host instances for given board and pool.
        """
        self.board = board
        self.pool = pool
        self.num_available = num_available
        self.num_required = num_required
        self.hosts = hosts
        self.bug_id = None
        self.suite_name = None
        self.build = None


    def __repr__(self):
        return (
            '<{cls} at 0x{id:x} with'
            ' board={this.board!r},'
            ' pool={this.pool!r},'
            ' num_available={this.num_available!r},'
            ' num_required={this.num_required!r},'
            ' bug_id={this.bug_id!r},'
            ' suite_name={this.suite_name!r},'
            ' build={this.build!r}>'
            .format(cls=type(self).__name__, id=id(self), this=self)
        )


    def __str__(self):
        msg_parts = [
            'Not enough DUTs for board: {this.board}, pool: {this.pool};'
            ' required: {this.num_required}, found: {this.num_available}'
        ]
        if self.bug_id is not None:
            msg_parts.append(
                'bug: {this._BUG_URL_PREFIX}{this.bug_id!s}'
            )
        if self.suite_name is not None:
            msg_parts.append(
                'suite: {this.suite_name}'
            )
        if self.build is not None:
            msg_parts.append(
                'build: {this.build}'
            )
        return ', '.join(msg_parts).format(this=self)


    def add_bug_id(self, bug_id):
        """Add crbug id associated with this exception.

        @param bug_id  crbug id whose str() value is used in a crbug URL.
        """
        self.bug_id = bug_id


    def add_suite_name(self, suite_name):
        """Add name of test suite that needed the DUTs.

        @param suite_name  Name of test suite.
        """
        self.suite_name = suite_name


    def add_build(self, build):
        """Add name of build of job that needed the DUTs.

        @param build  Name of build.
        """
        self.build = build


class SimpleTimer(object):
    """A simple timer used to periodically check if a deadline has passed."""

    def _reset(self):
        """Reset the deadline."""
        if not self.interval_hours or self.interval_hours < 0:
            logging.error('Bad interval %s', self.interval_hours)
            self.deadline = None
            return
        self.deadline = datetime.now() + datetime_base.timedelta(
                hours=self.interval_hours)


    def __init__(self, interval_hours=0.5):
        """Initialize a simple periodic deadline timer.

        @param interval_hours: Interval of the deadline.
        """
        self.interval_hours = interval_hours
        self._reset()


    def poll(self):
        """Poll the timer to see if we've hit the deadline.

        This method resets the deadline if it has passed. If the deadline
        hasn't been set, or the current time is less than the deadline, the
        method returns False.

        @return: True if the deadline has passed, False otherwise.
        """
        if not self.deadline or datetime.now() < self.deadline:
            return False
        self._reset()
        return True


class JobTimer(object):
    """Utility class capable of measuring job timeouts.
    """

    # Format used in datetime - string conversion.
    time_format = '%m-%d-%Y [%H:%M:%S]'

    def __init__(self, job_created_time, timeout_mins):
        """JobTimer constructor.

        @param job_created_time: float representing the time a job was
            created. Eg: time.time()
        @param timeout_mins: float representing the timeout in minutes.
        """
        self.job_created_time = datetime.fromtimestamp(job_created_time)
        self.timeout_hours = datetime_base.timedelta(hours=timeout_mins/60.0)
        self.debug_output_timer = SimpleTimer(interval_hours=0.5)
        self.past_halftime = False


    @classmethod
    def format_time(cls, datetime_obj):
        """Get the string formatted version of the datetime object.

        @param datetime_obj: A datetime.datetime object.
            Eg: datetime.datetime.now()

        @return: A formatted string containing the date/time of the
            input datetime.
        """
        return datetime_obj.strftime(cls.time_format)


    def elapsed_time(self):
        """Get the time elapsed since this job was created.

        @return: A timedelta object representing the elapsed time.
        """
        return datetime.now() - self.job_created_time


    def is_suite_timeout(self):
        """Check if the suite timed out.

        @return: True if more than timeout_hours has elapsed since the suite job
            was created.
        """
        if self.elapsed_time() >= self.timeout_hours:
            logging.info('Suite timed out. Started on %s, timed out on %s',
                         self.format_time(self.job_created_time),
                         self.format_time(datetime.now()))
            return True
        return False


    def first_past_halftime(self):
        """Check if we just crossed half time.

        This method will only return True once, the first time it is called
        after a job's elapsed time is past half its timeout.

        @return True: If this is the first call of the method after halftime.
        """
        if (not self.past_halftime and
            self.elapsed_time() > self.timeout_hours/2):
            self.past_halftime = True
            return True
        return False


class RPCHelper(object):
    """A class to help diagnose a suite run through the rpc interface.
    """

    def __init__(self, rpc_interface):
        """Constructor for rpc helper class.

        @param rpc_interface: An rpc object, eg: A RetryingAFE instance.
        """
        self.rpc_interface = rpc_interface


    def diagnose_pool(self, board, pool, time_delta_hours, limit=10):
        """Log diagnostic information about a timeout for a board/pool.

        @param board: The board for which the current suite was run.
        @param pool: The pool against which the current suite was run.
        @param time_delta_hours: The time from which we should log information.
            This is a datetime.timedelta object, as stored by the JobTimer.
        @param limit: The maximum number of jobs per host, to log.

        @raises proxy.JSONRPCException: For exceptions thrown across the wire.
        """
        end_time = datetime.now()
        start_time = end_time - time_delta_hours
        get_histories = status_history.HostJobHistory.get_multiple_histories
        host_histories = get_histories(
                self.rpc_interface,
                time_utils.to_epoch_time(start_time),
                time_utils.to_epoch_time(end_time),
                board=board, pool=pool)
        if not host_histories:
            logging.error('No hosts found for board:%s in pool:%s',
                            board, pool)
            return
        status_map = {
            status_history.UNUSED: 'Unused',
            status_history.UNKNOWN: 'No job history',
            status_history.WORKING: 'Working',
            status_history.BROKEN: 'Failed repair'
        }
        for history in host_histories:
            count = 0
            job_info =''
            for job in history:
                start_time = (
                        time_utils.epoch_time_to_date_string(job.start_time))
                job_info += ('%s %s started on: %s status %s\n' %
                        (job.id, job.name, start_time, job.job_status))
                count += 1
                if count >= limit:
                    break
            host = history.host
            logging.error('host: %s, status: %s, locked: %s '
                          'diagnosis: %s\n'
                          'labels: %s\nLast %s jobs within %s:\n'
                          '%s',
                          history.hostname, host.status, host.locked,
                          status_map[history.last_diagnosis()[0]],
                          host.labels, limit, time_delta_hours,
                          job_info)


    def _is_host_available(self, host):
        """Check whether DUT host is available.

        @param host: The Host instance for the DUT.
        @return: bool
        """
        return not (host.locked or host.status in host_states.UNAVAILABLE_STATES)


    def check_dut_availability(self, board, pool, minimum_duts=0, skip_duts_check=False):
        """Check if DUT availability for a given board and pool is less than
        minimum.

        @param board: The board to check DUT availability.
        @param pool: The pool to check DUT availability.
        @param minimum_duts: Minimum Number of available machines required to
                             run the suite. Default is set to 0, which means do
                             not force the check of available machines before
                             running the suite.
        @param skip_duts_check: If True, skip minimum available DUTs check.
        @raise: NotEnoughDutsError if DUT availability is lower than minimum.
        @raise: BoardNotAvailableError if no host found for requested
                board/pool.
        """
        if minimum_duts == 0:
            return

        # TODO(ayatane): Replace label prefixes with constants in
        # site_utils.suite_scheduler.constants
        hosts = self.rpc_interface.get_hosts(
                invalid=False,
                multiple_labels=('pool:%s' % pool, 'board:%s' % board))
        if not hosts:
            raise BoardNotAvailableError(
                    'No hosts found for board:%s in pool:%s. The test lab '
                    'currently does not cover test for this board and pool.'%
                    (board, pool))

        if skip_duts_check:
            # Bypass minimum avilable DUTs check
            logging.debug('skip_duts_check is on, do not enforce minimum DUTs check.')
            return

        if len(hosts) < minimum_duts:
            logging.debug('The total number of DUTs for %s in pool:%s is %d, '
                          'which is less than %d, the required minimum number of'
                          ' available DUTS', board, pool, len(hosts),
                          minimum_duts)

        available_hosts = 0
        for host in hosts:
            if self._is_host_available(host):
                available_hosts += 1
        logging.debug('%d of %d DUTs are available for board %s pool %s.',
                      available_hosts, len(hosts), board, pool)
        if available_hosts < minimum_duts:
            raise NotEnoughDutsError(
                board=board,
                pool=pool,
                num_available=available_hosts,
                num_required=minimum_duts,
                hosts=hosts)


    def diagnose_job(self, job_id, instance_server):
        """Diagnose a suite job.

        Logs information about the jobs that are still to run in the suite.

        @param job_id: The id of the suite job to get information about.
            No meaningful information gets logged if the id is for a sub-job.
        @param instance_server: The instance server.
            Eg: cautotest, cautotest-cq, localhost.
        """
        incomplete_jobs = self.rpc_interface.get_jobs(
                parent_job_id=job_id, summary=True,
                hostqueueentry__complete=False)
        if incomplete_jobs:
            logging.info('\n%s printing summary of incomplete jobs (%s):\n',
                         JobTimer.format_time(datetime.now()),
                         len(incomplete_jobs))
            for job in incomplete_jobs:
                logging.info('%s: %s', job.testname[job.testname.rfind('/')+1:],
                             reporting_utils.link_job(job.id, instance_server))
        else:
            logging.info('All jobs in suite have already completed.')