"""
Autotest AFE Cleanup used by the scheduler
"""


import time, logging, random

from autotest_lib.frontend.afe import models
from autotest_lib.scheduler import email_manager, scheduler_config
from autotest_lib.client.common_lib import host_protections
from autotest_lib.client.common_lib.cros.graphite import autotest_stats

class PeriodicCleanup(object):


    def __init__(self, db, clean_interval_minutes, run_at_initialize=False):
        self._db = db
        self.clean_interval_minutes = clean_interval_minutes
        self._last_clean_time = time.time()
        self._run_at_initialize = run_at_initialize


    def initialize(self):
        if self._run_at_initialize:
            self._cleanup()


    def run_cleanup_maybe(self):
        should_cleanup = (self._last_clean_time +
                          self.clean_interval_minutes * 60
                          < time.time())
        if should_cleanup:
            self._cleanup()
            self._last_clean_time = time.time()


    def _cleanup(self):
        """Abrstract cleanup method."""
        raise NotImplementedError


class UserCleanup(PeriodicCleanup):
    """User cleanup that is controlled by the global config variable
       clean_interval_minutes in the SCHEDULER section.
    """
    timer = autotest_stats.Timer('monitor_db_cleanup.user_cleanup')


    def __init__(self, db, clean_interval_minutes):
        super(UserCleanup, self).__init__(db, clean_interval_minutes)
        self._last_reverify_time = time.time()


    @timer.decorate
    def _cleanup(self):
        logging.info('Running periodic cleanup')
        self._abort_timed_out_jobs()
        self._abort_jobs_past_max_runtime()
        self._clear_inactive_blocks()
        self._check_for_db_inconsistencies()
        self._clear_stuck_hosts()
        self._reverify_dead_hosts()
        self._django_session_cleanup()


    @timer.decorate
    def _abort_timed_out_jobs(self):
        msg = 'Aborting all jobs that have timed out and are not complete'
        logging.info(msg)
        query = models.Job.objects.filter(hostqueueentry__complete=False).extra(
            where=['created_on + INTERVAL timeout_mins MINUTE < NOW()'])
        for job in query.distinct():
            logging.warning('Aborting job %d due to job timeout', job.id)
            job.abort()


    @timer.decorate
    def _abort_jobs_past_max_runtime(self):
        """
        Abort executions that have started and are past the job's max runtime.
        """
        logging.info('Aborting all jobs that have passed maximum runtime')
        rows = self._db.execute("""
            SELECT hqe.id
            FROM afe_host_queue_entries AS hqe
            INNER JOIN afe_jobs ON (hqe.job_id = afe_jobs.id)
            WHERE NOT hqe.complete AND NOT hqe.aborted AND
            hqe.started_on + INTERVAL afe_jobs.max_runtime_mins MINUTE <
            NOW()""")
        query = models.HostQueueEntry.objects.filter(
            id__in=[row[0] for row in rows])
        for queue_entry in query.distinct():
            logging.warning('Aborting entry %s due to max runtime', queue_entry)
            queue_entry.abort()


    @timer.decorate
    def _check_for_db_inconsistencies(self):
        logging.info('Cleaning db inconsistencies')
        self._check_all_invalid_related_objects()


    def _check_invalid_related_objects_one_way(self, first_model,
                                               relation_field, second_model):
        if 'invalid' not in first_model.get_field_dict():
            return []
        invalid_objects = list(first_model.objects.filter(invalid=True))
        first_model.objects.populate_relationships(invalid_objects,
                                                   second_model,
                                                   'related_objects')
        error_lines = []
        for invalid_object in invalid_objects:
            if invalid_object.related_objects:
                related_list = ', '.join(str(related_object) for related_object
                                         in invalid_object.related_objects)
                error_lines.append('Invalid %s %s is related to %ss: %s'
                                   % (first_model.__name__, invalid_object,
                                      second_model.__name__, related_list))
                related_manager = getattr(invalid_object, relation_field)
                related_manager.clear()
        return error_lines


    def _check_invalid_related_objects(self, first_model, first_field,
                                       second_model, second_field):
        errors = self._check_invalid_related_objects_one_way(
            first_model, first_field, second_model)
        errors.extend(self._check_invalid_related_objects_one_way(
            second_model, second_field, first_model))
        return errors


    def _check_all_invalid_related_objects(self):
        model_pairs = ((models.Host, 'labels', models.Label, 'host_set'),
                       (models.AclGroup, 'hosts', models.Host, 'aclgroup_set'),
                       (models.AclGroup, 'users', models.User, 'aclgroup_set'),
                       (models.Test, 'dependency_labels', models.Label,
                        'test_set'))
        errors = []
        for first_model, first_field, second_model, second_field in model_pairs:
            errors.extend(self._check_invalid_related_objects(
                first_model, first_field, second_model, second_field))

        if errors:
            subject = ('%s relationships to invalid models, cleaned all' %
                       len(errors))
            message = '\n'.join(errors)
            logging.warning(subject)
            logging.warning(message)
            email_manager.manager.enqueue_notify_email(subject, message)


    @timer.decorate
    def _clear_inactive_blocks(self):
        msg = 'Clear out blocks for all completed jobs.'
        logging.info(msg)
        # this would be simpler using NOT IN (subquery), but MySQL
        # treats all IN subqueries as dependent, so this optimizes much
        # better
        self._db.execute("""
            DELETE ihq FROM afe_ineligible_host_queues ihq
            LEFT JOIN (SELECT DISTINCT job_id FROM afe_host_queue_entries
                       WHERE NOT complete) hqe
            USING (job_id) WHERE hqe.job_id IS NULL""")


    def _clear_stuck_hosts(self):
        """Clear hosts that are stuck in active states.

        DB can get corrupted, e.g. in scheduler crashes.
        After we recover from failures, we sometimes
        see hosts stuck in active states without an active special
        task or hqe associated with it. We need to reset these hosts by
        setting their state to 'Repair Failed' and with for the
        periodically reverify to get them back.
        """
        s = models.Host.Status
        states = (s.VERIFYING, s.REPAIRING, s.CLEANING,
                  s.RESETTING, s.PROVISIONING)
        hosts_stuck_special_tasks = self._db.execute("""
            SELECT afe_hosts.id, afe_hosts.hostname FROM afe_hosts
            LEFT OUTER JOIN afe_special_tasks
            ON (afe_hosts.id = afe_special_tasks.host_id
                AND afe_special_tasks.is_active = 1)
            WHERE afe_special_tasks.id IS NULL AND locked=0 and invalid=0 AND
                  afe_hosts.status in (%s, %s, %s, %s, %s);""" , states)

        hosts_stuck_hqes = self._db.execute("""
            SELECT afe_hosts.id, afe_hosts.hostname FROM afe_hosts
            LEFT OUTER JOIN afe_host_queue_entries
            ON (afe_hosts.id = afe_host_queue_entries.host_id
                AND afe_host_queue_entries.active = 1)
            WHERE afe_host_queue_entries.id IS NULL AND
                  afe_hosts.status=%s AND
                  afe_hosts.locked = 0 AND afe_hosts.invalid=0;""" ,
            (s.RUNNING,))
        stuck_hosts = hosts_stuck_special_tasks + hosts_stuck_hqes
        host_ids = [row[0] for row in stuck_hosts]
        hostnames = [row[1] for row in stuck_hosts]
        if stuck_hosts:
            models.Host.objects.filter(
                    id__in=host_ids).update(status=s.REPAIR_FAILED)
            logging.warning(
                    'Found hosts stuck in Reparing/Verifing/Cleaning/Resetting/'
                    'Provisioning/Running state with no active special tasks '
                    'or hqes. Set them to Repair Failed: %s', hostnames)


    def _should_reverify_hosts_now(self):
        reverify_period_sec = (scheduler_config.config.reverify_period_minutes
                               * 60)
        if reverify_period_sec == 0:
            return False
        return (self._last_reverify_time + reverify_period_sec) <= time.time()


    def _choose_subset_of_hosts_to_reverify(self, hosts):
        """Given hosts needing verification, return a subset to reverify."""
        max_at_once = scheduler_config.config.reverify_max_hosts_at_once
        if (max_at_once > 0 and len(hosts) > max_at_once):
            return random.sample(hosts, max_at_once)
        return sorted(hosts)


    @timer.decorate
    def _reverify_dead_hosts(self):
        if not self._should_reverify_hosts_now():
            return

        self._last_reverify_time = time.time()
        logging.info('Checking for dead hosts to reverify')
        hosts = models.Host.objects.filter(
                status=models.Host.Status.REPAIR_FAILED,
                locked=False,
                invalid=False)
        hosts = hosts.exclude(
                protection=host_protections.Protection.DO_NOT_VERIFY)
        if not hosts:
            return

        hosts = list(hosts)
        total_hosts = len(hosts)
        hosts = self._choose_subset_of_hosts_to_reverify(hosts)
        logging.info('Reverifying dead hosts (%d of %d) %s', len(hosts),
                     total_hosts, ', '.join(host.hostname for host in hosts))
        for host in hosts:
            models.SpecialTask.schedule_special_task(
                    host=host, task=models.SpecialTask.Task.VERIFY)


    @timer.decorate
    def _django_session_cleanup(self):
        """Clean up django_session since django doesn't for us.
           http://www.djangoproject.com/documentation/0.96/sessions/
        """
        logging.info('Deleting old sessions from django_session')
        sql = 'TRUNCATE TABLE django_session'
        self._db.execute(sql)


class TwentyFourHourUpkeep(PeriodicCleanup):
    """Cleanup that runs at the startup of monitor_db and every subsequent
       twenty four hours.
    """
    timer = autotest_stats.Timer('monitor_db_cleanup.twentyfourhour_cleanup')


    def __init__(self, db, run_at_initialize=True):
        clean_interval_minutes = 24 * 60 # 24 hours
        super(TwentyFourHourUpkeep, self).__init__(
            db, clean_interval_minutes, run_at_initialize=run_at_initialize)


    @timer.decorate
    def _cleanup(self):
        logging.info('Running 24 hour clean up')
        self._check_for_uncleanable_db_inconsistencies()


    @timer.decorate
    def _check_for_uncleanable_db_inconsistencies(self):
        logging.info('Checking for uncleanable DB inconsistencies')
        self._check_for_active_and_complete_queue_entries()
        self._check_for_multiple_platform_hosts()
        self._check_for_no_platform_hosts()
        self._check_for_multiple_atomic_group_hosts()


    @timer.decorate
    def _check_for_active_and_complete_queue_entries(self):
        query = models.HostQueueEntry.objects.filter(active=True, complete=True)
        if query.count() != 0:
            subject = ('%d queue entries found with active=complete=1'
                       % query.count())
            lines = []
            for entry in query:
                lines.append(str(entry.get_object_dict()))
                if entry.status == 'Aborted':
                    logging.error('Aborted entry: %s is both active and '
                                  'complete. Setting active value to False.',
                                  str(entry))
                    entry.active = False
                    entry.save()
            self._send_inconsistency_message(subject, lines)


    @timer.decorate
    def _check_for_multiple_platform_hosts(self):
        rows = self._db.execute("""
            SELECT afe_hosts.id, hostname, COUNT(1) AS platform_count,
                   GROUP_CONCAT(afe_labels.name)
            FROM afe_hosts
            INNER JOIN afe_hosts_labels ON
                    afe_hosts.id = afe_hosts_labels.host_id
            INNER JOIN afe_labels ON afe_hosts_labels.label_id = afe_labels.id
            WHERE afe_labels.platform
            GROUP BY afe_hosts.id
            HAVING platform_count > 1
            ORDER BY hostname""")
        if rows:
            subject = '%s hosts with multiple platforms' % self._db.rowcount
            lines = [' '.join(str(item) for item in row)
                     for row in rows]
            self._send_inconsistency_message(subject, lines)


    @timer.decorate
    def _check_for_no_platform_hosts(self):
        rows = self._db.execute("""
            SELECT hostname
            FROM afe_hosts
            LEFT JOIN afe_hosts_labels
              ON afe_hosts.id = afe_hosts_labels.host_id
              AND afe_hosts_labels.label_id IN (SELECT id FROM afe_labels
                                                WHERE platform)
            WHERE NOT afe_hosts.invalid AND afe_hosts_labels.host_id IS NULL""")
        if rows:
            logging.warning('%s hosts with no platform\n%s', self._db.rowcount,
                         ', '.join(row[0] for row in rows))


    @timer.decorate
    def _check_for_multiple_atomic_group_hosts(self):
        rows = self._db.execute("""
            SELECT afe_hosts.id, hostname,
                   COUNT(DISTINCT afe_atomic_groups.name) AS atomic_group_count,
                   GROUP_CONCAT(afe_labels.name),
                   GROUP_CONCAT(afe_atomic_groups.name)
            FROM afe_hosts
            INNER JOIN afe_hosts_labels ON
                    afe_hosts.id = afe_hosts_labels.host_id
            INNER JOIN afe_labels ON afe_hosts_labels.label_id = afe_labels.id
            INNER JOIN afe_atomic_groups ON
                       afe_labels.atomic_group_id = afe_atomic_groups.id
            WHERE NOT afe_hosts.invalid AND NOT afe_labels.invalid
            GROUP BY afe_hosts.id
            HAVING atomic_group_count > 1
            ORDER BY hostname""")
        if rows:
            subject = '%s hosts with multiple atomic groups' % self._db.rowcount
            lines = [' '.join(str(item) for item in row)
                     for row in rows]
            self._send_inconsistency_message(subject, lines)


    def _send_inconsistency_message(self, subject, lines):
        logging.error(subject)
        message = '\n'.join(lines)
        if len(message) > 5000:
            message = message[:5000] + '\n(truncated)\n'
        email_manager.manager.enqueue_notify_email(subject, message)