import itertools
import logging
import re
import time
import urllib
from collections import defaultdict
from datetime import datetime, timedelta
from decimal import Decimal

from typing import Any, Callable, Dict, List, \
    Optional, Set, Tuple, Type, Union

import pytz
from django.conf import settings
from django.urls import reverse
from django.db import connection
from django.db.models.query import QuerySet
from django.http import HttpRequest, HttpResponse, HttpResponseNotFound
from django.shortcuts import render
from django.template import loader
from django.utils.timezone import now as timezone_now, utc as timezone_utc
from django.utils.translation import ugettext as _
from django.utils.timesince import timesince
from django.core.validators import URLValidator
from django.core.exceptions import ValidationError
from jinja2 import Markup as mark_safe

from analytics.lib.counts import COUNT_STATS, CountStat
from analytics.lib.time_utils import time_range
from analytics.models import BaseCount, InstallationCount, \
    RealmCount, StreamCount, UserCount, last_successful_fill, installation_epoch
from confirmation.models import Confirmation, confirmation_url, _properties
from zerver.decorator import require_server_admin, require_server_admin_api, \
    to_utc_datetime, zulip_login_required, require_non_guest_user
from zerver.lib.exceptions import JsonableError
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.timestamp import convert_to_UTC, timestamp_to_datetime
from zerver.lib.realm_icon import realm_icon_url
from zerver.views.invite import get_invitee_emails_set
from zerver.lib.subdomains import get_subdomain_from_hostname
from zerver.lib.actions import do_change_plan_type, do_deactivate_realm, \
    do_send_realm_reactivation_email, do_scrub_realm
from zerver.lib.validator import to_non_negative_int
from confirmation.settings import STATUS_ACTIVE

if settings.BILLING_ENABLED:
    from corporate.lib.stripe import attach_discount_to_realm, get_discount_for_realm

from zerver.models import Client, get_realm, Realm, UserActivity, UserActivityInterval, \
    UserProfile, PreregistrationUser, MultiuseInvite

if settings.ZILENCER_ENABLED:
    from zilencer.models import RemoteInstallationCount, RemoteRealmCount, \
        RemoteZulipServer
else:
    from unittest.mock import Mock
    RemoteInstallationCount = Mock()  # type: ignore[misc] # https://github.com/JukkaL/mypy/issues/1188
    RemoteZulipServer = Mock()  # type: ignore[misc] # https://github.com/JukkaL/mypy/issues/1188
    RemoteRealmCount = Mock()  # type: ignore[misc] # https://github.com/JukkaL/mypy/issues/1188

MAX_TIME_FOR_FULL_ANALYTICS_GENERATION = timedelta(days=1, minutes=30)

def is_analytics_ready(realm: Realm) -> bool:
    return (timezone_now() - realm.date_created) > MAX_TIME_FOR_FULL_ANALYTICS_GENERATION

def render_stats(request: HttpRequest, data_url_suffix: str, target_name: str,
                 for_installation: bool=False, remote: bool=False,
                 analytics_ready: bool=True) -> HttpRequest:
    page_params = dict(
        data_url_suffix=data_url_suffix,
        for_installation=for_installation,
        remote=remote,
        debug_mode=False,
    )
    return render(request,
                  'analytics/stats.html',
                  context=dict(target_name=target_name,
                               page_params=page_params,
                               analytics_ready=analytics_ready))

@zulip_login_required
def stats(request: HttpRequest) -> HttpResponse:
    realm = request.user.realm
    if request.user.is_guest:
        # TODO: Make @zulip_login_required pass the UserProfile so we
        # can use @require_member_or_admin
        raise JsonableError(_("Not allowed for guest users"))
    return render_stats(request, '', realm.name or realm.string_id,
                        analytics_ready=is_analytics_ready(realm))

@require_server_admin
@has_request_variables
def stats_for_realm(request: HttpRequest, realm_str: str) -> HttpResponse:
    try:
        realm = get_realm(realm_str)
    except Realm.DoesNotExist:
        return HttpResponseNotFound("Realm %s does not exist" % (realm_str,))

    return render_stats(request, '/realm/%s' % (realm_str,), realm.name or realm.string_id,
                        analytics_ready=is_analytics_ready(realm))

@require_server_admin
@has_request_variables
def stats_for_remote_realm(request: HttpRequest, remote_server_id: str,
                           remote_realm_id: str) -> HttpResponse:
    server = RemoteZulipServer.objects.get(id=remote_server_id)
    return render_stats(request, '/remote/%s/realm/%s' % (server.id, remote_realm_id),
                        "Realm %s on server %s" % (remote_realm_id, server.hostname))

@require_server_admin_api
@has_request_variables
def get_chart_data_for_realm(request: HttpRequest, user_profile: UserProfile,
                             realm_str: str, **kwargs: Any) -> HttpResponse:
    try:
        realm = get_realm(realm_str)
    except Realm.DoesNotExist:
        raise JsonableError(_("Invalid organization"))

    return get_chart_data(request=request, user_profile=user_profile, realm=realm, **kwargs)

@require_server_admin_api
@has_request_variables
def get_chart_data_for_remote_realm(
        request: HttpRequest, user_profile: UserProfile, remote_server_id: str,
        remote_realm_id: str, **kwargs: Any) -> HttpResponse:
    server = RemoteZulipServer.objects.get(id=remote_server_id)
    return get_chart_data(request=request, user_profile=user_profile, server=server,
                          remote=True, remote_realm_id=int(remote_realm_id), **kwargs)

@require_server_admin
def stats_for_installation(request: HttpRequest) -> HttpResponse:
    return render_stats(request, '/installation', 'Installation', True)

@require_server_admin
def stats_for_remote_installation(request: HttpRequest, remote_server_id: str) -> HttpResponse:
    server = RemoteZulipServer.objects.get(id=remote_server_id)
    return render_stats(request, '/remote/%s/installation' % (server.id,),
                        'remote Installation %s' % (server.hostname,), True, True)

@require_server_admin_api
@has_request_variables
def get_chart_data_for_installation(request: HttpRequest, user_profile: UserProfile,
                                    chart_name: str=REQ(), **kwargs: Any) -> HttpResponse:
    return get_chart_data(request=request, user_profile=user_profile, for_installation=True, **kwargs)

@require_server_admin_api
@has_request_variables
def get_chart_data_for_remote_installation(
        request: HttpRequest,
        user_profile: UserProfile,
        remote_server_id: str,
        chart_name: str=REQ(),
        **kwargs: Any) -> HttpResponse:
    server = RemoteZulipServer.objects.get(id=remote_server_id)
    return get_chart_data(request=request, user_profile=user_profile, for_installation=True,
                          remote=True, server=server, **kwargs)

@require_non_guest_user
@has_request_variables
def get_chart_data(request: HttpRequest, user_profile: UserProfile, chart_name: str=REQ(),
                   min_length: Optional[int]=REQ(converter=to_non_negative_int, default=None),
                   start: Optional[datetime]=REQ(converter=to_utc_datetime, default=None),
                   end: Optional[datetime]=REQ(converter=to_utc_datetime, default=None),
                   realm: Optional[Realm]=None, for_installation: bool=False,
                   remote: bool=False, remote_realm_id: Optional[int]=None,
                   server: Optional[RemoteZulipServer]=None) -> HttpResponse:
    if for_installation:
        if remote:
            aggregate_table = RemoteInstallationCount
            assert server is not None
        else:
            aggregate_table = InstallationCount
    else:
        if remote:
            aggregate_table = RemoteRealmCount
            assert server is not None
            assert remote_realm_id is not None
        else:
            aggregate_table = RealmCount

    if chart_name == 'number_of_humans':
        stats = [
            COUNT_STATS['1day_actives::day'],
            COUNT_STATS['realm_active_humans::day'],
            COUNT_STATS['active_users_audit:is_bot:day']]
        tables = [aggregate_table]
        subgroup_to_label: Dict[CountStat, Dict[Optional[str], str]] = {
            stats[0]: {None: '_1day'},
            stats[1]: {None: '_15day'},
            stats[2]: {'false': 'all_time'}}
        labels_sort_function = None
        include_empty_subgroups = True
    elif chart_name == 'messages_sent_over_time':
        stats = [COUNT_STATS['messages_sent:is_bot:hour']]
        tables = [aggregate_table, UserCount]
        subgroup_to_label = {stats[0]: {'false': 'human', 'true': 'bot'}}
        labels_sort_function = None
        include_empty_subgroups = True
    elif chart_name == 'messages_sent_by_message_type':
        stats = [COUNT_STATS['messages_sent:message_type:day']]
        tables = [aggregate_table, UserCount]
        subgroup_to_label = {stats[0]: {'public_stream': _('Public streams'),
                                        'private_stream': _('Private streams'),
                                        'private_message': _('Private messages'),
                                        'huddle_message': _('Group private messages')}}
        labels_sort_function = lambda data: sort_by_totals(data['everyone'])
        include_empty_subgroups = True
    elif chart_name == 'messages_sent_by_client':
        stats = [COUNT_STATS['messages_sent:client:day']]
        tables = [aggregate_table, UserCount]
        # Note that the labels are further re-written by client_label_map
        subgroup_to_label = {stats[0]:
                             {str(id): name for id, name in Client.objects.values_list('id', 'name')}}
        labels_sort_function = sort_client_labels
        include_empty_subgroups = False
    else:
        raise JsonableError(_("Unknown chart name: %s") % (chart_name,))

    # Most likely someone using our API endpoint. The /stats page does not
    # pass a start or end in its requests.
    if start is not None:
        start = convert_to_UTC(start)
    if end is not None:
        end = convert_to_UTC(end)
    if start is not None and end is not None and start > end:
        raise JsonableError(_("Start time is later than end time. Start: %(start)s, End: %(end)s") %
                            {'start': start, 'end': end})

    if realm is None:
        # Note that this value is invalid for Remote tables; be
        # careful not to access it in those code paths.
        realm = user_profile.realm

    if remote:
        # For remote servers, we don't have fillstate data, and thus
        # should simply use the first and last data points for the
        # table.
        assert server is not None
        if not aggregate_table.objects.filter(server=server).exists():
            raise JsonableError(_("No analytics data available. Please contact your server administrator."))
        if start is None:
            start = aggregate_table.objects.filter(server=server).first().end_time
        if end is None:
            end = aggregate_table.objects.filter(server=server).last().end_time
    else:
        # Otherwise, we can use tables on the current server to
        # determine a nice range, and some additional validation.
        if start is None:
            if for_installation:
                start = installation_epoch()
            else:
                start = realm.date_created
        if end is None:
            end = max(last_successful_fill(stat.property) or
                      datetime.min.replace(tzinfo=timezone_utc) for stat in stats)

        if start > end and (timezone_now() - start > MAX_TIME_FOR_FULL_ANALYTICS_GENERATION):
            logging.warning("User from realm %s attempted to access /stats, but the computed "
                            "start time: %s (creation of realm or installation) is later than the computed "
                            "end time: %s (last successful analytics update). Is the "
                            "analytics cron job running?", realm.string_id, start, end)
            raise JsonableError(_("No analytics data available. Please contact your server administrator."))

    assert len({stat.frequency for stat in stats}) == 1
    end_times = time_range(start, end, stats[0].frequency, min_length)
    data: Dict[str, Any] = {'end_times': end_times, 'frequency': stats[0].frequency}

    aggregation_level = {
        InstallationCount: 'everyone',
        RealmCount: 'everyone',
        RemoteInstallationCount: 'everyone',
        RemoteRealmCount: 'everyone',
        UserCount: 'user',
    }
    # -1 is a placeholder value, since there is no relevant filtering on InstallationCount
    id_value = {
        InstallationCount: -1,
        RealmCount: realm.id,
        RemoteInstallationCount: server.id if server is not None else None,
        # TODO: RemoteRealmCount logic doesn't correctly handle
        # filtering by server_id as well.
        RemoteRealmCount: remote_realm_id,
        UserCount: user_profile.id,
    }
    for table in tables:
        data[aggregation_level[table]] = {}
        for stat in stats:
            data[aggregation_level[table]].update(get_time_series_by_subgroup(
                stat, table, id_value[table], end_times, subgroup_to_label[stat], include_empty_subgroups))

    if labels_sort_function is not None:
        data['display_order'] = labels_sort_function(data)
    else:
        data['display_order'] = None
    return json_success(data=data)

def sort_by_totals(value_arrays: Dict[str, List[int]]) -> List[str]:
    totals = [(sum(values), label) for label, values in value_arrays.items()]
    totals.sort(reverse=True)
    return [label for total, label in totals]

# For any given user, we want to show a fixed set of clients in the chart,
# regardless of the time aggregation or whether we're looking at realm or
# user data. This fixed set ideally includes the clients most important in
# understanding the realm's traffic and the user's traffic. This function
# tries to rank the clients so that taking the first N elements of the
# sorted list has a reasonable chance of doing so.
def sort_client_labels(data: Dict[str, Dict[str, List[int]]]) -> List[str]:
    realm_order = sort_by_totals(data['everyone'])
    user_order = sort_by_totals(data['user'])
    label_sort_values: Dict[str, float] = {}
    for i, label in enumerate(realm_order):
        label_sort_values[label] = i
    for i, label in enumerate(user_order):
        label_sort_values[label] = min(i-.1, label_sort_values.get(label, i))
    return [label for label, sort_value in sorted(label_sort_values.items(),
                                                  key=lambda x: x[1])]

def table_filtered_to_id(table: Type[BaseCount], key_id: int) -> QuerySet:
    if table == RealmCount:
        return RealmCount.objects.filter(realm_id=key_id)
    elif table == UserCount:
        return UserCount.objects.filter(user_id=key_id)
    elif table == StreamCount:
        return StreamCount.objects.filter(stream_id=key_id)
    elif table == InstallationCount:
        return InstallationCount.objects.all()
    elif table == RemoteInstallationCount:
        return RemoteInstallationCount.objects.filter(server_id=key_id)
    elif table == RemoteRealmCount:
        return RemoteRealmCount.objects.filter(realm_id=key_id)
    else:
        raise AssertionError("Unknown table: %s" % (table,))

def client_label_map(name: str) -> str:
    if name == "website":
        return "Website"
    if name.startswith("desktop app"):
        return "Old desktop app"
    if name == "ZulipElectron":
        return "Desktop app"
    if name == "ZulipAndroid":
        return "Old Android app"
    if name == "ZulipiOS":
        return "Old iOS app"
    if name == "ZulipMobile":
        return "Mobile app"
    if name in ["ZulipPython", "API: Python"]:
        return "Python API"
    if name.startswith("Zulip") and name.endswith("Webhook"):
        return name[len("Zulip"):-len("Webhook")] + " webhook"
    return name

def rewrite_client_arrays(value_arrays: Dict[str, List[int]]) -> Dict[str, List[int]]:
    mapped_arrays: Dict[str, List[int]] = {}
    for label, array in value_arrays.items():
        mapped_label = client_label_map(label)
        if mapped_label in mapped_arrays:
            for i in range(0, len(array)):
                mapped_arrays[mapped_label][i] += value_arrays[label][i]
        else:
            mapped_arrays[mapped_label] = [value_arrays[label][i] for i in range(0, len(array))]
    return mapped_arrays

def get_time_series_by_subgroup(stat: CountStat,
                                table: Type[BaseCount],
                                key_id: int,
                                end_times: List[datetime],
                                subgroup_to_label: Dict[Optional[str], str],
                                include_empty_subgroups: bool) -> Dict[str, List[int]]:
    queryset = table_filtered_to_id(table, key_id).filter(property=stat.property) \
                                                  .values_list('subgroup', 'end_time', 'value')
    value_dicts: Dict[Optional[str], Dict[datetime, int]] = defaultdict(lambda: defaultdict(int))
    for subgroup, end_time, value in queryset:
        value_dicts[subgroup][end_time] = value
    value_arrays = {}
    for subgroup, label in subgroup_to_label.items():
        if (subgroup in value_dicts) or include_empty_subgroups:
            value_arrays[label] = [value_dicts[subgroup][end_time] for end_time in end_times]

    if stat == COUNT_STATS['messages_sent:client:day']:
        # HACK: We rewrite these arrays to collapse the Client objects
        # with similar names into a single sum, and generally give
        # them better names
        return rewrite_client_arrays(value_arrays)
    return value_arrays


eastern_tz = pytz.timezone('US/Eastern')

def make_table(title: str, cols: List[str], rows: List[Any], has_row_class: bool=False) -> str:

    if not has_row_class:
        def fix_row(row: Any) -> Dict[str, Any]:
            return dict(cells=row, row_class=None)
        rows = list(map(fix_row, rows))

    data = dict(title=title, cols=cols, rows=rows)

    content = loader.render_to_string(
        'analytics/ad_hoc_query.html',
        dict(data=data)
    )

    return content

def dictfetchall(cursor: connection.cursor) -> List[Dict[str, Any]]:
    "Returns all rows from a cursor as a dict"
    desc = cursor.description
    return [
        dict(list(zip([col[0] for col in desc], row)))
        for row in cursor.fetchall()
    ]


def get_realm_day_counts() -> Dict[str, Dict[str, str]]:
    query = '''
        select
            r.string_id,
            (now()::date - date_sent::date) age,
            count(*) cnt
        from zerver_message m
        join zerver_userprofile up on up.id = m.sender_id
        join zerver_realm r on r.id = up.realm_id
        join zerver_client c on c.id = m.sending_client_id
        where
            (not up.is_bot)
        and
            date_sent > now()::date - interval '8 day'
        and
            c.name not in ('zephyr_mirror', 'ZulipMonitoring')
        group by
            r.string_id,
            age
        order by
            r.string_id,
            age
    '''
    cursor = connection.cursor()
    cursor.execute(query)
    rows = dictfetchall(cursor)
    cursor.close()

    counts: Dict[str, Dict[int, int]] = defaultdict(dict)
    for row in rows:
        counts[row['string_id']][row['age']] = row['cnt']

    result = {}
    for string_id in counts:
        raw_cnts = [counts[string_id].get(age, 0) for age in range(8)]
        min_cnt = min(raw_cnts[1:])
        max_cnt = max(raw_cnts[1:])

        def format_count(cnt: int, style: Optional[str]=None) -> str:
            if style is not None:
                good_bad = style
            elif cnt == min_cnt:
                good_bad = 'bad'
            elif cnt == max_cnt:
                good_bad = 'good'
            else:
                good_bad = 'neutral'

            return '<td class="number %s">%s</td>' % (good_bad, cnt)

        cnts = (format_count(raw_cnts[0], 'neutral')
                + ''.join(map(format_count, raw_cnts[1:])))
        result[string_id] = dict(cnts=cnts)

    return result

def get_plan_name(plan_type: int) -> str:
    return ['', 'self hosted', 'limited', 'standard', 'open source'][plan_type]

def realm_summary_table(realm_minutes: Dict[str, float]) -> str:
    now = timezone_now()

    query = '''
        SELECT
            realm.string_id,
            realm.date_created,
            realm.plan_type,
            coalesce(user_counts.dau_count, 0) dau_count,
            coalesce(wau_counts.wau_count, 0) wau_count,
            (
                SELECT
                    count(*)
                FROM zerver_userprofile up
                WHERE up.realm_id = realm.id
                AND is_active
                AND not is_bot
            ) user_profile_count,
            (
                SELECT
                    count(*)
                FROM zerver_userprofile up
                WHERE up.realm_id = realm.id
                AND is_active
                AND is_bot
            ) bot_count
        FROM zerver_realm realm
        LEFT OUTER JOIN
            (
                SELECT
                    up.realm_id realm_id,
                    count(distinct(ua.user_profile_id)) dau_count
                FROM zerver_useractivity ua
                JOIN zerver_userprofile up
                    ON up.id = ua.user_profile_id
                WHERE
                    up.is_active
                AND (not up.is_bot)
                AND
                    query in (
                        '/json/send_message',
                        'send_message_backend',
                        '/api/v1/send_message',
                        '/json/update_pointer',
                        '/json/users/me/pointer',
                        'update_pointer_backend'
                    )
                AND
                    last_visit > now() - interval '1 day'
                GROUP BY realm_id
            ) user_counts
            ON user_counts.realm_id = realm.id
        LEFT OUTER JOIN
            (
                SELECT
                    realm_id,
                    count(*) wau_count
                FROM (
                    SELECT
                        realm.id as realm_id,
                        up.delivery_email
                    FROM zerver_useractivity ua
                    JOIN zerver_userprofile up
                        ON up.id = ua.user_profile_id
                    JOIN zerver_realm realm
                        ON realm.id = up.realm_id
                    WHERE up.is_active
                    AND (not up.is_bot)
                    AND
                        ua.query in (
                            '/json/send_message',
                            'send_message_backend',
                            '/api/v1/send_message',
                            '/json/update_pointer',
                            '/json/users/me/pointer',
                            'update_pointer_backend'
                        )
                    GROUP by realm.id, up.delivery_email
                    HAVING max(last_visit) > now() - interval '7 day'
                ) as wau_users
                GROUP BY realm_id
            ) wau_counts
            ON wau_counts.realm_id = realm.id
        WHERE EXISTS (
                SELECT *
                FROM zerver_useractivity ua
                JOIN zerver_userprofile up
                    ON up.id = ua.user_profile_id
                WHERE
                    up.realm_id = realm.id
                AND up.is_active
                AND (not up.is_bot)
                AND
                    query in (
                        '/json/send_message',
                        '/api/v1/send_message',
                        'send_message_backend',
                        '/json/update_pointer',
                        '/json/users/me/pointer',
                        'update_pointer_backend'
                    )
                AND
                    last_visit > now() - interval '2 week'
        )
        ORDER BY dau_count DESC, string_id ASC
        '''

    cursor = connection.cursor()
    cursor.execute(query)
    rows = dictfetchall(cursor)
    cursor.close()

    # Fetch all the realm administrator users
    realm_admins: Dict[str, List[str]] = defaultdict(list)
    for up in UserProfile.objects.select_related("realm").filter(
        role=UserProfile.ROLE_REALM_ADMINISTRATOR,
        is_active=True
    ):
        realm_admins[up.realm.string_id].append(up.delivery_email)

    for row in rows:
        row['date_created_day'] = row['date_created'].strftime('%Y-%m-%d')
        row['plan_type_string'] = get_plan_name(row['plan_type'])
        row['age_days'] = int((now - row['date_created']).total_seconds()
                              / 86400)
        row['is_new'] = row['age_days'] < 12 * 7
        row['realm_admin_email'] = ', '.join(realm_admins[row['string_id']])

    # get messages sent per day
    counts = get_realm_day_counts()
    for row in rows:
        try:
            row['history'] = counts[row['string_id']]['cnts']
        except Exception:
            row['history'] = ''

    # estimate annual subscription revenue
    total_amount = 0
    if settings.BILLING_ENABLED:
        from corporate.lib.stripe import estimate_annual_recurring_revenue_by_realm
        estimated_arrs = estimate_annual_recurring_revenue_by_realm()
        for row in rows:
            if row['string_id'] in estimated_arrs:
                row['amount'] = estimated_arrs[row['string_id']]
        total_amount += sum(estimated_arrs.values())

    # augment data with realm_minutes
    total_hours = 0.0
    for row in rows:
        string_id = row['string_id']
        minutes = realm_minutes.get(string_id, 0.0)
        hours = minutes / 60.0
        total_hours += hours
        row['hours'] = str(int(hours))
        try:
            row['hours_per_user'] = '%.1f' % (hours / row['dau_count'],)
        except Exception:
            pass

    # formatting
    for row in rows:
        row['stats_link'] = realm_stats_link(row['string_id'])
        row['string_id'] = realm_activity_link(row['string_id'])

    # Count active sites
    def meets_goal(row: Dict[str, int]) -> bool:
        return row['dau_count'] >= 5

    num_active_sites = len(list(filter(meets_goal, rows)))

    # create totals
    total_dau_count = 0
    total_user_profile_count = 0
    total_bot_count = 0
    total_wau_count = 0
    for row in rows:
        total_dau_count += int(row['dau_count'])
        total_user_profile_count += int(row['user_profile_count'])
        total_bot_count += int(row['bot_count'])
        total_wau_count += int(row['wau_count'])

    total_row = dict(
        string_id='Total',
        plan_type_string="",
        amount=total_amount,
        stats_link = '',
        date_created_day='',
        realm_admin_email='',
        dau_count=total_dau_count,
        user_profile_count=total_user_profile_count,
        bot_count=total_bot_count,
        hours=int(total_hours),
        wau_count=total_wau_count,
    )

    rows.insert(0, total_row)

    content = loader.render_to_string(
        'analytics/realm_summary_table.html',
        dict(rows=rows, num_active_sites=num_active_sites,
             now=now.strftime('%Y-%m-%dT%H:%M:%SZ'))
    )
    return content


def user_activity_intervals() -> Tuple[mark_safe, Dict[str, float]]:
    day_end = timestamp_to_datetime(time.time())
    day_start = day_end - timedelta(hours=24)

    output = "Per-user online duration for the last 24 hours:\n"
    total_duration = timedelta(0)

    all_intervals = UserActivityInterval.objects.filter(
        end__gte=day_start,
        start__lte=day_end
    ).select_related(
        'user_profile',
        'user_profile__realm'
    ).only(
        'start',
        'end',
        'user_profile__delivery_email',
        'user_profile__realm__string_id'
    ).order_by(
        'user_profile__realm__string_id',
        'user_profile__delivery_email'
    )

    by_string_id = lambda row: row.user_profile.realm.string_id
    by_email = lambda row: row.user_profile.delivery_email

    realm_minutes = {}

    for string_id, realm_intervals in itertools.groupby(all_intervals, by_string_id):
        realm_duration = timedelta(0)
        output += '<hr>%s\n' % (string_id,)
        for email, intervals in itertools.groupby(realm_intervals, by_email):
            duration = timedelta(0)
            for interval in intervals:
                start = max(day_start, interval.start)
                end = min(day_end, interval.end)
                duration += end - start

            total_duration += duration
            realm_duration += duration
            output += "  %-*s%s\n" % (37, email, duration)

        realm_minutes[string_id] = realm_duration.total_seconds() / 60

    output += "\nTotal Duration:                      %s\n" % (total_duration,)
    output += "\nTotal Duration in minutes:           %s\n" % (total_duration.total_seconds() / 60.,)
    output += "Total Duration amortized to a month: %s" % (total_duration.total_seconds() * 30. / 60.,)
    content = mark_safe('<pre>' + output + '</pre>')
    return content, realm_minutes

def sent_messages_report(realm: str) -> str:
    title = 'Recently sent messages for ' + realm

    cols = [
        'Date',
        'Humans',
        'Bots'
    ]

    query = '''
        select
            series.day::date,
            humans.cnt,
            bots.cnt
        from (
            select generate_series(
                (now()::date - interval '2 week'),
                now()::date,
                interval '1 day'
            ) as day
        ) as series
        left join (
            select
                date_sent::date date_sent,
                count(*) cnt
            from zerver_message m
            join zerver_userprofile up on up.id = m.sender_id
            join zerver_realm r on r.id = up.realm_id
            where
                r.string_id = %s
            and
                (not up.is_bot)
            and
                date_sent > now() - interval '2 week'
            group by
                date_sent::date
            order by
                date_sent::date
        ) humans on
            series.day = humans.date_sent
        left join (
            select
                date_sent::date date_sent,
                count(*) cnt
            from zerver_message m
            join zerver_userprofile up on up.id = m.sender_id
            join zerver_realm r on r.id = up.realm_id
            where
                r.string_id = %s
            and
                up.is_bot
            and
                date_sent > now() - interval '2 week'
            group by
                date_sent::date
            order by
                date_sent::date
        ) bots on
            series.day = bots.date_sent
    '''
    cursor = connection.cursor()
    cursor.execute(query, [realm, realm])
    rows = cursor.fetchall()
    cursor.close()

    return make_table(title, cols, rows)

def ad_hoc_queries() -> List[Dict[str, str]]:
    def get_page(query: str, cols: List[str], title: str,
                 totals_columns: List[int]=[]) -> Dict[str, str]:
        cursor = connection.cursor()
        cursor.execute(query)
        rows = cursor.fetchall()
        rows = list(map(list, rows))
        cursor.close()

        def fix_rows(i: int,
                     fixup_func: Union[Callable[[Realm], mark_safe], Callable[[datetime], str]]) -> None:
            for row in rows:
                row[i] = fixup_func(row[i])

        total_row = []
        for i, col in enumerate(cols):
            if col == 'Realm':
                fix_rows(i, realm_activity_link)
            elif col in ['Last time', 'Last visit']:
                fix_rows(i, format_date_for_activity_reports)
            elif col == 'Hostname':
                for row in rows:
                    row[i] = remote_installation_stats_link(row[0], row[i])
            if len(totals_columns) > 0:
                if i == 0:
                    total_row.append("Total")
                elif i in totals_columns:
                    total_row.append(str(sum(row[i] for row in rows if row[i] is not None)))
                else:
                    total_row.append('')
        if len(totals_columns) > 0:
            rows.insert(0, total_row)

        content = make_table(title, cols, rows)

        return dict(
            content=content,
            title=title
        )

    pages = []

    ###

    for mobile_type in ['Android', 'ZulipiOS']:
        title = '%s usage' % (mobile_type,)

        query = '''
            select
                realm.string_id,
                up.id user_id,
                client.name,
                sum(count) as hits,
                max(last_visit) as last_time
            from zerver_useractivity ua
            join zerver_client client on client.id = ua.client_id
            join zerver_userprofile up on up.id = ua.user_profile_id
            join zerver_realm realm on realm.id = up.realm_id
            where
                client.name like '%s'
            group by string_id, up.id, client.name
            having max(last_visit) > now() - interval '2 week'
            order by string_id, up.id, client.name
        ''' % (mobile_type,)

        cols = [
            'Realm',
            'User id',
            'Name',
            'Hits',
            'Last time'
        ]

        pages.append(get_page(query, cols, title))

    ###

    title = 'Desktop users'

    query = '''
        select
            realm.string_id,
            client.name,
            sum(count) as hits,
            max(last_visit) as last_time
        from zerver_useractivity ua
        join zerver_client client on client.id = ua.client_id
        join zerver_userprofile up on up.id = ua.user_profile_id
        join zerver_realm realm on realm.id = up.realm_id
        where
            client.name like 'desktop%%'
        group by string_id, client.name
        having max(last_visit) > now() - interval '2 week'
        order by string_id, client.name
    '''

    cols = [
        'Realm',
        'Client',
        'Hits',
        'Last time'
    ]

    pages.append(get_page(query, cols, title))

    ###

    title = 'Integrations by realm'

    query = '''
        select
            realm.string_id,
            case
                when query like '%%external%%' then split_part(query, '/', 5)
                else client.name
            end client_name,
            sum(count) as hits,
            max(last_visit) as last_time
        from zerver_useractivity ua
        join zerver_client client on client.id = ua.client_id
        join zerver_userprofile up on up.id = ua.user_profile_id
        join zerver_realm realm on realm.id = up.realm_id
        where
            (query in ('send_message_backend', '/api/v1/send_message')
            and client.name not in ('Android', 'ZulipiOS')
            and client.name not like 'test: Zulip%%'
            )
        or
            query like '%%external%%'
        group by string_id, client_name
        having max(last_visit) > now() - interval '2 week'
        order by string_id, client_name
    '''

    cols = [
        'Realm',
        'Client',
        'Hits',
        'Last time'
    ]

    pages.append(get_page(query, cols, title))

    ###

    title = 'Integrations by client'

    query = '''
        select
            case
                when query like '%%external%%' then split_part(query, '/', 5)
                else client.name
            end client_name,
            realm.string_id,
            sum(count) as hits,
            max(last_visit) as last_time
        from zerver_useractivity ua
        join zerver_client client on client.id = ua.client_id
        join zerver_userprofile up on up.id = ua.user_profile_id
        join zerver_realm realm on realm.id = up.realm_id
        where
            (query in ('send_message_backend', '/api/v1/send_message')
            and client.name not in ('Android', 'ZulipiOS')
            and client.name not like 'test: Zulip%%'
            )
        or
            query like '%%external%%'
        group by client_name, string_id
        having max(last_visit) > now() - interval '2 week'
        order by client_name, string_id
    '''

    cols = [
        'Client',
        'Realm',
        'Hits',
        'Last time'
    ]

    pages.append(get_page(query, cols, title))

    title = 'Remote Zulip servers'

    query = '''
        with icount as (
            select
                server_id,
                max(value) as max_value,
                max(end_time) as max_end_time
            from zilencer_remoteinstallationcount
            where
                property='active_users:is_bot:day'
                and subgroup='false'
            group by server_id
            ),
        remote_push_devices as (
            select server_id, count(distinct(user_id)) as push_user_count from zilencer_remotepushdevicetoken
            group by server_id
        )
        select
            rserver.id,
            rserver.hostname,
            rserver.contact_email,
            max_value,
            push_user_count,
            max_end_time
        from zilencer_remotezulipserver rserver
        left join icount on icount.server_id = rserver.id
        left join remote_push_devices on remote_push_devices.server_id = rserver.id
        order by max_value DESC NULLS LAST, push_user_count DESC NULLS LAST
    '''

    cols = [
        'ID',
        'Hostname',
        'Contact email',
        'Analytics users',
        'Mobile users',
        'Last update time',
    ]

    pages.append(get_page(query, cols, title,
                          totals_columns=[3, 4]))

    return pages

@require_server_admin
@has_request_variables
def get_activity(request: HttpRequest) -> HttpResponse:
    duration_content, realm_minutes = user_activity_intervals()
    counts_content: str = realm_summary_table(realm_minutes)
    data = [
        ('Counts', counts_content),
        ('Durations', duration_content),
    ]
    for page in ad_hoc_queries():
        data.append((page['title'], page['content']))

    title = 'Activity'

    return render(
        request,
        'analytics/activity.html',
        context=dict(data=data, title=title, is_home=True),
    )

def get_confirmations(types: List[int], object_ids: List[int],
                      hostname: Optional[str]=None) -> List[Dict[str, Any]]:
    lowest_datetime = timezone_now() - timedelta(days=30)
    confirmations = Confirmation.objects.filter(type__in=types, object_id__in=object_ids,
                                                date_sent__gte=lowest_datetime)
    confirmation_dicts = []
    for confirmation in confirmations:
        realm = confirmation.realm
        content_object = confirmation.content_object

        if realm is not None:
            realm_host = realm.host
        elif isinstance(content_object, Realm):
            realm_host = content_object.host
        else:
            realm_host = hostname

        type = confirmation.type
        days_to_activate = _properties[type].validity_in_days
        expiry_date = confirmation.date_sent + timedelta(days=days_to_activate)

        if hasattr(content_object, "status"):
            if content_object.status == STATUS_ACTIVE:
                link_status = "Link has been clicked"
            else:
                link_status = "Link has never been clicked"
        else:
            link_status = ""

        if timezone_now() < expiry_date:
            expires_in = timesince(confirmation.date_sent, expiry_date)
        else:
            expires_in = "Expired"

        url = confirmation_url(confirmation.confirmation_key, realm_host, type)
        confirmation_dicts.append({"object": confirmation.content_object,
                                   "url": url, "type": type, "link_status": link_status,
                                   "expires_in": expires_in})
    return confirmation_dicts

@require_server_admin
def support(request: HttpRequest) -> HttpResponse:
    context: Dict[str, Any] = {}
    if settings.BILLING_ENABLED and request.method == "POST":
        realm_id = request.POST.get("realm_id", None)
        realm = Realm.objects.get(id=realm_id)

        new_plan_type = request.POST.get("plan_type", None)
        if new_plan_type is not None:
            new_plan_type = int(new_plan_type)
            current_plan_type = realm.plan_type
            do_change_plan_type(realm, new_plan_type)
            msg = "Plan type of {} changed from {} to {} ".format(realm.name,
                                                                  get_plan_name(current_plan_type),
                                                                  get_plan_name(new_plan_type))
            context["message"] = msg

        new_discount = request.POST.get("discount", None)
        if new_discount is not None:
            new_discount = Decimal(new_discount)
            current_discount = get_discount_for_realm(realm)
            attach_discount_to_realm(realm, new_discount)
            msg = "Discount of {} changed to {} from {} ".format(realm.name, new_discount, current_discount)
            context["message"] = msg

        status = request.POST.get("status", None)
        if status is not None:
            if status == "active":
                do_send_realm_reactivation_email(realm)
                context["message"] = "Realm reactivation email sent to admins of {}.".format(realm.name)
            elif status == "deactivated":
                do_deactivate_realm(realm, request.user)
                context["message"] = "{} deactivated.".format(realm.name)

        scrub_realm = request.POST.get("scrub_realm", None)
        if scrub_realm is not None:
            if scrub_realm == "scrub_realm":
                do_scrub_realm(realm)
                context["message"] = "{} scrubbed.".format(realm.name)

    query = request.GET.get("q", None)
    if query:
        key_words = get_invitee_emails_set(query)

        context["users"] = UserProfile.objects.filter(delivery_email__in=key_words)
        realms = set(Realm.objects.filter(string_id__in=key_words))

        for key_word in key_words:
            try:
                URLValidator()(key_word)
                parse_result = urllib.parse.urlparse(key_word)
                hostname = parse_result.hostname
                assert hostname is not None
                if parse_result.port:
                    hostname = "{}:{}".format(hostname, parse_result.port)
                subdomain = get_subdomain_from_hostname(hostname)
                try:
                    realms.add(get_realm(subdomain))
                except Realm.DoesNotExist:
                    pass
            except ValidationError:
                pass

        context["realms"] = realms

        confirmations: List[Dict[str, Any]] = []

        preregistration_users = PreregistrationUser.objects.filter(email__in=key_words)
        confirmations += get_confirmations([Confirmation.USER_REGISTRATION, Confirmation.INVITATION,
                                            Confirmation.REALM_CREATION], preregistration_users,
                                           hostname=request.get_host())

        multiuse_invites = MultiuseInvite.objects.filter(realm__in=realms)
        confirmations += get_confirmations([Confirmation.MULTIUSE_INVITE], multiuse_invites)

        confirmations += get_confirmations([Confirmation.REALM_REACTIVATION], [realm.id for realm in realms])

        context["confirmations"] = confirmations

    def realm_admin_emails(realm: Realm) -> str:
        return ", ".join(realm.get_human_admin_users().order_by('delivery_email').values_list(
            "delivery_email", flat=True))

    context["realm_admin_emails"] = realm_admin_emails
    context["get_discount_for_realm"] = get_discount_for_realm
    context["realm_icon_url"] = realm_icon_url
    context["Confirmation"] = Confirmation
    return render(request, 'analytics/support.html', context=context)

def get_user_activity_records_for_realm(realm: str, is_bot: bool) -> QuerySet:
    fields = [
        'user_profile__full_name',
        'user_profile__delivery_email',
        'query',
        'client__name',
        'count',
        'last_visit',
    ]

    records = UserActivity.objects.filter(
        user_profile__realm__string_id=realm,
        user_profile__is_active=True,
        user_profile__is_bot=is_bot
    )
    records = records.order_by("user_profile__delivery_email", "-last_visit")
    records = records.select_related('user_profile', 'client').only(*fields)
    return records

def get_user_activity_records_for_email(email: str) -> List[QuerySet]:
    fields = [
        'user_profile__full_name',
        'query',
        'client__name',
        'count',
        'last_visit'
    ]

    records = UserActivity.objects.filter(
        user_profile__delivery_email=email
    )
    records = records.order_by("-last_visit")
    records = records.select_related('user_profile', 'client').only(*fields)
    return records

def raw_user_activity_table(records: List[QuerySet]) -> str:
    cols = [
        'query',
        'client',
        'count',
        'last_visit'
    ]

    def row(record: QuerySet) -> List[Any]:
        return [
            record.query,
            record.client.name,
            record.count,
            format_date_for_activity_reports(record.last_visit)
        ]

    rows = list(map(row, records))
    title = 'Raw Data'
    return make_table(title, cols, rows)

def get_user_activity_summary(records: List[QuerySet]) -> Dict[str, Dict[str, Any]]:
    #: `Any` used above should be `Union(int, datetime)`.
    #: However current version of `Union` does not work inside other function.
    #: We could use something like:
    # `Union[Dict[str, Dict[str, int]], Dict[str, Dict[str, datetime]]]`
    #: but that would require this long `Union` to carry on throughout inner functions.
    summary: Dict[str, Dict[str, Any]] = {}

    def update(action: str, record: QuerySet) -> None:
        if action not in summary:
            summary[action] = dict(
                count=record.count,
                last_visit=record.last_visit
            )
        else:
            summary[action]['count'] += record.count
            summary[action]['last_visit'] = max(
                summary[action]['last_visit'],
                record.last_visit
            )

    if records:
        summary['name'] = records[0].user_profile.full_name

    for record in records:
        client = record.client.name
        query = record.query

        update('use', record)

        if client == 'API':
            m = re.match('/api/.*/external/(.*)', query)
            if m:
                client = m.group(1)
                update(client, record)

        if client.startswith('desktop'):
            update('desktop', record)
        if client == 'website':
            update('website', record)
        if ('send_message' in query) or re.search('/api/.*/external/.*', query):
            update('send', record)
        if query in ['/json/update_pointer', '/json/users/me/pointer', '/api/v1/update_pointer',
                     'update_pointer_backend']:
            update('pointer', record)
        update(client, record)

    return summary

def format_date_for_activity_reports(date: Optional[datetime]) -> str:
    if date:
        return date.astimezone(eastern_tz).strftime('%Y-%m-%d %H:%M')
    else:
        return ''

def user_activity_link(email: str) -> mark_safe:
    url_name = 'analytics.views.get_user_activity'
    url = reverse(url_name, kwargs=dict(email=email))
    email_link = '<a href="%s">%s</a>' % (url, email)
    return mark_safe(email_link)

def realm_activity_link(realm_str: str) -> mark_safe:
    url_name = 'analytics.views.get_realm_activity'
    url = reverse(url_name, kwargs=dict(realm_str=realm_str))
    realm_link = '<a href="%s">%s</a>' % (url, realm_str)
    return mark_safe(realm_link)

def realm_stats_link(realm_str: str) -> mark_safe:
    url_name = 'analytics.views.stats_for_realm'
    url = reverse(url_name, kwargs=dict(realm_str=realm_str))
    stats_link = '<a href="{}"><i class="fa fa-pie-chart"></i>{}</a>'.format(url, realm_str)
    return mark_safe(stats_link)

def remote_installation_stats_link(server_id: int, hostname: str) -> mark_safe:
    url_name = 'analytics.views.stats_for_remote_installation'
    url = reverse(url_name, kwargs=dict(remote_server_id=server_id))
    stats_link = '<a href="{}"><i class="fa fa-pie-chart"></i>{}</a>'.format(url, hostname)
    return mark_safe(stats_link)

def realm_client_table(user_summaries: Dict[str, Dict[str, Dict[str, Any]]]) -> str:
    exclude_keys = [
        'internal',
        'name',
        'use',
        'send',
        'pointer',
        'website',
        'desktop',
    ]

    rows = []
    for email, user_summary in user_summaries.items():
        email_link = user_activity_link(email)
        name = user_summary['name']
        for k, v in user_summary.items():
            if k in exclude_keys:
                continue
            client = k
            count = v['count']
            last_visit = v['last_visit']
            row = [
                format_date_for_activity_reports(last_visit),
                client,
                name,
                email_link,
                count,
            ]
            rows.append(row)

    rows = sorted(rows, key=lambda r: r[0], reverse=True)

    cols = [
        'Last visit',
        'Client',
        'Name',
        'Email',
        'Count',
    ]

    title = 'Clients'

    return make_table(title, cols, rows)

def user_activity_summary_table(user_summary: Dict[str, Dict[str, Any]]) -> str:
    rows = []
    for k, v in user_summary.items():
        if k == 'name':
            continue
        client = k
        count = v['count']
        last_visit = v['last_visit']
        row = [
            format_date_for_activity_reports(last_visit),
            client,
            count,
        ]
        rows.append(row)

    rows = sorted(rows, key=lambda r: r[0], reverse=True)

    cols = [
        'last_visit',
        'client',
        'count',
    ]

    title = 'User Activity'
    return make_table(title, cols, rows)

def realm_user_summary_table(all_records: List[QuerySet],
                             admin_emails: Set[str]) -> Tuple[Dict[str, Dict[str, Any]], str]:
    user_records = {}

    def by_email(record: QuerySet) -> str:
        return record.user_profile.delivery_email

    for email, records in itertools.groupby(all_records, by_email):
        user_records[email] = get_user_activity_summary(list(records))

    def get_last_visit(user_summary: Dict[str, Dict[str, datetime]], k: str) -> Optional[datetime]:
        if k in user_summary:
            return user_summary[k]['last_visit']
        else:
            return None

    def get_count(user_summary: Dict[str, Dict[str, str]], k: str) -> str:
        if k in user_summary:
            return user_summary[k]['count']
        else:
            return ''

    def is_recent(val: Optional[datetime]) -> bool:
        age = timezone_now() - val
        return age.total_seconds() < 5 * 60

    rows = []
    for email, user_summary in user_records.items():
        email_link = user_activity_link(email)
        sent_count = get_count(user_summary, 'send')
        cells = [user_summary['name'], email_link, sent_count]
        row_class = ''
        for field in ['use', 'send', 'pointer', 'desktop', 'ZulipiOS', 'Android']:
            visit = get_last_visit(user_summary, field)
            if field == 'use':
                if visit and is_recent(visit):
                    row_class += ' recently_active'
                if email in admin_emails:
                    row_class += ' admin'
            val = format_date_for_activity_reports(visit)
            cells.append(val)
        row = dict(cells=cells, row_class=row_class)
        rows.append(row)

    def by_used_time(row: Dict[str, Any]) -> str:
        return row['cells'][3]

    rows = sorted(rows, key=by_used_time, reverse=True)

    cols = [
        'Name',
        'Email',
        'Total sent',
        'Heard from',
        'Message sent',
        'Pointer motion',
        'Desktop',
        'ZulipiOS',
        'Android',
    ]

    title = 'Summary'

    content = make_table(title, cols, rows, has_row_class=True)
    return user_records, content

@require_server_admin
def get_realm_activity(request: HttpRequest, realm_str: str) -> HttpResponse:
    data: List[Tuple[str, str]] = []
    all_user_records: Dict[str, Any] = {}

    try:
        admins = Realm.objects.get(string_id=realm_str).get_human_admin_users()
    except Realm.DoesNotExist:
        return HttpResponseNotFound("Realm %s does not exist" % (realm_str,))

    admin_emails = {admin.delivery_email for admin in admins}

    for is_bot, page_title in [(False, 'Humans'), (True, 'Bots')]:
        all_records = list(get_user_activity_records_for_realm(realm_str, is_bot))

        user_records, content = realm_user_summary_table(all_records, admin_emails)
        all_user_records.update(user_records)

        data += [(page_title, content)]

    page_title = 'Clients'
    content = realm_client_table(all_user_records)
    data += [(page_title, content)]

    page_title = 'History'
    content = sent_messages_report(realm_str)
    data += [(page_title, content)]

    title = realm_str
    return render(
        request,
        'analytics/activity.html',
        context=dict(data=data, realm_link=None, title=title),
    )

@require_server_admin
def get_user_activity(request: HttpRequest, email: str) -> HttpResponse:
    records = get_user_activity_records_for_email(email)

    data: List[Tuple[str, str]] = []
    user_summary = get_user_activity_summary(records)
    content = user_activity_summary_table(user_summary)

    data += [('Summary', content)]

    content = raw_user_activity_table(records)
    data += [('Info', content)]

    title = email
    return render(
        request,
        'analytics/activity.html',
        context=dict(data=data, title=title),
    )