from datetime import datetime, timedelta as td
import json
from urllib.parse import urlencode

from croniter import croniter
from django.conf import settings
from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.core import signing
from django.db.models import Count
from django.http import (
    Http404,
    HttpResponse,
    HttpResponseBadRequest,
    HttpResponseForbidden,
    JsonResponse,
)
from django.shortcuts import get_object_or_404, redirect, render
from django.template.loader import get_template, render_to_string
from django.urls import reverse
from django.utils import timezone
from django.utils.crypto import get_random_string
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import require_POST
from hc.accounts.models import Project
from hc.api.models import (
    DEFAULT_GRACE,
    DEFAULT_TIMEOUT,
    MAX_DELTA,
    Channel,
    Check,
    Ping,
    Notification,
)
from hc.api.transports import Telegram
from hc.front.forms import (
    AddWebhookForm,
    NameTagsForm,
    TimeoutForm,
    AddUrlForm,
    AddEmailForm,
    AddOpsGenieForm,
    CronForm,
    AddSmsForm,
    ChannelNameForm,
    EmailSettingsForm,
    AddMatrixForm,
    AddAppriseForm,
)
from hc.front.schemas import telegram_callback
from hc.front.templatetags.hc_extras import num_down_title, down_title, sortchecks
from hc.lib import jsonschema
from hc.lib.badges import get_badge_url
import pytz
from pytz.exceptions import UnknownTimeZoneError
import requests


VALID_SORT_VALUES = ("name", "-name", "last_ping", "-last_ping", "created")
STATUS_TEXT_TMPL = get_template("front/log_status_text.html")
LAST_PING_TMPL = get_template("front/last_ping_cell.html")
EVENTS_TMPL = get_template("front/details_events.html")
DOWNTIMES_TMPL = get_template("front/details_downtimes.html")


def _tags_statuses(checks):
    tags, down, grace, num_down = {}, {}, {}, 0
    for check in checks:
        status = check.get_status(with_started=False)

        if status == "down":
            num_down += 1
            for tag in check.tags_list():
                down[tag] = "down"
        elif status == "grace":
            for tag in check.tags_list():
                grace[tag] = "grace"
        else:
            for tag in check.tags_list():
                tags[tag] = "up"

    tags.update(grace)
    tags.update(down)
    return tags, num_down


def _get_check_for_user(request, code):
    """ Return specified check if current user has access to it. """

    if not request.user.is_authenticated:
        raise Http404("not found")

    if request.user.is_superuser:
        q = Check.objects
    else:
        q = request.profile.checks_from_all_projects()

    try:
        return q.get(code=code)
    except Check.DoesNotExist:
        raise Http404("not found")


def _get_project_for_user(request, project_code):
    """ Return true if current user has access to the specified account. """

    if request.user.is_superuser:
        q = Project.objects
    else:
        q = request.profile.projects()

    try:
        return q.get(code=project_code)
    except Project.DoesNotExist:
        raise Http404("not found")


@login_required
def my_checks(request, code):
    project = _get_project_for_user(request, code)

    if request.GET.get("sort") in VALID_SORT_VALUES:
        request.profile.sort = request.GET["sort"]
        request.profile.save()

    if request.profile.current_project_id != project.id:
        request.profile.current_project = project
        request.profile.save()

    q = Check.objects.filter(project=project)
    checks = list(q.prefetch_related("channel_set"))
    sortchecks(checks, request.profile.sort)

    tags_statuses, num_down = _tags_statuses(checks)
    pairs = list(tags_statuses.items())
    pairs.sort(key=lambda pair: pair[0].lower())

    channels = Channel.objects.filter(project=project)
    channels = list(channels.order_by("created"))

    hidden_checks = set()
    # Hide checks that don't match selected tags:
    selected_tags = set(request.GET.getlist("tag", []))
    if selected_tags:
        for check in checks:
            if not selected_tags.issubset(check.tags_list()):
                hidden_checks.add(check)

    # Hide checks that don't match the search string:
    search = request.GET.get("search", "")
    if search:
        for check in checks:
            search_key = "%s\n%s" % (check.name.lower(), check.code)
            if search not in search_key:
                hidden_checks.add(check)

    # Do we need to show the "Last Duration" header?
    show_last_duration = False
    for check in checks:
        if check.clamped_last_duration():
            show_last_duration = True
            break

    ctx = {
        "page": "checks",
        "checks": checks,
        "channels": channels,
        "num_down": num_down,
        "now": timezone.now(),
        "tags": pairs,
        "ping_endpoint": settings.PING_ENDPOINT,
        "timezones": pytz.all_timezones,
        "project": project,
        "num_available": project.num_checks_available(),
        "sort": request.profile.sort,
        "selected_tags": selected_tags,
        "search": search,
        "hidden_checks": hidden_checks,
        "show_last_duration": show_last_duration,
    }

    return render(request, "front/my_checks.html", ctx)


@login_required
def status(request, code):
    _get_project_for_user(request, code)

    checks = list(Check.objects.filter(project__code=code))

    details = []
    for check in checks:
        ctx = {"check": check}
        details.append(
            {
                "code": str(check.code),
                "status": check.get_status(),
                "last_ping": LAST_PING_TMPL.render(ctx),
            }
        )

    tags_statuses, num_down = _tags_statuses(checks)
    return JsonResponse(
        {"details": details, "tags": tags_statuses, "title": num_down_title(num_down)}
    )


@login_required
@require_POST
def switch_channel(request, code, channel_code):
    check = _get_check_for_user(request, code)

    channel = get_object_or_404(Channel, code=channel_code)
    if channel.project_id != check.project_id:
        return HttpResponseBadRequest()

    if request.POST.get("state") == "on":
        channel.checks.add(check)
    else:
        channel.checks.remove(check)

    return HttpResponse()


def index(request):
    if request.user.is_authenticated:
        projects = list(request.profile.projects())

        ctx = {"page": "projects", "projects": projects}
        return render(request, "front/projects.html", ctx)

    check = Check()

    ctx = {
        "page": "welcome",
        "check": check,
        "ping_url": check.url(),
        "enable_pushbullet": settings.PUSHBULLET_CLIENT_ID is not None,
        "enable_pushover": settings.PUSHOVER_API_TOKEN is not None,
        "enable_discord": settings.DISCORD_CLIENT_ID is not None,
        "enable_telegram": settings.TELEGRAM_TOKEN is not None,
        "enable_sms": settings.TWILIO_AUTH is not None,
        "enable_whatsapp": settings.TWILIO_USE_WHATSAPP,
        "enable_pd": settings.PD_VENDOR_KEY is not None,
        "enable_trello": settings.TRELLO_APP_KEY is not None,
        "enable_matrix": settings.MATRIX_ACCESS_TOKEN is not None,
        "enable_apprise": settings.APPRISE_ENABLED is True,
        "registration_open": settings.REGISTRATION_OPEN,
    }

    return render(request, "front/welcome.html", ctx)


def docs(request):
    ctx = {
        "page": "docs",
        "section": "home",
        "ping_endpoint": settings.PING_ENDPOINT,
        "ping_email": "your-uuid-here@%s" % settings.PING_EMAIL_DOMAIN,
        "ping_email_domain": settings.PING_EMAIL_DOMAIN,
        "ping_url": settings.PING_ENDPOINT + "your-uuid-here",
    }

    return render(request, "front/docs.html", ctx)


def docs_api(request):
    ctx = {
        "page": "docs",
        "section": "api",
        "SITE_ROOT": settings.SITE_ROOT,
        "PING_ENDPOINT": settings.PING_ENDPOINT,
        "default_timeout": int(DEFAULT_TIMEOUT.total_seconds()),
        "default_grace": int(DEFAULT_GRACE.total_seconds()),
    }

    return render(request, "front/docs_api.html", ctx)


def docs_cron(request):
    ctx = {"page": "docs", "section": "cron"}
    return render(request, "front/docs_cron.html", ctx)


def docs_resources(request):
    ctx = {"page": "docs", "section": "resources"}
    return render(request, "front/docs_resources.html", ctx)


@require_POST
@login_required
def add_check(request, code):
    project = _get_project_for_user(request, code)
    if project.num_checks_available() <= 0:
        return HttpResponseBadRequest()

    check = Check(project=project)
    check.save()

    check.assign_all_channels()

    url = reverse("hc-details", args=[check.code])
    return redirect(url + "?new")


@require_POST
@login_required
def update_name(request, code):
    check = _get_check_for_user(request, code)
    form = NameTagsForm(request.POST)
    if form.is_valid():
        check.name = form.cleaned_data["name"]
        check.tags = form.cleaned_data["tags"]
        check.desc = form.cleaned_data["desc"]
        check.save()

    if "/details/" in request.META.get("HTTP_REFERER", ""):
        return redirect("hc-details", code)

    return redirect("hc-checks", check.project.code)


@require_POST
@login_required
def email_settings(request, code):
    check = _get_check_for_user(request, code)
    form = EmailSettingsForm(request.POST)
    if form.is_valid():
        check.subject = form.cleaned_data["subject"]
        check.save()

    return redirect("hc-details", code)


@require_POST
@login_required
def update_timeout(request, code):
    check = _get_check_for_user(request, code)

    kind = request.POST.get("kind")
    if kind == "simple":
        form = TimeoutForm(request.POST)
        if not form.is_valid():
            return HttpResponseBadRequest()

        check.kind = "simple"
        check.timeout = form.cleaned_data["timeout"]
        check.grace = form.cleaned_data["grace"]
    elif kind == "cron":
        form = CronForm(request.POST)
        if not form.is_valid():
            return HttpResponseBadRequest()

        check.kind = "cron"
        check.schedule = form.cleaned_data["schedule"]
        check.tz = form.cleaned_data["tz"]
        check.grace = td(minutes=form.cleaned_data["grace"])

    check.alert_after = check.going_down_after()
    check.save()

    if "/details/" in request.META.get("HTTP_REFERER", ""):
        return redirect("hc-details", code)

    return redirect("hc-checks", check.project.code)


@require_POST
def cron_preview(request):
    schedule = request.POST.get("schedule", "")
    tz = request.POST.get("tz")
    ctx = {"tz": tz, "dates": []}

    try:
        zone = pytz.timezone(tz)
        now_local = timezone.localtime(timezone.now(), zone)

        if len(schedule.split()) != 5:
            raise ValueError()

        it = croniter(schedule, now_local)
        for i in range(0, 6):
            ctx["dates"].append(it.get_next(datetime))
    except UnknownTimeZoneError:
        ctx["bad_tz"] = True
    except:
        ctx["bad_schedule"] = True

    return render(request, "front/cron_preview.html", ctx)


def ping_details(request, code, n=None):
    check = _get_check_for_user(request, code)
    q = Ping.objects.filter(owner=check)
    if n:
        q = q.filter(n=n)

    ping = q.latest("created")

    ctx = {"check": check, "ping": ping}

    return render(request, "front/ping_details.html", ctx)


@require_POST
@login_required
def pause(request, code):
    check = _get_check_for_user(request, code)

    check.status = "paused"
    check.last_start = None
    check.alert_after = None
    check.save()

    if "/details/" in request.META.get("HTTP_REFERER", ""):
        return redirect("hc-details", code)

    return redirect("hc-checks", check.project.code)


@require_POST
@login_required
def remove_check(request, code):
    check = _get_check_for_user(request, code)
    project = check.project
    check.delete()
    return redirect("hc-checks", project.code)


def _get_events(check, limit):
    pings = Ping.objects.filter(owner=check).order_by("-id")[:limit]
    pings = list(pings)

    prev = None
    for ping in pings:
        if ping.kind == "start" and prev and prev.kind != "start":
            delta = prev.created - ping.created
            if delta < MAX_DELTA:
                setattr(prev, "delta", delta)

        prev = ping

    alerts = []
    if len(pings):
        cutoff = pings[-1].created
        alerts = Notification.objects.select_related("channel").filter(
            owner=check, check_status="down", created__gt=cutoff
        )

    events = pings + list(alerts)
    events.sort(key=lambda el: el.created, reverse=True)
    return events


@login_required
def log(request, code):
    check = _get_check_for_user(request, code)

    limit = check.project.owner_profile.ping_log_limit
    ctx = {
        "project": check.project,
        "check": check,
        "events": _get_events(check, limit),
        "limit": limit,
        "show_limit_notice": check.n_pings > limit and settings.USE_PAYMENTS,
    }

    return render(request, "front/log.html", ctx)


@login_required
def details(request, code):
    check = _get_check_for_user(request, code)

    channels = Channel.objects.filter(project=check.project)
    channels = list(channels.order_by("created"))

    ctx = {
        "page": "details",
        "project": check.project,
        "check": check,
        "channels": channels,
        "timezones": pytz.all_timezones,
        "downtimes": check.downtimes(months=3),
        "is_new": "new" in request.GET,
    }

    return render(request, "front/details.html", ctx)


@login_required
def transfer(request, code):
    check = _get_check_for_user(request, code)

    if request.method == "POST":
        target_project = _get_project_for_user(request, request.POST["project"])
        if target_project.num_checks_available() <= 0:
            return HttpResponseBadRequest()

        check.project = target_project
        check.save()

        check.assign_all_channels()

        request.profile.current_project = target_project
        request.profile.save()

        messages.success(request, "Check transferred successfully!")

        return redirect("hc-details", code)

    ctx = {"check": check}
    return render(request, "front/transfer_modal.html", ctx)


@login_required
def status_single(request, code):
    check = _get_check_for_user(request, code)

    status = check.get_status()
    events = _get_events(check, 20)
    updated = "1"
    if len(events):
        updated = str(events[0].created.timestamp())

    doc = {
        "status": status,
        "status_text": STATUS_TEXT_TMPL.render({"check": check}),
        "title": down_title(check),
        "updated": updated,
    }

    if updated != request.GET.get("u"):
        doc["events"] = EVENTS_TMPL.render({"check": check, "events": events})
        doc["downtimes"] = DOWNTIMES_TMPL.render({"downtimes": check.downtimes(3)})

    return JsonResponse(doc)


@login_required
def badges(request, code):
    project = _get_project_for_user(request, code)

    tags = set()
    for check in Check.objects.filter(project=project):
        tags.update(check.tags_list())

    sorted_tags = sorted(tags, key=lambda s: s.lower())
    sorted_tags.append("*")  # For the "overall status" badge

    urls = []
    for tag in sorted_tags:
        urls.append(
            {
                "tag": tag,
                "svg": get_badge_url(project.badge_key, tag),
                "json": get_badge_url(project.badge_key, tag, format="json"),
            }
        )

    ctx = {
        "have_tags": len(urls) > 1,
        "page": "badges",
        "project": project,
        "badges": urls,
    }

    return render(request, "front/badges.html", ctx)


@login_required
def channels(request):

    if not request.project:
        # This can happen when the user deletes their only project.
        return redirect("hc-index")

    if request.method == "POST":
        code = request.POST["channel"]
        try:
            channel = Channel.objects.get(code=code)
        except Channel.DoesNotExist:
            return HttpResponseBadRequest()
        if channel.project_id != request.project.id:
            return HttpResponseForbidden()

        new_checks = []
        for key in request.POST:
            if key.startswith("check-"):
                code = key[6:]
                try:
                    check = Check.objects.get(code=code)
                except Check.DoesNotExist:
                    return HttpResponseBadRequest()
                if check.project_id != request.project.id:
                    return HttpResponseForbidden()
                new_checks.append(check)

        channel.checks.set(new_checks)
        return redirect("hc-channels")

    channels = Channel.objects.filter(project=request.project)
    channels = channels.order_by("created")
    channels = channels.annotate(n_checks=Count("checks"))

    ctx = {
        "page": "channels",
        "project": request.project,
        "profile": request.project.owner_profile,
        "channels": channels,
        "enable_pushbullet": settings.PUSHBULLET_CLIENT_ID is not None,
        "enable_pushover": settings.PUSHOVER_API_TOKEN is not None,
        "enable_discord": settings.DISCORD_CLIENT_ID is not None,
        "enable_telegram": settings.TELEGRAM_TOKEN is not None,
        "enable_sms": settings.TWILIO_AUTH is not None,
        "enable_whatsapp": settings.TWILIO_USE_WHATSAPP,
        "enable_pd": settings.PD_VENDOR_KEY is not None,
        "enable_trello": settings.TRELLO_APP_KEY is not None,
        "enable_matrix": settings.MATRIX_ACCESS_TOKEN is not None,
        "enable_apprise": settings.APPRISE_ENABLED is True,
        "use_payments": settings.USE_PAYMENTS,
    }

    return render(request, "front/channels.html", ctx)


@login_required
def channel_checks(request, code):
    channel = get_object_or_404(Channel, code=code)
    if channel.project_id != request.project.id:
        return HttpResponseForbidden()

    assigned = set(channel.checks.values_list("code", flat=True).distinct())
    checks = Check.objects.filter(project=request.project).order_by("created")

    ctx = {"checks": checks, "assigned": assigned, "channel": channel}

    return render(request, "front/channel_checks.html", ctx)


@require_POST
@login_required
def update_channel_name(request, code):
    channel = get_object_or_404(Channel, code=code)
    if channel.project_id != request.project.id:
        return HttpResponseForbidden()

    form = ChannelNameForm(request.POST)
    if form.is_valid():
        channel.name = form.cleaned_data["name"]
        channel.save()

    return redirect("hc-channels")


def verify_email(request, code, token):
    channel = get_object_or_404(Channel, code=code)
    if channel.make_token() == token:
        channel.email_verified = True
        channel.save()
        return render(request, "front/verify_email_success.html")

    return render(request, "bad_link.html")


def unsubscribe_email(request, code, token):
    channel = get_object_or_404(Channel, code=code)
    if channel.make_token() != token:
        return render(request, "bad_link.html")

    if channel.kind != "email":
        return HttpResponseBadRequest()

    # Some email servers open links in emails to check for malicious content.
    # To work around this, we serve a form that auto-submits with JS.
    if "ask" in request.GET and request.method != "POST":
        return render(request, "accounts/unsubscribe_submit.html")

    channel.delete()
    return render(request, "front/unsubscribe_success.html")


@require_POST
@login_required
def send_test_notification(request, code):
    channel = get_object_or_404(Channel, code=code)
    if channel.project_id != request.project.id:
        return HttpResponseForbidden()

    dummy = Check(name="TEST", status="down")
    dummy.last_ping = timezone.now() - td(days=1)
    dummy.n_pings = 42

    if channel.kind == "email":
        error = channel.transport.notify(dummy, channel.get_unsub_link())
    else:
        error = channel.transport.notify(dummy)

    if error:
        messages.warning(request, "Could not send a test notification: %s" % error)
    else:
        messages.success(request, "Test notification sent!")

    return redirect("hc-channels")


@require_POST
@login_required
def remove_channel(request, code):
    # user may refresh the page during POST and cause two deletion attempts
    channel = Channel.objects.filter(code=code).first()
    if channel:
        if channel.project_id != request.project.id:
            return HttpResponseForbidden()
        channel.delete()

    return redirect("hc-channels")


@login_required
def add_email(request):
    if request.method == "POST":
        form = AddEmailForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="email")
            channel.value = json.dumps(
                {
                    "value": form.cleaned_data["value"],
                    "up": form.cleaned_data["up"],
                    "down": form.cleaned_data["down"],
                }
            )
            channel.save()

            channel.assign_all_checks()

            is_own_email = form.cleaned_data["value"] == request.user.email
            if is_own_email or not settings.EMAIL_USE_VERIFICATION:
                # If user is subscribing *their own* address
                # we can skip the verification step.

                # Additionally, in self-hosted setting, administator has the
                # option to disable the email verification step altogether.

                channel.email_verified = True
                channel.save()
            else:
                channel.send_verify_link()

            return redirect("hc-channels")
    else:
        form = AddEmailForm()

    ctx = {
        "page": "channels",
        "project": request.project,
        "use_verification": settings.EMAIL_USE_VERIFICATION,
        "form": form,
    }
    return render(request, "integrations/add_email.html", ctx)


@login_required
def add_webhook(request):
    if request.method == "POST":
        form = AddWebhookForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="webhook")
            channel.value = form.get_value()
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddWebhookForm()

    ctx = {
        "page": "channels",
        "project": request.project,
        "form": form,
        "now": timezone.now().replace(microsecond=0).isoformat(),
    }
    return render(request, "integrations/add_webhook.html", ctx)


def _prepare_state(request, session_key):
    state = get_random_string()
    request.session[session_key] = state
    return state


def _get_validated_code(request, session_key, key="code"):
    if session_key not in request.session:
        return None

    session_state = request.session.pop(session_key)
    request_state = request.GET.get("state")
    if session_state is None or session_state != request_state:
        return None

    return request.GET.get(key)


def add_pd(request, state=None):
    if settings.PD_VENDOR_KEY is None:
        raise Http404("pagerduty integration is not available")

    if state and request.user.is_authenticated:
        if "pd" not in request.session:
            return HttpResponseBadRequest()

        session_state = request.session.pop("pd")
        if session_state != state:
            return HttpResponseBadRequest()

        if request.GET.get("error") == "cancelled":
            messages.warning(request, "PagerDuty setup was cancelled")
            return redirect("hc-channels")

        channel = Channel(kind="pd", project=request.project)
        channel.user = request.project.owner
        channel.value = json.dumps(
            {
                "service_key": request.GET.get("service_key"),
                "account": request.GET.get("account"),
            }
        )
        channel.save()
        channel.assign_all_checks()
        messages.success(request, "The PagerDuty integration has been added!")
        return redirect("hc-channels")

    state = _prepare_state(request, "pd")
    callback = settings.SITE_ROOT + reverse("hc-add-pd-state", args=[state])
    connect_url = "https://connect.pagerduty.com/connect?" + urlencode(
        {"vendor": settings.PD_VENDOR_KEY, "callback": callback}
    )

    ctx = {"page": "channels", "project": request.project, "connect_url": connect_url}
    return render(request, "integrations/add_pd.html", ctx)


@login_required
def add_pagertree(request):
    if request.method == "POST":
        form = AddUrlForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="pagertree")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {"page": "channels", "project": request.project, "form": form}
    return render(request, "integrations/add_pagertree.html", ctx)


@login_required
def add_pagerteam(request):
    if request.method == "POST":
        form = AddUrlForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="pagerteam")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {"page": "channels", "project": request.project, "form": form}
    return render(request, "integrations/add_pagerteam.html", ctx)


def add_slack(request):
    if not settings.SLACK_CLIENT_ID and not request.user.is_authenticated:
        return redirect("hc-login")

    if request.method == "POST":
        form = AddUrlForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="slack")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {
        "page": "channels",
        "form": form,
        "slack_client_id": settings.SLACK_CLIENT_ID,
    }

    if request.user.is_authenticated:
        ctx["project"] = request.project

    if settings.SLACK_CLIENT_ID and request.user.is_authenticated:
        ctx["state"] = _prepare_state(request, "slack")

    return render(request, "integrations/add_slack.html", ctx)


@login_required
def add_mattermost(request):
    if request.method == "POST":
        form = AddUrlForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="mattermost")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {"page": "channels", "form": form, "project": request.project}

    return render(request, "integrations/add_mattermost.html", ctx)


@login_required
def add_slack_btn(request):
    code = _get_validated_code(request, "slack")
    if code is None:
        return HttpResponseBadRequest()

    result = requests.post(
        "https://slack.com/api/oauth.access",
        {
            "client_id": settings.SLACK_CLIENT_ID,
            "client_secret": settings.SLACK_CLIENT_SECRET,
            "code": code,
        },
    )

    doc = result.json()
    if doc.get("ok"):
        channel = Channel(kind="slack", project=request.project)
        channel.user = request.project.owner
        channel.value = result.text
        channel.save()
        channel.assign_all_checks()
        messages.success(request, "The Slack integration has been added!")
    else:
        s = doc.get("error")
        messages.warning(request, "Error message from slack: %s" % s)

    return redirect("hc-channels")


@login_required
def add_pushbullet(request):
    if settings.PUSHBULLET_CLIENT_ID is None:
        raise Http404("pushbullet integration is not available")

    if "code" in request.GET:
        code = _get_validated_code(request, "pushbullet")
        if code is None:
            return HttpResponseBadRequest()

        result = requests.post(
            "https://api.pushbullet.com/oauth2/token",
            {
                "client_id": settings.PUSHBULLET_CLIENT_ID,
                "client_secret": settings.PUSHBULLET_CLIENT_SECRET,
                "code": code,
                "grant_type": "authorization_code",
            },
        )

        doc = result.json()
        if "access_token" in doc:
            channel = Channel(kind="pushbullet", project=request.project)
            channel.user = request.project.owner
            channel.value = doc["access_token"]
            channel.save()
            channel.assign_all_checks()
            messages.success(request, "The Pushbullet integration has been added!")
        else:
            messages.warning(request, "Something went wrong")

        return redirect("hc-channels")

    redirect_uri = settings.SITE_ROOT + reverse("hc-add-pushbullet")
    authorize_url = "https://www.pushbullet.com/authorize?" + urlencode(
        {
            "client_id": settings.PUSHBULLET_CLIENT_ID,
            "redirect_uri": redirect_uri,
            "response_type": "code",
            "state": _prepare_state(request, "pushbullet"),
        }
    )

    ctx = {
        "page": "channels",
        "project": request.project,
        "authorize_url": authorize_url,
    }
    return render(request, "integrations/add_pushbullet.html", ctx)


@login_required
def add_discord(request):
    if settings.DISCORD_CLIENT_ID is None:
        raise Http404("discord integration is not available")

    redirect_uri = settings.SITE_ROOT + reverse("hc-add-discord")
    if "code" in request.GET:
        code = _get_validated_code(request, "discord")
        if code is None:
            return HttpResponseBadRequest()

        result = requests.post(
            "https://discordapp.com/api/oauth2/token",
            {
                "client_id": settings.DISCORD_CLIENT_ID,
                "client_secret": settings.DISCORD_CLIENT_SECRET,
                "code": code,
                "grant_type": "authorization_code",
                "redirect_uri": redirect_uri,
            },
        )

        doc = result.json()
        if "access_token" in doc:
            channel = Channel(kind="discord", project=request.project)
            channel.user = request.project.owner
            channel.value = result.text
            channel.save()
            channel.assign_all_checks()
            messages.success(request, "The Discord integration has been added!")
        else:
            messages.warning(request, "Something went wrong")

        return redirect("hc-channels")

    auth_url = "https://discordapp.com/api/oauth2/authorize?" + urlencode(
        {
            "client_id": settings.DISCORD_CLIENT_ID,
            "scope": "webhook.incoming",
            "redirect_uri": redirect_uri,
            "response_type": "code",
            "state": _prepare_state(request, "discord"),
        }
    )

    ctx = {"page": "channels", "project": request.project, "authorize_url": auth_url}

    return render(request, "integrations/add_discord.html", ctx)


def add_pushover(request):
    if (
        settings.PUSHOVER_API_TOKEN is None
        or settings.PUSHOVER_SUBSCRIPTION_URL is None
    ):
        raise Http404("pushover integration is not available")

    if not request.user.is_authenticated:
        ctx = {"page": "channels"}
        return render(request, "integrations/add_pushover.html", ctx)

    if request.method == "POST":
        # Initiate the subscription
        state = _prepare_state(request, "pushover")

        failure_url = settings.SITE_ROOT + reverse("hc-channels")
        success_url = (
            settings.SITE_ROOT
            + reverse("hc-add-pushover")
            + "?"
            + urlencode(
                {
                    "state": state,
                    "prio": request.POST.get("po_priority", "0"),
                    "prio_up": request.POST.get("po_priority_up", "0"),
                }
            )
        )
        subscription_url = (
            settings.PUSHOVER_SUBSCRIPTION_URL
            + "?"
            + urlencode({"success": success_url, "failure": failure_url})
        )

        return redirect(subscription_url)

    # Handle successful subscriptions
    if "pushover_user_key" in request.GET:
        key = _get_validated_code(request, "pushover", "pushover_user_key")
        if key is None:
            return HttpResponseBadRequest()

        # Validate priority
        prio = request.GET.get("prio")
        if prio not in ("-2", "-1", "0", "1", "2"):
            return HttpResponseBadRequest()

        prio_up = request.GET.get("prio_up")
        if prio_up not in ("-2", "-1", "0", "1", "2"):
            return HttpResponseBadRequest()

        if request.GET.get("pushover_unsubscribed") == "1":
            # Unsubscription: delete all Pushover channels for this project
            Channel.objects.filter(project=request.project, kind="po").delete()
            return redirect("hc-channels")

        # Subscription
        channel = Channel(project=request.project, kind="po")
        channel.value = "%s|%s|%s" % (key, prio, prio_up)
        channel.save()
        channel.assign_all_checks()

        messages.success(request, "The Pushover integration has been added!")
        return redirect("hc-channels")

    # Show Integration Settings form
    ctx = {
        "page": "channels",
        "project": request.project,
        "po_retry_delay": td(seconds=settings.PUSHOVER_EMERGENCY_RETRY_DELAY),
        "po_expiration": td(seconds=settings.PUSHOVER_EMERGENCY_EXPIRATION),
    }
    return render(request, "integrations/add_pushover.html", ctx)


@login_required
def add_opsgenie(request):
    if request.method == "POST":
        form = AddOpsGenieForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="opsgenie")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {"page": "channels", "project": request.project, "form": form}
    return render(request, "integrations/add_opsgenie.html", ctx)


@login_required
def add_victorops(request):
    if request.method == "POST":
        form = AddUrlForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="victorops")
            channel.value = form.cleaned_data["value"]
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddUrlForm()

    ctx = {"page": "channels", "project": request.project, "form": form}
    return render(request, "integrations/add_victorops.html", ctx)


@csrf_exempt
@require_POST
def telegram_bot(request):
    try:
        doc = json.loads(request.body.decode())
        jsonschema.validate(doc, telegram_callback)
    except ValueError:
        return HttpResponseBadRequest()
    except jsonschema.ValidationError:
        # We don't recognize the message format, but don't want Telegram
        # retrying this over and over again, so respond with 200 OK
        return HttpResponse()

    if "/start" not in doc["message"]["text"]:
        return HttpResponse()

    chat = doc["message"]["chat"]
    name = max(chat.get("title", ""), chat.get("username", ""))

    invite = render_to_string(
        "integrations/telegram_invite.html",
        {"qs": signing.dumps((chat["id"], chat["type"], name))},
    )

    Telegram.send(chat["id"], invite)
    return HttpResponse()


@login_required
def add_telegram(request):
    chat_id, chat_type, chat_name = None, None, None
    qs = request.META["QUERY_STRING"]
    if qs:
        chat_id, chat_type, chat_name = signing.loads(qs, max_age=600)

    if request.method == "POST":
        channel = Channel(project=request.project, kind="telegram")
        channel.value = json.dumps(
            {"id": chat_id, "type": chat_type, "name": chat_name}
        )
        channel.save()

        channel.assign_all_checks()
        messages.success(request, "The Telegram integration has been added!")
        return redirect("hc-channels")

    ctx = {
        "page": "channels",
        "project": request.project,
        "chat_id": chat_id,
        "chat_type": chat_type,
        "chat_name": chat_name,
        "bot_name": settings.TELEGRAM_BOT_NAME,
    }

    return render(request, "integrations/add_telegram.html", ctx)


@login_required
def add_sms(request):
    if settings.TWILIO_AUTH is None:
        raise Http404("sms integration is not available")

    if request.method == "POST":
        form = AddSmsForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="sms")
            channel.name = form.cleaned_data["label"]
            channel.value = json.dumps({"value": form.cleaned_data["value"]})
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddSmsForm()

    ctx = {
        "page": "channels",
        "project": request.project,
        "form": form,
        "profile": request.project.owner_profile,
    }
    return render(request, "integrations/add_sms.html", ctx)


@login_required
def add_whatsapp(request):
    if not settings.TWILIO_USE_WHATSAPP:
        raise Http404("whatsapp integration is not available")

    if request.method == "POST":
        form = AddSmsForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="whatsapp")
            channel.name = form.cleaned_data["label"]
            channel.value = json.dumps(
                {
                    "value": form.cleaned_data["value"],
                    "up": form.cleaned_data["up"],
                    "down": form.cleaned_data["down"],
                }
            )
            channel.save()

            channel.assign_all_checks()
            return redirect("hc-channels")
    else:
        form = AddSmsForm()

    ctx = {
        "page": "channels",
        "project": request.project,
        "form": form,
        "profile": request.project.owner_profile,
    }
    return render(request, "integrations/add_whatsapp.html", ctx)


@login_required
def add_trello(request):
    if settings.TRELLO_APP_KEY is None:
        raise Http404("trello integration is not available")

    if request.method == "POST":
        channel = Channel(project=request.project, kind="trello")
        channel.value = request.POST["settings"]
        channel.save()

        channel.assign_all_checks()
        return redirect("hc-channels")

    authorize_url = "https://trello.com/1/authorize?" + urlencode(
        {
            "expiration": "never",
            "name": settings.SITE_NAME,
            "scope": "read,write",
            "response_type": "token",
            "key": settings.TRELLO_APP_KEY,
            "return_url": settings.SITE_ROOT + reverse("hc-add-trello"),
        }
    )

    ctx = {
        "page": "channels",
        "project": request.project,
        "authorize_url": authorize_url,
    }

    return render(request, "integrations/add_trello.html", ctx)


@login_required
def add_matrix(request):
    if settings.MATRIX_ACCESS_TOKEN is None:
        raise Http404("matrix integration is not available")

    if request.method == "POST":
        form = AddMatrixForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="matrix")
            channel.value = form.cleaned_data["room_id"]

            # If user supplied room alias instead of ID, use it as channel name
            alias = form.cleaned_data["alias"]
            if not alias.startswith("!"):
                channel.name = alias

            channel.save()

            channel.assign_all_checks()
            messages.success(request, "The Matrix integration has been added!")
            return redirect("hc-channels")
    else:
        form = AddMatrixForm()

    ctx = {
        "page": "channels",
        "project": request.project,
        "form": form,
        "matrix_user_id": settings.MATRIX_USER_ID,
    }
    return render(request, "integrations/add_matrix.html", ctx)


@login_required
def add_apprise(request):
    if not settings.APPRISE_ENABLED:
        raise Http404("apprise integration is not available")

    if request.method == "POST":
        form = AddAppriseForm(request.POST)
        if form.is_valid():
            channel = Channel(project=request.project, kind="apprise")
            channel.value = form.cleaned_data["url"]
            channel.save()

            channel.assign_all_checks()
            messages.success(request, "The Apprise integration has been added!")
            return redirect("hc-channels")
    else:
        form = AddAppriseForm()

    ctx = {"page": "channels", "project": request.project, "form": form}
    return render(request, "integrations/add_apprise.html", ctx)


@login_required
@require_POST
def trello_settings(request):
    token = request.POST.get("token")

    url = "https://api.trello.com/1/members/me/boards?" + urlencode(
        {
            "key": settings.TRELLO_APP_KEY,
            "token": token,
            "fields": "id,name",
            "lists": "open",
            "list_fields": "id,name",
        }
    )

    r = requests.get(url)
    ctx = {"token": token, "data": r.json()}
    return render(request, "integrations/trello_settings.html", ctx)