# Webhooks for external integrations.
from typing import Any, Dict, Iterable

from django.http import HttpRequest, HttpResponse

from zerver.decorator import webhook_view
from zerver.lib.exceptions import UnsupportedWebhookEventType
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import UserProfile

PAGER_DUTY_EVENT_NAMES = {
    "incident.trigger": "triggered",
    "incident.acknowledge": "acknowledged",
    "incident.unacknowledge": "unacknowledged",
    "incident.resolve": "resolved",
    "incident.assign": "assigned",
    "incident.escalate": "escalated",
    "incident.delegate": "delineated",
}

PAGER_DUTY_EVENT_NAMES_V2 = {
    "incident.trigger": "triggered",
    "incident.acknowledge": "acknowledged",
    "incident.resolve": "resolved",
    "incident.assign": "assigned",
}

ASSIGNEE_TEMPLATE = "[{username}]({url})"

INCIDENT_WITH_SERVICE_AND_ASSIGNEE = (
    "Incident [{incident_num}]({incident_url}) {action} by [{service_name}]"
    "({service_url}) (assigned to {assignee_info}):\n\n``` quote\n{trigger_message}\n```"
)

INCIDENT_WITH_ASSIGNEE = """
Incident [{incident_num}]({incident_url}) {action} by {assignee_info}:

``` quote
{trigger_message}
```
""".strip()

INCIDENT_ASSIGNED = """
Incident [{incident_num}]({incident_url}) {action} to {assignee_info}:

``` quote
{trigger_message}
```
""".strip()

INCIDENT_RESOLVED_WITH_AGENT = """
Incident [{incident_num}]({incident_url}) resolved by {resolving_agent_info}:

``` quote
{trigger_message}
```
""".strip()

INCIDENT_RESOLVED = """
Incident [{incident_num}]({incident_url}) resolved:

``` quote
{trigger_message}
```
""".strip()


def build_pagerduty_formatdict(message: Dict[str, Any]) -> Dict[str, Any]:
    format_dict: Dict[str, Any] = {}
    format_dict["action"] = PAGER_DUTY_EVENT_NAMES[message["type"]]

    format_dict["incident_id"] = message["data"]["incident"]["id"]
    format_dict["incident_num"] = message["data"]["incident"]["incident_number"]
    format_dict["incident_url"] = message["data"]["incident"]["html_url"]

    format_dict["service_name"] = message["data"]["incident"]["service"]["name"]
    format_dict["service_url"] = message["data"]["incident"]["service"]["html_url"]

    if message["data"]["incident"].get("assigned_to_user", None):
        assigned_to_user = message["data"]["incident"]["assigned_to_user"]
        format_dict["assignee_info"] = ASSIGNEE_TEMPLATE.format(
            username=assigned_to_user["email"].split("@")[0],
            url=assigned_to_user["html_url"],
        )
    else:
        format_dict["assignee_info"] = "nobody"

    if message["data"]["incident"].get("resolved_by_user", None):
        resolved_by_user = message["data"]["incident"]["resolved_by_user"]
        format_dict["resolving_agent_info"] = ASSIGNEE_TEMPLATE.format(
            username=resolved_by_user["email"].split("@")[0],
            url=resolved_by_user["html_url"],
        )

    trigger_message = []
    trigger_summary_data = message["data"]["incident"]["trigger_summary_data"]
    if trigger_summary_data is not None:
        trigger_subject = trigger_summary_data.get("subject", "")
        if trigger_subject:
            trigger_message.append(trigger_subject)

        trigger_description = trigger_summary_data.get("description", "")
        if trigger_description:
            trigger_message.append(trigger_description)

    format_dict["trigger_message"] = "\n".join(trigger_message)
    return format_dict


def build_pagerduty_formatdict_v2(message: Dict[str, Any]) -> Dict[str, Any]:
    format_dict = {}
    format_dict["action"] = PAGER_DUTY_EVENT_NAMES_V2[message["event"]]

    format_dict["incident_id"] = message["incident"]["id"]
    format_dict["incident_num"] = message["incident"]["incident_number"]
    format_dict["incident_url"] = message["incident"]["html_url"]

    format_dict["service_name"] = message["incident"]["service"]["name"]
    format_dict["service_url"] = message["incident"]["service"]["html_url"]

    assignments = message["incident"]["assignments"]
    if assignments:
        assignee = assignments[0]["assignee"]
        format_dict["assignee_info"] = ASSIGNEE_TEMPLATE.format(
            username=assignee["summary"], url=assignee["html_url"]
        )
    else:
        format_dict["assignee_info"] = "nobody"

    last_status_change_by = message["incident"].get("last_status_change_by")
    if last_status_change_by is not None:
        format_dict["resolving_agent_info"] = ASSIGNEE_TEMPLATE.format(
            username=last_status_change_by["summary"],
            url=last_status_change_by["html_url"],
        )

    trigger_description = message["incident"].get("description")
    if trigger_description is not None:
        format_dict["trigger_message"] = trigger_description
    return format_dict


def send_formated_pagerduty(
    request: HttpRequest, user_profile: UserProfile, message_type: str, format_dict: Dict[str, Any]
) -> None:
    if message_type in ("incident.trigger", "incident.unacknowledge"):
        template = INCIDENT_WITH_SERVICE_AND_ASSIGNEE
    elif message_type == "incident.resolve" and format_dict.get("resolving_agent_info") is not None:
        template = INCIDENT_RESOLVED_WITH_AGENT
    elif message_type == "incident.resolve" and format_dict.get("resolving_agent_info") is None:
        template = INCIDENT_RESOLVED
    elif message_type == "incident.assign":
        template = INCIDENT_ASSIGNED
    else:
        template = INCIDENT_WITH_ASSIGNEE

    subject = "Incident {incident_num}".format(**format_dict)
    body = template.format(**format_dict)
    check_send_webhook_message(request, user_profile, subject, body)


@webhook_view("PagerDuty")
@has_request_variables
def api_pagerduty_webhook(
    request: HttpRequest,
    user_profile: UserProfile,
    payload: Dict[str, Iterable[Dict[str, Any]]] = REQ(argument_type="body"),
) -> HttpResponse:
    for message in payload["messages"]:
        message_type = message.get("type")

        # If the message has no "type" key, then this payload came from a
        # Pagerduty Webhook V2.
        if message_type is None:
            break

        if message_type not in PAGER_DUTY_EVENT_NAMES:
            raise UnsupportedWebhookEventType(message_type)

        format_dict = build_pagerduty_formatdict(message)
        send_formated_pagerduty(request, user_profile, message_type, format_dict)

    for message in payload["messages"]:
        event = message.get("event")

        # If the message has no "event" key, then this payload came from a
        # Pagerduty Webhook V1.
        if event is None:
            break

        if event not in PAGER_DUTY_EVENT_NAMES_V2:
            raise UnsupportedWebhookEventType(event)

        format_dict = build_pagerduty_formatdict_v2(message)
        send_formated_pagerduty(request, user_profile, event, format_dict)

    return json_success()