"""Taiga integration for Zulip.

Tips for notification output:

*Text formatting*: if there has been a change of a property, the new
value should always be in bold; otherwise the subject of US/task
should be in bold.
"""
from typing import Dict, List, Optional, Tuple, Union

from django.http import HttpRequest, HttpResponse

from zerver.decorator import webhook_view
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.validator import WildValue, check_bool, check_none_or, check_string, to_wild_value
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import UserProfile

EventType = Dict[str, Union[str, Dict[str, Optional[Union[str, bool]]]]]
ReturnType = Tuple[WildValue, WildValue]


@webhook_view("Taiga")
@has_request_variables
def api_taiga_webhook(
    request: HttpRequest,
    user_profile: UserProfile,
    message: WildValue = REQ(argument_type="body", converter=to_wild_value),
) -> HttpResponse:
    parsed_events = parse_message(message)
    content_lines = []
    for event in parsed_events:
        content_lines.append(generate_content(event) + "\n")
    content = "".join(sorted(content_lines))
    topic = "General"
    if message["data"].get("milestone") and "name" in message["data"]["milestone"]:
        topic = message["data"]["milestone"]["name"].tame(check_string)
    check_send_webhook_message(request, user_profile, topic, content)

    return json_success(request)


templates = {
    "epic": {
        "create": "[{user}]({user_link}) created epic {subject}.",
        "set_assigned_to": "[{user}]({user_link}) assigned epic {subject} to {new}.",
        "unset_assigned_to": "[{user}]({user_link}) unassigned epic {subject}.",
        "changed_assigned_to": "[{user}]({user_link}) reassigned epic {subject}"
        " from {old} to {new}.",
        "blocked": "[{user}]({user_link}) blocked epic {subject}.",
        "unblocked": "[{user}]({user_link}) unblocked epic {subject}.",
        "changed_status": "[{user}]({user_link}) changed status of epic {subject}"
        " from {old} to {new}.",
        "renamed": "[{user}]({user_link}) renamed epic from **{old}** to **{new}**.",
        "description_diff": "[{user}]({user_link}) updated description of epic {subject}.",
        "commented": "[{user}]({user_link}) commented on epic {subject}.",
        "delete": "[{user}]({user_link}) deleted epic {subject}.",
    },
    "relateduserstory": {
        "create": (
            "[{user}]({user_link}) added a related user story"
            " {userstory_subject} to the epic {epic_subject}."
        ),
        "delete": (
            "[{user}]({user_link}) removed a related user story"
            " {userstory_subject} from the epic {epic_subject}."
        ),
    },
    "userstory": {
        "create": "[{user}]({user_link}) created user story {subject}.",
        "set_assigned_to": "[{user}]({user_link}) assigned user story {subject} to {new}.",
        "unset_assigned_to": "[{user}]({user_link}) unassigned user story {subject}.",
        "changed_assigned_to": "[{user}]({user_link}) reassigned user story {subject}"
        " from {old} to {new}.",
        "points": "[{user}]({user_link}) changed estimation of user story {subject}.",
        "blocked": "[{user}]({user_link}) blocked user story {subject}.",
        "unblocked": "[{user}]({user_link}) unblocked user story {subject}.",
        "set_milestone": "[{user}]({user_link}) added user story {subject} to sprint {new}.",
        "unset_milestone": "[{user}]({user_link}) removed user story {subject} from sprint {old}.",
        "changed_milestone": "[{user}]({user_link}) changed sprint of user story {subject} from {old}"
        " to {new}.",
        "changed_status": "[{user}]({user_link}) changed status of user story {subject}"
        " from {old} to {new}.",
        "closed": "[{user}]({user_link}) closed user story {subject}.",
        "reopened": "[{user}]({user_link}) reopened user story {subject}.",
        "renamed": "[{user}]({user_link}) renamed user story from {old} to **{new}**.",
        "description_diff": "[{user}]({user_link}) updated description of user story {subject}.",
        "commented": "[{user}]({user_link}) commented on user story {subject}.",
        "delete": "[{user}]({user_link}) deleted user story {subject}.",
        "due_date": "[{user}]({user_link}) changed due date of user story {subject}"
        " from {old} to {new}.",
        "set_due_date": "[{user}]({user_link}) set due date of user story {subject} to {new}.",
    },
    "milestone": {
        "create": "[{user}]({user_link}) created sprint {subject}.",
        "renamed": "[{user}]({user_link}) renamed sprint from {old} to **{new}**.",
        "estimated_start": "[{user}]({user_link}) changed estimated start of sprint {subject}"
        " from {old} to {new}.",
        "estimated_finish": "[{user}]({user_link}) changed estimated finish of sprint {subject}"
        " from {old} to {new}.",
        "set_estimated_start": "[{user}]({user_link}) changed estimated start of sprint {subject}"
        " to {new}.",
        "set_estimated_finish": "[{user}]({user_link}) set estimated finish of sprint {subject}"
        " to {new}.",
        "delete": "[{user}]({user_link}) deleted sprint {subject}.",
    },
    "task": {
        "create": "[{user}]({user_link}) created task {subject}.",
        "set_assigned_to": "[{user}]({user_link}) assigned task {subject} to {new}.",
        "unset_assigned_to": "[{user}]({user_link}) unassigned task {subject}.",
        "changed_assigned_to": "[{user}]({user_link}) reassigned task {subject}"
        " from {old} to {new}.",
        "blocked": "[{user}]({user_link}) blocked task {subject}.",
        "unblocked": "[{user}]({user_link}) unblocked task {subject}.",
        "changed_status": "[{user}]({user_link}) changed status of task {subject}"
        " from {old} to {new}.",
        "renamed": "[{user}]({user_link}) renamed task {old} to **{new}**.",
        "description_diff": "[{user}]({user_link}) updated description of task {subject}.",
        "set_milestone": "[{user}]({user_link}) added task {subject} to sprint {new}.",
        "commented": "[{user}]({user_link}) commented on task {subject}.",
        "delete": "[{user}]({user_link}) deleted task {subject}.",
        "changed_us": "[{user}]({user_link}) moved task {subject} from user story {old} to {new}.",
        "due_date": "[{user}]({user_link}) changed due date of task {subject} from {old} to {new}.",
        "set_due_date": "[{user}]({user_link}) set due date of task {subject} to {new}.",
    },
    "issue": {
        "create": "[{user}]({user_link}) created issue {subject}.",
        "set_assigned_to": "[{user}]({user_link}) assigned issue {subject} to {new}.",
        "unset_assigned_to": "[{user}]({user_link}) unassigned issue {subject}.",
        "changed_assigned_to": "[{user}]({user_link}) reassigned issue {subject}"
        " from {old} to {new}.",
        "set_milestone": "[{user}]({user_link}) added issue {subject} to sprint {new}.",
        "unset_milestone": "[{user}]({user_link}) detached issue {subject} from sprint {old}.",
        "changed_priority": "[{user}]({user_link}) changed priority of issue "
        "{subject} from {old} to {new}.",
        "changed_severity": "[{user}]({user_link}) changed severity of issue "
        "{subject} from {old} to {new}.",
        "changed_status": "[{user}]({user_link}) changed status of issue {subject}"
        " from {old} to {new}.",
        "changed_type": "[{user}]({user_link}) changed type of issue {subject} from {old} to {new}.",
        "renamed": "[{user}]({user_link}) renamed issue {old} to **{new}**.",
        "description_diff": "[{user}]({user_link}) updated description of issue {subject}.",
        "commented": "[{user}]({user_link}) commented on issue {subject}.",
        "delete": "[{user}]({user_link}) deleted issue {subject}.",
        "due_date": "[{user}]({user_link}) changed due date of issue {subject}"
        " from {old} to {new}.",
        "set_due_date": "[{user}]({user_link}) set due date of issue {subject} to {new}.",
        "blocked": "[{user}]({user_link}) blocked issue {subject}.",
        "unblocked": "[{user}]({user_link}) unblocked issue {subject}.",
    },
    "webhook_test": {
        "test": "[{user}]({user_link}) triggered a test of the Taiga integration.",
    },
}


def get_old_and_new_values(change_type: str, message: WildValue) -> ReturnType:
    """Parses the payload and finds previous and current value of change_type."""
    old = message["change"]["diff"][change_type].get("from")
    new = message["change"]["diff"][change_type].get("to")
    return old, new


def parse_comment(
    message: WildValue,
) -> EventType:
    """Parses the comment to issue, task or US."""
    return {
        "event": "commented",
        "type": message["type"].tame(check_string),
        "values": {
            "user": get_owner_name(message),
            "user_link": get_owner_link(message),
            "subject": get_subject(message),
        },
    }


def parse_create_or_delete(
    message: WildValue,
) -> EventType:
    """Parses create or delete event."""
    if message["type"].tame(check_string) == "relateduserstory":
        return {
            "type": message["type"].tame(check_string),
            "event": message["action"].tame(check_string),
            "values": {
                "user": get_owner_name(message),
                "user_link": get_owner_link(message),
                "epic_subject": get_epic_subject(message),
                "userstory_subject": get_userstory_subject(message),
            },
        }

    return {
        "type": message["type"].tame(check_string),
        "event": message["action"].tame(check_string),
        "values": {
            "user": get_owner_name(message),
            "user_link": get_owner_link(message),
            "subject": get_subject(message),
        },
    }


def parse_change_event(change_type: str, message: WildValue) -> Optional[EventType]:
    """Parses change event."""
    evt: EventType = {}
    values: Dict[str, Optional[Union[str, bool]]] = {
        "user": get_owner_name(message),
        "user_link": get_owner_link(message),
        "subject": get_subject(message),
    }

    if change_type in ["description_diff", "points"]:
        event_type = change_type

    elif change_type in ["milestone", "assigned_to"]:
        old, new = get_old_and_new_values(change_type, message)
        tamed_old = old.tame(check_none_or(check_string))
        tamed_new = new.tame(check_none_or(check_string))
        if not tamed_old:
            event_type = "set_" + change_type
            values["new"] = tamed_new
        elif not tamed_new:
            event_type = "unset_" + change_type
            values["old"] = tamed_old
        else:
            event_type = "changed_" + change_type
            values.update(old=tamed_old, new=tamed_new)

    elif change_type == "is_blocked":
        if message["change"]["diff"]["is_blocked"]["to"].tame(check_bool):
            event_type = "blocked"
        else:
            event_type = "unblocked"

    elif change_type == "is_closed":
        if message["change"]["diff"]["is_closed"]["to"].tame(check_bool):
            event_type = "closed"
        else:
            event_type = "reopened"

    elif change_type == "user_story":
        old, new = get_old_and_new_values(change_type, message)
        event_type = "changed_us"
        tamed_old = old.tame(check_none_or(check_string))
        tamed_new = new.tame(check_none_or(check_string))
        values.update(old=tamed_old, new=tamed_new)

    elif change_type in ["subject", "name"]:
        event_type = "renamed"
        old, new = get_old_and_new_values(change_type, message)
        tamed_old = old.tame(check_none_or(check_string))
        tamed_new = new.tame(check_none_or(check_string))
        values.update(old=tamed_old, new=tamed_new)

    elif change_type in ["estimated_finish", "estimated_start", "due_date"]:
        old, new = get_old_and_new_values(change_type, message)
        tamed_old = old.tame(check_none_or(check_string))
        tamed_new = new.tame(check_none_or(check_string))
        if not tamed_old:
            event_type = "set_" + change_type
            values["new"] = tamed_new
        elif not tamed_old == tamed_new:
            event_type = change_type
            values.update(old=tamed_old, new=tamed_new)
        else:
            # date hasn't changed
            return None

    elif change_type in ["priority", "severity", "type", "status"]:
        event_type = "changed_" + change_type
        old, new = get_old_and_new_values(change_type, message)
        tamed_old = old.tame(check_none_or(check_string))
        tamed_new = new.tame(check_none_or(check_string))
        values.update(old=tamed_old, new=tamed_new)

    else:
        # we are not supporting this type of event
        return None

    evt.update(type=message["type"].tame(check_string), event=event_type, values=values)
    return evt


def parse_webhook_test(
    message: WildValue,
) -> EventType:
    return {
        "type": "webhook_test",
        "event": "test",
        "values": {
            "user": get_owner_name(message),
            "user_link": get_owner_link(message),
            "end_type": "test",
        },
    }


def parse_message(
    message: WildValue,
) -> List[EventType]:
    """Parses the payload by delegating to specialized functions."""
    events: List[EventType] = []
    if message["action"].tame(check_string) in ["create", "delete"]:
        events.append(parse_create_or_delete(message))
    elif message["action"].tame(check_string) == "change":
        if message["change"]["diff"]:
            for value in message["change"]["diff"].keys():
                parsed_event = parse_change_event(value, message)
                if parsed_event:
                    events.append(parsed_event)
        if message["change"]["comment"].tame(check_string):
            events.append(parse_comment(message))
    elif message["action"].tame(check_string) == "test":
        events.append(parse_webhook_test(message))

    return events


def generate_content(data: EventType) -> str:
    """Gets the template string and formats it with parsed data."""
    assert isinstance(data["type"], str) and isinstance(data["event"], str)
    template = templates[data["type"]][data["event"]]

    assert isinstance(data["values"], dict)
    content = template.format(**data["values"])
    return content


def get_owner_name(message: WildValue) -> str:
    return message["by"]["full_name"].tame(check_string)


def get_owner_link(message: WildValue) -> str:
    return message["by"]["permalink"].tame(check_string)


def get_subject(message: WildValue) -> str:
    data = message["data"]

    subject = data.get("subject").tame(check_none_or(check_string))
    subject_to_use = subject if subject else data["name"].tame(check_string)

    if "permalink" in data:
        return "[" + subject_to_use + "]" + "(" + data["permalink"].tame(check_string) + ")"
    return "**" + subject_to_use + "**"


def get_epic_subject(message: WildValue) -> str:
    if "permalink" in message["data"]["epic"]:
        return (
            "["
            + message["data"]["epic"]["subject"].tame(check_string)
            + "]"
            + "("
            + message["data"]["epic"]["permalink"].tame(check_string)
            + ")"
        )
    return "**" + message["data"]["epic"]["subject"].tame(check_string) + "**"


def get_userstory_subject(message: WildValue) -> str:
    if "permalink" in message["data"]["user_story"]:
        us_data = message["data"]["user_story"]
        return (
            "["
            + us_data["subject"].tame(check_string)
            + "]"
            + "("
            + us_data["permalink"].tame(check_string)
            + ")"
        )
    return "**" + message["data"]["user_story"]["subject"].tame(check_string) + "**"