# Webhooks for external integrations.
import re
import string
from typing import Callable, Dict, List, Optional

from django.core.exceptions import ValidationError
from django.db.models import Q
from django.http import HttpRequest, HttpResponse

from zerver.decorator import webhook_view
from zerver.lib.exceptions import AnomalousWebhookPayloadError, UnsupportedWebhookEventTypeError
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.validator import WildValue, check_none_or, check_string, to_wild_value
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import Realm, UserProfile, get_user_by_delivery_email

IGNORED_EVENTS = [
    "attachment_created",
    "issuelink_created",
    "issuelink_deleted",
    "jira:version_released",
    "jira:worklog_updated",
    "sprint_closed",
    "sprint_started",
    "worklog_created",
    "worklog_updated",
]


def guess_zulip_user_from_jira(jira_username: str, realm: Realm) -> Optional[UserProfile]:
    try:
        # Try to find a matching user in Zulip
        # We search a user's full name, short name,
        # and beginning of email address
        user = UserProfile.objects.filter(
            Q(full_name__iexact=jira_username) | Q(email__istartswith=jira_username),
            is_active=True,
            realm=realm,
        ).order_by("id")[0]
        return user
    except IndexError:
        return None


def convert_jira_markup(content: str, realm: Realm) -> str:
    # Attempt to do some simplistic conversion of Jira
    # formatting to Markdown, for consumption in Zulip

    # Jira uses *word* for bold, we use **word**
    content = re.sub(r"\*([^\*]+)\*", r"**\1**", content)

    # Jira uses {{word}} for monospacing, we use `word`
    content = re.sub(r"{{([^\*]+?)}}", r"`\1`", content)

    # Starting a line with bq. block quotes that line
    content = re.sub(r"bq\. (.*)", r"> \1", content)

    # Wrapping a block of code in {quote}stuff{quote} also block-quotes it
    quote_re = re.compile(r"{quote}(.*?){quote}", re.DOTALL)
    content = re.sub(quote_re, r"~~~ quote\n\1\n~~~", content)

    # {noformat}stuff{noformat} blocks are just code blocks with no
    # syntax highlighting
    noformat_re = re.compile(r"{noformat}(.*?){noformat}", re.DOTALL)
    content = re.sub(noformat_re, r"~~~\n\1\n~~~", content)

    # Code blocks are delineated by {code[: lang]} {code}
    code_re = re.compile(r"{code[^\n]*}(.*?){code}", re.DOTALL)
    content = re.sub(code_re, r"~~~\n\1\n~~~", content)

    # Links are of form: [https://www.google.com] or [Link Title|https://www.google.com]
    # In order to support both forms, we don't match a | in bare links
    content = re.sub(r"\[([^\|~]+?)\]", r"[\1](\1)", content)

    # Full links which have a | are converted into a better Markdown link
    full_link_re = re.compile(r"\[(?:(?P<title>[^|~]+)\|)(?P<url>[^\]]*)\]")
    content = re.sub(full_link_re, r"[\g<title>](\g<url>)", content)

    # Try to convert a Jira user mention of format [~username] into a
    # Zulip user mention. We don't know the email, just the Jira username,
    # so we naively guess at their Zulip account using this
    mention_re = re.compile("\\[~(.*?)\\]")
    for username in mention_re.findall(content):
        # Try to look up username
        user_profile = guess_zulip_user_from_jira(username, realm)
        if user_profile:
            replacement = f"**{user_profile.full_name}**"
        else:
            replacement = f"**{username}**"

        content = content.replace(f"[~{username}]", replacement)

    return content


def get_in(payload: WildValue, keys: List[str], default: str = "") -> WildValue:
    try:
        for key in keys:
            payload = payload[key]
    except (AttributeError, KeyError, TypeError, ValidationError):
        return WildValue("default", default)
    return payload


def get_issue_string(
    payload: WildValue, issue_id: Optional[str] = None, with_title: bool = False
) -> str:
    # Guess the URL as it is not specified in the payload
    # We assume that there is a /browse/BUG-### page
    # from the REST URL of the issue itself
    if issue_id is None:
        issue_id = get_issue_id(payload)

    if with_title:
        text = f"{issue_id}: {get_issue_title(payload)}"
    else:
        text = issue_id

    base_url = re.match(
        r"(.*)\/rest\/api/.*", get_in(payload, ["issue", "self"]).tame(check_string)
    )
    if base_url and len(base_url.groups()):
        return f"[{text}]({base_url.group(1)}/browse/{issue_id})"
    else:
        return text


def get_assignee_mention(assignee_email: str, realm: Realm) -> str:
    if assignee_email != "":
        try:
            assignee_name = get_user_by_delivery_email(assignee_email, realm).full_name
        except UserProfile.DoesNotExist:
            assignee_name = assignee_email
        return f"**{assignee_name}**"
    return ""


def get_issue_author(payload: WildValue) -> str:
    return get_in(payload, ["user", "displayName"]).tame(check_string)


def get_issue_id(payload: WildValue) -> str:
    if "issue" not in payload:
        # Some ancient version of Jira or one of its extensions posts
        # comment_created events without an "issue" element.  For
        # these, the best we can do is extract the Jira-internal
        # issue number and use that in the topic.
        #
        # Users who want better formatting can upgrade Jira.
        return payload["comment"]["self"].tame(check_string).split("/")[-3]

    return get_in(payload, ["issue", "key"]).tame(check_string)


def get_issue_title(payload: WildValue) -> str:
    if "issue" not in payload:
        # Some ancient version of Jira or one of its extensions posts
        # comment_created events without an "issue" element.  For
        # these, the best we can do is extract the Jira-internal
        # issue number and use that in the topic.
        #
        # Users who want better formatting can upgrade Jira.
        return "Upgrade Jira to get the issue title here."

    return get_in(payload, ["issue", "fields", "summary"]).tame(check_string)


def get_issue_subject(payload: WildValue) -> str:
    return f"{get_issue_id(payload)}: {get_issue_title(payload)}"


def get_sub_event_for_update_issue(payload: WildValue) -> str:
    sub_event = payload.get("issue_event_type_name", "").tame(check_string)
    if sub_event == "":
        if payload.get("comment"):
            return "issue_commented"
        elif payload.get("transition"):
            return "issue_transited"
    return sub_event


def get_event_type(payload: WildValue) -> Optional[str]:
    event = payload.get("webhookEvent").tame(check_none_or(check_string))
    if event is None and payload.get("transition"):
        event = "jira:issue_updated"
    return event


def add_change_info(
    content: str, field: Optional[str], from_field: Optional[str], to_field: Optional[str]
) -> str:
    content += f"* Changed {field}"
    if from_field:
        content += f" from **{from_field}**"
    if to_field:
        content += f" to {to_field}\n"
    return content


def handle_updated_issue_event(payload: WildValue, user_profile: UserProfile) -> str:
    # Reassigned, commented, reopened, and resolved events are all bundled
    # into this one 'updated' event type, so we try to extract the meaningful
    # event that happened
    issue_id = get_in(payload, ["issue", "key"]).tame(check_string)
    issue = get_issue_string(payload, issue_id, True)

    assignee_email = get_in(payload, ["issue", "fields", "assignee", "emailAddress"], "").tame(
        check_string
    )
    assignee_mention = get_assignee_mention(assignee_email, user_profile.realm)

    if assignee_mention != "":
        assignee_blurb = f" (assigned to {assignee_mention})"
    else:
        assignee_blurb = ""

    sub_event = get_sub_event_for_update_issue(payload)
    if "comment" in sub_event:
        if sub_event == "issue_commented":
            verb = "commented on"
        elif sub_event == "issue_comment_edited":
            verb = "edited a comment on"
        else:
            verb = "deleted a comment from"

        if payload.get("webhookEvent") == "comment_created":
            author = payload["comment"]["author"]["displayName"].tame(check_string)
        else:
            author = get_issue_author(payload)

        content = f"{author} {verb} {issue}{assignee_blurb}"
        comment = get_in(payload, ["comment", "body"]).tame(check_string)
        if comment:
            comment = convert_jira_markup(comment, user_profile.realm)
            content = f"{content}:\n\n``` quote\n{comment}\n```"
        else:
            content = f"{content}."
    else:
        content = f"{get_issue_author(payload)} updated {issue}{assignee_blurb}:\n\n"
        changelog = payload.get("changelog")

        if changelog:
            # Use the changelog to display the changes, whitelist types we accept
            items = changelog.get("items")
            for item in items:
                field = item.get("field").tame(check_none_or(check_string))

                if field == "assignee" and assignee_mention != "":
                    target_field_string = assignee_mention
                else:
                    # Convert a user's target to a @-mention if possible
                    target_field_string = "**{}**".format(
                        item.get("toString").tame(check_none_or(check_string))
                    )

                from_field_string = item.get("fromString").tame(check_none_or(check_string))
                if target_field_string or from_field_string:
                    content = add_change_info(
                        content, field, from_field_string, target_field_string
                    )

        elif sub_event == "issue_transited":
            from_field_string = get_in(payload, ["transition", "from_status"]).tame(check_string)
            target_field_string = "**{}**".format(
                get_in(payload, ["transition", "to_status"]).tame(check_string)
            )
            if target_field_string or from_field_string:
                content = add_change_info(content, "status", from_field_string, target_field_string)

    return content


def handle_created_issue_event(payload: WildValue, user_profile: UserProfile) -> str:
    template = """
{author} created {issue_string}:

* **Priority**: {priority}
* **Assignee**: {assignee}
""".strip()

    return template.format(
        author=get_issue_author(payload),
        issue_string=get_issue_string(payload, with_title=True),
        priority=get_in(payload, ["issue", "fields", "priority", "name"]).tame(check_string),
        assignee=get_in(payload, ["issue", "fields", "assignee", "displayName"], "no one").tame(
            check_string
        ),
    )


def handle_deleted_issue_event(payload: WildValue, user_profile: UserProfile) -> str:
    template = "{author} deleted {issue_string}{punctuation}"
    title = get_issue_title(payload)
    punctuation = "." if title[-1] not in string.punctuation else ""
    return template.format(
        author=get_issue_author(payload),
        issue_string=get_issue_string(payload, with_title=True),
        punctuation=punctuation,
    )


def normalize_comment(comment: str) -> str:
    # Here's how Jira escapes special characters in their payload:
    # ,.?\\!\n\"'\n\\[]\\{}()\n@#$%^&*\n~`|/\\\\
    # for some reason, as of writing this, ! has two '\' before it.
    normalized_comment = comment.replace("\\!", "!")
    return normalized_comment


def handle_comment_created_event(payload: WildValue, user_profile: UserProfile) -> str:
    title = get_issue_title(payload)
    return '{author} commented on issue: *"{title}"\
*\n``` quote\n{comment}\n```\n'.format(
        author=payload["comment"]["author"]["displayName"].tame(check_string),
        title=title,
        comment=normalize_comment(payload["comment"]["body"].tame(check_string)),
    )


def handle_comment_updated_event(payload: WildValue, user_profile: UserProfile) -> str:
    title = get_issue_title(payload)
    return '{author} updated their comment on issue: *"{title}"\
*\n``` quote\n{comment}\n```\n'.format(
        author=payload["comment"]["author"]["displayName"].tame(check_string),
        title=title,
        comment=normalize_comment(payload["comment"]["body"].tame(check_string)),
    )


def handle_comment_deleted_event(payload: WildValue, user_profile: UserProfile) -> str:
    title = get_issue_title(payload)
    return '{author} deleted their comment on issue: *"{title}"\
*\n``` quote\n~~{comment}~~\n```\n'.format(
        author=payload["comment"]["author"]["displayName"].tame(check_string),
        title=title,
        comment=normalize_comment(payload["comment"]["body"].tame(check_string)),
    )


JIRA_CONTENT_FUNCTION_MAPPER: Dict[str, Optional[Callable[[WildValue, UserProfile], str]]] = {
    "jira:issue_created": handle_created_issue_event,
    "jira:issue_deleted": handle_deleted_issue_event,
    "jira:issue_updated": handle_updated_issue_event,
    "comment_created": handle_comment_created_event,
    "comment_updated": handle_comment_updated_event,
    "comment_deleted": handle_comment_deleted_event,
}

ALL_EVENT_TYPES = list(JIRA_CONTENT_FUNCTION_MAPPER.keys())


@webhook_view("Jira", all_event_types=ALL_EVENT_TYPES)
@has_request_variables
def api_jira_webhook(
    request: HttpRequest,
    user_profile: UserProfile,
    payload: WildValue = REQ(argument_type="body", converter=to_wild_value),
) -> HttpResponse:

    event = get_event_type(payload)
    if event in IGNORED_EVENTS:
        return json_success(request)

    if event is None:
        raise AnomalousWebhookPayloadError()

    if event is not None:
        content_func = JIRA_CONTENT_FUNCTION_MAPPER.get(event)

    if content_func is None:
        raise UnsupportedWebhookEventTypeError(event)

    subject = get_issue_subject(payload)
    content: str = content_func(payload, user_profile)

    check_send_webhook_message(
        request, user_profile, subject, content, event, unquote_url_parameters=True
    )
    return json_success(request)