# Webhooks for external integrations.
import re

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_string, to_wild_value
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import UserProfile


@webhook_view("AppFollow")
@has_request_variables
def api_appfollow_webhook(
    request: HttpRequest,
    user_profile: UserProfile,
    payload: WildValue = REQ(argument_type="body", converter=to_wild_value),
) -> HttpResponse:
    message = payload["text"].tame(check_string)
    app_name_search = re.search(r"\A(.+)", message)
    assert app_name_search is not None
    app_name = app_name_search.group(0)
    topic = app_name

    check_send_webhook_message(request, user_profile, topic, body=convert_markdown(message))
    return json_success(request)


def convert_markdown(text: str) -> str:
    # Converts Slack-style Markdown to Zulip format
    # Implemented mainly for AppFollow messages
    # Not ready for general use as some edge-cases not handled
    # Convert bold
    text = re.sub(r"(?:(?<=\s)|(?<=^))\*(.+?\S)\*(?=\s|$)", r"**\1**", text)
    # Convert italics
    text = re.sub(r"\b_(\s*)(.+?)(\s*)_\b", r"\1*\2*\3", text)
    # Convert strikethrough
    text = re.sub(r"(?:(?<=\s)|(?<=^))~(.+?\S)~(?=\s|$)", r"~~\1~~", text)

    return text
