#!/usr/bin/env python3
# File: sniffa.py
# Location: https://gitlab.com/bgstack15/sniffa
# Author: danielmitterdorfer
# SPDX-License-Identifer: GPL-3.0
# Startdate: 2016-07-16
# Title: Discourse sniffer
# Purpose: Send alerts for saved searches on Discourse forum websites
# History:
#    2022-01-07 forked by bgstack15 to send discord messages
# Homepage: https://github.com/danielmitterdorfer/sniffa
# Usage:
#    ./sniffa.py aoe2
# Reference:
#    https://meta.discourse.org/t/watching-and-sending-notifications-for-keywords/59286
#    https://stackoverflow.com/questions/62731561/discord-send-message-only-from-python-app-to-discord-channel-one-way-communic/62731999#62731999
#    https://discordpy.readthedocs.io/en/latest/api.html#discord.Webhook.send
# Improve:
# Documentation: See README.md
# Dependencies:
#    req-fedora: python3-certifi
#    req-pip3: discord
#    A webhook given to me by discord "server" admin
import os, sys, errno, json, configparser, urllib3, urllib.parse, datetime, certifi, requests
from discord import Webhook, RequestsWebhookAdapter

DOMAIN_SECTION_KEY = "sniffa.domain"

def ensure_dir(directory):
    try:
        os.makedirs(directory)
    except OSError as exception:
        if exception.errno != errno.EEXIST:
            raise

def creation_date(item):
    return datetime.datetime.strptime(item["created_at"], "%Y-%m-%dT%H:%M:%S.%fZ").timestamp()

def main():
    if not len(sys.argv)  == 2:
        print("usage: %s domain_key" % sys.argv[0], file=sys.stderr)
        exit(1)
    
    domain_key = sys.argv[1]

    http = urllib3.PoolManager(cert_reqs="CERT_REQUIRED", ca_certs=certifi.where())

    watches_dir = "%s/.sniffa" % os.getenv("HOME")
    watches_file = "%s/watches-%s.ini" % (watches_dir, domain_key)

    ensure_dir(watches_dir)

    config = configparser.ConfigParser()
    config.read(watches_file)
    
    if not DOMAIN_SECTION_KEY in config or not "url" in config[DOMAIN_SECTION_KEY]:
        print("Invalid configuration in [%s]" % watches_file, file=sys.stderr)
        print("", file=sys.stderr)
        print("Please add a domain to query according to the following example in [%s]" % watches_file, file=sys.stderr)
        print("", file=sys.stderr)
        print("  [%s]" % DOMAIN_SECTION_KEY, file=sys.stderr)
        print("  url=https://discuss.example.org", file=sys.stderr)
        print("", file=sys.stderr)
        exit(1)

    domain = config[DOMAIN_SECTION_KEY]["url"]
    print("Checking for new posts on %s" % domain_key)
    
    for keyword in config.sections():
        if keyword == DOMAIN_SECTION_KEY:
            continue

        if "ids" in config[keyword]:
            ids = config[keyword]["ids"]
            if len(ids) > 0:
                known_ids = set([int(id) for id in config[keyword]["ids"].split(",")])
            else:
                known_ids = set()
        else:
            known_ids = set()

        query_string = urllib.parse.quote_plus("%s order:latest" % keyword)

        r = http.request("GET", "%s/search?q=%s" % (domain, query_string), headers={"Accept": "application/json"})
        results = json.loads(r.data.decode("utf-8"))

        topics_by_id = {}
        for topic in results["topics"]:
            topics_by_id[topic["id"]] = topic

        posts = []
        for post in results["posts"]:
            post_id = post["id"]
            if post_id not in known_ids:
                known_ids.add(post_id)
                posts.append(post)

        config[keyword]["ids"] = ",".join([str(id) for id in known_ids])

        sorted(posts, key=creation_date, reverse=True)

        if len(posts) > 0:
            webhook = Webhook.from_url(config[DOMAIN_SECTION_KEY]["webhook"], adapter=RequestsWebhookAdapter())
        for post in posts:
            topic = topics_by_id[post["topic_id"]]
            message = f"New post mentioning \"{keyword}\". Url=\"{domain}/t/{topic['slug']}/{topic['id']}\". group={str(topic['id'])}."
            print(message)
            webhook.send(f"{domain}/t/{topic['slug']}/{topic['id']}", username=config[DOMAIN_SECTION_KEY]["discord_user"])
    with open(watches_file, "w") as f:
        config.write(f)
    print("Finished")

if __name__ == "__main__":
    main()