#!/usr/bin/env python
# -*- coding: UTF-8 -*-
# SPDX-License-Identifier: MPL-2.0
# SPDX-FileCopyrightText: © 2025 A.M. Rowsell <https://frzn.dev/~amr>

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# DiscoRSS: A simple RSS feed reader for Discord. Takes RSS feeds and then sends them to
# webhooks. Intended to run using systemd timers.

import requests
import feedparser
import hashlib
import logging
from pathlib import Path
import json
import time
import os
import sys
import re

config_dir = os.environ.get("XDG_CONFIG_HOME")
home_dir = Path.home()
if config_dir is None:
    config_file_path = str(home_dir) + "/.config/discorss/discorss.conf"
    config_dir = str(home_dir) + "/.config/discorss"
else:
    config_file_path = config_dir + r"/discorss/discorss.conf"
log_dir = r"/var/log/discorss"
log_file_path = r"/app.log"
# Yes, I know you "can't parse HTML with regex", but
# just watch me.
html_filter = re.compile(r"\<\/?([A-Za-z0-9 \:\.\-\/\"\=])*\>")
success_codes = [200, 201, 202, 203, 204, 205, 206]
app_config = {}

# IDEA: Consider making this into a class-based program
# This would solve a couple issues around global variables and generally
# make things a bit neater


# This function gets and formats the brief excerpt that goes in the embed
# Different feeds put summaries in different fields, so we pick the best
# one and limit it to 250 characters.
# TODO: make the character limit smarter, as to split at a natural point
def get_description(feed, length=250):
    try:
        temporary_string = str(feed["summary_detail"]["value"])
        temporary_string = html_filter.sub("", temporary_string)
        while length > 150:
            if temporary_string[length - 1 : length] == " ":
                break
            else:
                length -= 1
        desc = (
            temporary_string[:length]
            if len(temporary_string) > length
            else temporary_string
        )
    except KeyError:
        temporary_string = str(feed["description"])
        temporary_string = html_filter.sub("", temporary_string)
        while length > 150:
            if temporary_string[length - 1 : length] == " ":
                break
            else:
                length -= 1
        desc = (
            temporary_string[:length]
            if len(temporary_string) > length
            else temporary_string
        )
    return desc


def setupPaths():
    global app_config
    global logger
    # Check for log and config files/paths, create empty directories if needed
    # TODO: make this cleaner
    if not Path(log_dir).exists():
        print("No log file path exists. Yark! We'll try and make {}...".format(log_dir))
        try:
            Path(log_dir).mkdir(parents=True, exist_ok=True)
        except FileExistsError:
            print("The path {} already exists and is not a directory!".format(log_dir))
    if not Path(config_file_path).exists():
        print(
            "No config file at {}! Snarf. We'll try and make {}...".format(
                config_file_path, config_dir
            )
        )
        try:
            Path(config_dir).mkdir(parents=True, exist_ok=True)
        except FileExistsError:
            print(
                "The config dir {} already exists and is not a directory! Please fix manually.".format(
                    config_dir
                )
            )
            sys.exit(255)
        return
    # Loading the config file
    with open(config_file_path, "r") as config_file:
        app_config = json.load(config_file)
    # Set up logging
    logger = logging.getLogger(__name__)
    logging.basicConfig(
        filename=str(log_dir + log_file_path),
        encoding="utf-8",
        level=logging.INFO,
        datefmt="%m/%d/%Y %H:%M:%S",
        format="%(asctime)s: %(levelname)s: %(message)s",
    )
    return


def main():
    os.environ["TZ"] = "America/Toronto"
    time.tzset()
    now = time.mktime(time.localtime())
    setupPaths()  # Handle the config and log paths
    try:
        last_check = app_config["lastupdate"]
    except KeyError:
        last_check = now - 21600  # first run, no lastupdate, check up to 6 hours ago
    for i, hook in enumerate(app_config["feeds"]):  # Feed loop start
        logger.debug("Parsing feed %s...", hook["name"])
        feeds = feedparser.parse(hook["url"])
        latest_post = []
        prev_best = 0
        for feed in feeds["entries"]:
            try:
                bad_time = False
                published_time = time.mktime(feed["published_parsed"])
                published_time = published_time + hook["offset"]
            except KeyError:
                published_time = time.mktime(feed["updated_parsed"])
                bad_time = True
            if published_time > prev_best:
                latest_post = feed
                prev_best = published_time
            else:
                continue
        if bad_time is True:
            logger.warning(
                "Feed %s doesn't supply a published time, using updated time instead",
                hook["name"],
            )
        # Hash the title and time of the latest post and use that to determine if it's been posted
        new_hash = hashlib.sha3_512(
            bytes(latest_post["title"] + str(published_time), "utf-8")
        ).hexdigest()
        try:
            if hook["lasthash"] != new_hash:
                app_config["feeds"][i]["lasthash"] = new_hash
            else:
                continue
        except KeyError:
            app_config["feeds"][i]["lasthash"] = new_hash
            logger.info(
                "Feed %s has no existing hash, likely a new feed!", hook["name"]
            )
        # Generate the webhook
        logger.info(
            "Publishing webhook for %s. Last check was %d, now is %d",
            hook["name"],
            last_check,
            now,
        )
        webhook = {
            "embeds": [
                {
                    "title": str(latest_post["title"]),
                    "url": str(latest_post["link"]),
                    "color": 216128,
                    "footer": {
                        "name": "DiscoRSS",
                        # "url": "https://git.frzn.dev/amr/discorss",
                    },
                    "author": {
                        "name": str(hook["name"]),
                        "url": str(hook["siteurl"]),
                    },
                    "fields": [
                        {
                            "name": "Excerpt from post:",
                            "value": get_description(latest_post),
                        }
                    ],
                }
            ],
            "attachments": [],
        }
        custom_header = {
            "user-agent": "DiscoRSS (https://git.frzn.dev/amr/discorss, 0.2rc3)",
            "content-type": "application/json",
        }
        webhook_string = json.dumps(webhook)

        r = requests.post(hook["webhook"], data=webhook_string, headers=custom_header)
        if r.status_code not in success_codes:
            logger.error(
                "Error %d while trying to post %s", r.status_code, hook["name"]
            )
        else:
            logger.debug("Got %d when posting %s", r.status_code, hook["name"])

    # End of feed loop

    # Dump updated config back to json file
    app_config["lastupdate"] = now
    with open(config_file_path, "w") as config_file:
        json.dump(app_config, config_file, indent=4)

    return


if __name__ == "__main__":
    main()