#!/usr/bin/env python3
import argparse
import logging
import time
from datetime import datetime
from pathlib import Path

import requests
import urllib3
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

urllib3.disable_warnings()


class WatchdogHandler(FileSystemEventHandler):
    def __init__(self, args):
        self.args = args

    def on_modified(self, event):
        if event.src_path == args.custom_path:
            file_modified(args)


def file_modified(args):
    response = requests.get(args.opnsense + "/api/unbound/settings/searchHostOverride", auth=(args.api_key, args.api_secret), verify=not args.insecure)

    if response.status_code == 200:
        data = response.json()
        current_overrides = set([(x['server'], x['domain']) for x in data.get('rows', []) if x['description'] != 'SAVE'])
        current_overrides_uuid = {x['domain']: x for x in data.get('rows', [])}
        pihole_custom = set([(x[0], x[1]) for x in [y.split(' ') for y in Path(args.custom_path).read_text().split('\n')] if len(x) > 1])

        to_remove = current_overrides - pihole_custom
        to_add = pihole_custom - current_overrides

        if not len(to_remove) and not len(to_add):
            logger.info('No changes.')
            return

        for item_ip, item_domain in to_remove:
            item_data = current_overrides_uuid[item_domain]
            p = requests.post(args.opnsense + f"/api/unbound/settings/delHostOverride/{item_data['uuid']}", auth=(args.api_key, args.api_secret), verify=not args.insecure)
            if p.status_code != 200:
                raise Exception(f'Failed to delete item {item_domain}: {p.status_code} - {p.text}')
            else:
                logger.info(f'Deleted: {item_domain}')

        now = datetime.now()
        dt_string = now.strftime("%m/%d/%Y %H:%M:%S")

        for item_ip, item_domain in to_add:
            p_data = {
                'host': {
                    'enabled': '1',
                    'hostname': '',
                    'domain': item_domain,
                    'rr': 'A',
                    'mxprio': '',
                    'mx': '',
                    'server': item_ip,
                    'description': f'Synced from Pi-hole {dt_string}'
                }
            }
            p = requests.post(args.opnsense + "/api/unbound/settings/addHostOverride", json=p_data, auth=(args.api_key, args.api_secret), verify=not args.insecure)
            if p.status_code != 200:
                raise Exception(f'Failed to add item {item_domain}: {p.status_code} - {p.text}')
            else:
                logger.info(f'Added: {item_domain}')

        p_reload = requests.post(args.opnsense + "/api/unbound/service/reconfigure", auth=(args.api_key, args.api_secret), verify=not args.insecure)
        if p_reload.status_code != 200:
            raise Exception(f'Failed to reload service: {p_reload.status_code} - {p_reload.text}')
        else:
            logger.info(f'Unbound reloaded.')

    else:
        raise Exception(f"Failed to fetch host overrides: {response.status_code} - {response.text}")


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Sync custom DNS entries in Pi-hole to OPNsense Unbound.')
    parser.add_argument('--opnsense', required=True, help='Address of your OPNsense server. Example: https://192.168.1.1')
    parser.add_argument('--custom-path', default='/etc/pihole/custom.list', help="Path to Pi-hole's custom.list. Default: /etc/pihole/custom.list")
    parser.add_argument('--api-key', required=True, help='OPNsense API key.')
    parser.add_argument('--api-secret', required=True, help='OPNsense API secret.')
    parser.add_argument('--insecure', action='store_true', help="Don't verify SSL.")
    args = parser.parse_args()

    logging.basicConfig()
    logger = logging.getLogger('syncer')
    logger.setLevel(logging.INFO)

    logger.info('Running initial sync...')
    file_modified(args)

    event_handler = WatchdogHandler(args)
    observer = Observer()
    observer.schedule(event_handler, path='/etc/pihole/', recursive=False)
    observer.start()
    logger.info('Started watchdog.')

    try:
        while True:
            time.sleep(100)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()