#!/usr/bin/env python3
"""Download community blocklists defined in config.json to disk.

Saves each community blocklist to blocklists/<save_as>.
Local blocklists are managed by the dashboard and are not downloaded here.

Run this on a schedule (e.g. daily) to refresh remote lists, then run
  sudo python3 core.py --merge-blocklists
to merge, update SQLite, and reload dnsmasq without restarting it.

Usage:
  sudo python3 dl_blocklists.py
"""

import json
import logging
import os
import sys
import urllib.request
from pathlib import Path

SCRIPT_DIR    = Path(__file__).parent
CONFIG_FILE   = SCRIPT_DIR / "config.json"
BLOCKLIST_DIR = SCRIPT_DIR / "blocklists"
LOG_FILE      = BLOCKLIST_DIR / ".log"
LAST_DL_FILE  = BLOCKLIST_DIR / ".last-dl"


def die(msg):
    print(f"ERROR: {msg}", file=sys.stderr)
    sys.exit(1)


def check_root():
    if os.geteuid() != 0:
        die("This script must be run as root (sudo).")


def load_config():
    if not CONFIG_FILE.exists():
        die(f"Config file not found: {CONFIG_FILE}")
    with open(CONFIG_FILE) as f:
        return json.load(f)


def setup_logging():
    BLOCKLIST_DIR.mkdir(exist_ok=True)
    try:
        file_handler = logging.FileHandler(LOG_FILE, mode='a')
    except PermissionError:
        print(f"WARNING: Cannot write to {LOG_FILE} -- run with sudo.")
        file_handler = None
    handlers = [logging.StreamHandler()]
    if file_handler:
        handlers.insert(0, file_handler)
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s  %(levelname)-8s  %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
        handlers=handlers,
        force=True,
    )


def download_blocklists(data):
    any_fail = False
    for bl in data.get("dns_blocking", {}).get("blocklists", []):
        if bl.get("bl_type") == "local":
            continue
        url     = bl.get("url", "")
        save_as = bl.get("save_as", "")
        name    = bl.get("name", "?")
        if not url or not save_as:
            logging.warning("Skipped '%s': missing url or save_as", name)
            continue
        try:
            req = urllib.request.Request(url, headers={"User-Agent": "routlin/1.0"})
            with urllib.request.urlopen(req, timeout=30) as r:
                content = r.read()
            (BLOCKLIST_DIR / save_as).write_bytes(content)
            logging.info("Downloaded: %s (%s bytes)", name, f"{len(content):,}")
        except Exception as e:
            logging.error("Failed to download '%s': %s", name, e)
            any_fail = True
    return not any_fail


def main():
    check_root()
    setup_logging()
    data = load_config()
    logging.info("Downloading blocklists ==========================================")
    success = download_blocklists(data)
    LAST_DL_FILE.write_text(str(int(__import__('time').time())))
    if not success:
        logging.warning("One or more downloads failed.")
        sys.exit(1)


if __name__ == "__main__":
    main()