#!/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 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"


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 download_blocklists(data):
    any_fail = False
    BLOCKLIST_DIR.mkdir(exist_ok=True)
    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:
            print(f"  Skipped '{name}': missing url or save_as")
            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)
            print(f"  Downloaded: {name} ({len(content):,} bytes)")
        except Exception as e:
            print(f"  ERROR: Failed to download '{name}': {e}")
            any_fail = True
    return not any_fail


def main():
    check_root()
    data = load_config()
    print("Downloading blocklists ==============================================")
    success = download_blocklists(data)
    if not success:
        print("WARNING: One or more downloads failed.")
        sys.exit(1)


if __name__ == "__main__":
    main()