"""Database settings for the Python tools (training, evaluation, backfills).

The service itself is ping-collector (rust/collector); it reads the same
environment / `.env` file (rust/collector/src/config.rs). PostgreSQL only:
POSTGRES_CONNECTION_STRING, or POSTGRES_HOST / POSTGRES_PORT / POSTGRES_DB /
POSTGRES_USER / POSTGRES_PASSWORD with the same defaults as ping-collector.
"""

import os
import urllib.parse
from typing import Optional

try:
    from dotenv import load_dotenv

    load_dotenv()
except ImportError:  # the systemd units pass the variables in directly
    pass


def database_url() -> Optional[str]:
    """The PostgreSQL connection string, or None when none is configured."""
    url = os.getenv("POSTGRES_CONNECTION_STRING", "").strip()
    if url:
        return url
    password = os.getenv("POSTGRES_PASSWORD")
    if not password:
        return None
    user = urllib.parse.quote(os.getenv("POSTGRES_USER", "postgres"), safe="")
    host = os.getenv("POSTGRES_HOST", "localhost")
    port = os.getenv("POSTGRES_PORT", "5432")
    name = os.getenv("POSTGRES_DB", "water_monitoring")
    return (
        f"postgresql://{user}:{urllib.parse.quote(password, safe='')}"
        f"@{host}:{port}/{name}"
    )


if __name__ == "__main__":
    url = database_url()
    if url and "@" in url:
        url = url.split("://", 1)[0] + "://***@" + url.rsplit("@", 1)[1]
    print(url or "no database configured")