"""Verify the countydata connection without exposing credentials or row data."""

from __future__ import annotations

import os
import sys

import psycopg2


REQUIRED_ENV_VARS = (
    "PGHOST",
    "PGPORT",
    "PGDATABASE",
    "PGUSER",
    "PGPASSWORD",
    "PGSSLMODE",
)


def main() -> int:
    missing = [name for name in REQUIRED_ENV_VARS if not os.environ.get(name)]
    if missing:
        print(
            "Missing database environment variables: " + ", ".join(missing),
            file=sys.stderr,
        )
        print("Run this through the VS Code task so .env is loaded safely.", file=sys.stderr)
        return 1

    if os.environ["PGSSLMODE"].lower() not in {"require", "verify-ca", "verify-full"}:
        print("Refusing to connect because PGSSLMODE does not require TLS.", file=sys.stderr)
        return 1

    try:
        connection = psycopg2.connect(
            application_name="summer_project_vscode_check",
            connect_timeout=10,
            options=(
                "-c default_transaction_read_only=on "
                "-c statement_timeout=30000"
            ),
        )
        connection.set_session(readonly=True)
    except psycopg2.Error as exc:
        print(f"Connection failed: {exc.diag.message_primary or type(exc).__name__}", file=sys.stderr)
        return 1

    try:
        with connection, connection.cursor() as cursor:
            cursor.execute(
                """
                SELECT
                    current_database(),
                    current_user,
                    current_setting('transaction_read_only'),
                    version()
                """
            )
            database, user, read_only, version = cursor.fetchone()

            cursor.execute(
                """
                SELECT ssl, version, cipher, bits
                FROM pg_stat_ssl
                WHERE pid = pg_backend_pid()
                """
            )
            ssl, tls_version, cipher, bits = cursor.fetchone()

            cursor.execute(
                """
                SELECT count(*)
                FROM pg_class AS c
                JOIN pg_namespace AS n ON n.oid = c.relnamespace
                WHERE c.relkind IN ('r', 'p', 'v', 'm', 'f')
                  AND n.nspname NOT IN ('pg_catalog', 'information_schema')
                  AND n.nspname NOT LIKE 'pg_toast%'
                """
            )
            relation_count = cursor.fetchone()[0]

        print("Countydata connection succeeded")
        print(f"  database: {database}")
        print(f"  user: {user}")
        print(f"  transaction read-only: {read_only}")
        print(f"  TLS: {ssl} ({tls_version}, {cipher}, {bits}-bit)")
        print(f"  visible non-system relations: {relation_count}")
        print(f"  server: {version}")
        return 0
    finally:
        connection.close()


if __name__ == "__main__":
    raise SystemExit(main())