# Copyright (c) Metakernel Development Team.
# Distributed under the terms of the Modified BSD License.

from __future__ import annotations

import json

from metakernel import Magic, MetaKernel


class ConnectInfoMagic(Magic):
    def line_connect_info(self, dummy: str | None = None) -> None:
        """
        %connect_info - show connection information

        This line magic will show the connection information for this
        language kernel instance. This information is only necessary
        if you are interested in making additional connections to the
        running kernel.

        Example:
            %connect_info

        Paste the given JSON into a file, and connect with:

            $> ipython <app> --existing <file>

        or, if you are local, you can connect with just:

            $> ipython <app> --existing %(key)s

        or even just:
            $> ipython <app> --existing

        if this is the most recent Jupyter session you have started.
        """
        connection_file = self.kernel.config["IPKernelApp"]["connection_file"]
        try:
            with open(connection_file) as f:
                config = json.load(f)
        except Exception:
            config = {
                "stdin_port": "UNKNOWN",
                "shell_port": "UNKNOWN",
                "iopub_port": "UNKNOWN",
                "hb_port": "UNKNOWN",
                "ip": "UNKNOWN",
                "key": "UNKNOWN",
                "signature_scheme": "UNKNOWN",
                "transport": "UNKNOWN",
            }
        retval = """{{
  "stdin_port": {stdin_port},
  "shell_port": {shell_port},
  "iopub_port": {iopub_port},
  "hb_port": {hb_port},
  "ip": "{ip}",
  "key": "{key}",
  "signature_scheme": "{signature_scheme}",
  "transport": "{transport}"
}}

Paste the above JSON into a file, and connect with:
    $> ipython <app> --existing <file>
or, if you are local, you can connect with just:
    $> ipython <app> --existing {key}

or even just:
    $> ipython <app> --existing
if this is the most recent Jupyter session you have started.
""".format(**config)
        self.kernel.Print(retval)


def register_magics(kernel: MetaKernel) -> None:
    kernel.register_magics(ConnectInfoMagic)
