"""
Improve the standard Python REPL.

This module attempts to emulate the workflow of ghci or lisp repls. It uses
importlib to load a namespace from the given path. It then binds 'r()' to a
function that reloads the same namespace.
"""

import importlib
import logging
import sys

from Biz import Log


def use(ns: str, path: str) -> None:
    """
    Load or reload the module named 'ns' from 'path'.

    Like `use` in the Guile Scheme repl.
    """
    logging.info("loading %s from %s", ns, path)
    spec = importlib.util.spec_from_file_location(ns, path)
    module = importlib.util.module_from_spec(spec)
    # delete module and its imported names if its already loaded
    if ns in sys.modules:
        del sys.modules[ns]
        for name in module.__dict__:
            if name in globals():
                del globals()[name]
    sys.modules[ns] = module
    spec.loader.exec_module(module)
    names = list(module.__dict__)
    globals().update({k: getattr(module, k) for k in names})


if __name__ == "__main__":
    Log.setup()
    NS = sys.argv[1]
    PATH = sys.argv[2]
    use(NS, PATH)

    logging.info("use reload() or _r() after making changes")
    sys.ps1 = f"{NS}> "
    sys.ps2 = f"{NS}| "

    def reload() -> None:
        """Reload the namespace."""
        return use(NS, PATH)

    def _r() -> None:
        """Shorthand: Reload the namespace."""
        return use(NS, PATH)