#!/usr/bin/env python3

"""Utility for doing simple FX conversions."""

from __future__ import annotations

import plistlib
import subprocess
import sys


def read_cache() -> dict[str, float]:
    return plistlib.loads(
        subprocess.check_output(
            ("defaults", "export", "com.apple.calculateframework", "-"),
        )
    )["currencyCache"]


def main() -> None:
    if len(sys.argv) == 1 or "--help" in sys.argv[1:] or "-h" in sys.argv[1:]:
        print(f"{sys.argv[0]} <value> <from_currency> [to_currency=USD]")
        print(__doc__)
        sys.exit(0)

    value_raw, *args = sys.argv[1:]
    value_raw = value_raw.replace(",", "").replace(" ", "")
    if not value_raw.isnumeric():
        value = float("".join(x for x in value_raw if x.isnumeric()) or "1")
        from_currency = "".join(x for x in value_raw if not x.isnumeric())
    else:
        value = float(value_raw)
        from_currency, *args = args
    if args:
        to_currency, *args = args
    else:
        to_currency = "USD"

    cache = read_cache()
    fx_rate = cache[to_currency] / cache[from_currency]
    print(f"{value * fx_rate:{',.2f' if value != 1.0 else ''}}")


if __name__ == "__main__":
    main()