from re import search
from typing import List, Callable
from sys import argv, exit

from piggybank import print_program_version
from piggybank.configuration import Configuration
from piggybank.currencies import CURRENCIES

__all__ = ["handle_default_arguments", "complement_array_of_coins"]


USAGE_COMMON: str = "Usage: piggybank-* " \
    "[(-h|--help)|(-v|--version)|(-L|--list-currencies)]\n" \
    "A set of common flags. Only one could be specified.\n" \
    "-h, --help                      -- print this help;\n" \
    "-v, --version                   -- print program version;\n" \
    "-L, --list-currencies           -- print supported currencies;\n" \
    "--set-default-currency CURRENCY -- set default currency.\n"


def parse_common_arguments(args: str):
    r = r"(?P<help>-h|--help)|(?P<version>-v|--version)" \
        r"|(?P<list_currencies>-L|--list-currencies)" \
        r"|(?=--set-default-currency (?P<default_currency>\w+))"
    argd = search(r, args)
    if not argd is None:
        argd = argd.groupdict()
        return {
            "help": argd["help"] is None,
            "version": argd["transactions"] is None,
            "list-currencies": argd["list_currencies"] is None,
            "default-currency": argd["default_currency"] }


def handle_default_arguments(args: dict, help_func: Callable) -> None:
    cargs = parse_common_arguments(' '.join(argv))

    if cargs["help"]:
        help_func()
        print(USAGE_COMMON)
        exit()
    elif cargs["version"]:
        print_program_version()
        exit()
    elif cargs["list-currencies"]:
        print_supported_currencies()
        exit()
    elif not cargs["default-currency"] is None:
        Configuration()["default-currency"] = cargs["default-currency"]
        exit()


def print_supported_currencies() -> None:
    """Print a list of supported currencies."""
    print("Supported currencies are:")
    for cur in CURRENCIES:
        print(f"  {cur:^4} ┃ {CURRENCIES[cur]['name']:^31}"
              f" ┃ {CURRENCIES[cur]['description']}")
    print("Default currency is", Configuration()["default-currency"])


def complement_array_of_coins(coins: List[int], currency: str,
                              _reversed: bool = False) -> List[int]:
    """Complements array of coins up to the count of currency's coins."""
    offset_array = [0] * (CURRENCIES[currency]["count"] - len(coins))
    return offset_array + coins if not _reversed else coins + offset_array