import argparse
import sys

import pyperclip

DOLLCODE_CHARS = ("▌", "▖", "▘")
BASE_NUM = 3


# encodes input string into integer by using ord() & base256
def encode_base256_int(input: str) -> int:
    result: int = 0

    for char in input:
        result = (result * 256) + ord(char)

    return result


# decodes input number back in char
def decode_base256_int(num: int) -> str:
    output: str = ""

    while num > 0:
        output = (chr(num % 256)) + output
        num = num // 256

    return output


# converts encoded base256 int -> bijective base-3 numeration
# then inserts corresponding number (3, 1, 2) into output list
def encode_dollcode(num: int) -> list[str]:
    output: list[str] = []
    window: int = num
    mod: int

    while window > 0:
        mod = window % BASE_NUM

        if mod == 0:
            window = (window - BASE_NUM) // BASE_NUM
        else:
            window = (window - mod) // BASE_NUM

        output.insert(0, DOLLCODE_CHARS[mod])

    return output


# decodes input dollcode -> integer
def decode_dollcode(input: str) -> int:
    result: int = 0

    for char in input:
        if char not in DOLLCODE_CHARS:
            raise ValueError(f"Invalid character '{char}' in input")
        elif char == DOLLCODE_CHARS[0]:
            result = (result + 1) * BASE_NUM
        else:
            result = result * BASE_NUM + DOLLCODE_CHARS.index(char)

    return result


def main(command: str, input: str, copy: bool):
    result: str = ""

    try:
        if command == "decode":
            result = decode_base256_int(decode_dollcode(input))
        else:
            encoded_dollcode = encode_dollcode(encode_base256_int(input))
            result = "".join(encoded_dollcode)

        if copy:
            pyperclip.copy(result)
            print(f"{result} -> 📋 copied!")
        else:
            print(result)
    except ValueError as e:
        print(f"Error: {e}")
        sys.exit(1)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="converts input into dollcode")
    subparsers = parser.add_subparsers(dest="command", required=True)

    # encode subcommand
    encode_parser = subparsers.add_parser("encode", help="encode text to dollcode")
    encode_parser.add_argument("input", type=str, help="text to encode")
    encode_parser.add_argument(
        "-c", action="store_true", help="copy output to clipboard"
    )

    # decode subcommand
    decode_parser = subparsers.add_parser("decode", help="decode dollcode to text")
    decode_parser.add_argument("input", type=str, help="dollcode to decode")
    decode_parser.add_argument(
        "-c", action="store_true", help="copy output to clipboard"
    )

    args = parser.parse_args()
    main(args.command, args.input, args.c)