import bitutilities as bu

operation = ""
method = ""

user_input = []


def process_command(symbol):
    global operation, method

    if symbol.lower() in "asmdq":
        operation = symbol
    elif operation == "m" and symbol in "1234":
        method = symbol
    elif operation == "d" and symbol in "12":
        method = symbol
    elif symbol in " ;:":
        pass
    else:
        print(f"Error: unexpected instruction '{symbol}', skipping")


def perform_operation(first_register: bu.BasicRegister, second_register: bu.BasicRegister):
    global operation, method

    match operation:
        case "a":
            result, carry = bu.binary_sum_with_carry(first_register, second_register)
            print(f"\nSum: {result}\nCarry: {int(carry)}")
            operation, method = "", ""
        case "s":
            result, carry = bu.binary_subtraction_second_complement(first_register, second_register)
            print(f"\nSubtraction: {result}\nCarry: {int(carry)}")
            operation, method = "", ""
        case "m":
            match method:
                case "1":
                    result, data_table = bu.binary_multiplication_method_1(first_register, second_register)
                    print(f"\nMultiplication (method 1):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case "2":
                    result, data_table = bu.binary_multiplication_method_2(first_register, second_register)
                    print(f"\nMultiplication (method 2):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case "3":
                    result, data_table = bu.binary_multiplication_method_3(first_register, second_register)
                    print(f"\nMultiplication (method 3):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case "4":
                    result, data_table = bu.binary_multiplication_method_4(first_register, second_register)
                    print(f"\nMultiplication (method 4):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case _:
                    pass
        case "d":
            match method:
                case "1":
                    result, data_table = bu.binary_division_method_1(first_register, second_register)
                    print(f"\nDivision (method 1):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case "2":
                    result, data_table = bu.binary_division_method_2(first_register, second_register)
                    print(f"\nDivision (method 2):\n{bu.format_device_state_table(data_table)}\nResult: {result}")
                    operation, method = "", ""
                case _:
                    pass
        case "q":
            exit(0)

        case _:
            pass


def get_prompt_text(operation: any, method: any) -> str:
    response = "({} {})"

    if operation:
        response += " {}"
    if operation and method:
        response += "/{}"

    return response


def input_handler(first_register: bu.BasicRegister, second_register: bu.BasicRegister):
    global user_input, operation
    first_register, second_register = bu.align_registers(first_register, second_register)

    print()
    print(first_register)
    print(second_register)

    while True:
        prompt_text: str = get_prompt_text(operation, method).format(first_register, second_register, operation, method)
        print()
        if operation == "":
            raw_user_input = input("Choose the operation:\n[a]ddition, [s]ubtraction, [m]ultiplication, [d]ivision, "
                                   "[q]uit\n" + prompt_text + " > ")
        elif operation == "m":
            raw_user_input = input("Choose method to use (1-4):\n" + prompt_text + " > ")
        elif operation == "d":
            raw_user_input = input("Choose method to use (1-2):\n" + prompt_text + " > ")

        user_input = list(raw_user_input)

        for symbol in user_input:
            process_command(symbol)
            perform_operation(first_register, second_register)


if __name__ == '__main__':
    reg1: bu.BasicRegister = bu.BasicRegister(bu.get_memory("first operand"))
    reg2: bu.BasicRegister = bu.BasicRegister(bu.get_memory("second operand"))

    # TODO live-swapping of registers!!!

    input_handler(reg1, reg2)