__author__ = "Tofu Gang"
__email__ = "tofugangsw@gmail.com"

from typing import Tuple
from itertools import product

"""
--- Day 14: Docking Data ---

As your ferry approaches the sea port, the captain asks for your help again. 
The computer system that runs this port isn't compatible with the docking 
program on the ferry, so the docking parameters aren't being correctly 
initialized in the docking program's memory.
"""

################################################################################

BITMASK_LENGTH = 36
BITMASK_INSTRUCTION = "mask"
BITMASK_FLOATING = 'X'
WRITE_INSTRUCTION = "mem"
INSTRUCTION_DELIMITER = '='
ADDRESS_DELIMITER_LEFT = '['
ADDRESS_DELIMITER_RIGHT = ']'

################################################################################

def puzzle_1() -> None:
    """
    --- Part One ---

    After a brief inspection, you discover that the sea port's computer system
    uses a strange bitmask system in its initialization program. Although you
    don't have the correct decoder chip handy, you can emulate it in software!

    The initialization program (your puzzle input) can either update the bitmask
    or write a value to memory. Values and memory addresses are both 36-bit
    unsigned integers. For example, ignoring bitmasks for a moment, a line like
    mem[8] = 11 would write the value 11 to memory address 8.

    The bitmask is always given as a string of 36 bits, written with the most
    significant bit (representing 2^35) on the left and the least significant
    bit (2^0, that is, the 1s bit) on the right. The current bitmask is applied
    to values immediately before they are written to memory: a 0 or 1 overwrites
    the corresponding bit in the value, while an X leaves the bit in the value
    unchanged.

    For example, consider the following program:

    mask = XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
    mem[8] = 11
    mem[7] = 101
    mem[8] = 0

    This program starts by specifying a bitmask (mask = ....). The mask it
    specifies will overwrite two bits in every written value: the 2s bit is
    overwritten with 0, and the 64s bit is overwritten with 1.

    The program then attempts to write the value 11 to memory address 8. By
    expanding everything out to individual bits, the mask is applied as follows:

    value:  000000000000000000000000000000001011  (decimal 11)
    mask:   XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
    result: 000000000000000000000000000001001001  (decimal 73)

    So, because of the mask, the value 73 is written to memory address 8
    instead. Then, the program tries to write 101 to address 7:

    value:  000000000000000000000000000001100101  (decimal 101)
    mask:   XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
    result: 000000000000000000000000000001100101  (decimal 101)

    This time, the mask has no effect, as the bits it overwrote were already the
    values the mask tried to set. Finally, the program tries to write 0 to
    address 8:

    value:  000000000000000000000000000000000000  (decimal 0)
    mask:   XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
    result: 000000000000000000000000000001000000  (decimal 64)

    64 is written to address 8 instead, overwriting the value that was there
    previously.

    To initialize your ferry's docking program, you need the sum of all values
    left in memory after the initialization program completes. (The entire
    36-bit address space begins initialized to the value 0 at every address.) In
    the above example, only two values in memory are not zero - 101 (at address
    7) and 64 (at address 8) - producing a sum of 165.

    Execute the initialization program. What is the sum of all values left in
    memory after it completes? (Do not truncate the sum to 36 bits.)

    The answer should be 14553106347726.
    """

    with open("day_14/input.txt", 'r') as f:
        program = [line.strip() for line in f.readlines()]
        bitmask = None
        memory = {}

        for line in program:
            if line.startswith(BITMASK_INSTRUCTION):
                bitmask = line.split(INSTRUCTION_DELIMITER)[1].strip()
            elif line.startswith(WRITE_INSTRUCTION):
                address = line.split(ADDRESS_DELIMITER_LEFT)[1] \
                    .split(ADDRESS_DELIMITER_RIGHT)[0].strip()
                value = int(line.split(INSTRUCTION_DELIMITER)[1].strip())
                memory[address] = _decode(value, bitmask)

        print(sum([memory[key] for key in memory]))

################################################################################

def puzzle_2() -> None:
    """
    --- Part Two ---

    For some reason, the sea port's computer system still can't communicate with
    your ferry's docking program. It must be using version 2 of the decoder
    chip!

    A version 2 decoder chip doesn't modify the values being written at all.
    Instead, it acts as a memory address decoder. Immediately before a value is
    written to memory, each bit in the bitmask modifies the corresponding bit of
    the destination memory address in the following way:

    -If the bitmask bit is 0, the corresponding memory address bit is unchanged.
    -If the bitmask bit is 1, the corresponding memory address bit is
     overwritten with 1.
    -If the bitmask bit is X, the corresponding memory address bit is floating.

    A floating bit is not connected to anything and instead fluctuates
    unpredictably. In practice, this means the floating bits will take on all
    possible values, potentially causing many memory addresses to be written all
    at once!

    For example, consider the following program:

    mask = 000000000000000000000000000000X1001X
    mem[42] = 100
    mask = 00000000000000000000000000000000X0XX
    mem[26] = 1

    When this program goes to write to memory address 42, it first applies the
    bitmask:

    address: 000000000000000000000000000000101010  (decimal 42)
    mask:    000000000000000000000000000000X1001X
    result:  000000000000000000000000000000X1101X

    After applying the mask, four bits are overwritten, three of which are
    different, and two of which are floating. Floating bits take on every
    possible combination of values; with two floating bits, four actual memory
    addresses are written:

    000000000000000000000000000000011010  (decimal 26)
    000000000000000000000000000000011011  (decimal 27)
    000000000000000000000000000000111010  (decimal 58)
    000000000000000000000000000000111011  (decimal 59)

    Next, the program is about to write to memory address 26 with a different
    bitmask:

    address: 000000000000000000000000000000011010  (decimal 26)
    mask:    00000000000000000000000000000000X0XX
    result:  00000000000000000000000000000001X0XX

    This results in an address with three floating bits, causing writes to eight
    memory addresses:

    000000000000000000000000000000010000  (decimal 16)
    000000000000000000000000000000010001  (decimal 17)
    000000000000000000000000000000010010  (decimal 18)
    000000000000000000000000000000010011  (decimal 19)
    000000000000000000000000000000011000  (decimal 24)
    000000000000000000000000000000011001  (decimal 25)
    000000000000000000000000000000011010  (decimal 26)
    000000000000000000000000000000011011  (decimal 27)

    The entire 36-bit address space still begins initialized to the value 0 at
    every address, and you still need the sum of all values left in memory at
    the end of the program. In this example, the sum is 208.

    Execute the initialization program using an emulator for a version 2 decoder
    chip. What is the sum of all values left in memory after it completes?

    The answer should be 2737766154126.
    """

    with open("day_14/input.txt", 'r') as f:
        program = [line.strip() for line in f.readlines()]
        bitmask = None
        memory = {}

        for line in program:
            if line.startswith(BITMASK_INSTRUCTION):
                bitmask = line.split(INSTRUCTION_DELIMITER)[1].strip()
            elif line.startswith(WRITE_INSTRUCTION):
                address = int(line.split(ADDRESS_DELIMITER_LEFT)[1] \
                              .split(ADDRESS_DELIMITER_RIGHT)[0].strip())
                value = int(line.split(INSTRUCTION_DELIMITER)[1].strip())
                [memory.__setitem__(address, value)
                 for address in _decode_2(address, bitmask)]

        print(sum([memory[key] for key in memory]))

################################################################################

def _decode(value: int, bitmask: str) -> int:
    """
    Applicable for puzzle 1.

    :param value: integer value from the program instruction
    :param bitmask: bitmask from the program instruction
    :return: decimal number created by applying the bitmask to the input value
    """

    value_bin = bin(value).replace("0b", '').zfill(BITMASK_LENGTH)
    value_masked = [
        bitmask[i]
        if bitmask[i] != BITMASK_FLOATING
        else value_bin[i]
        for i in range(BITMASK_LENGTH)]
    return int(''.join(value_masked), 2)

################################################################################

def _decode_2(address: int, bitmask: str) -> Tuple[int]:
    """
    Applicable for puzzle 2.

    :param address: integer value from the program instruction
    :param bitmask: bitmask from the program instruction
    :return: list of possible addresses considering all floating bits
    """

    address_bin = bin(address).replace("0b", '').zfill(BITMASK_LENGTH)
    address_masked = ''.join([
        address_bin[i]
        if bitmask[i] == '0'
        else bitmask[i]
        for i in range(BITMASK_LENGTH)])
    floating_bits_variations = [
        list(reversed(variation))
        for variation in product(
            range(2), repeat=address_masked.count(BITMASK_FLOATING))]

    return tuple([int(''.join([
        str(variation.pop())
        if address_masked[i] == BITMASK_FLOATING
        else address_masked[i]
        for i in range(len(address_masked))]), 2)
        for variation in floating_bits_variations])

################################################################################
