# --- Day 2: Password Philosophy ---

# Your flight departs in a few days from the coastal airport; the easiest way
# down to the coast from here is via toboggan.

# The shopkeeper at the North Pole Toboggan Rental Shop is having a bad day.
# "Something's wrong with our computers; we can't log in!" You ask if you can
# take a look.

# Their password database seems to be a little corrupted: some of the passwords
# wouldn't have been allowed by the Official Toboggan Corporate Policy that was
# in effect when they were chosen.

# To try to debug the problem, they have created a list (your puzzle input) of
# passwords (according to the corrupted database) and the corporate policy when
# that password was set.

# For example, suppose you have the following list:

# 1-3 a: abcde
# 1-3 b: cdefg
# 2-9 c: ccccccccc

# Each line gives the password policy and then the password. The password
# policy indicates the lowest and highest number of times a given letter must
# appear for the password to be valid. For example, 1-3 a means that the
# password must contain a at least 1 time and at most 3 times.

# In the above example, 2 passwords are valid. The middle password, cdefg, is
# not; it contains no instances of b, but needs at least 1. The first and third
# passwords are valid: they contain one a or nine c, both within the limits of
# their respective policies.

# How many passwords are valid according to their policies?


with open("files/P2.txt", "r") as f:
    passwds = [line.split() for line in f.read().strip().split("\n")]


def part_1() -> None:
    correct_passwds = 0
    for passwd in passwds:
        min_, max_ = passwd[0].split("-")

        if passwd[2].count(passwd[1][:-1]) >= int(min_) and passwd[2].count(
            passwd[1][:-1]
        ) <= int(max_):
            correct_passwds += 1

    print(f"There are {correct_passwds} valid passwords in the database")


# --- Part Two ---

# While it appears you validated the passwords correctly, they don't seem to be
# what the Official Toboggan Corporate Authentication System is expecting.

# The shopkeeper suddenly realizes that he just accidentally explained the
# password policy rules from his old job at the sled rental place down the
# street! The Official Toboggan Corporate Policy actually works a little
# differently.

# Each policy actually describes two positions in the password, where 1 means
# the first character, 2 means the second character, and so on. (Be careful;
# Toboggan Corporate Policies have no concept of "index zero"!) Exactly one of
# these positions must contain the given letter. Other occurrences of the
# letter are irrelevant for the purposes of policy enforcement.

# Given the same example list from above:

#     1-3 a: abcde is valid: position 1 contains a and position 3 does not.
#     1-3 b: cdefg is invalid: neither position 1 nor position 3 contains b.
#     2-9 c: ccccccccc is invalid: both position 2 and position 9 contain c.

# How many passwords are valid according to the new interpretation of the
# policies?


def part_2() -> None:
    correct_passwds = 0
    for passwd in passwds:
        pos1, pos2 = passwd[0].split("-")
        checks = 0
        if passwd[2][int(pos1) - 1] == passwd[1][:-1]:
            checks += 1
        if passwd[2][int(pos2) - 1] == passwd[1][:-1]:
            checks += 1
        if checks == 1:
            correct_passwds += 1

    print(f"There are {correct_passwds} valid passwords in the database")


if __name__ == "__main__":
    part_1()
    part_2()