require_relative 'util'

# --- Day 2: I Was Told There Would Be No Math ---

# The elves are running low on wrapping paper, and so they need to
# submit an order for more. They have a list of the dimensions (length
# `l`, width `w`, and height `h`) of each present, and only want to
# order exactly as much as they need.

# Fortunately, every present is a box (a perfect right rectangular
# prism), which makes calculating the required wrapping paper for each
# gift a little easier: find the surface area of the box, which is
# `2*l*w + 2*w*h + 2*h*l`. The elves also need a little extra paper
# for each present: the area of the smallest side.

# For example:

# - A present with dimensions `2x3x4` requires `2*6 + 2*12 + 2*8 = 52`
#   square feet of wrapping paper plus 6 square feet of slack, for a
#   total of 58 square feet.
# - A present with dimensions `1x1x10` requires `2*1 + 2*10 + 2*10 =
#   42` square feet of wrapping paper plus 1 square foot of slack, for
#   a total of 43 square feet.

# All numbers in the elves' list are in feet. How many total square
# feet of wrapping paper should they order?

input = File.open('02.txt') { |f| f.readlines.map(&:chomp) }

def easy(input)
  l, w, h = input.split('x').map(&:to_i)
  x, y = [l, w, h].min(2)
  slack = x * y
  surface = 2 * l * w + 2 * w * h + 2 * h * l
  surface + slack
end

assert(easy('2x3x4') == 58)
assert(easy('1x1x10') == 43)
puts "easy(input): #{input.map { |line| easy(line) }.sum}"

# --- Part Two ---

# The elves are also running low on ribbon. Ribbon is all the same
# width, so they only have to worry about the length they need to
# order, which they would again like to be exact.

# The ribbon required to wrap a present is the shortest distance
# around its sides, or the smallest perimeter of any one face. Each
# present also requires a bow made out of ribbon as well; the feet of
# ribbon required for the perfect bow is equal to the cubic feet of
# volume of the present. Don't ask how they tie the bow, though;
# they'll never tell.

# For example:

# - A present with dimensions `2x3x4` requires `2+2+3+3 = 10` feet of
#   ribbon to wrap the present plus `2*3*4 = 24` feet of ribbon for
#   the bow, for a total of 34 feet.

# - A present with dimensions `1x1x10` requires `1+1+1+1 = 4` feet of
#   ribbon to wrap the present plus `1*1*10 = 10` feet of ribbon for
#   the bow, for a total of 14 feet.

# How many total feet of ribbon should they order?

def hard(input)
  l, w, h = input.split('x').map(&:to_i)
  x, y = [l, w, h].min(2)
  ribbon = 2 * x + 2 * y
  bow = l * w * h
  ribbon + bow
end

assert(hard('2x3x4') == 34)
assert(hard('1x1x10') == 14)
puts "hard(input): #{input.map { |line| hard(line) }.sum}"