;;;; 2015.02.01-first-attempt.lisp
;;;; Advent of Code 2015
;;;; Day 2: I Was Told There Would Be No Math
;;;; Attempt 1: First attempt in Common Lisp

;; ---------------------------------------------------------------------
;;; Package Definition
;; ---------------------------------------------------------------------

(ql:quickload :cl-ppcre)
(ql:quickload :alexandria)

(defpackage :2015-02-01-first-attempt
  (:use #:common-lisp
        #:cl-ppcre
        #:alexandria))
(in-package :2015-02-01-first-attempt)




;; ---------------------------------------------------------------------
;;; Definitions
;; ---------------------------------------------------------------------

(defconstant +PUZZLE-INPUT-FILE+ "~/proj/Learn/aoc/src/2015.02._PUZZLE-INPUT.txt"
  "File to be used as input to the program.")

(defconstant +PUZZLE-INPUT-STRING+ (uiop:read-file-string +PUZZLE-INPUT-FILE+)
  "Single-string version of the text in `+PUZZLE-INPUT-FILE+'.")

(defconstant +PUZZLE-INPUT-STRING-LIST+
  (loop for line in (ppcre:split #\Newline +PUZZLE-INPUT-STRING+)
        collect (ppcre:all-matches-as-strings "-?\\d+" line))
  "List of sublists containing string versions of the dimensions of presents.")

(defconstant +PUZZLE-INPUT-LIST+
  (loop for sublist in +PUZZLE-INPUT-STRING-LIST+
        collect (sort (mapcar #'parse-integer sublist) #'>))
  "A list of presents and their numerical dimensions.
Represented as a list of sublists, with each sublist containing the 3
dimensions of a particular present.")




;; ---------------------------------------------------------------------
;;; Part 1
;; -------
;; 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?
;; ---------------------------------------------------------------------

(defun wrapping-paper-base (DIMENSIONS)
  "Calculate the base amount of wrapping paper needed for a present with `DIMENSIONS'.
`DIMENSIONS' is assumed to be a list of 3 elements."
  (apply #'+ (list (* 2 (first DIMENSIONS) (second DIMENSIONS))
                   (* 2 (first DIMENSIONS) (third DIMENSIONS))
                   (* 2 (second DIMENSIONS) (third DIMENSIONS)))))

(assert (= 52 (wrapping-paper-base '(4 3 2))))
(assert (= 42 (wrapping-paper-base '(10 1 1))))


(defun wrapping-paper-extra (DIMENSIONS)
  "Calculate the extra amount of wrapping paper needed for a present with `DIMENSIONS'.
`DIMENSIONS' is assumed to be a list of 3 elements sorted highest to lowest."
  (apply #'* (cdr DIMENSIONS)))


(defun wrapping-paper-area (DIMENSIONS)
  "Calculate the total amount of paper needed for a present with `DIMENSIONS'.
`DIMENSIONS' is assumed to be a list of 3 elements."
  (+ (wrapping-paper-base DIMENSIONS)
     (wrapping-paper-extra DIMENSIONS)))

(assert (= 58 (wrapping-paper-area '(4 3 2))))
(assert (= 43 (wrapping-paper-area '(10 1 1))))


(defun wrapping-paper-total (PRESENTS)
  "Calculate the total amount of wrapping paper needed for the entire list of `PRESENTS'.
`PRESENTS' is assumed to be a list of sublists of 3 elements each."
  (apply #'+ (mapcar #'wrapping-paper-area PRESENTS)))


;; Test correct answer
(assert (= 1586300 (wrapping-paper-total +PUZZLE-INPUT-LIST+)))




;; ---------------------------------------------------------------------
;;; Part 2
;; -------
;; 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?
;; ---------------------------------------------------------------------