#!/usr/bin/env -S emacs --script

;; -*- lexical-binding: t; -*-

;; Copyright (C) 2022 

;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

(add-to-list 'load-path "../")

(require 'ert)
(require 'cl-lib)
(require 'aoc)

(defvar input-file "../../input/day-1.txt")

(defvar test-input-file "../../input/day-1-example.txt")

(defun eat (data)
  (let ((lines (string-lines data)))
    (cl-loop for line in lines
             if (not (zerop (length line)))
             collect (string-to-number line) into group
             else
             collect group into groups
             and do (setq group nil)
             finally (return (if group
                                 (append groups (list group))
                               groups)))))

(defun sum-calories-per-group (groups)
  (let ((sums (seq-map (lambda (g)
                        (apply '+ g))
                      groups)))
    (seq-sort '>= sums)))

(princ (eat (aoc-read-file test-input-file)) 'external-debugging-output)

(ert-deftest part-1-test ()
  (let ((calories (sum-calories-per-group (eat (aoc-read-file test-input-file)))))
    (should (equal 24000 (nth 0 calories)))))

(ert-deftest part-1 ()
  (let ((calories (sum-calories-per-group (eat (aoc-read-file input-file)))))
    (should (equal 68292 (nth 0 calories)))))

(ert-deftest part-2-test ()
  (let ((calories (sum-calories-per-group (eat (aoc-read-file test-input-file)))))
    (should (equal 45000 (apply '+ (seq-take calories 3))))))

(ert-deftest part-2 ()
  (let ((calories (sum-calories-per-group (eat (aoc-read-file input-file)))))
    (should (equal 203203 (apply '+ (seq-take calories 3))))))

(ert-run-tests-batch-and-exit)