day02.scm

(import (chicken io))
(import (chicken format))
(import (chicken string))
(import srfi-1)

(define (parse-line line)
    (let ((words (string-split line)))
        (list (car words) (string->number (car (cdr words))))))

(define (parse inputs)
    (let ((line (read-line)))
        (if (not (eof-object? line))
            (cons (parse-line line) (parse inputs))
            inputs)))

(define (part1-direction head tail h d)
    (let ((command (car head))
          (offset (car (cdr head)))) 
        (cond ((equal? command "forward") 
               (part1 tail (+ h offset) d))
              ((equal? command "down")
               (part1 tail h (+ d offset)))
              ((equal? command "up")
               (part1 tail h (- d offset)))
              (else (format #t "que~%")))))

(define (part1 directions h d)
    (if (not (null? directions))
        (part1-direction (car directions) (cdr directions) h d)
        (* h d)))


(define (part2-direction head tail horiz depth aim)
    (let ((command (car head))
          (offset (car (cdr head)))) 
        (cond ((equal? command "forward") 
               (part2 tail (+ horiz offset) (+ depth (* aim offset)) aim))
              ((equal? command "down")
               (part2 tail horiz depth (+ aim offset)))
              ((equal? command "up")
               (part2 tail horiz depth (- aim offset)))
              (else (format #t "que~%")))))

(define (part2 directions horiz depth aim)
    (if (not (null? directions))
        (part2-direction (car directions) (cdr directions) horiz depth aim)
        (* horiz depth)))
    

(let ((directions (parse '())))
    (format #t "part1 = ~A~%" (part1 directions 0 0))
    (format #t "part2 = ~A~%" (part2 directions 0 0 0)))