(define-module (src dates)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-19)
  #:export (string/ISO->date
            date->string/RFC3339
            unix-date
            newest
            find-newest))

(define (string/ISO->date string)
  (string->date string "~Y-~m-~d"))

(define (date->string/RFC3339 date)
  (date->string date "~4"))

(define unix-date (string/ISO->date "1970-01-01"))

(define (newest a b) (if (time>? (date->time-utc a) (date->time-utc b)) a b))

(define (find-newest dates) (reduce newest unix-date dates))