(define-module (cybo))

(use-modules
 (ice-9 rdelim)
 )

(define UTF-8_ENCODING "UTF-8")
(define TAG_LENGTH_PRIORITY 3)
(define TAG_INDEX_PRIORITY 0)

(define-public next-actions
  (lambda (filename)
    (sort-by-priority (all-tasks filename))))

(define (sort-by-priority task-list)
  (stable-sort task-list (lambda (task1 task2)
                           (string<? (priority task1)
                                     (priority task2)))))

(define (priority task)
  (substring task TAG_INDEX_PRIORITY TAG_LENGTH_PRIORITY))

(define (all-tasks filename)
  (if (exist? filename)
      (todo.txt->scm filename)
      '()))

(define (exist? filename)
  (access? filename F_OK))

(define (todo.txt->scm filename)
  (call-with-input-file filename
    (lambda (file-port)
      (let loop ((line (read-line file-port)) (todo-list '()))
        (if (eof-object? line) (reverse todo-list)
            (loop (read-line file-port) (cons line todo-list)))))
    #:encoding UTF-8_ENCODING))