;;
;; util-string.scm
;;
;; Various string utilities.
;;
;; ISC License
;;
;; Copyright 2023 Brmlab, z.s.
;; Dominik Pantůček <dominik.pantucek@trustica.cz>
;;
;; Permission to use, copy, modify, and/or distribute this software
;; for any purpose with or without fee is hereby granted, provided
;; that the above copyright notice and this permission notice appear
;; in all copies.
;; 
;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
;; WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
;; AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
;; CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
;; OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
;; NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
;; CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
;;

(declare (unit util-string))

(module
 util-string
 (
  string-repeat
  string-first+rest
  )

 (import scheme
	 (chicken base)
	 (chicken string)
	 (chicken irregex)
	 testing)

  ;; Repeats given string.
 (define (string-repeat str rep)
   (let loop ((rep rep)
	      (res '()))
     (if (> rep 0)
	 (loop (sub1 rep)
	       (cons str res))
	 (string-intersperse res ""))))

 ;; Extracts first token and the rest as separate string
 (define (string-first+rest str)
   (let ((dm (irregex-search (irregex "[ \\t]" 'u) str)))
     (if dm
	 (let* ((sep-idx (irregex-match-start-index dm))
		(key-str (substring str 0 sep-idx))
		(sep+val (substring str sep-idx))
		(val (irregex-replace (irregex "^[ \\t]*" 'u) sep+val "")))
	   (cons key-str val))
	 (cons str ""))))
	 
 ;; Performs utils module self-tests.
 (define (utils-tests!)
   (run-tests
    utils
    (test-equal? string-repeat
		 (string-repeat "-" 4)
		 "----")
    (test-equal? string-repeat
		 (string-repeat "š" 4)
		 "šššš")
    (test-equal? string-first+rest
		 (string-first+rest "asdf rest")
		 '("asdf" . "rest"))
    (test-equal? string-first+rest
		 (string-first+rest "asdf   rest test  rest")
		 '("asdf" . "rest test  rest"))
    (test-equal? string-first+rest
		 (string-first+rest "asdf")
		 '("asdf" . ""))
    ))

 )