;;; The Inevitable Game
;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
;;;
;;; 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
;;; <http://www.gnu.org/licenses/>.

(define-module (utils)
  #:use-module (srfi srfi-1)
  #:use-module (ice-9 match)
  #:use-module (config)
  #:export (arrange-text))

(define* (arrange-text text #:key
                       (character-width 8.0)
                       (margin 0.0)
                       (max-width %width))
  "Take the string TEXT and split it at spaces so that it fits in the
given MAX-WIDTH.  Return a list of lines."
  (match (fold (lambda (chunk acc)
                 (match acc
                   ((#:width width #:result (and (current-line . tail) lines))
                    (let* ((len (+ 1 (string-length chunk)))
                           (chunk-width (* len character-width))
                           (new-width (+ chunk-width width)))
                      (if (< (+ new-width margin) max-width)
                          `(#:width ,new-width
                            #:result ,(cons (string-append current-line " " chunk) tail))
                          `(#:width ,chunk-width
                            #:result ,(cons chunk lines)))))))
               '(#:width 0 #:result (""))
               (string-tokenize text))
    ((#:width _ #:result lines)
     (reverse lines))))