From 610b7177e53272972c18e212acefd564d8d2c76a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@hornquist.se>
Date: Wed, 24 Apr 2019 01:01:17 +0200
Subject: Improve text layout code.

---
 module/output/terminal.scm |  6 +++---
 module/output/text.scm     | 52 +++++++++++++++++++++++-----------------------
 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/module/output/terminal.scm b/module/output/terminal.scm
index 2b04c7c6..92e93cc8 100644
--- a/module/output/terminal.scm
+++ b/module/output/terminal.scm
@@ -89,9 +89,9 @@
                   (or (and=> (attr ev 'LOCATION) (cut string-append "Plats: " <> "\n")) "")
                   (time->string (attr ev 'DTSTART) "~1 ~3")
                   (time->string (attr ev 'DTEND) "~1 ~3")
-                  (flow-text (or (attr ev 'DESCRIPTION) "")
-                             #:width (min 70 width)
-                             #:height (- height 8 2 (length events) 5)))))
+                  (unlines (take-to (flow-text (or (attr ev 'DESCRIPTION) "")
+                                               #:width (min 70 width))
+                                    (- height 8 2 (length events) 5))))))
 
       (let ((char (read-char)))
         ;; (format (current-error-port)
diff --git a/module/output/text.scm b/module/output/text.scm
index cca87678..7c99e12f 100644
--- a/module/output/text.scm
+++ b/module/output/text.scm
@@ -1,4 +1,5 @@
 (define-module (output text)
+  #:use-module (srfi srfi-1)
   #:use-module (util)
   #:export (justify-line flow-text))
 
@@ -8,23 +9,21 @@
 (define-public (lines str) (string-split str #\newline))
 (define-public (unlines list) (string-join list "\n" 'infix))
 
-(define* (add-some list amount item #:optional flipflop?)
-  (cond ((zero? amount) list)
-        ((null? list) '())
-        (else
-         (cons (if flipflop? item (car list))
-               (add-some (if flipflop? list (cdr list))
-                         (if flipflop? (1- amount) amount)
-                         item (not flipflop?))))))
-
 ;; (str) -> str
 (define* (justify-line-helper words #:key (width 70))
-  (let* ((len (1- (apply + (map (compose 1+ string-length) words))))
-         (to-add (- width len))
+  (let* ((phrase-length (string-length (string-concatenate/shared words)))
+         (needed-spaces (- width phrase-length))
          (slots (1- (length words)))
-         (sp-per (ceiling-quotient to-add slots)))
-
-    (unwords (add-some words to-add (make-string (1- sp-per) #\space)))))
+         (space-list
+          (let loop ((n needed-spaces) (d slots))
+            (if (zero? d) '()
+                (let ((v (round (/ n d))))
+                  (cons v (loop (- n v)
+                                (1- d))))))))
+    (string-concatenate/shared
+     (merge words (map (lambda (n) (make-string n #\space))
+                       space-list)
+            (let ((f #t)) (lambda _ (mod! f not)))))))
 
 
 ;; Splits and justifies the given line to @var{#:width}.
@@ -38,19 +37,20 @@
                            (< (mod! w = (+ 1 (string-length word)))
                               width)))
                        lst)))
-      (if (null? tail)
-          (list (unwords head)) ; Don't justify last line.
-          (cons (justify-line-helper head #:width width)
-                (recur tail))))))
+      (cond ((null? tail) (list (unwords head))) ; Don't justify last line.
+            ((null? head)
+             ;; an empty head implies that we found a word longer
+             ;; than our max width. Add it as is and continue
+             ;; (while crying).
+             (cons (car tail) (recur (cdr tail))))
+            (else (cons (justify-line-helper head #:width width)
+                        (recur tail)))))))
 
-;; str -> str
-(define* (flow-text str #:key (width 70) (height 10))
-  (unlines
-   (take-to
-    (flatten
-     (map (lambda (line) (justify-line line #:width width))
-          (lines str)))
-    height)))
+;; str -> (str)
+(define* (flow-text str #:key (width 70))
+  (flatten
+   (map (lambda (line) (justify-line line #:width width))
+        (lines str))))
 
 (define-public (trim-to-width str len)
   (let ((trimmed (string-pad-right str len)))
-- 
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