Factor out average-crop-requirement-nutrient-values.

2 files changed, 19 insertions, 17 deletions

diff --git a/handlers.rkt b/handlers.rkt
index a5c9d6b..a4de123 100644
--- a/handlers.rkt
+++ b/handlers.rkt
@@ -70,23 +70,8 @@
 (define (create-target req)
   (define-values (effective-on crop-requirement-mix)
     (formlet-process (targets-formlet) req))
-
-  (define (average-nutrient-values mix)
-    (define average-values
-      (for/fold ([acc (hash)]) ([pair (in-list mix)])
-        (define crop-requirement (car pair))
-        (define percentage (/ (cdr pair) 100))
-        (for/fold ([acc acc])
-                  ([nv (in-list (get-crop-requirement-values crop-requirement))])
-          (define n (car nv))
-          (define v (cdr nv))
-          (hash-update acc n
-                       (λ (old) (+ old (* v percentage)))
-                       (λ () (* v percentage))))))
-    (for/list ([(k v) (in-hash average-values)])
-      (cons k v)))
-
-  (define target-nutrient-values (average-nutrient-values crop-requirement-mix))
+  (define target-nutrient-values
+    (average-crop-requirement-nutrient-values crop-requirement-mix))
   (create-nutrient-target! effective-on target-nutrient-values)
   (redirect-to "/"))
 
diff --git a/models/crop-requirement.rkt b/models/crop-requirement.rkt
index 4faa6bb..23740e7 100644
--- a/models/crop-requirement.rkt
+++ b/models/crop-requirement.rkt
@@ -143,3 +143,20 @@
   (query-exec (current-conn)
               (delete #:from crop_requirements
                       #:where (= id ,id))))
+
+
+;; Helpers
+
+(define (average-crop-requirement-nutrient-values mix)
+  (define average-values
+    (for/fold ([acc (hash)]) ([pair (in-list mix)])
+      (define crop-requirement (car pair))
+      (define percentage (/ (cdr pair) 100))
+      (for/fold ([acc acc])
+                ([nv (in-list (get-crop-requirement-values crop-requirement))])
+        (match-define (cons n v) nv)
+        (hash-update acc n
+                     (λ (old) (+ old (* v percentage)))
+                     (λ () (* v percentage))))))
+  (for/list ([(n v) (in-hash average-values)])
+    (cons n v)))