Add a function to invert the table in a decoded json.

src/cipher_analytical_machine/parsers/simple_substitution.clj

@@ -2,6 +2,7 @@
   (:require
    [cipher-analytical-machine.ciphers.simple-substitution :as ss]
    [cipher-analytical-machine.parsers.parsers :as ps]
+   [clojure.set :as set]
    [cheshire.core :as cc])
   (:gen-class))
 
@@ -42,3 +43,12 @@
         (assoc "table" (ss/generate-substitution-table symbols)))
     (decode-key-and-substitution-table-from-json key-or-json)))
 
+(defn invert-table-in-map
+  "Invert the table in a decoded json (key, table)"
+  [decoded-json]
+  (->>
+   (-> decoded-json
+       (get "table")
+       (set/map-invert))
+   (assoc decoded-json "table")))
+

test/cipher_analytical_machine/parsers/simple_substitution_test.clj

@@ -39,3 +39,11 @@
         "1" {"key" 1 "table" {0 \a 1 \b 2 \c}}
         "2" {"key" 2 "table" {\a 0 \b 1 \c 2}}))))
 
+(deftest invert-table-in-map-test
+  (testing "The function invert the table in a decoded json."
+    (are [decoded-json expected-data]
+        (= expected-data
+           (invert-table-in-map decoded-json))
+      {"key" 1 "table" {0 \a 1 \b 2 \c}} {"key" 1 "table" {\a 0 \b 1 \c 2}}
+      {"key" 2 "table" {\a 0 \b 1 \c 2}} {"key" 2 "table" {0 \a 1 \b 2 \c}})))
+