going somewhere.

src/clj/skirmish/ledger/data_layer.clj

@@ -1,6 +1,7 @@
 (ns skirmish.ledger.data-layer
   (:require [datomic.api :as d]
-            [infix.macros :refer [infix]]))
+            [infix.macros :refer [infix]]
+            [slingshot.slingshot :refer [throw+]]))
 
 (defn get-all-account-public-key [db]
   (d/q '[:find ?pk :where [?e :skirmish.ledger/owner-public-key ?pk]] db))
@@ -123,6 +124,31 @@
         res (assoc res (:to-account-id transaction) to-account)]
     res))
 
+(defn validate-transactions [transactions]
+  (loop [transactions transactions]
+    (when (seq transactions)
+      (let [transaction (first transactions)]
+        (when (not= (-> transaction :from-account :skirmish.ledger/sec)
+                    (-> transaction :to-account :skirmish.ledger/sec))
+          (throw+ {:error-type :4XX
+                   :status 400
+                   :body {:error "Part of the transaction includes a transaction between two wallets of different underlying securities."}}))
+        (recur (rest transactions)))))
+  transactions)
+
+(defn validate-resulting-transactions [transactions]
+  (loop [transactions transactions]
+    (when (seq transactions)
+      (let [transaction (first  transactions)]
+        (when (neg? (get transaction 3))
+          (throw+ {:error-type :4XX
+                   :status 400
+                   :body {:error "Transaction would result in a negative amount in a wallet."}})))
+      (recur (rest transactions))))
+  transactions)
+
 (defn create-transactions [db transactions]
-  (let [transactions (map #(assoc-accounts db %) transactions)]
-    (into #{} (vals (reduce compute-transactions {} transactions)))))
+  (let [transactions (map #(assoc-accounts db %) transactions)
+        transactions (validate-transactions transactions)
+        ret (vals (reduce compute-transactions {} transactions))]
+    (validate-resulting-transactions ret)))