From 54579cab94db606e00f378b737453b3887fa2988 Mon Sep 17 00:00:00 2001
From: Pierre-Yves Ritschard <pyr@spootnik.org>
Date: Thu, 14 Sep 2023 13:20:14 +0200
Subject: [PATCH] mutation: support running multiple queries

---
 src/seql/mutation.clj                      | 18 +++++---
 test/seql/multi_query_integration_test.clj | 52 ++++++++++++++++++++++
 2 files changed, 64 insertions(+), 6 deletions(-)
 create mode 100644 test/seql/multi_query_integration_test.clj

diff --git a/src/seql/mutation.clj b/src/seql/mutation.clj
index f4a8662..483af48 100644
--- a/src/seql/mutation.clj
+++ b/src/seql/mutation.clj
@@ -40,6 +40,12 @@
                                    :pre      (dissoc pre :valid? :query)}))))))
           pre)))
 
+(defn- wrap-statements
+  "Transform returned statement value into a vector, allowing handlers to return
+   multiple statements"
+  [x]
+  (if (vector? x) x [x]))
+
 (defn mutate!
   "Perform a mutation. Since mutations are spec'd, parameters are
    expected to conform it."
@@ -56,15 +62,15 @@
                         :code    400
                         :explain (s/explain-str spec params)})))
      (let [cparams     (c/write-map params)
-           statement   (-> cparams
-                           (assoc ::schema (env/schema env))
-                           (assoc ::metadata metadata)
-                           handler
-                           sql/format)
+           statements  (map sql/format (-> cparams
+                                           (assoc ::schema (env/schema env))
+                                           (assoc ::metadata metadata)
+                                           handler
+                                           wrap-statements))
            result      (jdbc/with-transaction [tx (env/jdbc env)]
                          ;; if we have preconditions check these first
                          (run-preconditions! tx mutation (dissoc cparams ::schema ::metadata) pre)
-                         (jdbc/execute! tx statement))]
+                         (last (map #(jdbc/execute! tx %) statements)))]
        (when-not (success-result? result)
          (throw (ex-info (format "the mutation has failed: %s" mutation)
                          {:type     :error/mutation-failed
diff --git a/test/seql/multi_query_integration_test.clj b/test/seql/multi_query_integration_test.clj
new file mode 100644
index 0000000..b9959a4
--- /dev/null
+++ b/test/seql/multi_query_integration_test.clj
@@ -0,0 +1,52 @@
+(ns seql.multi-query-integration-test
+  (:require [seql.mutation :refer [mutate!]]
+            [clojure.spec.alpha :as s]
+            [seql.env :as env]
+            [seql.query    :as q]
+            [seql.helpers       :refer [make-schema entity-from-spec mutation-fn]]
+            [db.fixtures        :refer [jdbc-config with-db-fixtures]]
+            [clojure.test       :refer [use-fixtures testing deftest is]]))
+
+(use-fixtures :each (with-db-fixtures :small))
+
+(create-ns 'my.entities)
+(create-ns 'my.entities.account)
+(alias 'account 'my.entities.account)
+
+(s/def ::account/name string?)
+(s/def ::account/id nat-int?)
+(s/def ::account/state #{:active :suspended :terminated})
+(s/def ::account/account (s/keys :req [::account/name ::account/state]))
+(s/def ::account/create ::account/account)
+
+(def schema
+  "As gradually explained in the project's README"
+  (make-schema
+   (entity-from-spec ::account/account
+                     (mutation-fn ::account/delete-two any?
+                                  (constantly
+                                   [{:delete-from :account :where [:= :id 1]}
+                                    {:delete-from :account :where [:= :id 2]}]))
+                     (mutation-fn ::account/add-two any?
+                                  (constantly
+                                   [{:insert-into :account
+                                     :columns [:id :name :state]
+                                     :values [[1 "hello" "active"]]}
+                                    {:insert-into :account
+                                     :columns [:id :name :state]
+                                     :values [[2 "bye" "suspended"]]}])))))
+
+(def env
+  (env/make-env jdbc-config schema))
+
+(deftest multi-query-test
+  (testing "adding two new accounts via a multi query mutation"
+    (mutate! env ::account/add-two {}))
+
+  (testing "retrieving newly created account by name"
+    (let [{::account/keys [state]} (q/execute env [::account/name "hello"])]
+      (is (= state :active)))
+    (let [{::account/keys [state]} (q/execute env [::account/name "bye"])]
+      (is (= state :suspended))))
+
+  (mutate! env ::account/delete-two {}))