fix: Return error when subscribing to the same subreddit more than once

1 files changed, 15 insertions, 5 deletions

diff --git a/src/routes/index.js b/src/routes/index.js
index f703d2e..a1153d8 100644
--- a/src/routes/index.js
+++ b/src/routes/index.js
@@ -104,11 +104,21 @@ router.post("/subscribe", async (req, res) => {
                 .query("SELECT * FROM users WHERE username = ?", [username])
                 .get();
         if (user) {
-                db.run("INSERT INTO subscriptions (user_id, subreddit) VALUES (?, ?)", [
-                        user.id,
-                        subreddit,
-                ]);
-                res.status(201).send("Subscribed successfully");
+                const existingSubscription = db
+                        .query("SELECT * FROM subscriptions WHERE user_id = ? AND subreddit = ?", [
+                                user.id,
+                                subreddit,
+                        ])
+                        .get();
+                if (existingSubscription) {
+                        res.status(400).send("Already subscribed to this subreddit");
+                } else {
+                        db.run("INSERT INTO subscriptions (user_id, subreddit) VALUES (?, ?)", [
+                                user.id,
+                                subreddit,
+                        ]);
+                        res.status(201).send("Subscribed successfully");
+                }
         } else {
                 res.status(404).send("User not found");
         }