feat(auth): enhance signIn and signUp with error handling and form value types

src/app/actions/auth.ts

@@ -4,16 +4,37 @@ import bcrypt from "bcrypt";
 import prisma from "@/lib/prisma";
 import { signIn } from "@/lib/auth";
 import { authSchema } from "@/lib/zod";
-import { redirect } from "next/navigation";
+import { Prisma } from "@prisma/client";
+import { CredentialsSignInFormValues } from "@/components/credentials-sign-in-form";
+import { CredentialsSignUpFormValues } from "@/components/credentials-sign-up-form";
 
 const saltRounds = 10;
 
-export async function signInWithCredentials(formData: { email: string; password: string }) {
-  await signIn("credentials", formData);
+export async function signInWithCredentials(formData: CredentialsSignInFormValues) {
+  try {
+    await signIn("credentials", {
+      ...formData,
+      redirect: false,
+    });
+    return { success: true };
+  } catch (error) {
+    if (error instanceof Error) {
+      return { error: error.message };
+    }
+    return { error: "Failed to sign in. Please try again." };
+  }
 }
 
-export async function signUpWithCredentials(formData: { email: string; password: string }) {
+export async function signUpWithCredentials(formData: CredentialsSignUpFormValues) {
+  try {
     const validatedData = await authSchema.parseAsync(formData);
+    const existingUser = await prisma.user.findUnique({
+      where: { email: validatedData.email },
+    });
+
+    if (existingUser) {
+      throw new Error("User already exists");
+    }
 
     const pwHash = await bcrypt.hash(validatedData.password, saltRounds);
 
@@ -32,5 +53,16 @@ export async function signUpWithCredentials(formData: { email: string; password:
       });
     }
 
-  redirect("/sign-in");
+    return { success: true };
+  } catch (error) {
+    if (error instanceof Prisma.PrismaClientKnownRequestError) {
+      if (error.code === "P2002") {
+        return { error: "Email already registered" };
+      }
+    }
+    if (error instanceof Error) {
+      return { error: error.message };
+    }
+    return { error: "Registration failed. Please try again." };
+  }
 }