Move sign in to service

src/app/(auth)/login/page.tsx

@@ -11,9 +11,7 @@ import {
 	Button,
 	Alert,
 } from "@mantine/core";
-import { redirect } from "next/navigation";
-import { useRouter } from "next/navigation";
-import React, { useEffect, useState } from "react";
+import React from "react";
 import { useFormState } from "react-dom";
 
 const initialState = {

src/modules/auth/actions/signInAction.ts

@@ -1,68 +1,41 @@
 "use server";
-import prisma from "@/core/db";
-import { User } from "@prisma/client";
 import { cookies } from "next/headers";
 import { redirect } from "next/navigation";
-import { revalidatePath } from "next/cache";
 import AuthError from "../error/AuthError";
-import comparePassword from "../utils/comparePassword";
-import { createJwtToken } from "../utils/createJwtToken";
+import signIn from "../services/signIn";
 
 /**
- * Handles the sign-in process for a user.
+ * Asynchronously handles the sign-in process for a user by validating their credentials against the database.
+ * Upon successful validation, the user is redirected to the dashboard, and a JWT token is set as a cookie.
+ * If validation fails, a custom `AuthError` is thrown, and detailed error information is provided to the caller.
  * 
- * This function validates a user's credentials (email and password), checks against the database,
- * and on successful validation, redirects the user to the dashboard and sets a cookie with a JWT token.
- * If the validation fails at any stage, it throws a custom AuthError.
+ * Note: Future enhancements should include throttling to prevent brute force attacks and a check to prevent
+ * sign-in attempts if the user is already logged in.
  * 
- * @param prevState - The previous state of the application, not currently used.
- * @param rawFormData - The raw form data containing the user's email and password.
- * @returns A promise that resolves to a redirect to the dashboard on successful authentication,
- *          or an object containing error details on failure.
- * @throws Specific authentication error based on the failure stage.
+ * @param prevState - The previous state of the application. Currently not utilized but may be used for future enhancements.
+ * @param rawFormData - The raw form data obtained from the sign-in form, containing the user's email and password.
+ * @returns A promise that, upon successful authentication, resolves to a redirection to the dashboard. If authentication fails,
+ *          it resolves to an object containing error details.
+ * @throws {AuthError} - Throws a custom `AuthError` with specific error codes for different stages of the authentication failure.
  */
-export default async function signIn(prevState: any, rawFormData: FormData) {
+export default async function signInAction(prevState: any, rawFormData: FormData) {
 	//TODO: Add Throttling
 	//TODO: Add validation check if the user is already logged in
 	try {
+		// Extract email and password from the raw form data.
 		const formData = {
 			email: rawFormData.get("email") as string,
 			password: rawFormData.get("password") as string,
 		};
 
-		// Retrieve user from the database by email
-		const user = await prisma.user.findUnique({
-			where: { email: formData.email },
-		});
+		// Attempt to sign in with the provided credentials.
+		const result = await signIn(formData)
 
-		// Throw if user not found
-		if (!user)
-			throw new AuthError({
-				errorCode: "EMAIL_NOT_FOUND",
-				message: "Email or Password does not match",
-			});
+		// Set the JWT token in cookies upon successful sign-in.
+		cookies().set("token", result.token);
 
-		// Throw if user has no password hash
-		// TODO: Add check if the user uses another provider
-		if (!user.passwordHash)
-			throw new AuthError({ errorCode: "EMPTY_USER_HASH" });
-
-		// Compare the provided password with the user's stored password hash
-		const isMatch = await comparePassword(
-			formData.password,
-			user.passwordHash
-		);
-		if (!isMatch)
-			throw new AuthError({
-				errorCode: "INVALID_CREDENTIALS",
-				message: "Email or Password does not match",
-			});
-
-		//Set cookie
-		//TODO: Auth: Add expiry
-		const token = createJwtToken({ id: user.id });
-
-		cookies().set("token", token);
+		// Redirect to the dashboard after successful sign-in.
+		redirect("/dashboard");
 	} catch (e: unknown) {
 		// Custom error handling for authentication errors
 		if (e instanceof AuthError) {
@@ -94,6 +67,4 @@ export default async function signIn(prevState: any, rawFormData: FormData) {
 			},
 		};
 	}
-
-	redirect("/dashboard");
 }

src/modules/auth/services/signIn.ts

@@ -0,0 +1,54 @@
+import "server-only";
+import SignInFormData from "../types/SignInFormData";
+import db from "@/core/db";
+import AuthError from "../error/AuthError";
+import comparePassword from "../utils/comparePassword";
+import { createJwtToken } from "../utils/createJwtToken";
+
+/**
+ * Authenticates a user with email and password credentials.
+ *
+ * This function looks up the user in the database by email. If the user exists and the password matches
+ * the hashed password in the database, a JWT token is created and returned. If any step of this process fails,
+ * an `AuthError` with a specific error code and message is thrown.
+ *
+ * @param rawCredential - Contains the email and password provided by the user.
+ * @returns An object containing a JWT token if authentication is successful.
+ * @throws {AuthError} - Throws an `AuthError` with an appropriate error code and message for various failure scenarios.
+ */
+export default async function signIn(rawCredential: SignInFormData) {
+	const user = await db.user.findUnique({
+		where: { email: rawCredential.email },
+	});
+
+	if (!user)
+		throw new AuthError({
+			errorCode: "EMAIL_NOT_FOUND",
+			message: "Email or Password does not match",
+		});
+
+	//TODO: Add handle for empty password hash
+	// Ensure there is a password hash to compare against.
+	if (!user.passwordHash)
+		throw new AuthError({
+			errorCode: "EMPTY_USER_HASH",
+			message: "Something wrong. Please contact your administrator",
+		});
+
+	// Compare the provided password with the stored hash.
+	const isMatch = await comparePassword(
+		rawCredential.password,
+		user.passwordHash
+	);
+
+	// Create a JWT token upon successful authentication.
+	if (!isMatch)
+		throw new AuthError({
+			errorCode: "INVALID_CREDENTIALS",
+			message: "Email or Password does not match",
+		});
+
+	const token = createJwtToken({ id: user.id });
+
+	return { token };
+}

src/modules/auth/types/SignInFormData.d.ts

@@ -0,0 +1,21 @@
+/**
+ * Defines the structure for sign-in form data.
+ * 
+ * This interface is utilized to type-check the data received from the sign-in form, ensuring that it contains
+ * both an `email` and a `password` field of type `string`. The `email` field represents the user's email address,
+ * and the `password` field represents the user's password. Both fields are required for the sign-in process.
+ */
+export default interface SignInFormData {
+    /**
+     * The user's email address.
+     * Must be a valid email format.
+     */
+    email: string;
+
+    /**
+     * The user's password.
+     * There are no specific constraints defined here for the password's format or strength, but it is expected
+     * to comply with the application's password policy.
+     */
+    password: string;
+}