fix(auth): correct localStorage boolean type mismatch causing auth bypass

log/login.js

@@ -1,49 +1,122 @@
-document.addEventListener("DOMContentLoaded", () => {
-    const loginForm = document.getElementById("loginForm");
-    const registerForm = document.getElementById("registerForm");
-
-    // Check if user is already logged in, redirect to home if true
-    if (window.location.pathname.includes("login.html") && localStorage.getItem("isLoggedIn") === true) {
-        window.location.href = "../home.html";
-    }
-
-    // Login Form Submission
-    if (loginForm) {
-        loginForm.addEventListener("submit", (e) => {
-            e.preventDefault();
-            const email = document.getElementById("email").value;
-            const password = document.getElementById("password").value;
-
-            const storedUser = JSON.parse(localStorage.getItem("user"));
-
-            if (storedUser && storedUser.email === email && storedUser.password === password) {
-                localStorage.setItem("isLoggedIn", "true"); // Mark user as logged in
-                alert("Login successful! Redirecting to Home...");
-                window.location.href = "../home.html"; // Redirect to home page
-            } 
-            else {
-                alert("Invalid email or password.");
-            }
-        });
-    }
-
-    // Registration Form Submission
-    if (registerForm) {
-        registerForm.addEventListener("submit", (e) => {
-            e.preventDefault();
-            const fullname = document.getElementById("fullname").value;
-            const email = document.getElementById("email").value;
-            const password = document.getElementById("password").value;
-
-            if (fullname && email && password) {
-                const user = { fullname, email, password };
-                localStorage.setItem("user", JSON.stringify(user)); // Save user in localStorage
-
-                alert("Registration successful! Redirecting to login...");
-                window.location.href = "login.html"; // Redirect to login page
-            } else {
-                alert("Please fill out all fields.");
-            }
-        });
-    }
-});
+/**
+ * login.js — LearnSphere Authentication Logic
+ *
+ * Handles login and registration form submission using localStorage.
+ * Note: This is a client-side demo implementation. In production,
+ * authentication must be handled server-side with hashed passwords
+ * and proper session management.
+ */
+
+document.addEventListener("DOMContentLoaded", () => {
+    const loginForm = document.getElementById("loginForm");
+    const registerForm = document.getElementById("registerForm");
+
+    // BUG FIX: localStorage always returns strings, never booleans.
+    // Previously: localStorage.getItem("isLoggedIn") === true  → always false
+    // Fixed:      localStorage.getItem("isLoggedIn") === "true" → correct
+    if (
+        window.location.pathname.includes("login.html") &&
+        localStorage.getItem("isLoggedIn") === "true"
+    ) {
+        window.location.href = "../home.html";
+        return; // Prevent further execution after redirect
+    }
+
+    // ── Login Form ──────────────────────────────────────────────────
+    if (loginForm) {
+        loginForm.addEventListener("submit", (e) => {
+            e.preventDefault();
+
+            const email = document.getElementById("email").value.trim();
+            const password = document.getElementById("password").value;
+
+            if (!email || !password) {
+                showError("Please fill in all fields.");
+                return;
+            }
+
+            const storedUser = JSON.parse(localStorage.getItem("user"));
+
+            if (
+                storedUser &&
+                storedUser.email === email &&
+                storedUser.password === password
+            ) {
+                localStorage.setItem("isLoggedIn", "true"); // Store as string "true"
+                window.location.href = "../home.html";
+            } else {
+                showError("Invalid email or password. Please try again.");
+            }
+        });
+    }
+
+    // ── Registration Form ────────────────────────────────────────────
+    if (registerForm) {
+        registerForm.addEventListener("submit", (e) => {
+            e.preventDefault();
+
+            const fullname = document.getElementById("fullname").value.trim();
+            const email = document.getElementById("email").value.trim();
+            const password = document.getElementById("password").value;
+
+            if (!fullname || !email || !password) {
+                showError("Please fill out all fields.");
+                return;
+            }
+
+            if (password.length < 6) {
+                showError("Password must be at least 6 characters.");
+                return;
+            }
+
+            const user = { fullname, email, password };
+            localStorage.setItem("user", JSON.stringify(user));
+
+            // Show success before redirecting
+            showSuccess("Account created! Redirecting to login...");
+            setTimeout(() => {
+                window.location.href = "login.html";
+            }, 1500);
+        });
+    }
+});
+
+/**
+ * Displays an inline error message instead of using alert().
+ * @param {string} message
+ */
+function showError(message) {
+    let errorEl = document.getElementById("auth-error");
+    if (!errorEl) {
+        errorEl = document.createElement("p");
+        errorEl.id = "auth-error";
+        errorEl.setAttribute("role", "alert");
+        errorEl.setAttribute("aria-live", "assertive");
+        errorEl.style.cssText =
+            "color:#ff6b6b;font-size:0.9rem;margin-top:10px;font-weight:bold;";
+        const form = document.querySelector("form");
+        if (form) form.appendChild(errorEl);
+    }
+    errorEl.textContent = message;
+    errorEl.style.display = "block";
+}
+
+/**
+ * Displays an inline success message instead of using alert().
+ * @param {string} message
+ */
+function showSuccess(message) {
+    let successEl = document.getElementById("auth-success");
+    if (!successEl) {
+        successEl = document.createElement("p");
+        successEl.id = "auth-success";
+        successEl.setAttribute("role", "status");
+        successEl.setAttribute("aria-live", "polite");
+        successEl.style.cssText =
+            "color:#66fcf1;font-size:0.9rem;margin-top:10px;font-weight:bold;";
+        const form = document.querySelector("form");
+        if (form) form.appendChild(successEl);
+    }
+    successEl.textContent = message;
+    successEl.style.display = "block";
+}