📊 Feedback System — Project Report

DB key constants — Defines the DB object mapping 7 collection names (USERS, SUBJECTS, QUESTIONNAIRES, ENROLLMENTS, RESPONSES, ATTENDANCE, SETTINGS) to their sfft_* localStorage keys. Centralises all key strings to prevent typos across the codebase.

CRUD helpers — Four tiny arrow functions: get()/set() parse/stringify JSON arrays, getObj()/setObj() do the same for plain objects. Used by every higher-level function to read/write localStorage.

Password hashing (hashPassword) — Async function. Tries crypto.subtle.digest('SHA-256') (available only on HTTPS). Falls back to a self-contained pure-JS SHA-256 implementation for HTTP environments. Returns a lowercase hex string. Both admin, teacher and student default demo passwords are pre-hashed with this function.

Database initialisation (initDB) — Runs once per device (guarded by sfft_initialized flag). Seeds: 1 admin + 3 sample teachers + 5 sample students with SHA-256 hashed passwords; 5 subjects; detailed 5-section questionnaires per subject (Math, Physics, English, CS, Chemistry); empty arrays for enrollments, attendance and responses; default settings object with college domain, name and minimum score threshold.

Settings CRUD — getSettings() returns the settings object; saveSettings(s) persists it. Used by admin panel to store/read college name, email domain and min threshold.

User CRUD — getUsers(), getUserByEmail() (case-insensitive), getUserById(). saveUser(u) upserts by id. deleteUser(id) removes a user and cascades deletion of their enrollments and responses. getTeachers()/getStudents() are role-filtered views.

Enrollment functions — getEnrollments() returns all enrollment records. getTeachersForStudent(studentId) returns teacher objects augmented with _enrolledSubjectId — one entry per teacher-subject pair. getStudentsForTeacher(teacherId) returns matching student objects.

Feedback response functions — hasSubmitted(studentId, teacherId, subjectId) checks if feedback already exists for the specific teacher+subject pair. saveResponse(r) inserts a response only if no duplicate exists. getResponsesForTeacher(teacherId) returns all responses for a teacher. getTeacherStats(teacherId) computes overall average, per-section averages, rating distribution histogram, trend data and comment list from the stored responses.

Session key + token generator — SESSION_KEY constant for sessionStorage. generateSessionToken() creates a random token (timestamp base-36 + random suffix) to detect concurrent logins.

Firestore user fetch fallback (fetchUserFromFirestore) — When a user logs in on a new device and their data isn't in localStorage yet, this async function queries the Firestore users collection by email and merges the result into localStorage. Handles case-sensitivity differences in stored emails.

Email/password login (login) — Resolves the local user, then calls Firebase auth.signInWithEmailAndPassword. If the Firebase account doesn't exist yet (first login after admin setup), it auto-creates a Firebase Auth account using the supplied password (auto-migration). Falls back to anonymous sign-in if creation fails. Writes the user doc to Firestore as a non-blocking background operation (errors are caught and logged as console warnings), stores Firebase UID in localStorage, and saves a session object in sessionStorage.

Google Sign-In (googleLogin, googleLoginWithPopup) — googleLogin decodes the Google JWT, looks up the user by email, signs in with Firebase signInWithCredential, and creates a session. googleLoginWithPopup wraps Google Identity Services (GIS) one-tap prompt with a rendered fallback button if the prompt is suppressed.

Session concurrency listener (startSessionListener) — Writes the session token to the Firestore user doc, then subscribes to real-time updates. If another device changes the token, the listener signs the current session out and redirects to the home page with an alert.

Logout & auth guards — logout() clears sessionStorage and Firebase Auth state. getSession() reads the current session. requireAuth(expectedRole) redirects to home if no session or role mismatch — called at the top of every dashboard.

Password management — changePassword() verifies the current password (hashed), updates Firebase Auth password, rehashes and saves the new password in localStorage and Firestore. adminResetPassword() skips the current-password check (admin only). validateCollegeEmail() checks that the email domain matches the configured college domain.

Firestore write helpers — fsSetDoc(collection, docId, data) strips password and passwordHash fields before writing (security). For the users collection it prefers the Firebase UID as the document key. fsDeleteDoc(collection, docId) deletes a Firestore document; both functions catch errors and log console warnings without propagating them, so the UI is never blocked by sync failures.

Merge helpers — mergeById(arr, item) upserts an item into an array matching on id or email (fallback). mergeByField(arr, item, field) does the same for arbitrary fields (used for enrollments and attendance). Prevents duplicates when Firestore snapshots arrive out of order.

Role-based pull sync — syncFromFirestore(role, userId) fetches only the data relevant to the logged-in role. Students fetch their own enrollments and responses. Teachers fetch responses for their teacher ID. Admins fetch all collections. A 5-minute timestamp cache prevents redundant Firestore reads.

Push sync (localStorage → Firestore) — pushToFirestore() reads every localStorage collection and writes each item to Firestore as a separate document. Called non-blocking (not awaited) after any write operation so the UI stays responsive.

Real-time listener setup — setupRealtimeSync(role, userId) attaches Firestore onSnapshot listeners so that changes made by an admin (new users, enrollments, settings) propagate to other open sessions without a page reload. Updates are merged into localStorage via the helper functions above.

Instance registry — chartInstances object tracks live Chart.js instances by canvas ID. destroyChart(id) destroys an existing chart before re-rendering to prevent memory leaks and duplicate canvas contexts.

renderRadar(canvasId, teacherId) — Calls getTeacherStats() from data.js, extracts section labels and averages, and renders a purple radar chart showing performance across teaching categories (e.g., Teaching Methodology, Communication Skills, etc.).

renderBar(canvasId, teacherId) — Renders a stacked bar chart showing the distribution of 1–5 star ratings for a teacher. Each bar is colour-coded (red → green → purple) for quick visual interpretation of feedback quality.

renderTrend(canvasId, teacherId) — Renders a filled line (area) chart of average score over time (each submission as a data point). Uses the trendData array from getTeacherStats() to show performance evolution.

renderInstitutionBar(canvasId) — Admin-only chart. Calls getInstitutionStats() (returns per-teacher averages) and renders a bar chart comparing all teachers side-by-side. Cycles through 6 purple shades for visual variety.

Head & dependencies — Loads style.css, Firebase SDK, data.js, auth.js and firebase-sync.js. All scripts deferred so the form HTML is parsed first.

Attendance gate — On page load, calls requireAuth('student'), then reads the teacher and subject IDs from URL params. Fetches the student's attendance record and compares it against ATTENDANCE_THRESHOLD (75%). If below threshold, replaces the form with a locked message showing the student's actual percentage.

Already-submitted guard — Calls hasSubmitted(studentId, teacherId, subjectId). If true, shows a "Feedback already submitted" banner and hides the form. Prevents duplicate responses for the same teacher-subject pair.

Dynamic form builder — Reads the questionnaire for the selected subject from data.js. For each section, generates a card with the section title and a 1–5 star rating input (radio buttons styled as stars) for each question. All sections are rendered dynamically — no hardcoded questions in HTML.

Submission handler — Collects all star-rating values, validates that every question has been answered, builds a response object ({ studentId, teacherId, subjectId, scores, comment, anonymous, timestamp }), calls saveResponse() and fsSetDoc() to persist locally and to Firestore. Redirects back to the student dashboard on success.

Head / sidebar setup — Standard dashboard shell: loads style.css, Firebase, data/auth/sync scripts, and renders a sidebar with the student's name and role badge.

Profile tab — Displays the student's name, email, roll number, department and section. Shows a list of enrolled teachers with their subject. Roll numbers are sorted ascending before rendering (CSE-101 before CSE-201).

Feedback status tab — Iterates over each teacher-subject pair returned by getTeachersForStudent(). For each pair, checks hasSubmitted() and renders a green "Submitted ✓" badge or a "Give Feedback" button. The button navigates to feedback-form.html with the teacher and subject IDs as URL query parameters.

Notifications tab — Reads the push-notification permission state. Shows a "Enable Notifications" toggle that calls the Firebase Cloud Messaging subscription flow. Displays recent notification history from localStorage.

Init logic — requireAuth('student') guard, Firestore sync, then calls render functions for each tab. Handles tab switching via sidebar nav items. Change-password modal and logout are in the header area.

Head + Chart.js — Loads Chart.js 4.4.0 CDN, style.css, data.js, charts.js, auth.js, firebase-sync.js. Script load order matters: data.js must come before charts.js since charts call getTeacherStats().

Overview tab — Shows 4 stat cards (overall avg, total responses, top category, response count). Renders radar chart (section breakdown), bar chart (rating distribution) and trend line chart using the charts.js helpers. A status banner shows green/amber/red based on the score relative to the minimum threshold from settings.

Category breakdown tab — For each feedback section, renders a horizontal progress bar showing the section average out of 5, colour-coded (green ≥4, amber ≥3, red <3). Clicking a section expands an accordion showing individual question averages.

Student responses tab — A filterable table of all submitted feedback. Columns: student (or "Anonymous"), subject, overall score, date, expandable row for per-question scores and comment. Filter dropdown by subject.

Report generator — The generateReport() function builds a self-contained HTML string with inline SVG bar/radar charts, a summary card grid, a full data table and a comments section. Opens in a new tab via window.open() (note: may be blocked by the browser's popup blocker — users should allow popups for the site). The report uses @media print so it can be saved as PDF from the browser print dialog.

Init & change password — requireAuth('teacher') guard, then syncFromFirestore('teacher'). Renders all tabs. Change-password modal POSTs to changePassword() in auth.js. Logout clears the session and redirects to index.html.

Head + dependencies — Loads Chart.js, all JS modules. Defines the 7-tab sidebar navigation: Dashboard, Website Reviews, User Management, Subjects & Questionnaires, Teacher Assignment, Feedback Oversight, Reports & Analytics, Attendance, Settings.

Dashboard tab — Institution-wide stats (total users, teachers, students, responses). Renders the institution-wide bar chart (renderInstitutionBar()). Shows per-teacher summary cards with average score, response count and a colour-coded performance badge.

User Management tab — Full CRUD for students and teachers. Add/edit user modal with fields: name, email, password, role, department, section, roll number. Bulk CSV import (normalises column headers, generates unique IDs). "Delete Selected" with checkboxes + "Select All". All operations cascade to Firestore via fsSetDoc/fsDeleteDoc. Table sorted by roll number for students.

Subjects & Questionnaires tab — Add/delete subjects. For each subject, a questionnaire editor: add sections, add questions per section, reorder or delete questions. Changes saved to sfft_questionnaires localStorage key and synced to Firestore.

Teacher Assignment tab — Visual card grid of teachers. Each card expands a student checklist showing all students with checkboxes (sorted by roll number). Selecting students and clicking Save creates enrollment records linking student IDs to the teacher and their subject ID. Supports multi-subject assignment per teacher.

Feedback Oversight tab — Table of all submitted responses with filters by teacher and date range. "Select All" checkbox, "Delete Selected" and "Clear All" buttons. Deletions sync to Firestore. Export button generates a CSV with per-section scores, overall average, comment and a summary row.

Reports & Analytics tab — Admin-level HTML report generator: institution-wide SVG bar chart, per-teacher breakdown table with section averages, top/bottom performers highlighted. Downloadable as a self-contained HTML file. Also renders a doughnut chart for role distribution.

Attendance tab — CSV upload to bulk-import attendance records (columns: email/rollNo, percentage). Validates that each row has a numeric percentage. Stores records in sfft_attendance. "Clear All Attendance" button with Firestore sync. Used by the feedback form's attendance gate.

Settings tab & init — Editable fields: college name, email domain, minimum score threshold. Saved to sfft_settings and Firestore. The init block at the bottom runs requireAuth('admin'), syncFromFirestore('admin'), seeds demo data via initDB(), and renders the default tab. Also registers the service worker for push notifications.

Firebase app init — Contains the Firebase project config object (apiKey, authDomain, projectId, storageBucket, messagingSenderId, appId). Calls firebase.initializeApp(firebaseConfig) and exports db = firebase.firestore() and auth = firebase.auth() as global variables used by all other scripts. Uses the Firebase Compat SDK (v8 API) to avoid ES module bundling requirements.