═══════════════════════════════════════════════════════════════════════════════
  SLIDEMAP API DOCUMENTATION
  HF Space: https://Mafia2008-sar.hf.space
  API Docs UI: https://Mafia2008-sar.hf.space/api-docs
  CORS: Enabled (any frontend can call these APIs)
  Protocol: REST (JSON) + SSE (Server-Sent Events)
═══════════════════════════════════════════════════════════════════════════════

BASE URL
────────
  https://Mafia2008-sar.hf.space

HOW IT WORKS (Flow)
───────────────────
  1. Teacher creates a session  →  gets a 4-digit room code
  2. Students look up session by room code  →  get sessionId
  3. Both Teacher & Students subscribe to /api/events (SSE stream)
  4. Teacher uploads slides  →  students see them live via SSE
  5. Teacher creates polls  →  students vote via API
  6. Students submit doubts  →  teacher resolves via API
  7. Teacher ends session  →  all students notified via SSE


═══════════════════════════════════════════════════════════════════════════════
  1. SESSION API
  POST /api/session
═══════════════════════════════════════════════════════════════════════════════

── 1.1 Create Session (Teacher) ─────────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    {
      "action":      "create",      // Required
      "teacherId":   "string",      // Required - unique teacher ID
      "teacherName": "string",      // Required - display name
      "sessionName": "string",      // Required - class/session name
      "description": "string"       // Optional
    }

  Response:
    {
      "success": true,
      "data": {
        "id":          "uuid-string",
        "roomCode":    "4821",        // 4-digit code for students
        "name":        "Physics Ch5",
        "teacherId":   "teacher-001",
        "teacherName": "Mr. Sharma",
        "isActive":    true,
        "currentSlide": 0,
        "totalSlides":  0,
        "studentCount": 0,
        "createdAt":   "2026-04-14T16:00:00.000Z"
      }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/session', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create',
        teacherId: 'teacher-001',
        teacherName: 'Mr. Sharma',
        sessionName: 'Physics – Chapter 5'
      })
    });


── 1.2 Lookup Session by Room Code ──────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    {
      "action":   "lookup",   // Required
      "roomCode": "4821"      // Required - 4-digit room code
    }

  Response:
    {
      "success": true,
      "data": { "id": "uuid", "roomCode": "4821", ... }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/session', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ action: 'lookup', roomCode: '4821' })
    });


── 1.3 Join Session (Student) ───────────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    {
      "action":    "join",           // Required
      "sessionId": "4821",           // Required - sessionId OR room code
      "userId":    "student-xyz",    // Required - unique student ID
      "userName":  "Rahul Kumar"     // Required - display name
    }

  Response:
    {
      "success": true,
      "data": {
        "user":            { "id": "...", "name": "Rahul Kumar", "role": "student" },
        "session":         { ... },
        "currentSlide":    0,
        "activePoll":      null,
        "whiteboardStrokes": [],
        "reactions":       {}
      }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/session', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'join',
        sessionId: '4821',      // room code accepted
        userId: 'student-xyz',
        userName: 'Rahul Kumar'
      })
    });


── 1.4 End Session (Teacher) ────────────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    {
      "action":    "end",    // Required
      "sessionId": "uuid"    // Required
    }

  Response:
    { "success": true, "message": "Session ended successfully" }

  SSE broadcast: session_ended → all connected clients


── 1.5 List All Active Sessions ─────────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    { "action": "list" }

  Response:
    {
      "success": true,
      "data": [ { "id": "...", "roomCode": "4821", ... } ]
    }


── 1.6 Get Session State ────────────────────────────────────────────────────

  POST /api/session
  Content-Type: application/json

  Request Body:
    {
      "action":    "get",   // Required
      "sessionId": "uuid"   // Required
    }

  Response:
    {
      "success": true,
      "data": {
        "session":          { ... },
        "currentSlide":     2,
        "activePoll":       { ... } | null,
        "doubts":           [ ... ],
        "recentChats":      [ ... ],
        "whiteboardStrokes": [ ... ],
        "reactions":        { "👍": 3, "❤️": 1 },
        "onlineUsers":      [ ... ]
      }
    }


═══════════════════════════════════════════════════════════════════════════════
  2. EVENTS API (SSE - Server-Sent Events)
  GET /api/events
═══════════════════════════════════════════════════════════════════════════════

  Opens a persistent SSE stream. Connect immediately after joining a session.
  Both teacher AND students should connect to this endpoint.

  URL:
    GET /api/events?sessionId=UUID&userId=YOUR_USER_ID

  Query Parameters:
    sessionId  string   Required  The session ID
    userId     string   Required  Your unique user ID

  Response Headers:
    Content-Type: text/event-stream
    Cache-Control: no-cache
    Access-Control-Allow-Origin: *

  ── SSE Events Table ──────────────────────────────────────────────────────

  Event Name        | Triggered When                     | Data Fields
  ──────────────────|────────────────────────────────────|────────────────────
  connected         | Stream opens                        | sessionId, userId, full session state
  slide_change      | Teacher changes/uploads slide       | slideNumber, imageBase64, totalSlides, timestamp
  new_poll          | Teacher creates a poll              | id, question, options[], isActive, ...
  poll_update       | A student votes                     | pollId, results{}, totalVotes, timestamp
  poll_ended        | Teacher ends poll                   | pollId, results{}, totalVotes, correctAnswer
  correct_answer    | Teacher reveals correct answer      | pollId, correctOptionIds[], correctAnswer
  new_doubt         | Student submits a doubt             | id, studentName, question, slideNumber, status
  doubt_solved      | Teacher resolves a doubt            | id, status, teacherResponse, annotatedImage
  doubt_updated     | Doubt status changes                | id, status
  student_joined    | A new student joins                 | userId, userName, studentCount
  student_left      | A student disconnects               | userId, userName, studentCount
  session_ended     | Teacher ends the session            | sessionId, endedAt
  chat_message      | Someone sends a chat message        | id, userId, userName, message, isTeacher
  reaction          | Someone reacts                      | reactions{}, lastReaction
  state_sync        | Reconnect (sends full state again)  | full session state

  Example (JS):
    const es = new EventSource(
      'https://Mafia2008-sar.hf.space/api/events?sessionId=UUID&userId=STUDENT_ID'
    );

    // Connected - get initial state
    es.addEventListener('connected', e => {
      const state = JSON.parse(e.data);
      console.log('Session state:', state);
    });

    // Slide changed by teacher
    es.addEventListener('slide_change', e => {
      const { slideNumber, imageBase64, totalSlides } = JSON.parse(e.data);
      document.getElementById('slide-img').src = imageBase64;
    });

    // New poll created
    es.addEventListener('new_poll', e => {
      const poll = JSON.parse(e.data);
      showPollUI(poll);
    });

    // Live vote update
    es.addEventListener('poll_update', e => {
      const { pollId, results, totalVotes } = JSON.parse(e.data);
      updatePollResults(results);
    });

    // Poll ended
    es.addEventListener('poll_ended', e => {
      const { pollId, results, correctAnswer } = JSON.parse(e.data);
      showFinalResults(results, correctAnswer);
    });

    // Teacher reveals correct answer
    es.addEventListener('correct_answer', e => {
      const { pollId, correctOptionIds } = JSON.parse(e.data);
      highlightCorrectAnswer(correctOptionIds);
    });

    // Student submitted a doubt (Teacher listens to this)
    es.addEventListener('new_doubt', e => {
      const doubt = JSON.parse(e.data);
      addDoubtCard(doubt);
    });

    // Teacher resolved a doubt (Student listens to this)
    es.addEventListener('doubt_solved', e => {
      const doubt = JSON.parse(e.data);
      updateDoubtStatus(doubt);
    });

    // Session ended
    es.addEventListener('session_ended', e => {
      alert('Session has ended');
      es.close();
    });

    // Heartbeat (keep-alive, every 15s) - no action needed
    es.onerror = err => {
      console.error('SSE error:', err);
      // Reconnect logic here
    };


═══════════════════════════════════════════════════════════════════════════════
  3. SLIDE API
  POST /api/slide
═══════════════════════════════════════════════════════════════════════════════

── 3.1 Upload & Broadcast Slide (Teacher → Students) ────────────────────────

  POST /api/slide
  Content-Type: application/json

  Request Body:
    {
      "action":      "upload",         // Required
      "sessionId":   "uuid",           // Required
      "slideImage":  "data:image/png;base64,iVBOR...",  // Required - base64 image
      "slideNumber": 3                 // Optional - replaces slide at index; omit to append
    }

  Notes:
    - slideImage can be a data URL ("data:image/png;base64,...") or raw base64
    - Automatically broadcasts slide_change SSE to ALL connected students
    - Students receive the imageBase64 directly — no separate fetch needed

  Response:
    {
      "success": true,
      "data": { "slideNumber": 3, "totalSlides": 4 }
    }

  Example (Electron / SlideMap app):
    const canvas = document.getElementById('myCanvas');
    const base64 = canvas.toDataURL('image/png');

    fetch('https://Mafia2008-sar.hf.space/api/slide', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'upload',
        sessionId: SESSION_ID,
        slideImage: base64,
        slideNumber: currentSlideIndex  // optional
      })
    });


── 3.2 Go to Slide (Teacher) ────────────────────────────────────────────────

  POST /api/slide
  Content-Type: application/json

  Request Body:
    {
      "action":      "goto",   // Required
      "sessionId":   "uuid",   // Required
      "slideNumber": 2         // Required - 0-indexed slide number
    }

  Response:
    { "success": true, "data": { "slideNumber": 2, "totalSlides": 5 } }


── 3.3 Next Slide ───────────────────────────────────────────────────────────

  POST /api/slide
  Body: { "action": "next", "sessionId": "uuid" }

  Response:
    { "success": true, "data": { "slideNumber": 3, "totalSlides": 5 } }


── 3.4 Previous Slide ───────────────────────────────────────────────────────

  POST /api/slide
  Body: { "action": "prev", "sessionId": "uuid" }

  Response:
    { "success": true, "data": { "slideNumber": 1, "totalSlides": 5 } }


═══════════════════════════════════════════════════════════════════════════════
  4. POLL API
  POST /api/poll    (create/vote/end/setCorrectAnswers)
  GET  /api/poll    (fetch polls)
═══════════════════════════════════════════════════════════════════════════════

── 4.1 Create Poll (Teacher) ────────────────────────────────────────────────

  POST /api/poll
  Content-Type: application/json

  Request Body:
    {
      "action":        "create",       // Required
      "sessionId":     "uuid",         // Required
      "question":      "string",       // Required
      "options":       ["A","B","C"],  // Required - min 2 items
      "type":          "single",       // Optional - "single"|"multiple" (default: "single")
      "correctAnswer": "A",            // Optional - marks correct option
      "duration":      0               // Optional - auto-end after N seconds (0 = manual)
    }

  Notes:
    - Any existing active poll is auto-ended before creating a new one
    - Broadcasts new_poll SSE to ALL students immediately

  Response:
    {
      "success": true,
      "data": {
        "id":           "poll-uuid",
        "sessionId":    "uuid",
        "question":     "What is Newton's 2nd Law?",
        "options": [
          { "id": "option_0", "text": "F=ma",  "isCorrect": true,  "votes": 0 },
          { "id": "option_1", "text": "E=mc²", "isCorrect": false, "votes": 0 }
        ],
        "type":         "single",
        "isActive":     true,
        "results":      { "F=ma": 0, "E=mc²": 0 },
        "totalVotes":   0,
        "votedStudents": [],
        "createdAt":    "2026-04-14T16:00:00.000Z"
      }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/poll', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create',
        sessionId: SESSION_ID,
        question: "What is Newton's 2nd Law?",
        options: ['F=ma', 'E=mc²', 'PV=nRT', 'V=IR'],
        correctAnswer: 'F=ma',
        duration: 0
      })
    });


── 4.2 Vote on Poll (Student) ───────────────────────────────────────────────

  POST /api/poll
  Content-Type: application/json

  Request Body:
    {
      "action":    "vote",          // Required
      "sessionId": "uuid",          // Required
      "pollId":    "poll-uuid",     // Required
      "option":    "F=ma",          // Required - the option text student selected
      "studentId": "student-xyz"    // Required - student unique ID
    }

  Notes:
    - Each student can vote only ONCE per poll
    - Broadcasts poll_update SSE to ALL clients with live vote counts

  Response:
    {
      "success": true,
      "data": {
        "pollId":     "poll-uuid",
        "results":    { "F=ma": 5, "E=mc²": 2 },
        "totalVotes": 7,
        "voted":      true
      }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/poll', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'vote',
        sessionId: SESSION_ID,
        pollId: POLL_ID,
        option: 'F=ma',
        studentId: MY_STUDENT_ID
      })
    });


── 4.3 End Poll (Teacher) ───────────────────────────────────────────────────

  POST /api/poll
  Content-Type: application/json

  Request Body:
    {
      "action":    "end",         // Required
      "sessionId": "uuid",        // Required
      "pollId":    "poll-uuid"    // Required
    }

  Notes:
    - Broadcasts poll_ended SSE with final results + correctAnswer

  Response:
    { "success": true, "message": "Poll ended successfully" }


── 4.4 Reveal Correct Answer (Teacher) ──────────────────────────────────────

  POST /api/poll
  Content-Type: application/json

  Request Body:
    {
      "action":           "setCorrectAnswers",   // Required
      "sessionId":        "uuid",                // Required
      "pollId":           "poll-uuid",           // Required
      "correctAnswer":    "F=ma",                // Optional - option text
      "correctOptionIds": ["option_0"]           // Optional - option id array
    }

  Notes:
    - Broadcasts correct_answer SSE so students can highlight the correct option
    - Use this AFTER ending the poll to reveal the answer

  Response:
    { "success": true, "message": "Correct answers broadcast to students" }


── 4.5 Get All Polls ────────────────────────────────────────────────────────

  GET /api/poll?sessionId=UUID

  Response:
    {
      "success": true,
      "data": {
        "polls":      [ { ... }, { ... } ],
        "activePoll": { ... } | null,
        "totalPolls": 3
      }
    }


═══════════════════════════════════════════════════════════════════════════════
  5. DOUBT API
  POST /api/doubt    (submit/resolve/update)
  GET  /api/doubt    (fetch doubts)
═══════════════════════════════════════════════════════════════════════════════

── 5.1 Submit Doubt (Student → Teacher) ─────────────────────────────────────

  POST /api/doubt
  Content-Type: application/json

  Request Body:
    {
      "action":      "create",         // Required
      "sessionId":   "uuid",           // Required
      "studentId":   "student-xyz",    // Required
      "studentName": "Rahul Kumar",    // Required
      "question":    "string",         // Required - the doubt text
      "image":       "data:image/png;base64,...",  // Optional
      "slideNumber": 3                 // Optional - slide where doubt occurred
    }

  Notes:
    - Broadcasts new_doubt SSE to the teacher (and all connected clients)
    - slideNumber auto-filled from current slide if not provided

  Response:
    {
      "success": true,
      "data": {
        "id":          "doubt-uuid",
        "sessionId":   "uuid",
        "studentId":   "student-xyz",
        "studentName": "Rahul Kumar",
        "question":    "Why F=ma and not F=mv?",
        "slideNumber": 3,
        "status":      "pending",
        "createdAt":   "2026-04-14T16:00:00.000Z"
      }
    }

  Example (JS):
    fetch('https://Mafia2008-sar.hf.space/api/doubt', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create',
        sessionId: SESSION_ID,
        studentId: MY_STUDENT_ID,
        studentName: MY_NAME,
        question: "I don't understand why F=ma and not F=mv",
        slideNumber: 3
      })
    });


── 5.2 Resolve Doubt (Teacher) ──────────────────────────────────────────────

  POST /api/doubt
  Content-Type: application/json

  Request Body:
    {
      "action":          "solve",            // Required
      "sessionId":       "uuid",             // Required
      "doubtId":         "doubt-uuid",       // Required
      "teacherResponse": "string",           // Optional - text explanation
      "annotatedImage":  "data:image/..."    // Optional - annotated image
    }

  Notes:
    - Broadcasts doubt_solved SSE so the student sees the resolution

  Response:
    {
      "success": true,
      "data": {
        "id":              "doubt-uuid",
        "status":          "solved",
        "teacherResponse": "Because acceleration = rate of change of velocity...",
        "solvedAt":        "2026-04-14T16:05:00.000Z"
      }
    }


── 5.3 Update Doubt Status (Teacher) ────────────────────────────────────────

  POST /api/doubt
  Content-Type: application/json

  Request Body:
    {
      "action":    "update",          // Required
      "sessionId": "uuid",            // Required
      "doubtId":   "doubt-uuid",      // Required
      "status":    "in_progress"      // Required: "pending"|"in_progress"|"solved"
    }

  Notes:
    - Broadcasts doubt_updated SSE to all clients

  Response:
    { "success": true, "data": { "id": "...", "status": "in_progress" } }


── 5.4 Get All Doubts (Teacher) ─────────────────────────────────────────────

  GET /api/doubt?sessionId=UUID

  Response:
    {
      "success": true,
      "data": {
        "doubts": [ { ... }, { ... } ],
        "summary": {
          "total":      7,
          "pending":    2,
          "inProgress": 1,
          "solved":     4
        }
      }
    }


═══════════════════════════════════════════════════════════════════════════════
  6. CHAT API
  POST /api/chat    (send message)
  GET  /api/chat    (get history)
═══════════════════════════════════════════════════════════════════════════════

── 6.1 Send Chat Message ────────────────────────────────────────────────────

  POST /api/chat
  Content-Type: application/json

  Request Body:
    {
      "sessionId": "uuid",          // Required
      "userId":    "user-xyz",      // Required
      "userName":  "Rahul",         // Required
      "message":   "Can you explain again?",  // Required
      "isTeacher": false            // Optional (default: false)
    }

  Notes:
    - Broadcasts chat_message SSE to ALL participants

  Response:
    {
      "success": true,
      "data": {
        "id":        "msg-uuid",
        "userId":    "user-xyz",
        "userName":  "Rahul",
        "message":   "Can you explain again?",
        "isTeacher": false,
        "timestamp": "2026-04-14T16:10:00.000Z"
      }
    }


── 6.2 Get Chat History ─────────────────────────────────────────────────────

  GET /api/chat?sessionId=UUID&limit=100

  Query Parameters:
    sessionId  string  Required  Session ID
    limit      number  Optional  Max messages to return (default: 100, max stored: 500)

  Response:
    {
      "success": true,
      "data": {
        "messages": [ { "id": "...", "message": "...", ... } ],
        "count":    23
      }
    }


═══════════════════════════════════════════════════════════════════════════════
  ERROR RESPONSES
═══════════════════════════════════════════════════════════════════════════════

  All error responses follow this format:
    {
      "success": false,
      "error":   "Descriptive error message"
    }

  HTTP Status Codes:
    400  Bad Request      - Missing or invalid fields
    404  Not Found        - Session/Poll/Doubt not found
    500  Internal Error   - Server error


═══════════════════════════════════════════════════════════════════════════════
  COMPLETE INTEGRATION EXAMPLE (Student Frontend - Vanilla JS)
═══════════════════════════════════════════════════════════════════════════════

  const BASE = 'https://Mafia2008-sar.hf.space';
  let sessionId = null;
  let myUserId  = 'student-' + Math.random().toString(36).substr(2, 9);
  let myName    = 'Rahul Kumar';

  // STEP 1: Look up session by room code
  async function joinByRoomCode(roomCode) {
    // Lookup
    const lookup = await fetch(`${BASE}/api/session`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ action: 'lookup', roomCode })
    }).then(r => r.json());

    if (!lookup.success) return alert('Room not found');
    sessionId = lookup.data.id;

    // Join
    await fetch(`${BASE}/api/session`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'join',
        sessionId,
        userId: myUserId,
        userName: myName
      })
    });

    // STEP 2: Subscribe to SSE
    connectSSE();
  }

  // STEP 2: SSE Connection
  function connectSSE() {
    const es = new EventSource(`${BASE}/api/events?sessionId=${sessionId}&userId=${myUserId}`);

    es.addEventListener('slide_change', e => {
      const { imageBase64 } = JSON.parse(e.data);
      document.getElementById('slide').src = imageBase64;
    });

    es.addEventListener('new_poll', e => {
      const poll = JSON.parse(e.data);
      showPoll(poll);
    });

    es.addEventListener('correct_answer', e => {
      const { correctOptionIds } = JSON.parse(e.data);
      highlightAnswer(correctOptionIds);
    });

    es.addEventListener('doubt_solved', e => {
      const doubt = JSON.parse(e.data);
      showDoubtResolution(doubt);
    });

    es.addEventListener('session_ended', () => {
      alert('Class ended');
      es.close();
    });
  }

  // STEP 3: Vote on poll
  async function vote(pollId, option) {
    await fetch(`${BASE}/api/poll`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'vote', sessionId, pollId,
        option, studentId: myUserId
      })
    });
  }

  // STEP 4: Submit doubt
  async function submitDoubt(text) {
    await fetch(`${BASE}/api/doubt`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create', sessionId,
        studentId: myUserId, studentName: myName,
        question: text
      })
    });
  }


═══════════════════════════════════════════════════════════════════════════════
  COMPLETE INTEGRATION EXAMPLE (Teacher - Electron/SlideMap App)
═══════════════════════════════════════════════════════════════════════════════

  const BASE = 'https://Mafia2008-sar.hf.space';
  const teacherId   = 'teacher-001';
  const teacherName = 'Mr. Sharma';
  let sessionId = null;

  // STEP 1: Create session
  async function createSession(sessionName) {
    const res = await fetch(`${BASE}/api/session`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create', teacherId, teacherName, sessionName
      })
    }).then(r => r.json());

    sessionId = res.data.id;
    const roomCode = res.data.roomCode;  // Show this to students
    console.log('Room Code:', roomCode);

    // Connect SSE to receive doubts + student events
    connectSSE();
  }

  // STEP 2: Connect to SSE (teacher also connects to receive doubts)
  function connectSSE() {
    const es = new EventSource(`${BASE}/api/events?sessionId=${sessionId}&userId=${teacherId}`);

    es.addEventListener('new_doubt', e => {
      const doubt = JSON.parse(e.data);
      showDoubtInPanel(doubt);   // Teacher sees student doubt
    });

    es.addEventListener('student_joined', e => {
      const { userName, studentCount } = JSON.parse(e.data);
      console.log(`${userName} joined. Total: ${studentCount}`);
    });
  }

  // STEP 3: Send slide when screen changes
  async function sendSlide(base64Image, slideIndex) {
    await fetch(`${BASE}/api/slide`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'upload', sessionId,
        slideImage: base64Image,
        slideNumber: slideIndex
      })
    });
  }

  // STEP 4: Create poll
  async function createPoll(question, options, correctAnswer) {
    const res = await fetch(`${BASE}/api/poll`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'create', sessionId, question, options,
        correctAnswer, duration: 0
      })
    }).then(r => r.json());
    return res.data.id;  // pollId
  }

  // STEP 5: End poll and reveal answer
  async function endPoll(pollId, correctAnswer) {
    await fetch(`${BASE}/api/poll`, {
      method: 'POST', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ action: 'end', sessionId, pollId })
    });

    await fetch(`${BASE}/api/poll`, {
      method: 'POST', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'setCorrectAnswers', sessionId, pollId, correctAnswer
      })
    });
  }

  // STEP 6: Resolve a doubt
  async function resolveDoubt(doubtId, response) {
    await fetch(`${BASE}/api/doubt`, {
      method: 'POST', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'solve', sessionId, doubtId,
        teacherResponse: response
      })
    });
  }

  // STEP 7: End session
  async function endSession() {
    await fetch(`${BASE}/api/session`, {
      method: 'POST', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ action: 'end', sessionId })
    });
  }


═══════════════════════════════════════════════════════════════════════════════
  QUICK REFERENCE CHEATSHEET
═══════════════════════════════════════════════════════════════════════════════

  Action                    Method  Endpoint        action field
  ─────────────────────────────────────────────────────────────────────────
  Create session (T)        POST    /api/session    "create"
  Lookup by room code (S)   POST    /api/session    "lookup"
  Join session (S)          POST    /api/session    "join"
  End session (T)           POST    /api/session    "end"
  List all sessions         POST    /api/session    "list"
  ─────────────────────────────────────────────────────────────────────────
  Subscribe to live events  GET     /api/events     (SSE stream)
  ─────────────────────────────────────────────────────────────────────────
  Upload + broadcast slide  POST    /api/slide      "upload"
  Go to slide number (T)    POST    /api/slide      "goto"
  Next slide (T)            POST    /api/slide      "next"
  Prev slide (T)            POST    /api/slide      "prev"
  ─────────────────────────────────────────────────────────────────────────
  Create poll (T)           POST    /api/poll       "create"
  Vote on poll (S)          POST    /api/poll       "vote"
  End poll (T)              POST    /api/poll       "end"
  Reveal answer (T)         POST    /api/poll       "setCorrectAnswers"
  Get all polls             GET     /api/poll       ?sessionId=UUID
  ─────────────────────────────────────────────────────────────────────────
  Submit doubt (S)          POST    /api/doubt      "create"
  Resolve doubt (T)         POST    /api/doubt      "solve"
  Update doubt status (T)   POST    /api/doubt      "update"
  Get all doubts (T)        GET     /api/doubt      ?sessionId=UUID
  ─────────────────────────────────────────────────────────────────────────
  Send chat message         POST    /api/chat       (no action field)
  Get chat history          GET     /api/chat       ?sessionId=UUID&limit=N
  ─────────────────────────────────────────────────────────────────────────

  (T) = Teacher action   (S) = Student action

═══════════════════════════════════════════════════════════════════════════════
  END OF DOCUMENTATION
  Interactive UI: https://Mafia2008-sar.hf.space/api-docs
═══════════════════════════════════════════════════════════════════════════════