const router  = require('express').Router();
const multer  = require('multer');
const path    = require('path');
const crypto  = require('crypto');
const { authMiddleware, requireRole, requirePermission } = require('../middleware/auth');
const rateLimit = require('../middleware/rateLimit');
const c = require('../controllers/classroomController');

/* ── multer for chat image attachments ─────────────────────────────────── */
const _chatUploadsDir = path.join(__dirname, '../../uploads/chat');
const _chatStorage = multer.diskStorage({
  destination: (req, file, cb) => cb(null, _chatUploadsDir),
  filename:    (req, file, cb) => {
    const ext = path.extname(file.originalname).toLowerCase().replace(/[^.a-z0-9]/g, '');
    cb(null, crypto.randomBytes(14).toString('hex') + ext);
  },
});
const chatUpload = multer({
  storage: _chatStorage,
  limits:  { fileSize: 5 * 1024 * 1024 },
  fileFilter: (req, file, cb) => {
    const ok = ['image/jpeg','image/png','image/gif','image/webp'].includes(file.mimetype);
    cb(null, ok);
  },
});

const teacher = [authMiddleware, requireRole('teacher', 'admin')];
const auth    = [authMiddleware];

const chatLimiter     = rateLimit({ windowMs: 5_000,  max: 5,   message: 'Слишком много сообщений, подождите', byUser: true });
const reactionLimiter = rateLimit({ windowMs: 5_000,  max: 15,  message: 'Слишком много реакций, подождите',    byUser: true });
const handLimiter     = rateLimit({ windowMs: 5_000,  max: 5,   message: 'Не так часто',                        byUser: true });
const cursorLimiter   = rateLimit({ windowMs: 2_000,  max: 60,  message: 'Слишком часто',                       byUser: true });
const previewLimiter  = rateLimit({ windowMs: 2_000,  max: 60,  message: 'Слишком часто',                       byUser: true });
const signalLimiter   = rateLimit({ windowMs: 10_000, max: 30,  message: 'Слишком много сигналов',               byUser: true });
const strokesLimiter  = rateLimit({ windowMs: 5_000,  max: 100, message: 'Слишком много штрихов',                byUser: true });

// Template library — MUST be before /:id to avoid shadowing
router.get('/admin/active',               ...teacher, c.adminGetActiveSessions);
router.get('/admin/sessions',             ...teacher, c.adminGetAllSessions);
router.get('/admin/teachers-list',        ...teacher, c.adminGetTeachersList);
router.get('/templates',                  ...teacher, c.getTemplates);
router.delete('/templates/:tid',          ...teacher, c.deleteTemplate);

// History — MUST be before /:id to avoid shadowing
router.get('/my/history',                 ...auth,    c.getMyHistory);
router.get('/class/:classId/history',     ...auth,    c.getClassHistory);

// Session lifecycle
router.post('/',                          ...teacher, requirePermission('classroom.host'), c.createSession);
router.get('/online-students',            ...teacher, c.getOnlineStudents);
router.get('/my/session',                 ...auth,    c.getMySession);
router.get('/class/:classId/active',      ...auth,    c.getActiveSession);
router.get('/my/active',                  ...auth,    c.getMyActive);
router.get('/:id',                        ...auth,    c.getSession);
router.delete('/:id',                     ...teacher, c.endSession);

// Attendance
router.post('/:id/join',                  ...auth,    c.joinSession);
router.post('/:id/leave',                 ...auth,    c.leaveSession);
router.get('/:id/participants',           ...auth,    c.getParticipants);
router.get('/:id/attendance',             ...teacher, c.getAttendance);

// Chat
router.post('/:id/chat',                  ...auth, chatLimiter, c.sendChat);
router.get('/:id/chat',                   ...auth,    c.getChat);
router.post('/:id/chat/upload',           ...auth,    chatUpload.single('file'), c.uploadChatAttachment);
router.post('/:id/chat/:msgId/react',     ...auth, reactionLimiter, c.reactToMessage);

// WebRTC signaling
router.post('/:id/signal',                ...auth, signalLimiter, c.signal);

// Whiteboard strokes
router.post('/:id/strokes',               ...auth, strokesLimiter,  c.postStrokes);
router.get('/:id/strokes',                ...auth,                   c.getStrokes);
router.delete('/:id/strokes/:strokeId',   ...teacher,                c.deleteStroke);
router.patch('/:id/strokes/:strokeId',    ...auth,                   c.updateStroke);
router.post('/:id/stroke-preview',        ...auth, previewLimiter,  c.previewStroke);

// Multi-page
router.get('/:id/pages',                          ...auth,    c.getPages);
router.post('/:id/pages',                         ...teacher, c.addPage);
router.put('/:id/page',                           ...teacher, c.changePage);
router.patch('/:id/page-template',                ...teacher, c.updatePageTemplate);
router.patch('/:id/board-theme',                  ...teacher, c.updateBoardTheme);
router.patch('/:id/pages/:pageNum/name',          ...teacher, c.renamePage);
router.post('/:id/pages/:pageNum/duplicate',      ...teacher, c.duplicatePage);
router.delete('/:id/pages/:pageNum',              ...teacher, c.deletePage);

// Hand raise
router.post('/:id/hand',                  ...auth, handLimiter, c.raiseHand);
router.delete('/:id/hand',                ...auth, handLimiter, c.lowerHand);
router.get('/:id/hands',                  ...auth,    c.getHands);

// Whiteboard: clear page
router.post('/:id/clear-page',            ...teacher, c.clearPage);

// WebRTC: mute/unmute peer, screen share broadcast
router.post('/:id/mute',                  ...teacher, c.mutePeer);
router.delete('/:id/mute',                ...teacher, c.unmutePeer);
router.post('/:id/screen',                ...teacher, c.screenStart);
router.delete('/:id/screen',              ...teacher, c.screenStop);

// Simulation: open/close/state/mode for all participants
router.post('/:id/sim',                   ...teacher, c.simOpen);
router.delete('/:id/sim',                 ...teacher, c.simClose);
router.post('/:id/sim/state',             ...teacher, c.simState);
router.post('/:id/sim/mode',              ...teacher, c.simMode);
router.post('/:id/sim/annotate',          ...teacher, c.simAnnotate);

// Textbook: open/close/navigate for all participants
router.post('/:id/textbook',              ...teacher, c.textbookOpen);
router.delete('/:id/textbook',            ...teacher, c.textbookClose);
router.post('/:id/textbook/nav',          ...teacher, c.textbookNav);
router.post('/:id/textbook/mode',         ...teacher, c.textbookMode);

// Cursor broadcast (all participants)
router.post('/:id/cursor',                ...auth, cursorLimiter, c.broadcastCursor);

// Message pin (teacher only)
router.post('/:id/chat/:msgId/pin',       ...teacher, c.pinMessage);

// Collaborative drawing permissions
router.post('/:id/allow-draw/:userId',    ...teacher, c.allowDraw);
router.delete('/:id/allow-draw/:userId',  ...teacher, c.revokeDraw);

// Session notes (per user)
router.get('/:id/notes',                  ...auth,    c.getNotes);
router.put('/:id/notes',                  ...auth,    c.saveNotes);
router.get('/:id/notes/all',              ...teacher, c.getAllNotes);

// Session summary & history detail
router.get('/:id/summary',                ...auth,    c.getSessionSummary);
router.get('/:id/chat/export',            ...teacher, c.exportChat);
router.delete('/:id/history',             ...teacher, c.deleteHistorySession);

// Save current session as template
router.post('/:id/save-template',         ...teacher, c.saveTemplate);
// Load template into current session
router.post('/:id/load-template',         ...teacher, c.loadTemplate);

// Guest token (generate/revoke/get)
router.get('/:id/guest-token',            ...teacher, c.getGuestToken);
router.post('/:id/guest-token',           ...teacher, c.generateGuestToken);
router.delete('/:id/guest-token',         ...teacher, c.revokeGuestToken);

module.exports = router;