// ═══════════════════════════════════════════════════════════════════════════
// SESSION API - Create/Join/End Sessions
// ═══════════════════════════════════════════════════════════════════════════

import { NextRequest, NextResponse } from 'next/server';
import { sessionManager } from '@/lib/session-manager';
import { v4 as uuidv4 } from 'uuid';

export const runtime = 'nodejs';
export const dynamic = 'force-dynamic';

// Create a new session
export async function POST(request: NextRequest) {
  try {
    const body = await request.json();
    const { action, teacherId, teacherName, sessionName, slideUrls, userId, userName, sessionId } = body;

    // CREATE SESSION
    if (action === 'create') {
      if (!teacherId || !teacherName || !sessionName) {
        return NextResponse.json({ 
          success: false, 
          error: 'Missing required fields' 
        }, { status: 400 });
      }

      const session = await sessionManager.createSession(
        teacherId,
        teacherName,
        sessionName,
        slideUrls || []
      );

      // Auto-join teacher to session
      sessionManager.joinSession(session.id, teacherId, teacherName, 'teacher');

      return NextResponse.json({
        success: true,
        data: session
      });
    }

    // JOIN SESSION
    if (action === 'join') {
      if (!sessionId || !userId || !userName) {
        return NextResponse.json({ 
          success: false, 
          error: 'Missing required fields' 
        }, { status: 400 });
      }

      const session = sessionManager.getSession(sessionId);
      if (!session) {
        return NextResponse.json({ 
          success: false, 
          error: 'Session not found' 
        }, { status: 404 });
      }

      if (!session.isActive) {
        return NextResponse.json({ 
          success: false, 
          error: 'Session is not active' 
        }, { status: 400 });
      }

      const user = sessionManager.joinSession(sessionId, userId, userName, 'student');

      return NextResponse.json({
        success: true,
        data: {
          session,
          user,
          currentSlide: session.currentSlide,
          slideUrl: session.slideUrls[session.currentSlide] || null,
          whiteboardStrokes: sessionManager.getWhiteboardStrokes(sessionId),
          reactions: sessionManager.getReactions(sessionId)
        }
      });
    }

    // END SESSION
    if (action === 'end') {
      if (!sessionId) {
        return NextResponse.json({ 
          success: false, 
          error: 'Missing sessionId' 
        }, { status: 400 });
      }

      await sessionManager.endSession(sessionId);

      return NextResponse.json({
        success: true,
        message: 'Session ended'
      });
    }

    // GET SESSION INFO
    if (action === 'get') {
      if (!sessionId) {
        return NextResponse.json({ 
          success: false, 
          error: 'Missing sessionId' 
        }, { status: 400 });
      }

      const session = sessionManager.getSession(sessionId);
      if (!session) {
        return NextResponse.json({ 
          success: false, 
          error: 'Session not found' 
        }, { status: 404 });
      }

      return NextResponse.json({
        success: true,
        data: {
          session,
          currentSlide: session.currentSlide,
          slideUrl: session.slideUrls[session.currentSlide] || null,
          whiteboardStrokes: sessionManager.getWhiteboardStrokes(sessionId),
          reactions: sessionManager.getReactions(sessionId),
          doubts: sessionManager.getDoubts(sessionId),
          activePoll: sessionManager.getActivePoll(sessionId),
          onlineUsers: sessionManager.getOnlineUsers(sessionId)
        }
      });
    }

    return NextResponse.json({ 
      success: false, 
      error: 'Invalid action' 
    }, { status: 400 });

  } catch (error) {
    console.error('Session API error:', error);
    return NextResponse.json({ 
      success: false, 
      error: 'Internal server error' 
    }, { status: 500 });
  }
}