import { NextRequest, NextResponse } from 'next/server';
import { cookies } from 'next/headers';
import { createHmac } from 'node:crypto';
import { decryptSession } from '@/lib/auth/crypto';
import { sessionCookieName } from '@/lib/auth/session-cookie';
import { logger } from '@/lib/logger';

const JITSI_URL = (process.env.JITSI_URL || 'https://meet.src-advisory.com').replace(/\/+$/, '');

function base64url(input: Buffer): string {
  return input.toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
}

function b64u(input: string): string {
  return Buffer.from(input).toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
}

export async function POST(request: NextRequest) {
  try {
    const appId = process.env.JITSI_APP_ID;
    const appSecret = process.env.JITSI_APP_SECRET;
    if (!appId || !appSecret) {
      return NextResponse.json({ error: 'Jitsi is not configured' }, { status: 503 });
    }

    const cookieStore = await cookies();
    const sessionToken = cookieStore.get(sessionCookieName(0))?.value;
    if (!sessionToken) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
    }
    const session = decryptSession(sessionToken);
    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
    }
    const email = session.username;

    const body = await request.json().catch(() => ({}));
    const room = typeof body.room === 'string' ? body.room.trim() : '';
    if (!room || !/^[a-z0-9-]{1,100}$/i.test(room)) {
      return NextResponse.json({ error: 'Invalid room name' }, { status: 400 });
    }

    const domain = new URL(JITSI_URL).hostname;
    const now = Math.floor(Date.now() / 1000);
    const header = { alg: 'HS256', typ: 'JWT' };
    const payload = {
      iss: 'bulwark-webmail',
      sub: domain,
      aud: appId,
      room,
      iat: now,
      exp: now + 86400,
      context: {
        user: {
          email,
          name: email.split('@')[0],
        },
      },
    };

    const signingInput = `${b64u(JSON.stringify(header))}.${b64u(JSON.stringify(payload))}`;
    const signature = createHmac('sha256', appSecret).update(signingInput).digest();
    const token = `${signingInput}.${base64url(signature)}`;

    logger.info('Jitsi token issued', { room, email });

    return NextResponse.json({
      token,
      room,
      url: `${JITSI_URL}/${encodeURIComponent(room)}`,
    });
  } catch (error) {
    const message = error instanceof Error ? error.message : 'Unknown error';
    logger.error('Jitsi token issuance failed', { error: message });
    return NextResponse.json({ error: message }, { status: 500 });
  }
}