import { randomBytes } from 'crypto';
import { countActiveMagicBindings, listMagicDevices } from '../../db/devices';
import { requireUser } from '../../utils/auth';

/**
 * POST /api/magic/register
 *
 * Body: { deviceId: string, hostname: string, model?: string, osVersion?: string }
 *
 * Mac-App ruft nach Login auf. Registriert das Device als Magic-Client,
 * generiert DNS-Token und provisioniert AdGuard Persistent Client.
 *
 * Idempotent: wenn bereits gebunden → return existing token.
 * Wenn Limit erreicht → 409 mit activeBindings-Liste.
 */
export default defineEventHandler(async (event) => {
  const user = await requireUser(event);
  const body = await readBody(event);
  const { deviceId, hostname, model, osVersion } = body as {
    deviceId?: string;
    hostname?: string;
    model?: string;
    osVersion?: string;
  };

  if (!deviceId || !hostname) {
    throw createError({
      statusCode: 400,
      message: 'deviceId und hostname required',
    });
  }

  const db = usePrisma();

  // 1. Prüfe ob Device bereits als Magic-Client gebunden ist (idempotent)
  const existing = await db.userDevice.findUnique({
    where: { userId_deviceId: { userId: user.id, deviceId } },
    select: {
      id: true,
      userId: true,
      magicDnsToken: true,
      magicEnrolledAt: true,
      magicRevokedAt: true,
    },
  });

  // Wenn Token existiert und nicht revoked → return existing
  if (
    existing?.magicDnsToken &&
    existing.magicEnrolledAt &&
    !existing.magicRevokedAt
  ) {
    return {
      success: true,
      data: {
        deviceId,
        dnsToken: existing.magicDnsToken,
        profileUrl: `/api/magic/profile.mobileconfig?token=${existing.magicDnsToken}`,
        existing: true,
      },
    };
  }

  // 2. Limit-Check (nur wenn kein vorheriges Binding existiert)
  if (!existing || !existing.magicEnrolledAt) {
    const activeCount = await countActiveMagicBindings(user.id);
    if (activeCount >= MAGIC_DEVICE_LIMIT) {
      const activeBindings = await listMagicDevices(user.id);
      throw createError({
        statusCode: 409,
        message: `Magic-Device-Limit erreicht (max ${MAGIC_DEVICE_LIMIT})`,
        data: {
          code: 'limit_reached',
          activeBindings,
        },
      });
    }
  }

  // 3. Generiere DNS-Token (48 char base64url-safe)
  const dnsToken = randomBytes(36).toString('base64url');

  // 4. Provisioniere AdGuard Client
  const adguardClientName = `magic_${deviceId}`;
  try {
    await createAdGuardClient(adguardClientName, dnsToken, {
      use_global_settings: false,
      filtering_enabled: true,
      parental_enabled: false,
      safebrowsing_enabled: true,
      blocked_services: [], // TODO: Gambling-Filter via AdGuard Blocked-Services
    });
  } catch (err: any) {
    console.error('[Magic] AdGuard provisioning failed:', err);
    throw createError({
      statusCode: 502,
      message: 'DNS-Provisioning fehlgeschlagen',
    });
  }

  // 5. Upsert UserDevice (platform="macos")
  const device = await db.userDevice.upsert({
    where: { userId_deviceId: { userId: user.id, deviceId } },
    create: {
      userId: user.id,
      deviceId,
      platform: 'macos',
      model: model ?? null,
      name: hostname,
      osVersion: osVersion ?? null,
      magicDnsToken: dnsToken,
      magicEnrolledAt: new Date(),
      magicHostname: hostname,
    },
    update: {
      magicDnsToken: dnsToken,
      magicEnrolledAt: new Date(),
      magicRevokedAt: null, // Clear falls vorher revoked
      magicHostname: hostname,
      model: model ?? undefined,
      osVersion: osVersion ?? undefined,
      lastSeenAt: new Date(),
    },
    select: {
      deviceId: true,
      magicDnsToken: true,
    },
  });

  return {
    success: true,
    data: {
      deviceId: device.deviceId,
      dnsToken: device.magicDnsToken,
      profileUrl: `/api/magic/profile.mobileconfig?token=${device.magicDnsToken}`,
      existing: false,
    },
  };
});