import { Worker, type Job } from 'bullmq';
import { env } from '@/lib/env';
import { createHmac } from 'node:crypto';
import { lookup } from 'node:dns/promises';

import type { ConnectionOptions } from 'bullmq';
import { logger } from '@/lib/logger';
import { QUEUE_CONFIGS } from '@/lib/queue';
import { isLocalOrPrivateHost } from '@/lib/validators/webhooks';

/**
 * Resolve the webhook hostname and reject if any returned address is in a
 * disallowed range. Defends against DNS rebinding where the validator-time
 * resolution returned a public address but dispatch-time resolution
 * returns a private one.
 */
async function resolveAndCheckHost(
  rawUrl: string,
): Promise<{ ok: true } | { ok: false; reason: string }> {
  if (isLocalOrPrivateHost(rawUrl)) {
    return { ok: false, reason: 'webhook URL host blocked by static check' };
  }
  let host: string;
  try {
    host = new URL(rawUrl).hostname;
  } catch {
    return { ok: false, reason: 'invalid URL' };
  }
  try {
    const addresses = await lookup(host, { all: true });
    for (const a of addresses) {
      // Reuse the validator's literal-address checks on each resolved IP.
      if (isLocalOrPrivateHost(`https://${a.family === 6 ? `[${a.address}]` : a.address}`)) {
        return { ok: false, reason: `resolved address ${a.address} is in a blocked range` };
      }
    }
  } catch (err) {
    return {
      ok: false,
      reason: `DNS resolution failed: ${err instanceof Error ? err.message : 'unknown'}`,
    };
  }
  return { ok: true };
}

// ─── Job Payload ─────────────────────────────────────────────────────────────

interface WebhookDeliverPayload {
  webhookId: string;
  portId: string;
  event: string;
  deliveryId: string;
  payload: Record<string, unknown>;
}

// ─── Worker ──────────────────────────────────────────────────────────────────

export const webhooksWorker = new Worker(
  'webhooks',
  async (job: Job) => {
    logger.info({ jobId: job.id, jobName: job.name }, 'Processing webhooks job');

    if (job.name !== 'deliver') {
      logger.warn({ jobName: job.name }, 'Unknown webhooks job');
      return;
    }

    const { webhookId, portId, event, deliveryId, payload } = job.data as WebhookDeliverPayload;

    const { db } = await import('@/lib/db');
    const { webhooks, webhookDeliveries } = await import('@/lib/db/schema/system');
    const { userProfiles } = await import('@/lib/db/schema/users');
    const { decrypt } = await import('@/lib/utils/encryption');
    const { createNotification } = await import('@/lib/services/notifications.service');
    const { eq, and } = await import('drizzle-orm');

    // 1. Fetch webhook - skip if deleted
    const webhook = await db.query.webhooks.findFirst({
      where: eq(webhooks.id, webhookId),
    });

    if (!webhook) {
      logger.info({ webhookId }, 'Webhook deleted - skipping delivery');
      await db.delete(webhookDeliveries).where(eq(webhookDeliveries.id, deliveryId));
      return;
    }

    // Safety net: when EMAIL_REDIRECT_TO is set (dev / staging / migration
    // dry-run), short-circuit webhook delivery so we don't accidentally
    // ping a user-configured production endpoint with synthetic events.
    // Records the delivery as `dead_letter` with a clear reason so the
    // attempt is still visible in the deliveries listing.
    if (process.env.EMAIL_REDIRECT_TO) {
      logger.info(
        { webhookId, deliveryId, url: webhook.url },
        'Webhook delivery skipped (EMAIL_REDIRECT_TO is set - outbound comms are paused)',
      );
      await db
        .update(webhookDeliveries)
        .set({
          status: 'dead_letter',
          responseStatus: null,
          responseBody: 'Skipped: EMAIL_REDIRECT_TO is set, outbound comms paused.',
          deliveredAt: new Date(),
        })
        .where(eq(webhookDeliveries.id, deliveryId));
      return;
    }

    // 2. Decrypt secret
    let secret: string;
    try {
      secret = webhook.secret ? decrypt(webhook.secret) : '';
    } catch (err) {
      logger.error({ webhookId, err }, 'Failed to decrypt webhook secret');
      throw err; // Let BullMQ retry
    }

    // 3. Build final payload
    const finalPayload = {
      id: deliveryId,
      event,
      timestamp: new Date().toISOString(),
      port_id: portId,
      data: payload,
    };

    const bodyString = JSON.stringify(finalPayload);

    // 4. Sign with HMAC-SHA256
    const signature = secret
      ? `sha256=${createHmac('sha256', secret).update(bodyString).digest('hex')}`
      : '';

    const attempt = (job.attemptsMade ?? 0) + 1;

    // 5. POST to webhook URL with 10s timeout
    let responseStatus: number | null = null;
    let responseBody: string | null = null;
    let success = false;

    // SSRF gate: re-resolve the hostname at dispatch time and reject if it
    // points anywhere internal. The validator already filtered literal
    // hostnames at create/update time, but DNS rebinding could swap the
    // answer between then and now.
    const hostCheck = await resolveAndCheckHost(webhook.url);
    if (!hostCheck.ok) {
      logger.warn(
        { webhookId, deliveryId, url: webhook.url, reason: hostCheck.reason },
        'Webhook dispatch blocked by SSRF guard',
      );
      // Persist the failure so the deliveries listing reflects it.
      const { db: dbInner } = await import('@/lib/db');
      const { webhookDeliveries } = await import('@/lib/db/schema/system');
      const { eq } = await import('drizzle-orm');
      await dbInner
        .update(webhookDeliveries)
        .set({
          status: 'dead_letter',
          responseStatus: null,
          responseBody: `Blocked: ${hostCheck.reason}`,
          deliveredAt: new Date(),
        })
        .where(eq(webhookDeliveries.id, deliveryId));
      return;
    }

    try {
      const controller = new AbortController();
      const timeoutId = setTimeout(() => controller.abort(), 10_000);

      const response = await fetch(webhook.url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'User-Agent': 'PortNimara-Webhook/1.0',
          'X-Webhook-Id': webhookId,
          'X-Webhook-Event': event,
          'X-Webhook-Signature': signature,
          'X-Webhook-Delivery': deliveryId,
        },
        body: bodyString,
        signal: controller.signal,
      });

      clearTimeout(timeoutId);
      responseStatus = response.status;
      // Read up to 1KB of response body
      const rawBody = await response.text();
      responseBody = rawBody.slice(0, 1024);
      success = response.status >= 200 && response.status < 300;
    } catch (err) {
      // Network error or timeout
      logger.warn({ webhookId, deliveryId, err }, 'Webhook delivery network error');
      responseStatus = null;
      responseBody = err instanceof Error ? err.message.slice(0, 1024) : String(err).slice(0, 1024);
      success = false;
    }

    const maxAttempts = QUEUE_CONFIGS.webhooks.maxAttempts;
    const isFinalAttempt = attempt >= maxAttempts;

    const { createAuditLog } = await import('@/lib/audit');

    if (success) {
      // 6a. Record success
      await db
        .update(webhookDeliveries)
        .set({
          status: 'success',
          responseStatus,
          responseBody,
          attempt,
          deliveredAt: new Date(),
        })
        .where(eq(webhookDeliveries.id, deliveryId));

      logger.info({ webhookId, deliveryId, event }, 'Webhook delivered successfully');

      void createAuditLog({
        userId: null,
        portId,
        action: 'webhook_delivered',
        entityType: 'webhook_delivery',
        entityId: deliveryId,
        metadata: { webhookId, event, responseStatus, attempt },
        source: 'webhook',
        severity: 'info',
      });
    } else if (!success && isFinalAttempt) {
      // 6b. Final failure → dead_letter + system alert
      await db
        .update(webhookDeliveries)
        .set({
          status: 'dead_letter',
          responseStatus,
          responseBody,
          attempt,
        })
        .where(eq(webhookDeliveries.id, deliveryId));

      logger.error(
        { webhookId, deliveryId, event, attempt },
        'Webhook delivery permanently failed - dead_letter',
      );

      void createAuditLog({
        userId: null,
        portId,
        action: 'webhook_dead_letter',
        entityType: 'webhook_delivery',
        entityId: deliveryId,
        metadata: { webhookId, event, responseStatus, attempt, responseBody },
        source: 'webhook',
        severity: 'error',
      });

      // Notify all super admins
      try {
        const superAdmins = await db
          .select({ userId: userProfiles.userId })
          .from(userProfiles)
          .where(and(eq(userProfiles.isSuperAdmin, true), eq(userProfiles.isActive, true)));

        for (const admin of superAdmins) {
          void createNotification({
            portId,
            userId: admin.userId,
            type: 'system_alert',
            title: 'Webhook delivery failed permanently',
            description: `Webhook "${webhook.name}" failed to deliver event "${event}" after ${maxAttempts} attempts.`,
            link: `/admin/webhooks/${webhookId}`,
            entityType: 'webhook',
            entityId: webhookId,
            dedupeKey: `webhook:dead_letter:${deliveryId}`,
            cooldownMs: 0,
          });
        }
      } catch (notifyErr) {
        logger.error({ notifyErr }, 'Failed to send dead_letter notification');
      }

      // Throw to let BullMQ mark job as failed (it won't retry since it's the final attempt)
      throw new Error(
        `Webhook delivery failed after ${attempt} attempts. Status: ${responseStatus ?? 'network error'}`,
      );
    } else {
      // 6c. Non-final failure → update record then throw to trigger retry
      await db
        .update(webhookDeliveries)
        .set({
          status: 'failed',
          responseStatus,
          responseBody,
          attempt,
        })
        .where(eq(webhookDeliveries.id, deliveryId));

      void createAuditLog({
        userId: null,
        portId,
        action: 'webhook_failed',
        entityType: 'webhook_delivery',
        entityId: deliveryId,
        metadata: { webhookId, event, responseStatus, attempt },
        source: 'webhook',
        severity: 'warning',
      });

      throw new Error(
        `Webhook delivery attempt ${attempt} failed. Status: ${responseStatus ?? 'network error'}. Retrying...`,
      );
    }
  },
  {
    connection: { url: env.REDIS_URL } as ConnectionOptions,
    concurrency: QUEUE_CONFIGS.webhooks.concurrency,
  },
);

webhooksWorker.on('failed', (job, err) => {
  logger.error({ jobId: job?.id, jobName: job?.name, err }, 'Webhooks job failed');
});