/**
 * Autotask Webhook Receiver Endpoint
 * Receives and processes real-time webhook events from Autotask
 *
 * Actual Autotask payload format:
 *   { Action, Guid, EntityType (singular), Id, Fields, EventTime, SequenceNumber, PersonId }
 * Signature header: x-hook-signature: sha1=<base64>
 */

import { NextRequest, NextResponse } from 'next/server';
import { webhookService } from '@/lib/services/webhook-service';
import { AutotaskRawWebhookPayload, normalizeWebhookPayload } from '@/lib/types/webhook';

/**
 * POST /api/webhooks/autotask
 * Receives webhook events from Autotask
 */
export async function POST(request: NextRequest) {
  try {
    // Extract source IP — Autotask sends from 8.34.161.x via Cloudflare/Pangolin
    const sourceIp = request.headers.get('cf-connecting-ip')
                  || request.headers.get('x-forwarded-for')?.split(',')[0].trim()
                  || request.headers.get('x-real-ip')
                  || 'unknown';
    const userAgent = request.headers.get('user-agent') || 'unknown';

    // Read raw body for signature verification
    const rawBody = await request.text();

    // Verify webhook signature (x-hook-signature: sha1=<base64>)
    const signatureHeader = request.headers.get('x-hook-signature');
    if (!webhookService.verifySignature(rawBody, signatureHeader)) {
      console.warn(`[WEBHOOK API] Invalid signature from IP: ${sourceIp}`);
      return NextResponse.json(
        { error: 'Invalid webhook signature' },
        { status: 401 }
      );
    }

    // Parse raw Autotask payload
    const rawPayload: AutotaskRawWebhookPayload = JSON.parse(rawBody);

    // Validate required fields
    if (!rawPayload.Guid || !rawPayload.Action || !rawPayload.EntityType || !rawPayload.Id) {
      console.warn(`[WEBHOOK API] Invalid payload from IP: ${sourceIp}`, rawBody.substring(0, 200));
      return NextResponse.json(
        { error: 'Invalid webhook payload: missing required fields (Guid, Action, EntityType, Id)' },
        { status: 400 }
      );
    }

    // Normalize to our internal format
    const payload = normalizeWebhookPayload(rawPayload);

    console.log(`[WEBHOOK API] Received ${rawPayload.Action} event for ${rawPayload.EntityType} #${rawPayload.Id} from IP: ${sourceIp}`);

    // Process the webhook — return 200 quickly to avoid Autotask timeouts
    const result = await webhookService.processWebhook(payload, sourceIp, userAgent);

    if (result.success) {
      return NextResponse.json({
        success: true,
        eventId: result.eventId,
        action: result.action,
        processingTime: result.processingTime,
      });
    } else {
      // Return 200 even on processing failure to prevent Autotask retries/deactivation
      console.error(`[WEBHOOK API] Processing failed: ${result.error}`);
      return NextResponse.json({
        success: false,
        eventId: result.eventId,
        error: result.error,
      });
    }

  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : String(error);
    console.error('[WEBHOOK API] Error processing webhook:', errorMessage);

    // Return 200 to prevent Autotask from deactivating the webhook on errors
    return NextResponse.json(
      { error: 'Internal server error', details: errorMessage },
      { status: 200 }
    );
  }
}

/**
 * GET /api/webhooks/autotask
 * Health check endpoint for webhook receiver
 */
export async function GET() {
  return NextResponse.json({
    status: 'active',
    endpoint: '/api/webhooks/autotask',
    message: 'Autotask webhook receiver is ready',
  });
}