import { NextResponse } from 'next/server';

const ALLOWED_HOSTS = ['glitchtip.infra.mintel.me', 'errors.infra.mintel.me'];

export async function POST(req: Request) {
  try {
    const rawText = await req.text();
    const items = rawText.split('\n');
    
    if (items.length === 0 || !items[0]) {
      return NextResponse.json({ error: 'Empty payload' }, { status: 400 });
    }

    const header = JSON.parse(items[0]);
    // Use the server's configured DSN (if available) to override the client's potentially fake DSN
    // This allows the client to work without exposing NEXT_PUBLIC_SENTRY_DSN
    const dsn = process.env.SENTRY_DSN || header.dsn;
    if (!dsn) {
      return NextResponse.json({ error: 'No DSN found' }, { status: 400 });
    }

    const url = new URL(dsn);
    const projectId = url.pathname.replace('/', '');
    const host = url.hostname;

    if (!ALLOWED_HOSTS.includes(host)) {
      return NextResponse.json({ error: 'Invalid Sentry Host' }, { status: 400 });
    }

    // Rewrite the DSN in the envelope header so Glitchtip doesn't reject the fake client DSN
    if (process.env.SENTRY_DSN) {
      header.dsn = process.env.SENTRY_DSN;
      items[0] = JSON.stringify(header);
    }

    const sentryIngestUrl = `https://${host}/api/${projectId}/envelope/`;
    const payloadToForward = items.join('\n');

    const response = await fetch(sentryIngestUrl, {
      method: 'POST',
      body: payloadToForward,
      headers: {
        'Content-Type': 'application/x-sentry-envelope',
      },
    });

    if (!response.ok) {
      const errorText = await response.text();
      console.error(`[Sentry Tunnel] Relay rejected (${response.status}):`, errorText);
      return NextResponse.json({ error: 'Sentry rejection' }, { status: response.status });
    }

    return NextResponse.json({ success: true });
  } catch (e) {
    console.error("[Sentry Tunnel] Failed to parse or relay body", e);
    return NextResponse.json({ error: 'Relay failed' }, { status: 500 });
  }
}