import { Express, Response } from "express";
import { createProxyMiddleware } from "http-proxy-middleware";

const METASET_HOST = process.env.METASET_HOST || "metaset";
const METASET_PORT = parseInt(process.env.METASET_PORT || "8100", 10);
const METASET_TIMEOUT = 60000;

// Consulta o Kernel Registry para descobrir onde o Metaset está rodando
async function discoverMetasetEndpoint(): Promise<string | null> {
  try {
    // PRIORIDADE 1: Registry global (mesmo processo)
    const globalRegistry = (global as any).arcadiaKernelRegistry;
    if (globalRegistry) {
      const services = globalRegistry.getServices();
      const metasetService = services.find((s: any) => 
        s.id === 'metaset' || 
        s.name?.toLowerCase().includes('metaset') ||
        s.displayName?.toLowerCase().includes('metaset')
      );
      
      if (metasetService?.endpoint) {
        console.log(`[Metaset Proxy] Discovery via Kernel Registry: ${metasetService.endpoint}`);
        return metasetService.endpoint;
      }
    }

    // PRIORIDADE 2: HTTP request para porta 5001
    const response = await fetch('http://127.0.0.1:5001/api/services');
    if (response.ok) {
      const services = await response.json();
      const metasetService = services.find((s: any) => 
        s.id === 'metaset' || 
        s.name?.toLowerCase().includes('metaset')
      );
      
      if (metasetService?.endpoint) {
        console.log(`[Metaset Proxy] Discovery via HTTP: ${metasetService.endpoint}`);
        return metasetService.endpoint;
      }
    }
  } catch (error) {
    console.log('[Metaset Proxy] Discovery falhou, usando fallback:', error);
  }

  // FALLBACK: Configuração padrão
  return null;
}

export async function setupMetasetProxy(app: Express): Promise<void> {
  // Tenta descobrir endpoint via Kernel Discovery
  const discoveredEndpoint = await discoverMetasetEndpoint();
  const target = discoveredEndpoint || `http://${METASET_HOST}:${METASET_PORT}`;

  console.log(`[Metaset Proxy] Configurando proxy -> ${target}`);

  const metasetProxy = createProxyMiddleware({
    target,
    changeOrigin: true,
    timeout: METASET_TIMEOUT,
    proxyTimeout: METASET_TIMEOUT,
    pathRewrite: { "^/metaset": "" },
    on: {
      error: (err, _req, res) => {
        console.error("[Metaset Proxy] Error:", err.message);
        if (res && typeof (res as Response).status === "function") {
          (res as Response).status(502).json({
            error: "Metaset indisponível",
            message: "O Metaset BI está iniciando. Tente novamente em alguns segundos.",
            target,
          });
        }
      },
      proxyRes: (proxyRes) => {
        const location = proxyRes.headers["location"];
        if (location && typeof location === "string" && location.startsWith("/")) {
          proxyRes.headers["location"] = `/metaset${location}`;
        }
      },
    },
  });

  app.use("/metaset", metasetProxy);
  console.log(`[Metaset Proxy] Ativo em /metaset -> ${target}`);
}