// gateway is the Lakehouse-Go HTTP/gRPC ingress. In G0 it serves
// /health, /v1/ingest (501 stub, per D1.10), and /v1/sql (501 stub).
// D6 promotes the stubs to real reverse-proxies with a custom
// Director that strips the /v1 prefix before forwarding (per Kimi
// finding K2 — httputil.NewSingleHostReverseProxy preserves the
// inbound path by default).
package main

import (
	"flag"
	"log/slog"
	"net/http"
	"os"

	"git.agentview.dev/profit/golangLAKEHOUSE/internal/shared"
	"github.com/go-chi/chi/v5"
)

func main() {
	configPath := flag.String("config", "lakehouse.toml", "path to TOML config")
	flag.Parse()

	cfg, err := shared.LoadConfig(*configPath)
	if err != nil {
		slog.Error("config", "err", err)
		os.Exit(1)
	}

	if err := shared.Run("gateway", cfg.Gateway.Bind, func(r chi.Router) {
		// G0 stubs — D6.1 promotes these to real reverse-proxies via
		// httputil.ReverseProxy with a Director that strips /v1.
		r.Post("/v1/ingest", stubHandler)
		r.Post("/v1/sql", stubHandler)
	}); err != nil {
		slog.Error("server", "err", err)
		os.Exit(1)
	}
}

// stubHandler returns 501 with the X-Lakehouse-Stub header so the
// D6 promotion is a behavior change (handler swap), not an endpoint
// addition. Test clients can detect the stub by header presence.
func stubHandler(w http.ResponseWriter, _ *http.Request) {
	w.Header().Set("X-Lakehouse-Stub", "g0")
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusNotImplemented)
	_, _ = w.Write([]byte(`{"error":"not implemented in G0; promoted on D6.1"}`))
}