package main

import (
	"context"
	"errors"
	"flag"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
)

func main() {
	listen := flag.String("listen", envDefault("CONVERGE_RELAY_LISTEN", ":8080"), "address to listen on")
	secret := flag.String("secret", envDefault("CONVERGE_RELAY_SECRET", ""), "shared secret for Gitea webhook HMAC verification")
	flag.Parse()

	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelInfo}))
	slog.SetDefault(logger)

	broker := NewBroker()
	go broker.Run()

	mux := http.NewServeMux()
	mux.HandleFunc("POST /webhook", webhookHandler(broker, *secret))
	mux.HandleFunc("GET /events", sseHandler(broker))
	mux.HandleFunc("GET /health", healthHandler)

	srv := &http.Server{Addr: *listen, Handler: mux}

	// Graceful shutdown
	go func() {
		sig := make(chan os.Signal, 1)
		signal.Notify(sig, os.Interrupt)
		<-sig
		slog.Info("shutting down")
		broker.Stop()
		srv.Shutdown(context.Background())
	}()

	slog.Info("converge-relay starting", "listen", *listen)
	if err := srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
		slog.Error("server error", "error", err)
		os.Exit(1)
	}
}

func envDefault(key, fallback string) string {
	if v, ok := os.LookupEnv(key); ok {
		return v
	}
	return fallback
}

func healthHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	w.Write([]byte("ok\n"))
}