// Command validator-agent runs on a validator VM. It is stateless: every
// decision it makes is driven by polling the Control API, per the
// deployment constraint that validators must be able to restart freely
// without any local state to reconcile.
package main

import (
	"context"
	"flag"
	"log/slog"
	"net"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"syscall"

	"cloudipvalidator/internal/agentcore"
	"cloudipvalidator/internal/config"
)

func main() {
	configPath := flag.String("config", "configs/validator-agent.yaml", "path to validator-agent config file")
	stubPorts := flag.String("stub-ports", "", "TEST ONLY: comma-separated TCP ports to accept-and-close on, standing in for the validator's real listening services in the offline end-to-end harness (see docs/LOCAL_E2E.md)")
	flag.Parse()

	log := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo}))

	cfg, err := config.LoadValidatorAgent(*configPath)
	if err != nil {
		log.Error("load config", "err", err)
		os.Exit(1)
	}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	if *stubPorts != "" {
		startStubListeners(ctx, log, *stubPorts)
	}

	token := os.Getenv(cfg.ControlAPITokenEnv)
	if token == "" {
		log.Warn("agent token is not set: result/event/complete calls will be rejected by an authenticated control-api", "env", cfg.ControlAPITokenEnv)
	}
	agent := agentcore.New(cfg, log).WithToken(token)
	if err := agent.Run(ctx); err != nil && err != context.Canceled {
		log.Error("agent stopped", "err", err)
		os.Exit(1)
	}
}

// startStubListeners binds trivial accept-and-close TCP listeners on the
// given ports, standing in for the base-minimum services (22/80/443/8080)
// a real validator would already run, so an offline prober has something
// to successfully connect to. ICMP needs no stub: the kernel answers echo
// requests to any locally-bound address on its own.
func startStubListeners(ctx context.Context, log *slog.Logger, portsCSV string) {
	for _, p := range strings.Split(portsCSV, ",") {
		p = strings.TrimSpace(p)
		if p == "" {
			continue
		}
		port, err := strconv.Atoi(p)
		if err != nil {
			log.Error("invalid stub port", "value", p, "err", err)
			continue
		}
		ln, err := net.Listen("tcp", ":"+strconv.Itoa(port))
		if err != nil {
			log.Error("stub listener", "port", port, "err", err)
			continue
		}
		log.Info("stub listener up", "port", port)
		go func() {
			<-ctx.Done()
			ln.Close()
		}()
		go func() {
			for {
				conn, err := ln.Accept()
				if err != nil {
					return
				}
				conn.Close()
			}
		}()
	}
}