package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/cosmic-clash/cosmic-clash/server/supervisor"
)

const usageText = `Usage: game-server-supervisor [options] -- <game-server-command> [args...]

The child command is started only after an allocated Agones endpoint has been
validated and, when configured, an explicit process-ready probe succeeds.
SIGTERM/SIGINT requests authenticated drain before the bounded grace deadline.
`

func main() {
	args := os.Args[1:]
	separator := -1
	for i, arg := range args {
		if arg == "--" {
			separator = i
			break
		}
	}
	if separator < 0 || separator == len(args)-1 {
		fmt.Fprint(os.Stderr, usageText)
		os.Exit(2)
	}

	options := flag.NewFlagSet("game-server-supervisor", flag.ContinueOnError)
	options.SetOutput(os.Stderr)
	sdkBaseURL := options.String("sdk-base-url", "", "Agones SDK REST base URL; empty enables direct mode")
	readyURL := options.String("ready-url", "", "explicit process-ready probe URL")
	drainURL := options.String("drain-url", "", "loopback drain URL")
	drainTokenEnv := options.String("drain-token-env", "COSMIC_CLASH_DRAIN_TOKEN", "environment variable containing the drain bearer token")
	transport := options.String("transport", "enet", "enet or steam_sdr")
	grace := options.Duration("drain-grace", supervisor.DefaultDrainGrace, "maximum graceful drain duration")
	controlPlaneURL := options.String("control-plane-url", "", "matchmaking control-plane base URL; empty skips process-ready registration entirely")
	workloadTokenPath := options.String("workload-token-path", "", "path to a projected workload service-account token, read fresh on every registration call; if unset, falls back to the cosmic-clash.io/workload-token annotation Agones applied to this GameServer at allocation time")
	serverIDEnv := options.String("server-id-env", "COSMIC_CLASH_SERVER_ID", "environment variable containing this GameServer's control-plane server ID (populate via the Kubernetes Downward API, fieldRef: metadata.name)")
	matchIDEnv := options.String("match-id-env", "COSMIC_CLASH_MATCH_ID", "environment variable containing the allocated match ID; if unset/empty, falls back to the cosmic-clash.io/match-id annotation on the allocated GameServer")
	protocolVersion := options.Int("protocol-version", 0, "protocol version reported at registration")
	imageDigestEnv := options.String("image-digest-env", "COSMIC_CLASH_IMAGE_DIGEST", "environment variable containing this build's sha256 image digest")
	assignmentReadyAttempts := options.Int("assignment-ready-attempts", 5, "retry attempts for assignment-ready registration after process-ready succeeds (a slow-to-propagate signed roster is not fatal)")
	assignmentReadyBackoff := options.Duration("assignment-ready-backoff", 2*time.Second, "delay between assignment-ready retry attempts")
	if err := options.Parse(args[:separator]); err != nil {
		os.Exit(2)
	}

	token := ""
	if *drainTokenEnv != "" {
		token = os.Getenv(*drainTokenEnv)
	}
	s, err := supervisor.New(supervisor.Config{
		Command:      args[separator+1:],
		SDKBaseURL:   *sdkBaseURL,
		ReadyURL:     *readyURL,
		DrainURL:     *drainURL,
		DrainToken:   token,
		Transport:    *transport,
		ReadyTimeout: 30 * time.Second,

		ControlPlaneURL:   *controlPlaneURL,
		WorkloadTokenPath: *workloadTokenPath,
		ServerID:          os.Getenv(*serverIDEnv),
		MatchID:           os.Getenv(*matchIDEnv),
		ProtocolVersion:   *protocolVersion,
		ImageDigest:       os.Getenv(*imageDigestEnv),

		AssignmentReadyAttempts: *assignmentReadyAttempts,
		AssignmentReadyBackoff:  *assignmentReadyBackoff,
	})
	if err != nil {
		fmt.Fprintf(os.Stderr, "game-server-supervisor: %v\n", err)
		os.Exit(2)
	}
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()
	if err := s.Run(ctx, *grace); err != nil {
		fmt.Fprintf(os.Stderr, "game-server-supervisor: %v\n", err)
		os.Exit(1)
	}
}