// Command agent is the Pangolin node agent. It runs on every acceleration node,
// self-enrolls over mTLS, dials the control plane, applies the streamed command
// feed by managing the local sing-box user table, and reports heartbeat/usage.
//
// Configuration comes from flags or PANGOLIN_AGENT_* environment variables
// (cloud-init injects the latter). The node holds zero user identities on disk.
package main

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

	"github.com/wangjia/pangolin/server/internal/agentd"
)

func main() {
	cfg := agentd.Config{}
	var singboxUnit string

	flag.StringVar(&cfg.ControlPlaneAddr, "control-plane", env("PANGOLIN_AGENT_CONTROL_PLANE", ""), "control plane gRPC address host:port")
	flag.StringVar(&cfg.ServerName, "server-name", env("PANGOLIN_AGENT_SERVER_NAME", ""), "TLS SNI to validate (defaults to control-plane host)")
	flag.StringVar(&cfg.BootstrapToken, "bootstrap-token", env("PANGOLIN_AGENT_BOOTSTRAP_TOKEN", ""), "one-time enrollment token")
	flag.StringVar(&cfg.StateDir, "state-dir", env("PANGOLIN_AGENT_STATE_DIR", agentd.DefaultStateDir), "directory for node key/cert/ca/state")
	flag.StringVar(&cfg.SingboxConfigPath, "singbox-config", env("PANGOLIN_AGENT_SINGBOX_CONFIG", agentd.DefaultSingboxCfg), "path to rendered sing-box config")
	flag.StringVar(&cfg.DeriveKey, "derive-key", env("PANGOLIN_AGENT_DERIVE_KEY", ""), "Hy2 password derivation key")
	flag.StringVar(&cfg.AgentVersion, "agent-version", env("PANGOLIN_AGENT_VERSION", "dev"), "reported agent version")
	flag.StringVar(&singboxUnit, "singbox-unit", env("PANGOLIN_AGENT_SINGBOX_UNIT", "sing-box"), "systemd unit to restart on config change")
	flag.BoolVar(&cfg.Insecure, "insecure", env("PANGOLIN_AGENT_INSECURE", "") == "1", "dial without mTLS (dev only)")
	flag.Parse()

	if cfg.ControlPlaneAddr == "" {
		log.Fatal("agent: --control-plane (or PANGOLIN_AGENT_CONTROL_PLANE) is required")
	}

	agent := agentd.New(cfg, agentd.WithRestarter(agentd.SystemdRestarter{Unit: singboxUnit}))
	// 真实流量采集:读本地 v2ray_api StatsService 的 per-user 计数器,按 dp_uuid 精确上报。
	agent.UseV2RayUsage()

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

	log.Printf("[pangolin-agent] starting (control-plane=%s, version=%s)", cfg.ControlPlaneAddr, cfg.AgentVersion)
	start := time.Now()
	if err := agent.Run(ctx); err != nil {
		log.Fatalf("[pangolin-agent] exited after %s: %v", time.Since(start), err)
	}
	log.Printf("[pangolin-agent] shut down cleanly after %s", time.Since(start))
}

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