package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/signal"
	"runtime"
	"syscall"
	"time"

	"nexusrmm.local/agent/internal/collector"
	"nexusrmm.local/agent/internal/config"
	"nexusrmm.local/agent/internal/connection"
	"nexusrmm.local/agent/internal/executor"
	pb "nexusrmm.local/agent/pkg/proto"
)

var version = "dev"

func main() {
	log.Printf("NexusRMM Agent %s starting on %s/%s", version, runtime.GOOS, runtime.GOARCH)

	cfg, err := config.Load("nexus-agent.yaml")
	if err != nil {
		log.Fatalf("Config load error: %v", err)
	}

	client, err := connection.ConnectWithRetry(cfg.ServerAddress, 10)
	if err != nil {
		log.Fatalf("Failed to connect: %v", err)
	}
	defer client.Close()

	if cfg.AgentID == "" {
		hostname, _ := os.Hostname()
		metrics, _ := collector.Collect()
		mac, ip := "", ""
		if len(metrics.Networks) > 0 {
			mac = metrics.Networks[0].MAC
			ip = metrics.Networks[0].IPAddress
		}

		resp, err := client.Client.Enroll(context.Background(), &pb.EnrollRequest{
			Hostname:     hostname,
			OsType:       runtime.GOOS,
			OsVersion:    fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH),
			MacAddress:   mac,
			IpAddress:    ip,
			AgentVersion: version,
		})
		if err != nil {
			log.Fatalf("Enrollment failed: %v", err)
		}
		cfg.AgentID = resp.AgentId
		cfg.HeartbeatInterval = int(resp.HeartbeatInterval)
		if err := cfg.Save("nexus-agent.yaml"); err != nil {
			log.Printf("Warning: could not save config: %v", err)
		}
		log.Printf("Enrolled with ID: %s", cfg.AgentID)
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	ticker := time.NewTicker(time.Duration(cfg.HeartbeatInterval) * time.Second)
	defer ticker.Stop()

	log.Printf("Agent running. Heartbeat every %ds", cfg.HeartbeatInterval)
	doHeartbeat(ctx, client, cfg)

	for {
		select {
		case <-ticker.C:
			doHeartbeat(ctx, client, cfg)
		case <-sigCh:
			log.Println("Shutting down...")
			return
		case <-ctx.Done():
			return
		}
	}
}

func doHeartbeat(ctx context.Context, client *connection.GrpcClient, cfg *config.Config) {
	metrics, err := collector.Collect()
	if err != nil {
		log.Printf("Metric collection error: %v", err)
		return
	}

	req := &pb.HeartbeatRequest{
		AgentId: cfg.AgentID,
		Metrics: &pb.SystemMetrics{
			CpuUsagePercent:      metrics.CPUPercent,
			MemoryUsagePercent:   metrics.MemoryPercent,
			MemoryTotalBytes:     int64(metrics.MemoryTotal),
			MemoryAvailableBytes: int64(metrics.MemoryAvailable),
			UptimeSeconds:        metrics.UptimeSeconds,
		},
	}
	for _, d := range metrics.Disks {
		req.Metrics.Disks = append(req.Metrics.Disks, &pb.DiskInfo{
			MountPoint: d.MountPoint,
			TotalBytes: int64(d.Total),
			FreeBytes:  int64(d.Free),
			Filesystem: d.Filesystem,
		})
	}

	resp, err := client.Client.Heartbeat(ctx, req)
	if err != nil {
		log.Printf("Heartbeat error: %v", err)
		return
	}

	for _, cmd := range resp.PendingCommands {
		log.Printf("Executing command %s (type: %v)", cmd.CommandId, cmd.Type)
		go executeCommand(ctx, client, cfg.AgentID, cmd)
	}
}

func executeCommand(ctx context.Context, client *connection.GrpcClient, agentID string, cmd *pb.AgentCommand) {
	var result *executor.Result
	switch cmd.Type {
	case pb.CommandType_COMMAND_TYPE_SHELL:
		result = executor.Execute(ctx, cmd.Payload, 300)
	default:
		result = &executor.Result{ExitCode: -1, Stderr: fmt.Sprintf("unknown command type: %v", cmd.Type)}
	}

	if err := func() error {
		_, err := client.Client.ReportCommandResult(ctx, &pb.CommandResult{
			AgentId:   agentID,
			CommandId: cmd.CommandId,
			ExitCode:  int32(result.ExitCode),
			Stdout:    result.Stdout,
			Stderr:    result.Stderr,
			Success:   result.Success,
		})
		return err
	}(); err != nil {
		log.Printf("Failed to report result for %s: %v", cmd.CommandId, err)
	}
}