package main

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

	"tyto/internal/agent"
	"tyto/internal/api"
	"tyto/internal/config"
	"tyto/internal/server"
	"tyto/internal/sse"
)

func main() {
	cfg := config.Load()

	switch {
	case cfg.IsAgent():
		runAgent(cfg)
	case cfg.IsServer():
		runServer(cfg)
	default:
		runStandalone(cfg)
	}
}

// runStandalone starts Tyto in single-host monitoring mode.
// This is the default mode with no database or agent support.
func runStandalone(cfg *config.Config) {
	log.Printf("Starting Tyto in standalone mode on port %s", cfg.Port)
	log.Printf("Reading from: proc=%s, sys=%s", cfg.ProcPath, cfg.SysPath)
	log.Printf("Default refresh interval: %s", cfg.RefreshInterval)

	if cfg.AuthEnabled {
		log.Printf("Basic authentication enabled for user: %s", cfg.AuthUser)
	}

	if cfg.TLSEnabled {
		log.Printf("TLS enabled with cert: %s", cfg.TLSCertFile)
	}

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

	server := api.NewServer(cfg, broker)

	var err error
	if cfg.TLSEnabled {
		log.Printf("Starting HTTPS server on port %s", cfg.Port)
		err = server.RunTLS(cfg.TLSCertFile, cfg.TLSKeyFile)
	} else {
		err = server.Run()
	}

	if err != nil {
		log.Fatalf("Failed to start server: %v", err)
	}
}

// runServer starts Tyto in full server mode with database, agents, and auth.
func runServer(cfg *config.Config) {
	log.Printf("Starting Tyto in server mode on port %s", cfg.Port)
	log.Printf("gRPC port for agents: %d", cfg.Server.GRPCPort)
	log.Printf("Database: %s", cfg.Database.Type)

	// Set up signal handling
	_, cancel := context.WithCancel(context.Background())
	defer cancel()

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	// Initialize agent registry
	registryPath := "/var/lib/tyto/agents.json"
	if cfg.Database.Path != "" {
		registryPath = cfg.Database.Path + ".agents.json"
	}
	registry := server.NewRegistry(registryPath)
	log.Printf("Agent registry initialized: %s", registryPath)

	// Initialize Hub
	hubConfig := &server.HubConfig{
		RequireApproval: cfg.Server.Registration.RequireApproval,
		AutoApprove:     cfg.Server.Registration.AutoEnabled && !cfg.Server.Registration.RequireApproval,
	}
	hub := server.NewHub(registry, hubConfig)
	hub.Start()
	defer hub.Stop()
	log.Println("Agent hub started")

	// Initialize SSE bridge for multi-device streaming
	bridge := server.NewSSEBridge(hub)
	bridge.Start()
	defer bridge.Stop()

	// Initialize gRPC server for agent connections
	grpcServer, err := server.NewGRPCServer(hub, &cfg.Server)
	if err != nil {
		log.Fatalf("Failed to create gRPC server: %v", err)
	}

	// Start gRPC server in background
	go func() {
		log.Printf("Starting gRPC server on port %d", cfg.Server.GRPCPort)
		if err := grpcServer.Start(cfg.Server.GRPCPort); err != nil {
			log.Printf("gRPC server error: %v", err)
		}
	}()
	defer grpcServer.Stop()

	// Initialize SSE broker for local metrics (also runs in server mode)
	broker := sse.NewBroker(cfg)
	go broker.Run()

	// Initialize HTTP API server with agent management
	apiServer := api.NewServer(cfg, broker)

	// Add agent API routes
	agentAPI := api.NewAgentAPI(registry, hub)
	agentAPI.RegisterRoutes(apiServer.Router().Group("/api/v1"))

	// Start HTTP server in background
	go func() {
		var err error
		if cfg.TLSEnabled {
			log.Printf("Starting HTTPS server on port %s", cfg.Port)
			err = apiServer.RunTLS(cfg.TLSCertFile, cfg.TLSKeyFile)
		} else {
			log.Printf("Starting HTTP server on port %s", cfg.Port)
			err = apiServer.Run()
		}
		if err != nil {
			log.Printf("HTTP server error: %v", err)
		}
	}()

	// Wait for shutdown signal
	<-sigCh
	log.Println("Shutting down server...")
	cancel()
}

// runAgent starts Tyto as a lightweight agent that reports to a central server.
func runAgent(cfg *config.Config) {
	if cfg.Agent.ID == "" {
		log.Fatal("Agent ID is required in agent mode (set TYTO_AGENT_ID)")
	}
	if cfg.Agent.ServerURL == "" {
		log.Fatal("Server URL is required in agent mode (set TYTO_SERVER_URL)")
	}

	log.Printf("Starting Tyto agent '%s'", cfg.Agent.ID)
	log.Printf("Reporting to: %s", cfg.Agent.ServerURL)
	log.Printf("Collection interval: %s", cfg.Agent.Interval)

	// Set up signal handling
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	// Create agent
	a := agent.New(cfg)

	// Handle shutdown signal
	go func() {
		<-sigCh
		log.Println("Received shutdown signal, stopping agent...")
		a.Stop()
		cancel()
	}()

	// Run agent
	if err := a.Run(ctx); err != nil && err != context.Canceled {
		log.Fatalf("Agent error: %v", err)
	}

	log.Println("Agent stopped")
}