// local-mcp-go — localhost MCP server delivering user instructions to agents.
package main

import (
	"embed"
	"fmt"
	"io/fs"
	"log/slog"
	"net"
	"net/http"
	"os"
	"os/signal"
	"runtime"
	"syscall"

	"github.com/mark3labs/mcp-go/server"

	"github.com/local-mcp/local-mcp-go/internal/api"
	"github.com/local-mcp/local-mcp-go/internal/config"
	"github.com/local-mcp/local-mcp-go/internal/db"
	"github.com/local-mcp/local-mcp-go/internal/events"
	"github.com/local-mcp/local-mcp-go/internal/mcp"
	"github.com/local-mcp/local-mcp-go/internal/store"
)

//go:embed static
var staticFS embed.FS

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

	// Logger
	level := slog.LevelInfo
	switch cfg.LogLevel {
	case "DEBUG":
		level = slog.LevelDebug
	case "WARN", "WARNING":
		level = slog.LevelWarn
	case "ERROR":
		level = slog.LevelError
	}
	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: level})))

	// Database
	database, err := db.Open(cfg.DBPath)
	if err != nil {
		slog.Error("Failed to open database", "error", err)
		os.Exit(1)
	}
	defer database.Close()
	slog.Info("Database initialised", "path", cfg.DBPath)

	// Stores
	instStore := store.NewInstructionStore(database)
	settStore := store.NewSettingsStore(database)
	agentStore := store.NewAgentStore(database)

	// Event broker
	broker := events.NewBroker()

	// MCP server
	mcpHandler := mcp.New(instStore, settStore, agentStore, broker)
	sseServer := server.NewStreamableHTTPServer(
		mcpHandler.MCP,
		server.WithEndpointPath("/mcp"),
		server.WithStateLess(cfg.MCPStateless),
	)

	// HTTP router
	staticSubFS, _ := fs.Sub(staticFS, "static")

	router := api.NewRouter(
		api.Stores{
			Instructions: instStore,
			Settings:     settStore,
			Agents:       agentStore,
		},
		broker,
		cfg.APIToken,
		staticSubFS,
	)

	// Combined router: /mcp → MCP StreamableHTTP, /* → REST API
	mux := http.NewServeMux()
	mux.Handle("/mcp", sseServer)
	mux.Handle("/mcp/", http.StripPrefix("/mcp", sseServer))
	mux.Handle("/", router)

	// Server with auto port switching
	port := cfg.HTTPPort
	maxAttempts := 10
	var srv *http.Server
	var addr string

	for attempt := 0; attempt < maxAttempts; attempt++ {
		addr = fmt.Sprintf("%s:%s", cfg.Host, port)
		srv = &http.Server{Addr: addr, Handler: mux}

		// Try to listen
		ln, err := net.Listen("tcp", addr)
		if err == nil {
			ln.Close() // Close test listener
			break
		}

		// Port taken, try next
		portNum := 8000 + attempt
		port = fmt.Sprintf("%d", portNum+1)
		if attempt == maxAttempts-1 {
			slog.Error("Could not find available port", "tried", maxAttempts)
			os.Exit(1)
		}
	}

	if cfg.APIToken != "" {
		slog.Info("Token authentication enabled")
	} else {
		slog.Info("Token authentication disabled (set API_TOKEN to enable)")
	}

	httpURL := fmt.Sprintf("http://%s", addr)
	mcpURL := fmt.Sprintf("http://%s/mcp", addr)

	slog.Info("local-mcp-go ready",
		"version", config.AppVersion,
		"http", httpURL,
		"mcp", mcpURL,
		"stateless", cfg.MCPStateless,
	)

	// On Windows, show interactive prompt
	if runtime.GOOS == "windows" {
		fmt.Println()
		fmt.Println("╔══════════════════════════════════════════════════════════╗")
		fmt.Printf("║  local-mcp-go v%-6s ready on port %s%-14s║\n", config.AppVersion, port, "")
		fmt.Println("║                                                          ║")
		fmt.Printf("║  Web UI:  %-46s║\n", httpURL)
		fmt.Printf("║  MCP:     %-46s║\n", mcpURL)
		fmt.Println("║                                                          ║")
		fmt.Println("║  Press Ctrl+C to stop the server                         ║")
		fmt.Println("╚══════════════════════════════════════════════════════════╝")
		fmt.Println()
	}

	// Graceful shutdown on SIGINT / SIGTERM
	stop := make(chan os.Signal, 1)
	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
	go func() {
		<-stop
		fmt.Println()
		slog.Info("Shutting down gracefully...")
		_ = srv.Close()
	}()

	if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
		slog.Error("Server error", "error", err)
		os.Exit(1)
	}
}