package server

import (
	"context"
	"errors"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/go-chi/render"
)

const indexHtmlPath = ".client/index.html"

// BootConfig represents the client configuration
type BootConfig struct {
	SpaceFolderPath string `json:"spaceFolderPath"`
	IndexPage       string `json:"indexPage"`
	ReadOnly        bool   `json:"readOnly"`

	// Whether or not the client should push logs to the server
	LogPush bool `json:"logPush"`

	// Encryption
	EnableClientEncryption bool `json:"enableClientEncryption"`

}

func Router(config *ServerConfig) chi.Router {
	r := chi.NewRouter()

	if config.EnableHTTPLogging {
		r.Use(middleware.Logger)
	}

	r.Use(middleware.RealIP)
	r.Use(middleware.Compress(5, "application/json", "text/markdown", "text/javascript", "text/html", "text/css", "text/plain"))

	// Expose space primitives and path to the request
	r.Use(spaceMiddleware(config))

	r.Use(httpStatsMiddleware(config))

	// Authentication middleware (applies to all routes after this point)
	r.Use(authMiddleware(config))

	routes := chi.NewRouter()

	// Authentication endpoints (must come before auth middleware)
	addAuthEndpoints(routes, config)

	routes.Get("/.ping", func(w http.ResponseWriter, r *http.Request) {
		spaceConfig := spaceConfigFromContext(r.Context())
		w.Header().Set("Cache-Control", "no-cache")
		w.Header().Set("X-Space-Path", spaceConfig.SpaceFolderPath)
		w.Header().Set("X-Server-Version", config.Version)
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("OK"))
	})

	// Mount filesystem routes under /.fs
	routes.Mount("/.fs", buildFsRoutes())

	// Config endpoint
	routes.Get("/.config", func(w http.ResponseWriter, r *http.Request) {
		spaceConfig := spaceConfigFromContext(r.Context())
		clientConfig := &BootConfig{
			SpaceFolderPath: spaceConfig.SpaceFolderPath,
			IndexPage:       spaceConfig.IndexPage,
			ReadOnly:        spaceConfig.ReadOnlyMode,
			LogPush:         spaceConfig.LogPush,
			// Client encryption is offered as an option when auth is enabled only
			EnableClientEncryption: spaceConfig.Auth != nil,
		}

		w.Header().Set("Cache-Control", "no-cache")
		render.JSON(w, r, clientConfig)
	})

	// Shell endpoint
	routes.Post("/.shell", handleShellEndpoint)

	// Log collection endpoint
	routes.Post("/.logs", handleLogsEndpoint)

	// Runtime API: Lua evaluation endpoints (via CDP to headless Chrome)
	bridge := config.RuntimeBridge
	if bridge == nil {
		bridge = NewRuntimeBridge(nil)
	}
	routes.Group(func(r chi.Router) {
		r.Use(func(next http.Handler) http.Handler {
			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				spaceConfig := spaceConfigFromContext(r.Context())
				if !spaceConfig.EnableRuntimeAPI {
					writeJSON(w, http.StatusServiceUnavailable, map[string]any{"error": "Runtime API is not enabled"})
					return
				}
				next.ServeHTTP(w, r)
			})
		})
		r.Post("/.runtime/lua", bridge.HandleLuaAPI)
		r.Post("/.runtime/lua_script", bridge.HandleLuaScriptAPI)
		r.Get("/.runtime/screenshot", bridge.HandleScreenshot)
		r.Get("/.runtime/logs", bridge.HandleConsoleLogs)
	})

	// Proxy endpoint
	routes.HandleFunc("/.proxy/*", proxyHandler)

	// Manifest endpoint
	routes.HandleFunc("/.client/manifest.json", manifestHandler)

	routes.HandleFunc("/*", func(w http.ResponseWriter, r *http.Request) {
		path := DecodeURLParam(r, "*")

		spaceConfig := spaceConfigFromContext(r.Context())

		// See if it's in the client bundle
		data, meta, err := config.ClientBundle.ReadFile(path)
		if err == nil {
			// File is in the bundle, let's serve it
			if r.Header.Get("If-Modified-Since") == utcDateString(meta.LastModified) {
				w.WriteHeader(304)
				return
			}
			w.Header().Set("Content-Type", meta.ContentType)
			w.Header().Set("Last-Modified", utcDateString(meta.LastModified))
			w.WriteHeader(200)
			w.Write(data)
			return
		}

		// TODO: handle request types
		ServerSideRender(config, spaceConfig, path, w, r)
	})

	if config.HostURLPrefix == "" {
		r.Mount("/", routes)
	} else {
		r.Mount(config.HostURLPrefix, routes)
	}
	return r
}

func RunServer(config *ServerConfig) error {
	// Set up headless config runtime values and create RuntimeBridge
	if config.HeadlessConfig != nil {
		config.HeadlessConfig.ServerURL = fmt.Sprintf("http://127.0.0.1:%d%s", config.Port, config.HostURLPrefix)

		// Generate a random token for headless browser authentication
		token, err := generateRandomToken(32)
		if err != nil {
			log.Printf("[Headless] Warning: failed to generate auth token: %v", err)
		} else {
			config.HeadlessToken = token
			config.HeadlessConfig.HeadlessToken = token
		}

		config.RuntimeBridge = NewRuntimeBridge(config.HeadlessConfig)
	} else {
		config.RuntimeBridge = NewRuntimeBridge(nil)
	}

	r := Router(config)

	addr := fmt.Sprintf("%s:%d", config.BindHost, config.Port)
	listener, err := net.Listen("tcp", addr)
	if err != nil {
		return fmt.Errorf("failed to listen on %s: %w", addr, err)
	}

	// Display the final server running message
	visibleHostname := config.BindHost
	if config.BindHost == "127.0.0.1" {
		visibleHostname = "localhost"
	}
	log.Printf("SilverBullet is now running: http://%s:%d", visibleHostname, config.Port)

	server := &http.Server{
		Handler: r,
	}

	shutdownChannel := make(chan bool, 1)

	go func() {
		if err := server.Serve(listener); !errors.Is(err, http.ErrServerClosed) {
			log.Fatalf("HTTP server error: %v", err)
		}
		log.Println("Stopped serving new connections.")
		shutdownChannel <- true
	}()

	go runMetricsServer(config)

	signalChannel := make(chan os.Signal, 1)
	signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM)
	// Block on incoming signals.
	s := <-signalChannel
	log.Println("Received signal:", s)

	// Stop headless browser (if running) before server shutdown
	config.RuntimeBridge.Stop()

	shutdownCtx, shutdownRelease := context.WithTimeout(context.Background(), 10*time.Second)
	defer shutdownRelease()

	if err := server.Shutdown(shutdownCtx); err != nil {
		log.Fatalf("HTTP shutdown error: %v", err)
	}
	<-shutdownChannel
	log.Println("Graceful shutdown complete.")
	return nil
}