package cmd

import (
	"crypto/tls"
	"errors"
	"fmt"
	log2 "log"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"

	"github.com/NYTimes/logrotate"
	"github.com/apex/log"
	"github.com/apex/log/handlers/multi"
	"github.com/docker/docker/client"
	"github.com/gammazero/workerpool"
	"github.com/mitchellh/colorstring"
	"github.com/pkg/profile"
	"github.com/pterodactyl/wings/config"
	"github.com/pterodactyl/wings/environment"
	"github.com/pterodactyl/wings/loggers/cli"
	"github.com/pterodactyl/wings/panelapi"
	"github.com/pterodactyl/wings/router"
	"github.com/pterodactyl/wings/server"
	"github.com/pterodactyl/wings/sftp"
	"github.com/pterodactyl/wings/system"
	"github.com/spf13/cobra"
	"golang.org/x/crypto/acme"
	"golang.org/x/crypto/acme/autocert"
)

var (
	configPath = config.DefaultLocation
	debug      = false
)

var rootCommand = &cobra.Command{
	Use:   "wings",
	Short: "Runs the API server allowing programatic control of game servers for Pterodactyl Panel.",
	PreRun: func(cmd *cobra.Command, args []string) {
		if tls, _ := cmd.Flags().GetBool("auto-tls"); tls {
			if host, _ := cmd.Flags().GetString("tls-hostname"); host == "" {
				fmt.Println("A TLS hostname must be provided when running wings with automatic TLS, e.g.:\n\n    ./wings --auto-tls --tls-hostname my.example.com")
				os.Exit(1)
			}
		}
	},
	Run: rootCmdRun,
}

var versionCommand = &cobra.Command{
	Use:   "version",
	Short: "Prints the current executable version and exits.",
	Run: func(cmd *cobra.Command, _ []string) {
		fmt.Printf("wings v%s\nCopyright © 2018 - 2021 Dane Everitt & Contributors\n", system.Version)
	},
}

func Execute() {
	if err := rootCommand.Execute(); err != nil {
		log2.Fatalf("failed to execute command: %s", err)
	}
}

func init() {
	rootCommand.PersistentFlags().StringVar(&configPath, "config", config.DefaultLocation, "set the location for the configuration file")
	rootCommand.PersistentFlags().BoolVar(&debug, "debug", false, "pass in order to run wings in debug mode")

	// Flags specifically used when running the API.
	rootCommand.Flags().String("profiler", "", "the profiler to run for this instance")
	rootCommand.Flags().Bool("auto-tls", false, "pass in order to have wings generate and manage it's own SSL certificates using Let's Encrypt")
	rootCommand.Flags().String("tls-hostname", "", "required with --auto-tls, the FQDN for the generated SSL certificate")
	rootCommand.Flags().Bool("ignore-certificate-errors", false, "ignore certificate verification errors when executing API calls")

	rootCommand.AddCommand(versionCommand)
	rootCommand.AddCommand(configureCmd)
	rootCommand.AddCommand(diagnosticsCmd)
}

// Get the configuration path based on the arguments provided.
func readConfiguration() (*config.Configuration, error) {
	p := configPath
	if !strings.HasPrefix(p, "/") {
		d, err := os.Getwd()
		if err != nil {
			return nil, err
		}

		p = path.Clean(path.Join(d, configPath))
	}

	if s, err := os.Stat(p); err != nil {
		return nil, err
	} else if s.IsDir() {
		return nil, errors.New("cannot use directory as configuration file path")
	}

	return config.ReadConfiguration(p)
}

func rootCmdRun(cmd *cobra.Command, _ []string) {
	switch cmd.Flag("profiler").Value.String() {
	case "cpu":
		defer profile.Start(profile.CPUProfile).Stop()
	case "mem":
		defer profile.Start(profile.MemProfile).Stop()
	case "alloc":
		defer profile.Start(profile.MemProfile, profile.MemProfileAllocs()).Stop()
	case "heap":
		defer profile.Start(profile.MemProfile, profile.MemProfileHeap()).Stop()
	case "routines":
		defer profile.Start(profile.GoroutineProfile).Stop()
	case "mutex":
		defer profile.Start(profile.MutexProfile).Stop()
	case "threads":
		defer profile.Start(profile.ThreadcreationProfile).Stop()
	case "block":
		defer profile.Start(profile.BlockProfile).Stop()
	}

	// Only attempt configuration file relocation if a custom location has not
	// been specified in the command startup.
	if configPath == config.DefaultLocation {
		if err := RelocateConfiguration(); err != nil {
			if errors.Is(err, os.ErrNotExist) {
				exitWithConfigurationNotice()
			}
			panic(err)
		}
	}

	c, err := readConfiguration()
	if err != nil {
		panic(err)
	}

	if debug {
		c.Debug = true
	}

	printLogo()
	if err := configureLogging(c.System.LogDirectory, c.Debug); err != nil {
		panic(err)
	}

	log.WithField("path", c.GetPath()).Info("loading configuration from path")
	if c.Debug {
		log.Debug("running in debug mode")
	}

	if ok, _ := cmd.Flags().GetBool("ignore-certificate-errors"); ok {
		log.Warn("running with --ignore-certificate-errors: TLS certificate host chains and name will not be verified")
		http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{
			InsecureSkipVerify: true,
		}
	}

	config.Set(c)
	config.SetDebugViaFlag(debug)

	if err := c.System.ConfigureTimezone(); err != nil {
		log.WithField("error", err).Fatal("failed to detect system timezone or use supplied configuration value")
		return
	}

	log.WithField("timezone", c.System.Timezone).Info("configured wings with system timezone")

	if err := c.System.ConfigureDirectories(); err != nil {
		log.WithField("error", err).Fatal("failed to configure system directories for pterodactyl")
		return
	}

	if err := c.System.EnableLogRotation(); err != nil {
		log.WithField("error", err).Fatal("failed to configure log rotation on the system")
		return
	}

	log.WithField("username", c.System.Username).Info("checking for pterodactyl system user")
	if su, err := c.EnsurePterodactylUser(); err != nil {
		log.WithField("error", err).Fatal("failed to create pterodactyl system user")
		return
	} else {
		log.WithFields(log.Fields{
			"username": su.Username,
			"uid":      su.Uid,
			"gid":      su.Gid,
		}).Info("configured system user successfully")
	}

	panelClient := panelapi.CreateClient(
		config.Get().PanelLocation,
		config.Get().AuthenticationTokenId,
		config.Get().AuthenticationToken,
		panelapi.WithTimeout(time.Second*time.Duration(config.Get().RemoteQuery.Timeout)),
	)
	_ = panelClient

	serverManager := server.NewManager(panelClient)

	if err := serverManager.Initialize(int(c.RemoteQuery.BootServersPerPage)); err != nil {
		log.WithField("error", err).Fatal("failed to load server configurations")
		return
	}

	if err := environment.ConfigureDocker(&c.Docker); err != nil {
		log.WithField("error", err).Fatal("failed to configure docker environment")
		return
	}

	if err := c.WriteToDisk(); err != nil {
		log.WithField("error", err).Error("failed to save configuration to disk")
	}

	// Just for some nice log output.
	for _, s := range serverManager.GetAll() {
		log.WithField("server", s.Id()).Info("loaded configuration for server")
	}

	states, err := server.CachedServerStates()
	if err != nil {
		log.WithField("error", err).Error("failed to retrieve locally cached server states from disk, assuming all servers in offline state")
	}

	// Create a new workerpool that limits us to 4 servers being bootstrapped at a time
	// on Wings. This allows us to ensure the environment exists, write configurations,
	// and reboot processes without causing a slow-down due to sequential booting.
	pool := workerpool.New(4)

	for _, serv := range serverManager.GetAll() {
		s := serv

		pool.Submit(func() {
			s.Log().Info("configuring server environment and restoring to previous state")

			var st string
			if state, exists := states[s.Id()]; exists {
				st = state
			}

			r, err := s.Environment.IsRunning()
			// We ignore missing containers because we don't want to actually block booting of wings at this
			// point. If we didn't do this and you pruned all of the images and then started wings you could
			// end up waiting a long period of time for all of the images to be re-pulled on Wings boot rather
			// than when the server itself is started.
			if err != nil && !client.IsErrNotFound(err) {
				s.Log().WithField("error", err).Error("error checking server environment status")
			}

			// Check if the server was previously running. If so, attempt to start the server now so that Wings
			// can pick up where it left off. If the environment does not exist at all, just create it and then allow
			// the normal flow to execute.
			//
			// This does mean that booting wings after a catastrophic machine crash and wiping out the Docker images
			// as a result will result in a slow boot.
			if !r && (st == environment.ProcessRunningState || st == environment.ProcessStartingState) {
				if err := s.HandlePowerAction(server.PowerActionStart); err != nil {
					s.Log().WithField("error", err).Warn("failed to return server to running state")
				}
			} else if r || (!r && s.IsRunning()) {
				// If the server is currently running on Docker, mark the process as being in that state.
				// We never want to stop an instance that is currently running external from Wings since
				// that is a good way of keeping things running even if Wings gets in a very corrupted state.
				//
				// This will also validate that a server process is running if the last tracked state we have
				// is that it was running, but we see that the container process is not currently running.
				s.Log().Info("detected server is running, re-attaching to process...")

				s.Environment.SetState(environment.ProcessRunningState)
				if err := s.Environment.Attach(); err != nil {
					s.Log().WithField("error", err).Warn("failed to attach to running server environment")
				}
			} else {
				// At this point we've determined that the server should indeed be in an offline state, so we'll
				// make a call to set that state just to ensure we don't ever accidentally end up with some invalid
				// state being tracked.
				s.Environment.SetState(environment.ProcessOfflineState)
			}
		})
	}

	// Wait until all of the servers are ready to go before we fire up the SFTP and HTTP servers.
	pool.StopWait()

	// Initialize the SFTP server.
	if err := sftp.Initialize(c.System); err != nil {
		log.WithError(err).Fatal("failed to initialize the sftp server")
		return
	}

	// Ensure the archive directory exists.
	if err := os.MkdirAll(c.System.ArchiveDirectory, 0755); err != nil {
		log.WithField("error", err).Error("failed to create archive directory")
	}

	// Ensure the backup directory exists.
	if err := os.MkdirAll(c.System.BackupDirectory, 0755); err != nil {
		log.WithField("error", err).Error("failed to create backup directory")
	}

	autotls, _ := cmd.Flags().GetBool("auto-tls")
	tlshostname, _ := cmd.Flags().GetString("tls-hostname")
	if autotls && tlshostname == "" {
		autotls = false
	}

	log.WithFields(log.Fields{
		"use_ssl":      c.Api.Ssl.Enabled,
		"use_auto_tls": autotls,
		"host_address": c.Api.Host,
		"host_port":    c.Api.Port,
	}).Info("configuring internal webserver")

	// Configure the router.
	r := router.Configure(serverManager)

	s := &http.Server{
		Addr:    fmt.Sprintf("%s:%d", c.Api.Host, c.Api.Port),
		Handler: r,
		TLSConfig: &tls.Config{
			NextProtos: []string{"h2", "http/1.1"},
			// @see https://blog.cloudflare.com/exposing-go-on-the-internet
			CipherSuites: []uint16{
				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
				tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
			},
			PreferServerCipherSuites: true,
			MinVersion:               tls.VersionTLS12,
			MaxVersion:               tls.VersionTLS13,
			CurvePreferences:         []tls.CurveID{tls.X25519, tls.CurveP256},
		},
	}

	// Check if the server should run with TLS but using autocert.
	if autotls {
		m := autocert.Manager{
			Prompt:     autocert.AcceptTOS,
			Cache:      autocert.DirCache(path.Join(c.System.RootDirectory, "/.tls-cache")),
			HostPolicy: autocert.HostWhitelist(tlshostname),
		}

		log.WithField("hostname", tlshostname).
			Info("webserver is now listening with auto-TLS enabled; certificates will be automatically generated by Let's Encrypt")

		// Hook autocert into the main http server.
		s.TLSConfig.GetCertificate = m.GetCertificate
		s.TLSConfig.NextProtos = append(s.TLSConfig.NextProtos, acme.ALPNProto) // enable tls-alpn ACME challenges

		// Start the autocert server.
		go func() {
			if err := http.ListenAndServe(":http", m.HTTPHandler(nil)); err != nil {
				log.WithError(err).Error("failed to serve autocert http server")
			}
		}()

		// Start the main http server with TLS using autocert.
		if err := s.ListenAndServeTLS("", ""); err != nil {
			log.WithFields(log.Fields{"auto_tls": true, "tls_hostname": tlshostname, "error": err}).
				Fatal("failed to configure HTTP server using auto-tls")
		}

		return
	}

	// Check if main http server should run with TLS.
	if c.Api.Ssl.Enabled {
		if err := s.ListenAndServeTLS(strings.ToLower(c.Api.Ssl.CertificateFile), strings.ToLower(c.Api.Ssl.KeyFile)); err != nil {
			log.WithFields(log.Fields{"auto_tls": false, "error": err}).Fatal("failed to configure HTTPS server")
		}
		return
	}

	// Run the main http server without TLS.
	s.TLSConfig = nil
	if err := s.ListenAndServe(); err != nil {
		log.WithField("error", err).Fatal("failed to configure HTTP server")
	}

	// Cancel the context on all of the running servers at this point, even though the
	// program is just shutting down.
	for _, s := range serverManager.GetAll() {
		s.CtxCancel()
	}
}

// Configures the global logger for Zap so that we can call it from any location
// in the code without having to pass around a logger instance.
func configureLogging(logDir string, debug bool) error {
	if err := os.MkdirAll(path.Join(logDir, "/install"), 0700); err != nil {
		return err
	}

	p := filepath.Join(logDir, "/wings.log")
	w, err := logrotate.NewFile(p)
	if err != nil {
		return err
	}

	log.SetLevel(log.InfoLevel)
	if debug {
		log.SetLevel(log.DebugLevel)
	}

	log.SetHandler(multi.New(cli.Default, cli.New(w.File, false)))
	log.WithField("path", p).Info("writing log files to disk")

	return nil
}

// Prints the wings logo, nothing special here!
func printLogo() {
	fmt.Printf(colorstring.Color(`
                     ____
__ [blue][bold]Pterodactyl[reset] _____/___/_______ _______ ______
\_____\    \/\/    /   /       /  __   /   ___/
   \___\          /   /   /   /  /_/  /___   /
        \___/\___/___/___/___/___    /______/
                            /_______/ [bold]%s[reset]

Copyright © 2018 - 2021 Dane Everitt & Contributors

Website:  https://pterodactyl.io
 Source:  https://github.com/pterodactyl/wings
License:  https://github.com/pterodactyl/wings/blob/develop/LICENSE

This software is made available under the terms of the MIT license.
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.%s`), system.Version, "\n\n")
}

func exitWithConfigurationNotice() {
	fmt.Print(colorstring.Color(`
[_red_][white][bold]Error: Configuration File Not Found[reset]

Wings was not able to locate your configuration file, and therefore is not
able to complete its boot process.

Please ensure you have copied your instance configuration file into
the default location, or have provided the --config flag to use a
custom location.

Default Location: /etc/pterodactyl/config.yml

[yellow]This is not a bug with this software. Please do not make a bug report
for this issue, it will be closed.[reset]

`))
	os.Exit(1)
}