package tunnel

import (
	"crypto/tls"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/google/uuid"
	homedir "github.com/mitchellh/go-homedir"
	"github.com/pkg/errors"
	"github.com/rs/zerolog"
	"github.com/urfave/cli/v2"
	"golang.org/x/crypto/ssh/terminal"

	"github.com/cloudflare/cloudflared/cmd/cloudflared/buildinfo"
	"github.com/cloudflare/cloudflared/config"
	"github.com/cloudflare/cloudflared/connection"
	"github.com/cloudflare/cloudflared/edgediscovery"
	"github.com/cloudflare/cloudflared/h2mux"
	"github.com/cloudflare/cloudflared/ingress"
	"github.com/cloudflare/cloudflared/origin"
	"github.com/cloudflare/cloudflared/tlsconfig"
	tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
	"github.com/cloudflare/cloudflared/validation"
)

const LogFieldOriginCertPath = "originCertPath"

var (
	developerPortal = "https://developers.cloudflare.com/argo-tunnel"
	quickStartUrl   = developerPortal + "/quickstart/quickstart/"
	serviceUrl      = developerPortal + "/reference/service/"
	argumentsUrl    = developerPortal + "/reference/arguments/"

	LogFieldHostname = "hostname"
)

// returns the first path that contains a cert.pem file. If none of the DefaultConfigSearchDirectories
// contains a cert.pem file, return empty string
func findDefaultOriginCertPath() string {
	for _, defaultConfigDir := range config.DefaultConfigSearchDirectories() {
		originCertPath, _ := homedir.Expand(filepath.Join(defaultConfigDir, config.DefaultCredentialFile))
		if ok, _ := config.FileExists(originCertPath); ok {
			return originCertPath
		}
	}
	return ""
}

func generateRandomClientID(log *zerolog.Logger) (string, error) {
	u, err := uuid.NewRandom()
	if err != nil {
		log.Error().Msgf("couldn't create UUID for client ID %s", err)
		return "", err
	}
	return u.String(), nil
}

func logClientOptions(c *cli.Context, log *zerolog.Logger) {
	flags := make(map[string]interface{})
	for _, flag := range c.FlagNames() {
		flags[flag] = c.Generic(flag)
	}

	if len(flags) > 0 {
		log.Info().Msgf("Settings: %v", flags)
	}

	envs := make(map[string]string)
	// Find env variables for Argo Tunnel
	for _, env := range os.Environ() {
		// All Argo Tunnel env variables start with TUNNEL_
		if strings.Contains(env, "TUNNEL_") {
			vars := strings.Split(env, "=")
			if len(vars) == 2 {
				envs[vars[0]] = vars[1]
			}
		}
	}
	if len(envs) > 0 {
		log.Info().Msgf("Environmental variables %v", envs)
	}
}

func dnsProxyStandAlone(c *cli.Context, namedTunnel *connection.NamedTunnelConfig) bool {
	return c.IsSet("proxy-dns") && (!c.IsSet("hostname") && !c.IsSet("tag") && !c.IsSet("hello-world") && namedTunnel == nil)
}

func findOriginCert(originCertPath string, log *zerolog.Logger) (string, error) {
	if originCertPath == "" {
		log.Info().Msgf("Cannot determine default origin certificate path. No file %s in %v", config.DefaultCredentialFile, config.DefaultConfigSearchDirectories())
		if isRunningFromTerminal() {
			log.Error().Msgf("You need to specify the origin certificate path with --origincert option, or set TUNNEL_ORIGIN_CERT environment variable. See %s for more information.", argumentsUrl)
			return "", fmt.Errorf("client didn't specify origincert path when running from terminal")
		} else {
			log.Error().Msgf("You need to specify the origin certificate path by specifying the origincert option in the configuration file, or set TUNNEL_ORIGIN_CERT environment variable. See %s for more information.", serviceUrl)
			return "", fmt.Errorf("client didn't specify origincert path")
		}
	}
	var err error
	originCertPath, err = homedir.Expand(originCertPath)
	if err != nil {
		log.Err(err).Msgf("Cannot resolve origin certificate path")
		return "", fmt.Errorf("cannot resolve path %s", originCertPath)
	}
	// Check that the user has acquired a certificate using the login command
	ok, err := config.FileExists(originCertPath)
	if err != nil {
		log.Error().Err(err).Msgf("Cannot check if origin cert exists at path %s", originCertPath)
		return "", fmt.Errorf("cannot check if origin cert exists at path %s", originCertPath)
	}
	if !ok {
		log.Error().Msgf(`Cannot find a valid certificate for your origin at the path:

    %s

If the path above is wrong, specify the path with the -origincert option.
If you don't have a certificate signed by Cloudflare, run the command:

	%s login
`, originCertPath, os.Args[0])
		return "", fmt.Errorf("cannot find a valid certificate at the path %s", originCertPath)
	}

	return originCertPath, nil
}

func readOriginCert(originCertPath string) ([]byte, error) {
	// Easier to send the certificate as []byte via RPC than decoding it at this point
	originCert, err := ioutil.ReadFile(originCertPath)
	if err != nil {
		return nil, fmt.Errorf("cannot read %s to load origin certificate", originCertPath)
	}
	return originCert, nil
}

func getOriginCert(originCertPath string, log *zerolog.Logger) ([]byte, error) {
	if originCertPath, err := findOriginCert(originCertPath, log); err != nil {
		return nil, err
	} else {
		return readOriginCert(originCertPath)
	}
}

func prepareTunnelConfig(
	c *cli.Context,
	buildInfo *buildinfo.BuildInfo,
	version string,
	log, logTransport *zerolog.Logger,
	observer *connection.Observer,
	namedTunnel *connection.NamedTunnelConfig,
) (*origin.TunnelConfig, ingress.Ingress, error) {
	isNamedTunnel := namedTunnel != nil

	configHostname := c.String("hostname")
	hostname, err := validation.ValidateHostname(configHostname)
	if err != nil {
		log.Err(err).Str(LogFieldHostname, configHostname).Msg("Invalid hostname")
		return nil, ingress.Ingress{}, errors.Wrap(err, "Invalid hostname")
	}
	clientID := c.String("id")
	if !c.IsSet("id") {
		clientID, err = generateRandomClientID(log)
		if err != nil {
			return nil, ingress.Ingress{}, err
		}
	}

	tags, err := NewTagSliceFromCLI(c.StringSlice("tag"))
	if err != nil {
		log.Err(err).Msg("Tag parse failure")
		return nil, ingress.Ingress{}, errors.Wrap(err, "Tag parse failure")
	}

	tags = append(tags, tunnelpogs.Tag{Name: "ID", Value: clientID})

	var (
		ingressRules  ingress.Ingress
		classicTunnel *connection.ClassicTunnelConfig
	)
	cfg := config.GetConfiguration()
	if isNamedTunnel {
		clientUUID, err := uuid.NewRandom()
		if err != nil {
			return nil, ingress.Ingress{}, errors.Wrap(err, "can't generate connector UUID")
		}
		log.Info().Msgf("Generated Connector ID: %s", clientUUID)
		features := append(c.StringSlice("features"), origin.FeatureSerializedHeaders)
		namedTunnel.Client = tunnelpogs.ClientInfo{
			ClientID: clientUUID[:],
			Features: dedup(features),
			Version:  version,
			Arch:     buildInfo.OSArch(),
		}
		ingressRules, err = ingress.ParseIngress(cfg)
		if err != nil && err != ingress.ErrNoIngressRules {
			return nil, ingress.Ingress{}, err
		}
		if !ingressRules.IsEmpty() && c.IsSet("url") {
			return nil, ingress.Ingress{}, ingress.ErrURLIncompatibleWithIngress
		}
	} else {

		originCertPath := c.String("origincert")
		originCertLog := log.With().
			Str(LogFieldOriginCertPath, originCertPath).
			Logger()

		originCert, err := getOriginCert(originCertPath, &originCertLog)
		if err != nil {
			return nil, ingress.Ingress{}, errors.Wrap(err, "Error getting origin cert")
		}

		classicTunnel = &connection.ClassicTunnelConfig{
			Hostname:   hostname,
			OriginCert: originCert,
			// turn off use of reconnect token and auth refresh when using named tunnels
			UseReconnectToken: !isNamedTunnel && c.Bool("use-reconnect-token"),
		}
	}

	// Convert single-origin configuration into multi-origin configuration.
	if ingressRules.IsEmpty() {
		ingressRules, err = ingress.NewSingleOrigin(c, !isNamedTunnel)
		if err != nil {
			return nil, ingress.Ingress{}, err
		}
	}

	var warpRoutingService *ingress.WarpRoutingService
	warpRoutingEnabled := isWarpRoutingEnabled(cfg.WarpRouting, isNamedTunnel)
	if warpRoutingEnabled {
		warpRoutingService = ingress.NewWarpRoutingService()
		log.Info().Msgf("Warp-routing is enabled")
	}

	protocolSelector, err := connection.NewProtocolSelector(c.String("protocol"), warpRoutingEnabled, namedTunnel, edgediscovery.HTTP2Percentage, origin.ResolveTTL, log)
	if err != nil {
		return nil, ingress.Ingress{}, err
	}
	log.Info().Msgf("Initial protocol %s", protocolSelector.Current())

	edgeTLSConfigs := make(map[connection.Protocol]*tls.Config, len(connection.ProtocolList))
	for _, p := range connection.ProtocolList {
		tlsSettings := p.TLSSettings()
		if tlsSettings == nil {
			return nil, ingress.Ingress{}, fmt.Errorf("%s has unknown TLS settings", p)
		}
		edgeTLSConfig, err := tlsconfig.CreateTunnelConfig(c, tlsSettings.ServerName)
		if err != nil {
			return nil, ingress.Ingress{}, errors.Wrap(err, "unable to create TLS config to connect with edge")
		}
		if len(tlsSettings.NextProtos) > 0 {
			edgeTLSConfig.NextProtos = tlsSettings.NextProtos
		}
		edgeTLSConfigs[p] = edgeTLSConfig
	}

	originProxy := origin.NewOriginProxy(ingressRules, warpRoutingService, tags, log)
	gracePeriod, err := gracePeriod(c)
	if err != nil {
		return nil, ingress.Ingress{}, err
	}
	connectionConfig := &connection.Config{
		OriginProxy:     originProxy,
		GracePeriod:     gracePeriod,
		ReplaceExisting: c.Bool("force"),
	}
	muxerConfig := &connection.MuxerConfig{
		HeartbeatInterval: c.Duration("heartbeat-interval"),
		// Note TUN-3758 , we use Int because UInt is not supported with altsrc
		MaxHeartbeats: uint64(c.Int("heartbeat-count")),
		// Note TUN-3758 , we use Int because UInt is not supported with altsrc
		CompressionSetting: h2mux.CompressionSetting(uint64(c.Int("compression-quality"))),
		MetricsUpdateFreq:  c.Duration("metrics-update-freq"),
	}

	return &origin.TunnelConfig{
		ConnectionConfig: connectionConfig,
		OSArch:           buildInfo.OSArch(),
		ClientID:         clientID,
		EdgeAddrs:        c.StringSlice("edge"),
		Region:           c.String("region"),
		HAConnections:    c.Int("ha-connections"),
		IncidentLookup:   origin.NewIncidentLookup(),
		IsAutoupdated:    c.Bool("is-autoupdated"),
		LBPool:           c.String("lb-pool"),
		Tags:             tags,
		Log:              log,
		LogTransport:     logTransport,
		Observer:         observer,
		ReportedVersion:  version,
		// Note TUN-3758 , we use Int because UInt is not supported with altsrc
		Retries:          uint(c.Int("retries")),
		RunFromTerminal:  isRunningFromTerminal(),
		NamedTunnel:      namedTunnel,
		ClassicTunnel:    classicTunnel,
		MuxerConfig:      muxerConfig,
		ProtocolSelector: protocolSelector,
		EdgeTLSConfigs:   edgeTLSConfigs,
	}, ingressRules, nil
}

func gracePeriod(c *cli.Context) (time.Duration, error) {
	period := c.Duration("grace-period")
	if period > connection.MaxGracePeriod {
		return time.Duration(0), fmt.Errorf("grace-period must be equal or less than %v", connection.MaxGracePeriod)
	}
	return period, nil
}

func isWarpRoutingEnabled(warpConfig config.WarpRoutingConfig, isNamedTunnel bool) bool {
	return warpConfig.Enabled && isNamedTunnel
}

func isRunningFromTerminal() bool {
	return terminal.IsTerminal(int(os.Stdout.Fd()))
}

// Remove any duplicates from the slice
func dedup(slice []string) []string {

	// Convert the slice into a set
	set := make(map[string]bool, 0)
	for _, str := range slice {
		set[str] = true
	}

	// Convert the set back into a slice
	keys := make([]string, len(set))
	i := 0
	for str := range set {
		keys[i] = str
		i++
	}
	return keys
}