package command

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
	"os"
	"runtime"
	"strings"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
	"google.golang.org/grpc/credentials/tls/certprovider"
	"google.golang.org/grpc/credentials/tls/certprovider/pemfile"
	"google.golang.org/grpc/reflection"

	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/s3_pb"
	"github.com/seaweedfs/seaweedfs/weed/security"

	"github.com/gorilla/mux"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/s3api"
	stats_collect "github.com/seaweedfs/seaweedfs/weed/stats"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

var (
	s3StandaloneOptions S3Options
)

type S3Options struct {
	filer                     *string
	bindIp                    *string
	port                      *int
	portHttps                 *int
	portGrpc                  *int
	config                    *string
	domainName                *string
	allowedOrigins            *string
	tlsPrivateKey             *string
	tlsCertificate            *string
	tlsCACertificate          *string
	tlsVerifyClientCert       *bool
	metricsHttpPort           *int
	allowEmptyFolder          *bool
	allowDeleteBucketNotEmpty *bool
	auditLogConfig            *string
	localFilerSocket          *string
	dataCenter                *string
	localSocket               *string
	certProvider              certprovider.Provider
}

func init() {
	cmdS3.Run = runS3 // break init cycle
	s3StandaloneOptions.filer = cmdS3.Flag.String("filer", "localhost:8888", "filer server address")
	s3StandaloneOptions.bindIp = cmdS3.Flag.String("ip.bind", "", "ip address to bind to. Default to localhost.")
	s3StandaloneOptions.port = cmdS3.Flag.Int("port", 8333, "s3 server http listen port")
	s3StandaloneOptions.portHttps = cmdS3.Flag.Int("port.https", 0, "s3 server https listen port")
	s3StandaloneOptions.portGrpc = cmdS3.Flag.Int("port.grpc", 0, "s3 server grpc listen port")
	s3StandaloneOptions.domainName = cmdS3.Flag.String("domainName", "", "suffix of the host name in comma separated list, {bucket}.{domainName}")
	s3StandaloneOptions.allowedOrigins = cmdS3.Flag.String("allowedOrigins", "*", "comma separated list of allowed origins")
	s3StandaloneOptions.dataCenter = cmdS3.Flag.String("dataCenter", "", "prefer to read and write to volumes in this data center")
	s3StandaloneOptions.config = cmdS3.Flag.String("config", "", "path to the config file")
	s3StandaloneOptions.auditLogConfig = cmdS3.Flag.String("auditLogConfig", "", "path to the audit log config file")
	s3StandaloneOptions.tlsPrivateKey = cmdS3.Flag.String("key.file", "", "path to the TLS private key file")
	s3StandaloneOptions.tlsCertificate = cmdS3.Flag.String("cert.file", "", "path to the TLS certificate file")
	s3StandaloneOptions.tlsCACertificate = cmdS3.Flag.String("cacert.file", "", "path to the TLS CA certificate file")
	s3StandaloneOptions.tlsVerifyClientCert = cmdS3.Flag.Bool("tlsVerifyClientCert", false, "whether to verify the client's certificate")
	s3StandaloneOptions.metricsHttpPort = cmdS3.Flag.Int("metricsPort", 0, "Prometheus metrics listen port")
	s3StandaloneOptions.allowEmptyFolder = cmdS3.Flag.Bool("allowEmptyFolder", true, "allow empty folders")
	s3StandaloneOptions.allowDeleteBucketNotEmpty = cmdS3.Flag.Bool("allowDeleteBucketNotEmpty", true, "allow recursive deleting all entries along with bucket")
	s3StandaloneOptions.localFilerSocket = cmdS3.Flag.String("localFilerSocket", "", "local filer socket path")
	s3StandaloneOptions.localSocket = cmdS3.Flag.String("localSocket", "", "default to /tmp/seaweedfs-s3-<port>.sock")
}

var cmdS3 = &Command{
	UsageLine: "s3 [-port=8333] [-filer=<ip:port>] [-config=</path/to/config.json>]",
	Short:     "start a s3 API compatible server that is backed by a filer",
	Long: `start a s3 API compatible server that is backed by a filer.

	By default, you can use any access key and secret key to access the S3 APIs.
	To enable credential based access, create a config.json file similar to this:

{
  "identities": [
    {
      "name": "anonymous",
      "actions": [
        "Read"
      ]
    },
    {
      "name": "some_admin_user",
      "credentials": [
        {
          "accessKey": "some_access_key1",
          "secretKey": "some_secret_key1"
        }
      ],
      "actions": [
        "Admin",
        "Read",
        "List",
        "Tagging",
        "Write"
      ]
    },
    {
      "name": "some_read_only_user",
      "credentials": [
        {
          "accessKey": "some_access_key2",
          "secretKey": "some_secret_key2"
        }
      ],
      "actions": [
        "Read"
      ]
    },
    {
      "name": "some_normal_user",
      "credentials": [
        {
          "accessKey": "some_access_key3",
          "secretKey": "some_secret_key3"
        }
      ],
      "actions": [
        "Read",
        "List",
        "Tagging",
        "Write"
      ]
    },
    {
      "name": "user_limited_to_bucket1",
      "credentials": [
        {
          "accessKey": "some_access_key4",
          "secretKey": "some_secret_key4"
        }
      ],
      "actions": [
        "Read:bucket1",
        "List:bucket1",
        "Tagging:bucket1",
        "Write:bucket1"
      ]
    }
  ]
}

`,
}

func runS3(cmd *Command, args []string) bool {

	util.LoadConfiguration("security", false)

	go stats_collect.StartMetricsServer(*s3StandaloneOptions.bindIp, *s3StandaloneOptions.metricsHttpPort)

	return s3StandaloneOptions.startS3Server()

}

// GetCertificateWithUpdate Auto refreshing TSL certificate
func (S3opt *S3Options) GetCertificateWithUpdate(*tls.ClientHelloInfo) (*tls.Certificate, error) {
	certs, err := S3opt.certProvider.KeyMaterial(context.Background())
	return &certs.Certs[0], err
}

func (s3opt *S3Options) startS3Server() bool {

	filerAddress := pb.ServerAddress(*s3opt.filer)

	filerBucketsPath := "/buckets"
	filerGroup := ""

	grpcDialOption := security.LoadClientTLS(util.GetViper(), "grpc.client")

	// metrics read from the filer
	var metricsAddress string
	var metricsIntervalSec int

	for {
		err := pb.WithGrpcFilerClient(false, 0, filerAddress, grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
			resp, err := client.GetFilerConfiguration(context.Background(), &filer_pb.GetFilerConfigurationRequest{})
			if err != nil {
				return fmt.Errorf("get filer %s configuration: %v", filerAddress, err)
			}
			filerBucketsPath = resp.DirBuckets
			filerGroup = resp.FilerGroup
			metricsAddress, metricsIntervalSec = resp.MetricsAddress, int(resp.MetricsIntervalSec)
			glog.V(0).Infof("S3 read filer buckets dir: %s", filerBucketsPath)
			return nil
		})
		if err != nil {
			glog.V(0).Infof("wait to connect to filer %s grpc address %s", *s3opt.filer, filerAddress.ToGrpcAddress())
			time.Sleep(time.Second)
		} else {
			glog.V(0).Infof("connected to filer %s grpc address %s", *s3opt.filer, filerAddress.ToGrpcAddress())
			break
		}
	}

	go stats_collect.LoopPushingMetric("s3", stats_collect.SourceName(uint32(*s3opt.port)), metricsAddress, metricsIntervalSec)

	router := mux.NewRouter().SkipClean(true)
	var localFilerSocket string
	if s3opt.localFilerSocket != nil {
		localFilerSocket = *s3opt.localFilerSocket
	}
	s3ApiServer, s3ApiServer_err := s3api.NewS3ApiServer(router, &s3api.S3ApiServerOption{
		Filer:                     filerAddress,
		Port:                      *s3opt.port,
		Config:                    *s3opt.config,
		DomainName:                *s3opt.domainName,
		AllowedOrigins:            strings.Split(*s3opt.allowedOrigins, ","),
		BucketsPath:               filerBucketsPath,
		GrpcDialOption:            grpcDialOption,
		AllowEmptyFolder:          *s3opt.allowEmptyFolder,
		AllowDeleteBucketNotEmpty: *s3opt.allowDeleteBucketNotEmpty,
		LocalFilerSocket:          localFilerSocket,
		DataCenter:                *s3opt.dataCenter,
		FilerGroup:                filerGroup,
	})
	if s3ApiServer_err != nil {
		glog.Fatalf("S3 API Server startup error: %v", s3ApiServer_err)
	}

	httpS := &http.Server{Handler: router}

	if *s3opt.portGrpc == 0 {
		*s3opt.portGrpc = 10000 + *s3opt.port
	}
	if *s3opt.bindIp == "" {
		*s3opt.bindIp = "localhost"
	}

	if runtime.GOOS != "windows" {
		localSocket := *s3opt.localSocket
		if localSocket == "" {
			localSocket = fmt.Sprintf("/tmp/seaweedfs-s3-%d.sock", *s3opt.port)
		}
		if err := os.Remove(localSocket); err != nil && !os.IsNotExist(err) {
			glog.Fatalf("Failed to remove %s, error: %s", localSocket, err.Error())
		}
		go func() {
			// start on local unix socket
			s3SocketListener, err := net.Listen("unix", localSocket)
			if err != nil {
				glog.Fatalf("Failed to listen on %s: %v", localSocket, err)
			}
			httpS.Serve(s3SocketListener)
		}()
	}

	listenAddress := fmt.Sprintf("%s:%d", *s3opt.bindIp, *s3opt.port)
	s3ApiListener, s3ApiLocalListener, err := util.NewIpAndLocalListeners(*s3opt.bindIp, *s3opt.port, time.Duration(10)*time.Second)
	if err != nil {
		glog.Fatalf("S3 API Server listener on %s error: %v", listenAddress, err)
	}

	if len(*s3opt.auditLogConfig) > 0 {
		s3err.InitAuditLog(*s3opt.auditLogConfig)
		if s3err.Logger != nil {
			defer s3err.Logger.Close()
		}
	}

	// starting grpc server
	grpcPort := *s3opt.portGrpc
	grpcL, grpcLocalL, err := util.NewIpAndLocalListeners(*s3opt.bindIp, grpcPort, 0)
	if err != nil {
		glog.Fatalf("s3 failed to listen on grpc port %d: %v", grpcPort, err)
	}
	grpcS := pb.NewGrpcServer(security.LoadServerTLS(util.GetViper(), "grpc.s3"))
	s3_pb.RegisterSeaweedS3Server(grpcS, s3ApiServer)
	reflection.Register(grpcS)
	if grpcLocalL != nil {
		go grpcS.Serve(grpcLocalL)
	}
	go grpcS.Serve(grpcL)

	if *s3opt.tlsPrivateKey != "" {
		pemfileOptions := pemfile.Options{
			CertFile:        *s3opt.tlsCertificate,
			KeyFile:         *s3opt.tlsPrivateKey,
			RefreshDuration: security.CredRefreshingInterval,
		}
		if s3opt.certProvider, err = pemfile.NewProvider(pemfileOptions); err != nil {
			glog.Fatalf("pemfile.NewProvider(%v) failed: %v", pemfileOptions, err)
		}

		caCertPool := x509.NewCertPool()
		if *s3Options.tlsCACertificate != "" {
			// load CA certificate file and add it to list of client CAs
			caCertFile, err := ioutil.ReadFile(*s3opt.tlsCACertificate)
			if err != nil {
				glog.Fatalf("error reading CA certificate: %v", err)
			}
			caCertPool.AppendCertsFromPEM(caCertFile)
		}

		clientAuth := tls.NoClientCert
		if *s3Options.tlsVerifyClientCert {
			clientAuth = tls.RequireAndVerifyClientCert
		}

		httpS.TLSConfig = &tls.Config{
			GetCertificate: s3opt.GetCertificateWithUpdate,
			ClientAuth:     clientAuth,
			ClientCAs:      caCertPool,
		}
		if *s3opt.portHttps == 0 {
			glog.V(0).Infof("Start Seaweed S3 API Server %s at https port %d", util.Version(), *s3opt.port)
			if s3ApiLocalListener != nil {
				go func() {
					if err = httpS.ServeTLS(s3ApiLocalListener, "", ""); err != nil {
						glog.Fatalf("S3 API Server Fail to serve: %v", err)
					}
				}()
			}
			if err = httpS.ServeTLS(s3ApiListener, "", ""); err != nil {
				glog.Fatalf("S3 API Server Fail to serve: %v", err)
			}
		} else {
			glog.V(0).Infof("Start Seaweed S3 API Server %s at https port %d", util.Version(), *s3opt.portHttps)
			s3ApiListenerHttps, s3ApiLocalListenerHttps, _ := util.NewIpAndLocalListeners(
				*s3opt.bindIp, *s3opt.portHttps, time.Duration(10)*time.Second)
			if s3ApiLocalListenerHttps != nil {
				go func() {
					if err = httpS.ServeTLS(s3ApiLocalListenerHttps, "", ""); err != nil {
						glog.Fatalf("S3 API Server Fail to serve: %v", err)
					}
				}()
			}
			go func() {
				if err = httpS.ServeTLS(s3ApiListenerHttps, "", ""); err != nil {
					glog.Fatalf("S3 API Server Fail to serve: %v", err)
				}
			}()
		}
	}
	if *s3opt.tlsPrivateKey == "" || *s3opt.portHttps > 0 {
		glog.V(0).Infof("Start Seaweed S3 API Server %s at http port %d", util.Version(), *s3opt.port)
		if s3ApiLocalListener != nil {
			go func() {
				if err = httpS.Serve(s3ApiLocalListener); err != nil {
					glog.Fatalf("S3 API Server Fail to serve: %v", err)
				}
			}()
		}
		if err = httpS.Serve(s3ApiListener); err != nil {
			glog.Fatalf("S3 API Server Fail to serve: %v", err)
		}
	}

	return true

}