package weed_server

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/credential"
	"github.com/seaweedfs/seaweedfs/weed/stats"
	"golang.org/x/sync/singleflight"

	"google.golang.org/grpc"

	"github.com/seaweedfs/seaweedfs/weed/util/grace"

	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/util"
	util_http "github.com/seaweedfs/seaweedfs/weed/util/http"

	"github.com/seaweedfs/seaweedfs/weed/filer"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/arangodb"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/cassandra"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/cassandra2"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/elastic/v7"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/etcd"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/foundationdb"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/hbase"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/leveldb"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/leveldb2"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/leveldb3"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/mongodb"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/mysql"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/mysql2"
	"github.com/seaweedfs/seaweedfs/weed/filer/posixlock"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/postgres"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/postgres2"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/redis"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/redis2"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/redis3"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/sqlite"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/tarantool"
	_ "github.com/seaweedfs/seaweedfs/weed/filer/ydb"
	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/notification"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/aws_sqs"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/gocdk_pub_sub"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/google_pub_sub"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/kafka"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/log"
	_ "github.com/seaweedfs/seaweedfs/weed/notification/webhook"
	"github.com/seaweedfs/seaweedfs/weed/security"
)

type FilerOption struct {
	Masters                   *pb.ServerDiscovery
	FilerGroup                string
	Collection                string
	DefaultReplication        string
	DisableDirListing         bool
	MaxMB                     int
	DirListingLimit           int
	DataCenter                string
	Rack                      string
	DataNode                  string
	DefaultLevelDbDir         string
	DisableHttp               bool
	Host                      pb.ServerAddress
	recursiveDelete           bool
	Cipher                    bool
	SaveToFilerLimit          int64
	ConcurrentUploadLimit     int64
	ConcurrentFileUploadLimit int64
	ShowUIDirectoryDelete     bool
	DownloadMaxBytesPs        int64
	DiskType                  string
	AllowedOrigins            []string
	ExposeDirectoryData       bool
	TusBasePath               string
	TusMaxSize                int64
	TusSessionExpiry          time.Duration
	S3ConfigFile              string // optional path to static S3 identity config file
	CredentialManager         *credential.CredentialManager
}

type FilerServer struct {
	inFlightDataSize int64
	inFlightUploads  int64

	inFlightDataLimitCond *sync.Cond

	filer_pb.UnimplementedSeaweedFilerServer
	option         *FilerOption
	filer          *filer.Filer
	filerGuard     *security.Guard
	volumeGuard    *security.Guard
	grpcDialOption grpc.DialOption

	// metrics read from the master
	metricsAddress     string
	metricsIntervalSec int

	// track known metadata listeners
	knownListenersLock sync.Mutex
	knownListeners     map[int32]int32
	// live metadata subscribers (FUSE mounts, S3, peer filers, ...) keyed by
	// clientId, guarded by knownListenersLock. Exposed via ListMetadataSubscribers.
	subscribers map[int32]*metadataSubscriber

	// deduplicates concurrent remote object caching operations
	remoteCacheGroup singleflight.Group

	recentCopyRequestsMu sync.Mutex
	recentCopyRequests   map[string]recentCopyRequest

	// credential manager for IAM operations
	CredentialManager *credential.CredentialManager

	// mountPeerRegistry backs the MountRegister / MountList RPCs for peer
	// chunk sharing (tier 1). Always populated.
	mountPeerRegistry *filer.MountPeerRegistry

	// entryLockTable serializes mutations to the same entry path on this filer.
	// CreateEntry takes it today; UpdateEntry and DeleteEntry are intended to take
	// it too as their callers route a key's writes to this node, making it the
	// local serialization point for read-modify-write operations that replaces
	// the distributed lock for that key. Idle keys are evicted automatically, so
	// the table stays bounded.
	entryLockTable *util.LockTable[util.FullPath]

	// posixLocks is the in-memory authority for cross-mount POSIX advisory locks
	// on inodes this filer owns (per the route-by-key ring). Lock state is kept
	// here rather than in replicated metadata: it is transient coordination, so
	// keeping it off the meta-log avoids churn.
	posixLocks *posixlock.Manager
	// posixLockSweeperStop stops the lease-reaping sweeper goroutine on Shutdown.
	posixLockSweeperStop chan struct{}
	// posixLockReadyAt is the unix-nanos when this filer began serving POSIX
	// locks. For posixLockWarmup after it, the owner defers would-be grants while
	// mounts re-assert, so a (re)started owner does not double-grant from empty
	// state. Atomic so the handler reads it without locking; 0 means "not warming
	// up" (e.g. in tests).
	posixLockReadyAt atomic.Int64
}

func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption) (fs *FilerServer, err error) {

	v := util.GetViper()
	signingKey := v.GetString("jwt.filer_signing.key")
	v.SetDefault("jwt.filer_signing.expires_after_seconds", 10)
	expiresAfterSec := v.GetInt("jwt.filer_signing.expires_after_seconds")

	readSigningKey := v.GetString("jwt.filer_signing.read.key")
	v.SetDefault("jwt.filer_signing.read.expires_after_seconds", 60)
	readExpiresAfterSec := v.GetInt("jwt.filer_signing.read.expires_after_seconds")

	volumeSigningKey := v.GetString("jwt.signing.key")
	v.SetDefault("jwt.signing.expires_after_seconds", 10)
	volumeExpiresAfterSec := v.GetInt("jwt.signing.expires_after_seconds")

	volumeReadSigningKey := v.GetString("jwt.signing.read.key")
	v.SetDefault("jwt.signing.read.expires_after_seconds", 60)
	volumeReadExpiresAfterSec := v.GetInt("jwt.signing.read.expires_after_seconds")

	v.SetDefault("cors.allowed_origins.values", "*")

	allowedOrigins := v.GetString("cors.allowed_origins.values")
	domains := strings.Split(allowedOrigins, ",")
	option.AllowedOrigins = domains

	v.SetDefault("filer.expose_directory_metadata.enabled", true)
	returnDirMetadata := v.GetBool("filer.expose_directory_metadata.enabled")
	option.ExposeDirectoryData = returnDirMetadata

	fs = &FilerServer{
		option:                option,
		grpcDialOption:        security.LoadClientTLS(util.GetViper(), "grpc.filer"),
		knownListeners:        make(map[int32]int32),
		subscribers:           make(map[int32]*metadataSubscriber),
		inFlightDataLimitCond: sync.NewCond(new(sync.Mutex)),
		recentCopyRequests:    make(map[string]recentCopyRequest),
		CredentialManager:     option.CredentialManager,
		entryLockTable:        util.NewLockTable[util.FullPath](),
		posixLocks:            posixlock.NewManager(),
	}
	fs.startPosixLockSweeper()
	fs.mountPeerRegistry = filer.NewMountPeerRegistry()
	go fs.runMountPeerRegistrySweeper()

	option.Masters.RefreshBySrvIfAvailable()
	if len(option.Masters.GetInstances()) == 0 {
		glog.Fatal("master list is required!")
	}

	if !util.LoadConfiguration("filer", false) {
		v.SetDefault("leveldb2.enabled", true)
		v.SetDefault("leveldb2.dir", option.DefaultLevelDbDir)
		_, err := os.Stat(option.DefaultLevelDbDir)
		if os.IsNotExist(err) {
			os.MkdirAll(option.DefaultLevelDbDir, 0755)
		}
		glog.V(0).Infof("default to create filer store dir in %s", option.DefaultLevelDbDir)
	} else {
		glog.Warningf("skipping default store dir in %s", option.DefaultLevelDbDir)
	}
	util.LoadConfiguration("notification", false)

	v.SetDefault("filer.options.max_file_name_length", 255)
	maxFilenameLength := v.GetUint32("filer.options.max_file_name_length")
	glog.V(0).Infof("max_file_name_length %d", maxFilenameLength)
	fs.filer = filer.NewFiler(*option.Masters, fs.grpcDialOption, option.Host, option.FilerGroup, option.Collection, option.DefaultReplication, option.DataCenter, maxFilenameLength, nil)
	fs.filer.Cipher = option.Cipher
	fs.filer.DefaultDiskType = option.DiskType
	// we do not support IP whitelist right now https://github.com/seaweedfs/seaweedfs/issues/7094
	if v.GetString("guard.white_list") != "" {
		glog.Warningf("filer: guard.white_list is configured but the IP whitelist feature is currently disabled. See https://github.com/seaweedfs/seaweedfs/issues/7094")
	}
	fs.filerGuard = security.NewGuard([]string{}, signingKey, expiresAfterSec, readSigningKey, readExpiresAfterSec)
	fs.volumeGuard = security.NewGuard([]string{}, volumeSigningKey, volumeExpiresAfterSec, volumeReadSigningKey, volumeReadExpiresAfterSec)

	fs.checkWithMaster()

	go stats.LoopPushingMetric("filer", string(fs.option.Host), fs.metricsAddress, fs.metricsIntervalSec)
	go fs.filer.MasterClient.KeepConnectedToMaster(context.Background())

	fs.option.recursiveDelete = v.GetBool("filer.options.recursive_delete")
	v.SetDefault("filer.options.buckets_folder", "/buckets")
	fs.filer.DirBucketsPath = v.GetString("filer.options.buckets_folder")
	// TODO deprecated, will be removed after 2020-12-31
	// replaced by https://github.com/seaweedfs/seaweedfs/wiki/Path-Specific-Configuration
	// fs.filer.FsyncBuckets = v.GetStringSlice("filer.options.buckets_fsync")
	isFresh := fs.filer.LoadConfiguration(v)

	notification.LoadConfiguration(v, "notification.")

	handleStaticResources(defaultMux)
	if !option.DisableHttp {
		defaultMux.HandleFunc("/healthz", requestIDMiddleware(fs.filerHealthzHandler))
		defaultMux.HandleFunc("/readyz", requestIDMiddleware(fs.filerHealthzHandler))
		// TUS resumable upload protocol handler
		if option.TusBasePath != "" {
			// Normalize TusPath to always have a leading slash and no trailing slash
			if !strings.HasPrefix(option.TusBasePath, "/") {
				option.TusBasePath = "/" + option.TusBasePath
			}
			option.TusBasePath = strings.TrimRight(option.TusBasePath, "/")

			// Disallow using "/" as TUS base to avoid hijacking all filer routes
			if option.TusBasePath == "" {
				glog.Warningf("Invalid TUS base path; TUS disabled (must not be root '/')")
			} else {
				if option.TusMaxSize <= 0 {
					option.TusMaxSize = TusDefaultMaxSize
				}
				if option.TusSessionExpiry <= 0 {
					option.TusSessionExpiry = TusDefaultSessionExpiry
				}
				handlePath := option.TusBasePath + "/"
				defaultMux.HandleFunc(handlePath, fs.filerGuard.WhiteList(requestIDMiddleware(fs.tusHandler)))
				// Start background cleanup of expired TUS sessions (every hour)
				fs.StartTusSessionCleanup(1 * time.Hour)
			}
		}
		defaultMux.HandleFunc("/", fs.filerGuard.WhiteList(requestIDMiddleware(fs.filerHandler)))
	}
	if defaultMux != readonlyMux {
		handleStaticResources(readonlyMux)
		readonlyMux.HandleFunc("/healthz", requestIDMiddleware(fs.filerHealthzHandler))
		readonlyMux.HandleFunc("/readyz", requestIDMiddleware(fs.filerHealthzHandler))
		readonlyMux.HandleFunc("/", fs.filerGuard.WhiteList(requestIDMiddleware(fs.readonlyFilerHandler)))
	}

	existingNodes := fs.filer.ListExistingPeerUpdates(context.Background())
	startFromTime := time.Now().Add(-filer.LogFlushInterval)
	if isFresh {
		glog.V(0).Infof("%s bootstrap from peers %+v", option.Host, existingNodes)
		if err := fs.filer.MaybeBootstrapFromOnePeer(option.Host, existingNodes, startFromTime); err != nil {
			glog.Fatalf("%s bootstrap from %+v: %v", option.Host, existingNodes, err)
		}
	}
	v.SetDefault("filer.options.s3.empty_folder_cleanup_delay", "2m")
	if d, err := time.ParseDuration(v.GetString("filer.options.s3.empty_folder_cleanup_delay")); err == nil {
		fs.filer.EmptyFolderCleanupDelay = d
	}
	fs.filer.AggregateFromPeers(option.Host, existingNodes, startFromTime)

	fs.filer.LoadFilerConf()

	fs.filer.LoadRemoteStorageConfAndMapping()

	grace.OnReload(fs.Reload)

	fs.SetupDlmReplication()
	fs.filer.Dlm.LockRing.SetTakeSnapshotCallback(fs.OnDlmChangeSnapshot)

	if fs.CredentialManager != nil {
		fs.CredentialManager.SetFilerAddressFunc(func() pb.ServerAddress {
			return fs.option.Host
		}, fs.grpcDialOption)
		fs.CredentialManager.SetMasterClient(fs.filer.MasterClient, fs.grpcDialOption)
	}

	return fs, nil
}

func (fs *FilerServer) checkWithMaster() {

	isConnected := false
	for !isConnected {
		fs.option.Masters.RefreshBySrvIfAvailable()
		for _, master := range fs.option.Masters.GetInstances() {
			readErr := operation.WithMasterServerClient(context.Background(), false, master, fs.grpcDialOption, func(masterClient master_pb.SeaweedClient) error {
				resp, err := masterClient.GetMasterConfiguration(context.Background(), &master_pb.GetMasterConfigurationRequest{})
				if err != nil {
					return fmt.Errorf("get master %s configuration: %v", master, err)
				}
				fs.metricsAddress, fs.metricsIntervalSec = resp.MetricsAddress, int(resp.MetricsIntervalSeconds)
				return nil
			})
			if readErr == nil {
				isConnected = true
			} else {
				time.Sleep(7 * time.Second)
			}
		}
	}
}

// Shutdown gracefully shuts down the filer server by waiting for in-flight uploads to complete.
// This prevents data corruption when the process receives SIGTERM during active uploads.
func (fs *FilerServer) Shutdown() {
	glog.V(0).Infof("Shutting down filer")
	if fs.posixLockSweeperStop != nil {
		close(fs.posixLockSweeperStop)
	}
	fs.filer.Shutdown()
}

func (fs *FilerServer) Reload() {
	glog.V(0).Infoln("Reload filer server...")

	util.LoadConfiguration("security", false)
	v := util.GetViper()
	fs.filerGuard.UpdateSigningKeys(
		v.GetString("jwt.filer_signing.key"),
		v.GetInt("jwt.filer_signing.expires_after_seconds"),
		v.GetString("jwt.filer_signing.read.key"),
		v.GetInt("jwt.filer_signing.read.expires_after_seconds"),
	)
	fs.volumeGuard.UpdateSigningKeys(
		v.GetString("jwt.signing.key"),
		v.GetInt("jwt.signing.expires_after_seconds"),
		v.GetString("jwt.signing.read.key"),
		v.GetInt("jwt.signing.read.expires_after_seconds"),
	)
	util_http.ReloadJwtSigningReadConfig()
}