package weed_server

import (
	"context"
	"fmt"
	"math/rand/v2"
	"strings"
	"sync"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/stats"

	"github.com/seaweedfs/seaweedfs/weed/topology"

	"github.com/seaweedfs/raft"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/security"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/storage/super_block"
	"github.com/seaweedfs/seaweedfs/weed/storage/types"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

const (
	volumeGrowStepCount = 2
)

func (ms *MasterServer) DoAutomaticVolumeGrow(req *topology.VolumeGrowRequest) {
	if ms.option.VolumeGrowthDisabled {
		glog.V(1).Infof("automatic volume grow disabled")
		return
	}
	glog.V(1).Infoln("starting automatic volume grow")
	start := time.Now()
	newVidLocations, err := ms.vg.AutomaticGrowByType(req.Option, ms.grpcDialOption, ms.Topo, req.Count)
	glog.V(1).Infoln("finished automatic volume grow, cost ", time.Now().Sub(start))
	if err != nil {
		glog.V(1).Infof("automatic volume grow failed: %+v", err)
		return
	}
	ms.broadcastVolumeLocationsToClients(newVidLocations)
}

func (ms *MasterServer) ProcessGrowRequest() {
	go func() {
		ctx := context.Background()
		firstRun := true
		for {
			if firstRun {
				firstRun = false
			} else {
				time.Sleep(5*time.Minute + time.Duration(30*rand.Float32())*time.Second)
			}
			if !ms.Topo.IsLeader() {
				continue
			}
			dcs := ms.Topo.ListDCAndRacks()
			for _, vlc := range ms.Topo.ListVolumeLayoutCollections() {
				var err error
				vl := vlc.VolumeLayout
				lastGrowCount := vl.GetLastGrowCount()
				if vl.HasGrowRequest() {
					continue
				}
				writable, crowded := vl.GetWritableVolumeCount()
				mustGrow := int(lastGrowCount) - writable
				vgr := vlc.ToVolumeGrowRequest()
				underReplicated := vl.CountUnderReplicatedVolumes()
				stats.MasterVolumeLayoutWritable.WithLabelValues(vlc.Collection, vgr.DiskType, vgr.Replication, vgr.Ttl).Set(float64(writable))
				stats.MasterVolumeLayoutCrowded.WithLabelValues(vlc.Collection, vgr.DiskType, vgr.Replication, vgr.Ttl).Set(float64(crowded))
				stats.MasterUnderReplicatedVolumes.WithLabelValues(vlc.Collection, vgr.DiskType, vgr.Replication, vgr.Ttl).Set(float64(underReplicated))

				switch {
				case mustGrow > 0:
					if rp, rpErr := super_block.NewReplicaPlacementFromString(vgr.Replication); rpErr != nil {
						glog.V(0).Infof("failed to parse replica placement %s: %v", vgr.Replication, rpErr)
					} else {
						vgr.WritableVolumeCount = uint32(mustGrow)
						if ms.Topo.AvailableSpaceFor(&topology.VolumeGrowOption{DiskType: types.ToDiskType(vgr.DiskType)}) >= int64(vgr.WritableVolumeCount*uint32(rp.GetCopyCount())) {
							_, err = ms.VolumeGrow(ctx, vgr)
						}
					}
				case lastGrowCount > 0 && writable < int(lastGrowCount*2) && float64(crowded+volumeGrowStepCount) > float64(writable)*topology.VolumeGrowStrategy.Threshold:
					vgr.WritableVolumeCount = volumeGrowStepCount
					_, err = ms.VolumeGrow(ctx, vgr)
				}
				if err != nil {
					glog.V(0).Infof("volume grow request failed: %+v", err)
				}
				for _, plan := range vl.PlanRackAwareGrowth(dcs, lastGrowCount, volumeGrowStepCount) {
					vgr.DataCenter = plan.DataCenter
					vgr.Rack = plan.Rack
					vgr.WritableVolumeCount = plan.WritableVolumeCount
					if _, err = ms.VolumeGrow(ctx, vgr); err != nil {
						glog.V(0).Infof("volume grow request for dc:%s rack:%s failed: %+v", plan.DataCenter, plan.Rack, err)
					}
				}
			}
		}
	}()
	go func() {
		filter := sync.Map{}
		for {
			req, ok := <-ms.volumeGrowthRequestChan
			if !ok {
				break
			}

			option := req.Option
			vl := ms.Topo.GetVolumeLayout(option.Collection, option.ReplicaPlacement, option.Ttl, option.DiskType)

			if !ms.Topo.IsLeader() {
				//discard buffered requests
				time.Sleep(time.Second * 1)
				vl.DoneGrowRequest()
				continue
			}

			// filter out identical requests being processed
			found := false
			filter.Range(func(k, v interface{}) bool {
				existingReq := k.(*topology.VolumeGrowRequest)
				if existingReq.Equals(req) {
					found = true
				}
				return !found
			})

			// not atomic but it's okay
			if found || (!req.Force && !vl.ShouldGrowVolumes()) {
				glog.V(4).Infoln("discard volume grow request")
				time.Sleep(time.Millisecond * 211)
				vl.DoneGrowRequest()
				continue
			}

			filter.Store(req, nil)
			// we have lock called inside vg
			glog.V(0).Infof("volume grow %+v", req)
			go func(req *topology.VolumeGrowRequest, vl *topology.VolumeLayout) {
				// defer so a panic can't strand growRequest.
				defer filter.Delete(req)
				defer vl.DoneGrowRequest()
				ms.DoAutomaticVolumeGrow(req)
			}(req, vl)
		}
	}()
}

// LookupVolume resolves one or more volume ids (or "<vid>,<cookie>" file ids)
// to their current replica locations on the volume servers. Each returned
// entry carries DataInRemote per replica so the caller can prefer a local
// replica; entries carrying a file id also receive a freshly generated read
// jwt the volume server will accept.
func (ms *MasterServer) LookupVolume(ctx context.Context, req *master_pb.LookupVolumeRequest) (*master_pb.LookupVolumeResponse, error) {

	resp := &master_pb.LookupVolumeResponse{}
	volumeLocations := ms.lookupVolumeId(req.VolumeOrFileIds, req.Collection)

	notFoundCount := 0
	for _, volumeOrFileId := range req.VolumeOrFileIds {
		vid := volumeOrFileId
		commaSep := strings.Index(vid, ",")
		if commaSep > 0 {
			vid = vid[0:commaSep]
		}
		if result, found := volumeLocations[vid]; found {
			var locations []*master_pb.Location
			for _, loc := range result.Locations {
				locations = append(locations, &master_pb.Location{
					Url:          loc.Url,
					PublicUrl:    loc.PublicUrl,
					DataCenter:   loc.DataCenter,
					GrpcPort:     uint32(loc.GrpcPort),
					DataInRemote: loc.DataInRemote,
				})
			}
			var auth string
			if commaSep > 0 { // this is a file id
				auth = string(security.GenJwtForVolumeServer(ms.guard.SigningKey(), ms.guard.ExpiresAfterSec(), result.VolumeOrFileId))
			}
			if result.NotFound {
				notFoundCount++
			}
			resp.VolumeIdLocations = append(resp.VolumeIdLocations, &master_pb.LookupVolumeResponse_VolumeIdLocation{
				VolumeOrFileId: result.VolumeOrFileId,
				Locations:      locations,
				Error:          result.Error,
				Auth:           auth,
			})
		}
	}

	// While warming up, a not-found may only mean the volume server has not
	// reported yet, so no part of the answer can be treated as authoritative.
	// Callers retry Unavailable; a partial answer would let them take a
	// missing volume as gone.
	if notFoundCount > 0 && ms.Topo.IsLeader() && ms.Topo.IsWarmingUp() {
		glog.V(0).Infof("lookup volume warming up: topology is still loading (%d of %d not found)", notFoundCount, len(req.VolumeOrFileIds))
		return nil, status.Errorf(codes.Unavailable, "master is warming up, topology is still loading")
	}

	return resp, nil
}

// CollectionStatistics summarises every collection, so callers tracking usage
// do not pull the whole volume list to add it up themselves.
func (ms *MasterServer) CollectionStatistics(ctx context.Context, req *master_pb.CollectionStatisticsRequest) (*master_pb.CollectionStatisticsResponse, error) {
	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	stats := ms.Topo.CollectionStatistics()
	resp := &master_pb.CollectionStatisticsResponse{
		Collections: make([]*master_pb.CollectionStatistics, 0, len(stats)),
	}
	for _, s := range stats {
		resp.Collections = append(resp.Collections, &master_pb.CollectionStatistics{
			Collection:       s.Collection,
			FileCount:        s.FileCount,
			DeleteCount:      s.DeleteCount,
			DeletedByteCount: s.DeletedByteCount,
			Size:             s.Size,
			PhysicalSize:     s.PhysicalSize,
			VolumeCount:      s.VolumeCount,
		})
	}
	return resp, nil
}

func (ms *MasterServer) Statistics(ctx context.Context, req *master_pb.StatisticsRequest) (*master_pb.StatisticsResponse, error) {

	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	// an empty collection means all collections, and a named collection covers
	// all its layouts and EC volumes
	stats := ms.Topo.CollectionVolumeStats(req.Collection)
	totalSize := uint64(ms.Topo.GetDiskUsages().GetMaxVolumeCount() * int64(ms.option.VolumeSizeLimitMB) * 1024 * 1024)
	// capacity is cluster-wide, so what is left over is what every collection
	// has not taken, not just the one asked about
	clusterUsedSize := stats.UsedSize
	if req.Collection != "" {
		clusterUsedSize = ms.Topo.CollectionVolumeStats("").UsedSize
	}
	// volume slots are provisioning, not capacity: a cluster configured with
	// more of them than its disks hold would report space it can never take.
	// What the disks still have free, on top of what the cluster already wrote,
	// is the real ceiling.
	if freeBytes, reported := ms.Topo.FreeBytes(); reported {
		totalSize = min(totalSize, clusterUsedSize+freeBytes)
	}
	// and the free space holds that many copies fewer of whatever the caller writes
	var freeSize uint64
	if totalSize > clusterUsedSize {
		freeSize = (totalSize - clusterUsedSize) / uint64(ms.replicaCopyCount(req.Replication))
	}
	resp := &master_pb.StatisticsResponse{
		TotalSize:        totalSize,
		UsedSize:         stats.UsedSize,
		FileCount:        stats.FileCount,
		LogicalTotalSize: stats.LogicalUsedSize + freeSize,
		LogicalUsedSize:  stats.LogicalUsedSize,
	}

	return resp, nil
}

// replicaCopyCount returns how many copies the given replication makes, falling
// back to the master default and then to a single copy. Unparsable input is
// reported rather than failing the call: statistics are informational.
func (ms *MasterServer) replicaCopyCount(replication string) int {
	for _, s := range []string{replication, ms.option.DefaultReplicaPlacement} {
		if s == "" {
			continue
		}
		rp, err := super_block.NewReplicaPlacementFromString(s)
		if err != nil {
			glog.V(1).Infof("statistics replication %q: %v", s, err)
			continue
		}
		return rp.GetCopyCount()
	}
	return 1
}

func (ms *MasterServer) VolumeList(ctx context.Context, req *master_pb.VolumeListRequest) (*master_pb.VolumeListResponse, error) {

	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	filter, err := topology.NewVolumeFilter(req)
	if err != nil {
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	resp := &master_pb.VolumeListResponse{
		TopologyInfo:      ms.Topo.ToTopologyInfo(filter),
		VolumeSizeLimitMb: uint64(ms.option.VolumeSizeLimitMB),
	}

	return resp, nil
}

// VolumeListStream answers VolumeList without building the whole reply first.
// The topology goes out on its own, then the volumes in batches, so the master
// holds one batch rather than every volume in the cluster.
func (ms *MasterServer) VolumeListStream(req *master_pb.VolumeListRequest, stream master_pb.Seaweed_VolumeListStreamServer) error {

	if !ms.Topo.IsLeader() {
		return raft.NotLeaderError
	}

	filter, err := topology.NewVolumeFilter(req)
	if err != nil {
		return status.Error(codes.InvalidArgument, err.Error())
	}

	listed := ms.Topo.ToTopologyInfo(topology.NoVolumes())
	err = stream.Send(&master_pb.VolumeListStreamResponse{
		Header: &master_pb.VolumeListResponse{
			TopologyInfo:      listed,
			VolumeSizeLimitMb: uint64(ms.option.VolumeSizeLimitMB),
		},
	})
	if err != nil {
		return err
	}

	return ms.Topo.StreamVolumes(listed, filter, 0, stream.Send)
}

func (ms *MasterServer) LookupEcVolume(ctx context.Context, req *master_pb.LookupEcVolumeRequest) (*master_pb.LookupEcVolumeResponse, error) {

	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	resp := &master_pb.LookupEcVolumeResponse{}

	ecLocations, found := ms.Topo.LookupEcShards(needle.VolumeId(req.VolumeId))

	if !found {
		return resp, fmt.Errorf("ec volume %d not found", req.VolumeId)
	}

	resp.VolumeId = req.VolumeId

	for shardId, shardLocations := range ecLocations.Locations {
		var locations []*master_pb.Location
		for _, dn := range shardLocations {
			locations = append(locations, &master_pb.Location{
				Url:        dn.Url(),
				PublicUrl:  dn.PublicUrl,
				DataCenter: dn.GetDataCenterId(),
				// without this, clients derive grpc as httpPort+10000
				GrpcPort: uint32(dn.GrpcPort),
			})
		}
		resp.ShardIdLocations = append(resp.ShardIdLocations, &master_pb.LookupEcVolumeResponse_EcShardIdLocation{
			ShardId:   uint32(shardId),
			Locations: locations,
		})
	}

	return resp, nil
}

func (ms *MasterServer) VacuumVolume(ctx context.Context, req *master_pb.VacuumVolumeRequest) (*master_pb.VacuumVolumeResponse, error) {

	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	resp := &master_pb.VacuumVolumeResponse{}

	ms.Topo.Vacuum(ms.grpcDialOption, float64(req.GarbageThreshold), ms.option.MaxParallelVacuumPerServer, req.VolumeId, req.Collection, ms.preallocateSize, false)

	return resp, nil
}

func (ms *MasterServer) DisableVacuum(ctx context.Context, req *master_pb.DisableVacuumRequest) (*master_pb.DisableVacuumResponse, error) {
	// The caller explicitly indicates whether this disable request comes
	// from the vacuum plugin monitor. Track ownership so the safety net
	// in the vacuum loop won't override an operator's intentional disable.
	if req.GetByPlugin() {
		ms.Topo.DisableVacuumByPlugin()
	} else {
		ms.Topo.DisableVacuum()
	}
	resp := &master_pb.DisableVacuumResponse{}
	return resp, nil
}

func (ms *MasterServer) EnableVacuum(ctx context.Context, req *master_pb.EnableVacuumRequest) (*master_pb.EnableVacuumResponse, error) {
	if req.GetByPlugin() {
		ms.Topo.EnableVacuumByPlugin()
	} else {
		ms.Topo.EnableVacuum()
	}
	resp := &master_pb.EnableVacuumResponse{}
	return resp, nil
}

func (ms *MasterServer) VolumeMarkReadonly(ctx context.Context, req *master_pb.VolumeMarkReadonlyRequest) (*master_pb.VolumeMarkReadonlyResponse, error) {

	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}

	resp := &master_pb.VolumeMarkReadonlyResponse{}

	replicaPlacement, _ := super_block.NewReplicaPlacementFromByte(byte(req.ReplicaPlacement))
	vl := ms.Topo.GetVolumeLayout(req.Collection, replicaPlacement, needle.LoadTTLFromUint32(req.Ttl), types.ToDiskType(req.DiskType))
	vid := needle.VolumeId(req.VolumeId)
	dataNodes := ms.Topo.Lookup(req.Collection, vid)

	found := false
	for _, dn := range dataNodes {
		if dn.Ip == req.Ip && dn.Port == int(req.Port) {
			found = true
			if req.IsReadonly {
				vl.SetVolumeReadOnly(dn, vid)
				if pending := vl.GetPendingSize(vid); pending > 0 {
					glog.V(0).Infof("volume %d marked readonly with %d pending bytes", vid, pending)
				}
			} else {
				vl.SetVolumeWritable(dn, vid)
			}
		}
	}

	// A vacuum worker marks the volume writable after a successful commit. If the
	// index lost it meanwhile (e.g. a disconnect race during the vacuum), the loop
	// found nothing to update; re-register it from the node that still holds it so
	// LookupVolume stops returning "not found".
	if !found && !req.IsReadonly {
		if dn := ms.Topo.LookupDataNodeByAddress(pb.NewServerAddress(req.Ip, int(req.Port), 0)); dn != nil {
			if vi, err := dn.GetVolumesById(vid); err == nil {
				ms.Topo.RegisterVolumeLayout(vi, dn)
				glog.V(0).Infof("volume %d re-registered from %s:%d, was missing from the lookup index at mark-writable", vid, req.Ip, req.Port)
			}
		}
	}

	return resp, nil
}

func (ms *MasterServer) VolumeGrow(ctx context.Context, req *master_pb.VolumeGrowRequest) (*master_pb.VolumeGrowResponse, error) {
	if !ms.Topo.IsLeader() {
		return nil, raft.NotLeaderError
	}
	if req.Replication == "" {
		req.Replication = ms.option.DefaultReplicaPlacement
	}
	replicaPlacement, err := super_block.NewReplicaPlacementFromString(req.Replication)
	if err != nil {
		return nil, err
	}
	ttl, err := needle.ReadTTL(req.Ttl)
	if err != nil {
		return nil, err
	}
	if req.DataCenter != "" && !ms.Topo.DataCenterExists(req.DataCenter) {
		return nil, fmt.Errorf("data center not exists")
	}

	ver := needle.GetCurrentVersion()
	volumeGrowOption := topology.VolumeGrowOption{
		Collection:         req.Collection,
		ReplicaPlacement:   replicaPlacement,
		Ttl:                ttl,
		DiskType:           types.ToDiskType(req.DiskType),
		Preallocate:        ms.preallocateSize,
		DataCenter:         req.DataCenter,
		Rack:               req.Rack,
		DataNode:           req.DataNode,
		MemoryMapMaxSizeMb: req.MemoryMapMaxSizeMb,
		Version:            uint32(ver),
	}
	volumeGrowRequest := topology.VolumeGrowRequest{
		Option: &volumeGrowOption,
		Count:  req.WritableVolumeCount,
		Force:  true,
		Reason: "grpc volume grow",
	}
	replicaCount := int64(req.WritableVolumeCount * uint32(replicaPlacement.GetCopyCount()))

	if ms.Topo.AvailableSpaceFor(&volumeGrowOption) < replicaCount {
		return nil, fmt.Errorf("only %d volumes left, not enough for %d", ms.Topo.AvailableSpaceFor(&volumeGrowOption), replicaCount)
	}

	ms.DoAutomaticVolumeGrow(&volumeGrowRequest)

	return &master_pb.VolumeGrowResponse{}, nil
}
