package notify

import (
	"context"
	"errors"
	"io"
	"net"
	"strings"
	"sync"
	"sync/atomic"
	"time"
)

const (
	BulkOpenSignalKey    = "notify.bulk.open"
	BulkCloseSignalKey   = "notify.bulk.close"
	BulkResetSignalKey   = "notify.bulk.reset"
	BulkReadySignalKey   = "notify.bulk.ready"
	BulkReleaseSignalKey = "notify.bulk.release"

	defaultBulkChunkSize           = 1024 * 1024
	defaultBulkInboundQueueLimit   = 256
	defaultBulkInboundBytesLimit   = 64 * 1024 * 1024
	defaultBulkOpenWindowBytes     = 16 * 1024 * 1024
	defaultBulkOpenMaxInFlight     = 32
	defaultBulkControlReadTimeout  = 0
	defaultBulkControlWriteTimeout = 0
	defaultBulkAcceptReadyTimeout  = 10 * time.Second
)

type BulkMetadata map[string]string

type BulkRange struct {
	Offset int64
	Length int64
}

type BulkOpenMode uint8

const (
	// BulkOpenModeDefault keeps legacy behavior:
	// Dedicated=true -> dedicated, otherwise shared.
	BulkOpenModeDefault BulkOpenMode = iota
	// BulkOpenModeAuto prefers dedicated and falls back to shared.
	BulkOpenModeAuto
	// BulkOpenModeShared forces shared transport path.
	BulkOpenModeShared
	// BulkOpenModeDedicated forces dedicated transport path.
	BulkOpenModeDedicated
)

type BulkNetworkProfile uint8

const (
	// BulkNetworkProfileDefault keeps legacy defaults.
	BulkNetworkProfileDefault BulkNetworkProfile = iota
	// BulkNetworkProfileLAN is optimized for low-latency/local links.
	BulkNetworkProfileLAN
	// BulkNetworkProfileWAN is tuned for moderate RTT and occasional loss.
	BulkNetworkProfileWAN
	// BulkNetworkProfileConstrained is tuned for low bandwidth and unstable links.
	BulkNetworkProfileConstrained
)

type BulkDedicatedAttachConfig struct {
	// AttachLimit limits concurrent dedicated attach handshakes per client session.
	// 0 means unlimited.
	AttachLimit int
	// ActiveLimit limits active logical dedicated bulks per client session.
	// Physical sidecars remain bounded by LaneLimit.
	// 0 means unlimited.
	ActiveLimit int
	// LaneLimit limits dedicated physical sidecar lanes per client session.
	// 0 means unlimited.
	LaneLimit int
	// Retry controls extra retries after the first attach attempt.
	Retry int
	// Backoff is the base retry backoff.
	Backoff time.Duration
	// DialTimeout is used for dedicated sidecar dialing.
	DialTimeout time.Duration
	// HelloTimeout is used for dedicated attach request/response handshake.
	HelloTimeout time.Duration
}

type BulkOpenTuning struct {
	ChunkSize   int
	WindowBytes int
	MaxInFlight int
}

type bulkDedicatedAttachState uint8

const (
	bulkDedicatedAttachStatePending bulkDedicatedAttachState = iota
	bulkDedicatedAttachStateAttached
	bulkDedicatedAttachStateDegraded
	bulkDedicatedAttachStateClosed
)

type BulkOpenOptions struct {
	ID           string
	Range        BulkRange
	Metadata     BulkMetadata
	ReadTimeout  time.Duration
	WriteTimeout time.Duration
	Mode         BulkOpenMode
	// Deprecated: Dedicated is kept for backward compatibility.
	// Prefer Mode.
	Dedicated bool

	ChunkSize   int
	WindowBytes int
	MaxInFlight int
}

type BulkAcceptInfo struct {
	ID                  string
	Range               BulkRange
	Metadata            BulkMetadata
	Dedicated           bool
	LogicalConn         *LogicalConn
	TransportConn       *TransportConn
	TransportGeneration uint64
	Bulk                Bulk
}

type Bulk interface {
	io.Reader
	io.Writer
	io.Closer

	ID() string
	Range() BulkRange
	Metadata() BulkMetadata
	Context() context.Context

	LogicalConn() *LogicalConn
	TransportConn() *TransportConn
	TransportGeneration() uint64

	CloseWrite() error
	Reset(error) error
	Snapshot() BulkSnapshot
}

var (
	errBulkClientNil            = errors.New("bulk client is nil")
	errBulkServerNil            = errors.New("bulk server is nil")
	errBulkLogicalConnNil       = errors.New("bulk logical connection is nil")
	errBulkTransportNil         = errors.New("bulk transport connection is nil")
	errBulkRuntimeNil           = errors.New("bulk runtime is nil")
	errBulkIDEmpty              = errors.New("bulk id is empty")
	errBulkAlreadyExists        = errors.New("bulk already exists")
	errBulkNotFound             = errors.New("bulk not found")
	errBulkHandlerNotConfigured = errors.New("bulk handler is not configured")
	errBulkRejected             = errors.New("bulk open rejected")
	errBulkReset                = errors.New("bulk reset")
	errBulkDataIDEmpty          = errors.New("bulk data id is empty")
	errBulkDataPathNotReady     = errors.New("bulk data path is not implemented yet")
	errBulkRangeInvalid         = errors.New("bulk range is invalid")
	errBulkBackpressureExceeded = errors.New("bulk inbound backpressure exceeded")
	errBulkDedicatedStreamOnly  = errors.New("dedicated bulk requires stream transport")
	errBulkDedicatedSingleConn  = errors.New("dedicated bulk requires a dialable additional connection source; ConnectByConn only supports shared transport")
	errBulkDedicatedActiveLimit = errors.New("dedicated bulk active limit reached")
)

func clientDedicatedBulkSupportError(c *ClientCommon) error {
	if c == nil {
		return errBulkClientNil
	}
	if conn := c.clientTransportConnSnapshot(); conn != nil && isPacketTransportConn(conn) {
		return errBulkDedicatedStreamOnly
	}
	if source := c.clientConnectSourceSnapshot(); source != nil && source.isUDP() {
		return errBulkDedicatedStreamOnly
	}
	if source := c.clientConnectSourceSnapshot(); source != nil && !source.supportsAdditionalConn() {
		return errBulkDedicatedSingleConn
	}
	return nil
}

func logicalDedicatedBulkSupportError(logical *LogicalConn) error {
	if logical == nil {
		return errBulkLogicalConnNil
	}
	if transport := logical.CurrentTransportConn(); transport != nil {
		return transportDedicatedBulkSupportError(transport)
	}
	if addr := logical.RemoteAddr(); addr != nil && isPacketNetwork(addr.Network()) {
		return errBulkDedicatedStreamOnly
	}
	return nil
}

func transportDedicatedBulkSupportError(transport *TransportConn) error {
	if transport == nil {
		return errBulkTransportNil
	}
	if !transport.UsesStreamTransport() {
		return errBulkDedicatedStreamOnly
	}
	if addr := transport.RemoteAddr(); addr != nil && isPacketNetwork(addr.Network()) {
		return errBulkDedicatedStreamOnly
	}
	return nil
}

type bulkCloseSender func(context.Context, *bulkHandle, bool) error
type bulkResetSender func(context.Context, *bulkHandle, string) error
type bulkDataSender func(context.Context, *bulkHandle, []byte) error
type bulkWriteSender func(context.Context, *bulkHandle, uint64, []byte, bool) (int, error)
type bulkReleaseSender func(*bulkHandle, int64, int) error

type bulkAsyncWriteRequest struct {
	startSeq uint64
	payload  []byte
	chunks   int
}

var bulkAsyncWritePayloadPool sync.Pool

type bulkReadChunk struct {
	data    []byte
	release func()
}

func (c *bulkReadChunk) clear() {
	if c == nil {
		return
	}
	if c.release != nil {
		c.release()
	}
	c.data = nil
	c.release = nil
}

type bulkReadPayloadOwner struct {
	refs    atomic.Int32
	release func()
}

func newBulkReadPayloadOwner(release func()) *bulkReadPayloadOwner {
	if release == nil {
		return nil
	}
	owner := &bulkReadPayloadOwner{release: release}
	owner.refs.Store(1)
	return owner
}

func (o *bulkReadPayloadOwner) retainChunk() func() {
	if o == nil {
		return nil
	}
	o.refs.Add(1)
	return o.releaseChunk
}

func (o *bulkReadPayloadOwner) releaseChunk() {
	if o == nil {
		return
	}
	if o.refs.Add(-1) == 0 && o.release != nil {
		o.release()
	}
}

func (o *bulkReadPayloadOwner) done() {
	if o == nil {
		return
	}
	o.releaseChunk()
}

type bulkHandle struct {
	runtime              *bulkRuntime
	runtimeScope         string
	id                   string
	dataID               uint64
	fastPathVersion      uint8
	outboundSeq          uint64
	rangeSpec            BulkRange
	metadata             BulkMetadata
	sessionEpoch         uint64
	client               *ClientCommon
	logical              *LogicalConn
	transport            *TransportConn
	transportGeneration  uint64
	readTimeout          time.Duration
	writeTimeout         time.Duration
	dedicated            bool
	dedicatedLaneID      uint32
	dedicatedAttachToken string
	chunkSize            int
	windowBytes          int
	maxInFlight          int
	inboundQueueLimit    int
	inboundBytesLimit    int
	closeFn              bulkCloseSender
	resetFn              bulkResetSender
	sendDataFn           bulkDataSender
	sendWriteFn          bulkWriteSender
	releaseFn            bulkReleaseSender
	ctx                  context.Context
	cancel               context.CancelFunc
	writeCtx             context.Context
	writeCtxCancel       context.CancelFunc
	createdAt            time.Time

	writeMu sync.Mutex
	mu      sync.Mutex

	writeQueue           chan bulkAsyncWriteRequest
	writeWorkerDone      chan struct{}
	writeDrain           chan struct{}
	pendingAsyncWrites   int
	localClosed          bool
	localReadClosed      bool
	remoteClosed         bool
	peerReadClosed       bool
	resetErr             error
	readQueue            []bulkReadChunk
	readBuf              bulkReadChunk
	bufferedBytes        int
	readNotify           chan struct{}
	flowNotify           chan struct{}
	writeStateDone       chan struct{}
	writeStateClosed     bool
	releaseNotify        chan struct{}
	releaseWorkerDone    chan struct{}
	pendingReleaseBytes  int64
	pendingReleaseChunks int
	outboundAvailBytes   int64
	outboundInFlight     int
	bytesRead            int64
	bytesWritten         int64
	readCalls            int64
	writeCalls           int64
	lastReadAt           time.Time
	lastWriteAt          time.Time

	dedicatedMu          sync.Mutex
	dedicatedConn        net.Conn
	dedicatedConnOwned   bool
	dedicatedSender      *bulkDedicatedSender
	dedicatedReady       chan struct{}
	dedicatedWriteClosed bool
	dedicatedActiveLease bool
	dedicatedState       bulkDedicatedAttachState
	dedicatedAttempts    uint32
	dedicatedLastCode    string
	dedicatedDataStarted bool

	acceptMu         sync.Mutex
	acceptDispatched bool
	acceptReady      chan struct{}
	acceptReadyDone  bool
	acceptReadyErr   error
	acceptNotifyFn   func(error)
	acceptNotifySent bool
}

func newBulkHandle(parent context.Context, runtime *bulkRuntime, runtimeScope string, req BulkOpenRequest, sessionEpoch uint64, logical *LogicalConn, transport *TransportConn, transportGeneration uint64, closeFn bulkCloseSender, resetFn bulkResetSender, sendDataFn bulkDataSender, sendWriteFn bulkWriteSender, releaseFn bulkReleaseSender) *bulkHandle {
	if parent == nil {
		parent = context.Background()
	}
	ctx, cancel := context.WithCancel(parent)
	if transportGeneration == 0 && transport != nil {
		transportGeneration = transport.TransportGeneration()
	}
	if transportGeneration == 0 && logical != nil {
		transportGeneration = logical.transportGenerationSnapshot()
	}
	req = normalizeBulkOpenRequest(req)
	handle := &bulkHandle{
		runtime:              runtime,
		runtimeScope:         runtimeScope,
		id:                   req.BulkID,
		dataID:               req.DataID,
		fastPathVersion:      normalizeBulkFastPathVersion(req.FastPathVersion),
		rangeSpec:            req.Range,
		metadata:             cloneBulkMetadata(req.Metadata),
		sessionEpoch:         sessionEpoch,
		logical:              logical,
		transport:            transport,
		transportGeneration:  transportGeneration,
		readTimeout:          req.ReadTimeout,
		writeTimeout:         req.WriteTimeout,
		dedicated:            req.Dedicated,
		dedicatedLaneID:      req.DedicatedLaneID,
		dedicatedAttachToken: req.AttachToken,
		chunkSize:            req.ChunkSize,
		windowBytes:          req.WindowBytes,
		maxInFlight:          req.MaxInFlight,
		inboundQueueLimit:    defaultBulkInboundQueueLimit,
		inboundBytesLimit:    defaultBulkInboundBytesLimit,
		closeFn:              closeFn,
		resetFn:              resetFn,
		sendDataFn:           sendDataFn,
		sendWriteFn:          sendWriteFn,
		releaseFn:            releaseFn,
		ctx:                  ctx,
		cancel:               cancel,
		createdAt:            time.Now(),
		readNotify:           make(chan struct{}, 1),
		flowNotify:           make(chan struct{}, 1),
		writeStateDone:       make(chan struct{}),
		dedicatedReady:       make(chan struct{}),
		dedicatedState:       initialBulkDedicatedAttachState(req.Dedicated),
		acceptReady:          make(chan struct{}),
		outboundAvailBytes:   int64(req.WindowBytes),
	}
	drain := make(chan struct{})
	close(drain)
	handle.writeDrain = drain
	if sendWriteFn != nil {
		handle.writeCtx, handle.writeCtxCancel = context.WithCancel(ctx)
		handle.writeQueue = make(chan bulkAsyncWriteRequest, bulkAsyncWriteQueueSize(req.MaxInFlight))
		handle.writeWorkerDone = make(chan struct{})
		go func(parentDone <-chan struct{}, writeDone <-chan struct{}, cancel context.CancelFunc) {
			select {
			case <-parentDone:
			case <-writeDone:
				cancel()
			}
		}(ctx.Done(), handle.writeStateDone, handle.writeCtxCancel)
		go handle.runAsyncWriteLoop()
	}
	if handle.flowControlEnabled() {
		handle.releaseNotify = make(chan struct{}, 1)
		handle.releaseWorkerDone = make(chan struct{})
		go handle.runWindowReleaseLoop()
	}
	return handle
}

func (b *bulkHandle) ID() string {
	if b == nil {
		return ""
	}
	return b.id
}

func (b *bulkHandle) fastPathVersionSnapshot() uint8 {
	if b == nil {
		return bulkFastPathVersionV1
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return normalizeBulkFastPathVersion(b.fastPathVersion)
}

func (b *bulkHandle) FastPathVersion() uint8 {
	return b.fastPathVersionSnapshot()
}

func (b *bulkHandle) Range() BulkRange {
	if b == nil {
		return BulkRange{}
	}
	return b.rangeSpec
}

func (b *bulkHandle) Metadata() BulkMetadata {
	if b == nil {
		return nil
	}
	return cloneBulkMetadata(b.metadata)
}

func (b *bulkHandle) Context() context.Context {
	if b == nil || b.ctx == nil {
		return context.Background()
	}
	return b.ctx
}

func (b *bulkHandle) LogicalConn() *LogicalConn {
	if b == nil {
		return nil
	}
	return b.logical
}

func (b *bulkHandle) TransportConn() *TransportConn {
	if b == nil {
		return nil
	}
	return b.transport
}

func (b *bulkHandle) TransportGeneration() uint64 {
	if b == nil {
		return 0
	}
	return b.transportGeneration
}

func (b *bulkHandle) Dedicated() bool {
	if b == nil {
		return false
	}
	return b.dedicated
}

func (b *bulkHandle) dedicatedLaneIDSnapshot() uint32 {
	if b == nil {
		return 0
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedLaneID
}

func (b *bulkHandle) dedicatedAttachTokenSnapshot() string {
	if b == nil {
		return ""
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.dedicatedAttachToken
}

func (b *bulkHandle) setDedicatedAttachToken(token string) {
	if b == nil {
		return
	}
	b.mu.Lock()
	b.dedicatedAttachToken = token
	b.mu.Unlock()
}

func (b *bulkHandle) markDedicatedAttachAttempt() {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedAttempts++
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) setDedicatedAttachLastCode(code string) {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedLastCode = code
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) markDedicatedAttachDegraded(code string) {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedState = bulkDedicatedAttachStateDegraded
	b.dedicatedLastCode = code
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) markDedicatedAttachClosed() {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedState = bulkDedicatedAttachStateClosed
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) dedicatedAttachStateSnapshot() bulkDedicatedAttachState {
	if b == nil {
		return bulkDedicatedAttachStateClosed
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedState
}

func (b *bulkHandle) dedicatedAttachDiagnosticsSnapshot() (state bulkDedicatedAttachState, attempts uint32, lastCode string, dataStarted bool) {
	if b == nil {
		return bulkDedicatedAttachStateClosed, 0, "", false
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedState, b.dedicatedAttempts, b.dedicatedLastCode, b.dedicatedDataStarted
}

func (b *bulkHandle) dedicatedConnSnapshot() net.Conn {
	if b == nil {
		return nil
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedConn
}

func (b *bulkHandle) dedicatedSenderSnapshot() *bulkDedicatedSender {
	if b == nil {
		return nil
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedSender
}

func (b *bulkHandle) installDedicatedSender(sender *bulkDedicatedSender) *bulkDedicatedSender {
	if b == nil || sender == nil {
		return nil
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	if b.dedicatedSender != nil {
		return b.dedicatedSender
	}
	b.dedicatedSender = sender
	return sender
}

func (b *bulkHandle) clearDedicatedSender() *bulkDedicatedSender {
	if b == nil {
		return nil
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	sender := b.dedicatedSender
	b.dedicatedSender = nil
	return sender
}

func (b *bulkHandle) dedicatedAttachedSnapshot() bool {
	return b.dedicatedConnSnapshot() != nil
}

func (b *bulkHandle) dedicatedDataStartedSnapshot() bool {
	if b == nil {
		return false
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedDataStarted
}

func (b *bulkHandle) markDedicatedDataStarted() {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedDataStarted = true
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) waitDedicatedReady(ctx context.Context) error {
	if b == nil || !b.Dedicated() || b.dedicatedAttachedSnapshot() {
		return nil
	}
	if ctx == nil {
		ctx = context.Background()
	}
	if err := b.writeStateErrorSnapshot(); err != nil {
		return err
	}
	select {
	case <-b.dedicatedReady:
		return nil
	case <-ctx.Done():
		return ctx.Err()
	case <-b.Context().Done():
		if err := b.writeStateErrorSnapshot(); err != nil {
			return err
		}
		return context.Canceled
	}
}

func (b *bulkHandle) attachDedicatedConn(conn net.Conn) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if conn == nil {
		return net.ErrClosed
	}
	b.dedicatedMu.Lock()
	if b.dedicatedConn != nil {
		b.dedicatedMu.Unlock()
		return errors.New("bulk dedicated conn already attached")
	}
	b.dedicatedConn = conn
	b.dedicatedConnOwned = true
	b.dedicatedWriteClosed = false
	b.dedicatedState = bulkDedicatedAttachStateAttached
	b.dedicatedLastCode = ""
	ready := b.dedicatedReady
	b.dedicatedMu.Unlock()
	if ready != nil {
		select {
		case <-ready:
		default:
			close(ready)
		}
	}
	return nil
}

func (b *bulkHandle) attachDedicatedConnShared(conn net.Conn) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if conn == nil {
		return net.ErrClosed
	}
	b.dedicatedMu.Lock()
	if b.dedicatedConn != nil {
		if b.dedicatedConn == conn {
			b.dedicatedConnOwned = false
			b.dedicatedState = bulkDedicatedAttachStateAttached
			b.dedicatedLastCode = ""
			b.dedicatedMu.Unlock()
			return nil
		}
		b.dedicatedMu.Unlock()
		return errors.New("bulk dedicated conn already attached")
	}
	b.dedicatedConn = conn
	b.dedicatedConnOwned = false
	b.dedicatedWriteClosed = false
	b.dedicatedState = bulkDedicatedAttachStateAttached
	b.dedicatedLastCode = ""
	ready := b.dedicatedReady
	b.dedicatedMu.Unlock()
	if ready != nil {
		select {
		case <-ready:
		default:
			close(ready)
		}
	}
	return nil
}

func (b *bulkHandle) replaceDedicatedConn(conn net.Conn) (net.Conn, *bulkDedicatedSender, error) {
	if b == nil {
		return nil, nil, io.ErrClosedPipe
	}
	if conn == nil {
		return nil, nil, net.ErrClosed
	}
	b.dedicatedMu.Lock()
	oldConn := b.dedicatedConn
	oldOwned := b.dedicatedConnOwned
	oldSender := b.dedicatedSender
	b.dedicatedConn = conn
	b.dedicatedConnOwned = true
	b.dedicatedSender = nil
	b.dedicatedWriteClosed = false
	b.dedicatedState = bulkDedicatedAttachStateAttached
	b.dedicatedLastCode = ""
	ready := b.dedicatedReady
	b.dedicatedMu.Unlock()
	if ready != nil {
		select {
		case <-ready:
		default:
			close(ready)
		}
	}
	if !oldOwned {
		oldConn = nil
	}
	return oldConn, oldSender, nil
}

func (b *bulkHandle) replaceDedicatedConnShared(conn net.Conn) (net.Conn, *bulkDedicatedSender, error) {
	if b == nil {
		return nil, nil, io.ErrClosedPipe
	}
	if conn == nil {
		return nil, nil, net.ErrClosed
	}
	b.dedicatedMu.Lock()
	oldConn := b.dedicatedConn
	oldOwned := b.dedicatedConnOwned
	oldSender := b.dedicatedSender
	b.dedicatedConn = conn
	b.dedicatedConnOwned = false
	b.dedicatedSender = nil
	b.dedicatedWriteClosed = false
	b.dedicatedState = bulkDedicatedAttachStateAttached
	b.dedicatedLastCode = ""
	ready := b.dedicatedReady
	b.dedicatedMu.Unlock()
	if ready != nil {
		select {
		case <-ready:
		default:
			close(ready)
		}
	}
	if !oldOwned {
		oldConn = nil
	}
	return oldConn, oldSender, nil
}

func (b *bulkHandle) bestEffortCloseDedicatedWriteHalf() {
	if b == nil || !b.dedicated {
		return
	}
	b.dedicatedMu.Lock()
	conn := b.dedicatedConn
	owned := b.dedicatedConnOwned
	alreadyClosed := b.dedicatedWriteClosed
	b.dedicatedMu.Unlock()
	if conn == nil || alreadyClosed || !owned {
		return
	}
	type closeWriter interface {
		CloseWrite() error
	}
	if closeWriterConn, ok := conn.(closeWriter); ok {
		if err := closeWriterConn.CloseWrite(); err == nil {
			b.dedicatedMu.Lock()
			if b.dedicatedConn == conn {
				b.dedicatedWriteClosed = true
			}
			b.dedicatedMu.Unlock()
		}
	}
}

func (b *bulkHandle) dedicatedWriteHalfClosedSnapshot() bool {
	if b == nil {
		return false
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	return b.dedicatedWriteClosed
}

func (b *bulkHandle) setClientSnapshotOwner(client *ClientCommon) {
	if b == nil {
		return
	}
	b.client = client
}

func (b *bulkHandle) clearDedicatedConn() (net.Conn, bool) {
	if b == nil {
		return nil, false
	}
	b.dedicatedMu.Lock()
	conn := b.dedicatedConn
	owned := b.dedicatedConnOwned
	b.dedicatedConn = nil
	b.dedicatedConnOwned = false
	b.dedicatedWriteClosed = false
	b.dedicatedMu.Unlock()
	return conn, owned
}

func (b *bulkHandle) markDedicatedActiveReserved() {
	if b == nil {
		return
	}
	b.dedicatedMu.Lock()
	b.dedicatedActiveLease = true
	b.dedicatedMu.Unlock()
}

func (b *bulkHandle) releaseDedicatedActiveReserved() bool {
	if b == nil {
		return false
	}
	b.dedicatedMu.Lock()
	defer b.dedicatedMu.Unlock()
	if !b.dedicatedActiveLease {
		return false
	}
	b.dedicatedActiveLease = false
	return true
}

func (b *bulkHandle) markAcceptDispatched() bool {
	if b == nil {
		return false
	}
	b.acceptMu.Lock()
	defer b.acceptMu.Unlock()
	if b.acceptDispatched {
		return false
	}
	b.acceptDispatched = true
	return true
}

func (b *bulkHandle) markAcceptHandled() {
	if b == nil {
		return
	}
	b.acceptMu.Lock()
	b.acceptDispatched = true
	b.acceptMu.Unlock()
}

func (b *bulkHandle) setAcceptNotify(fn func(error)) {
	if b == nil {
		return
	}
	b.acceptMu.Lock()
	b.acceptNotifyFn = fn
	b.acceptMu.Unlock()
}

func (b *bulkHandle) clearAcceptNotify() {
	if b == nil {
		return
	}
	b.acceptMu.Lock()
	b.acceptNotifyFn = nil
	b.acceptMu.Unlock()
}

func (b *bulkHandle) markAcceptReady(err error) {
	if b == nil {
		return
	}
	b.acceptMu.Lock()
	if b.acceptReadyDone {
		b.acceptMu.Unlock()
		return
	}
	b.acceptReadyDone = true
	b.acceptReadyErr = err
	ch := b.acceptReady
	b.acceptMu.Unlock()
	if ch != nil {
		select {
		case <-ch:
		default:
			close(ch)
		}
	}
}

func (b *bulkHandle) waitAcceptReady(ctx context.Context) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if ctx == nil {
		ctx = context.Background()
	}
	b.acceptMu.Lock()
	if b.acceptReadyDone {
		err := b.acceptReadyErr
		b.acceptMu.Unlock()
		return err
	}
	ready := b.acceptReady
	b.acceptMu.Unlock()
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-b.Context().Done():
		if err := b.acceptReadyErrorSnapshot(); err != nil {
			return err
		}
		if err := b.resetErrSnapshot(); err != nil {
			return err
		}
		return context.Canceled
	case <-ready:
		return b.acceptReadyErrorSnapshot()
	}
}

func (b *bulkHandle) acceptReadyErrorSnapshot() error {
	if b == nil {
		return io.ErrClosedPipe
	}
	b.acceptMu.Lock()
	defer b.acceptMu.Unlock()
	return b.acceptReadyErr
}

func (b *bulkHandle) notifyAcceptStarted() {
	if b == nil {
		return
	}
	var notify func(error)
	b.acceptMu.Lock()
	if b.acceptNotifySent {
		b.acceptMu.Unlock()
		return
	}
	notify = b.acceptNotifyFn
	b.acceptNotifyFn = nil
	if notify == nil {
		b.acceptMu.Unlock()
		return
	}
	b.acceptNotifySent = true
	b.acceptMu.Unlock()
	go notify(nil)
}

func (b *bulkHandle) finishAcceptDispatch(err error) {
	if b == nil {
		return
	}
	var notify func(error)
	b.acceptMu.Lock()
	if b.acceptNotifySent {
		b.acceptMu.Unlock()
		return
	}
	notify = b.acceptNotifyFn
	b.acceptNotifyFn = nil
	b.acceptNotifySent = true
	b.acceptMu.Unlock()
	if notify != nil {
		go notify(err)
	}
}

func (b *bulkHandle) SessionEpoch() uint64 {
	if b == nil {
		return 0
	}
	return b.sessionEpoch
}

func (b *bulkHandle) acceptsClientSessionEpoch(epoch uint64) bool {
	if b == nil {
		return false
	}
	if b.sessionEpoch == 0 || epoch == 0 {
		return true
	}
	return b.sessionEpoch == epoch
}

func (b *bulkHandle) acceptsTransportGeneration(transport *TransportConn) bool {
	if b == nil {
		return false
	}
	if b.transportGeneration == 0 || transport == nil {
		return true
	}
	return b.transportGeneration == transport.TransportGeneration()
}

func (b *bulkHandle) dataIDSnapshot() uint64 {
	if b == nil {
		return 0
	}
	return b.dataID
}

func (b *bulkHandle) nextOutboundDataSeq() uint64 {
	return b.reserveOutboundDataSeqs(1)
}

func (b *bulkHandle) reserveOutboundDataSeqs(count int) uint64 {
	if b == nil || count <= 0 {
		return 0
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	start := b.outboundSeq + 1
	b.outboundSeq += uint64(count)
	return start
}

func (b *bulkHandle) Read(p []byte) (int, error) {
	if len(p) == 0 {
		return 0, nil
	}
	if b == nil {
		return 0, io.ErrClosedPipe
	}
	b.notifyAcceptStarted()
	for {
		b.mu.Lock()
		localReadClosed := b.localReadClosed
		if len(b.readBuf.data) > 0 {
			n := copy(p, b.readBuf.data)
			b.readBuf.data = b.readBuf.data[n:]
			b.bufferedBytes -= n
			if b.bufferedBytes < 0 {
				b.bufferedBytes = 0
			}
			if len(b.readBuf.data) == 0 {
				b.readBuf.clear()
			}
			b.recordReadLocked(n, time.Now())
			b.mu.Unlock()
			b.maybeSendWindowRelease(n, false)
			return n, nil
		}
		if len(b.readQueue) > 0 {
			b.readBuf = b.readQueue[0]
			b.readQueue[0] = bulkReadChunk{}
			b.readQueue = b.readQueue[1:]
			b.mu.Unlock()
			continue
		}
		resetErr := b.resetErr
		remoteClosed := b.remoteClosed
		notify := b.readNotify
		ctx := b.ctx
		readTimeout := b.readTimeout
		b.mu.Unlock()
		if localReadClosed {
			b.maybeSendWindowRelease(0, true)
			return 0, io.ErrClosedPipe
		}
		if resetErr != nil {
			b.maybeSendWindowRelease(0, true)
			return 0, resetErr
		}
		if remoteClosed {
			b.maybeSendWindowRelease(0, true)
			return 0, io.EOF
		}
		if err := b.waitReadable(ctx, notify, readTimeout); err != nil {
			b.maybeSendWindowRelease(0, true)
			return 0, err
		}
	}
}

func (b *bulkHandle) Write(p []byte) (int, error) {
	if len(p) == 0 {
		return 0, nil
	}
	if b == nil {
		return 0, io.ErrClosedPipe
	}
	b.notifyAcceptStarted()
	b.writeMu.Lock()
	defer b.writeMu.Unlock()
	b.mu.Lock()
	resetErr := b.resetErr
	localClosed := b.localClosed
	peerReadClosed := b.peerReadClosed
	sendDataFn := b.sendDataFn
	sendWriteFn := b.sendWriteFn
	chunkSize := b.chunkSize
	writeTimeout := b.writeTimeout
	bulkCtx := b.ctx
	b.mu.Unlock()
	if resetErr != nil {
		return 0, resetErr
	}
	if localClosed || peerReadClosed {
		return 0, io.ErrClosedPipe
	}
	if sendDataFn == nil {
		return 0, errBulkDataPathNotReady
	}
	if sendWriteFn != nil {
		written := 0
		for written < len(p) {
			end := len(p)
			if b.windowBytes > 0 && end-written > b.windowBytes {
				end = written + b.windowBytes
			}
			if chunkSize > 0 && b.maxInFlight > 0 {
				maxPartBytes := chunkSize * b.maxInFlight
				if maxPartBytes > 0 && end-written > maxPartBytes {
					end = written + maxPartBytes
				}
			}
			part := p[written:end]
			partChunks := bulkPayloadChunkCount(len(part), chunkSize)
			sendCtx, cancel, err := b.newWriteContext(bulkCtx, writeTimeout)
			if err != nil {
				return written, err
			}
			if err := b.acquireOutboundWindow(sendCtx, len(part), partChunks); err != nil {
				cancel()
				return written, b.normalizeWriteError(err)
			}
			startSeq := b.reserveOutboundDataSeqs(partChunks)
			if b.dedicated {
				partWritten, err := b.executeSendWrite(sendCtx, startSeq, part, partChunks, false)
				cancel()
				written += partWritten
				if err != nil {
					return written, err
				}
				continue
			}
			owned := getBulkAsyncWritePayload(len(part))
			copy(owned, part)
			err = b.enqueueAsyncWrite(sendCtx, bulkAsyncWriteRequest{
				startSeq: startSeq,
				payload:  owned,
				chunks:   partChunks,
			})
			cancel()
			if err != nil {
				putBulkAsyncWritePayload(owned)
				b.rollbackOutboundWindow(len(part), partChunks)
				return written, b.normalizeWriteError(err)
			}
			written += len(part)
		}
		return written, nil
	}
	if chunkSize <= 0 {
		chunkSize = defaultBulkChunkSize
	}
	written := 0
	for written < len(p) {
		end := written + chunkSize
		if end > len(p) {
			end = len(p)
		}
		chunk := p[written:end]
		sendCtx, cancel, err := b.newWriteContext(bulkCtx, writeTimeout)
		if err != nil {
			if written > 0 {
				b.recordWrite(written, time.Now())
			}
			return written, err
		}
		if err := b.acquireOutboundWindow(sendCtx, len(chunk), 1); err != nil {
			cancel()
			if written > 0 {
				b.recordWrite(written, time.Now())
			}
			return written, b.normalizeWriteError(err)
		}
		err = sendDataFn(sendCtx, b, chunk)
		cancel()
		if err != nil {
			b.rollbackOutboundWindow(len(chunk), 1)
			if written > 0 {
				b.recordWrite(written, time.Now())
			}
			return written, b.normalizeWriteError(err)
		}
		written = end
	}
	if written > 0 {
		b.recordWrite(written, time.Now())
	}
	return written, nil
}

func (b *bulkHandle) Close() error {
	return b.close(true)
}

func (b *bulkHandle) CloseWrite() error {
	return b.close(false)
}

func (b *bulkHandle) close(full bool) error {
	if b == nil {
		return nil
	}
	b.notifyAcceptStarted()
	b.writeMu.Lock()
	defer b.writeMu.Unlock()
	b.mu.Lock()
	if b.resetErr != nil {
		err := b.resetErr
		b.mu.Unlock()
		return err
	}
	if b.localClosed {
		if !full || b.localReadClosed {
			b.mu.Unlock()
			return nil
		}
		closeFn := b.closeFn
		b.mu.Unlock()
		if closeFn != nil && !b.dedicatedWriteHalfClosedSnapshot() {
			if err := closeFn(context.Background(), b, true); err != nil && !errors.Is(err, errBulkNotFound) && !b.canIgnoreDedicatedCloseSendError(err) {
				return err
			}
		}
		b.bestEffortCloseDedicatedWriteHalf()
		b.mu.Lock()
		if b.localReadClosed {
			b.mu.Unlock()
			return nil
		}
		b.localReadClosed = true
		b.clearBufferedDataLocked()
		b.closeWriteStateLocked()
		shouldFinalize := b.shouldFinalizeLocked()
		b.mu.Unlock()
		b.notifyReadable()
		if shouldFinalize {
			b.finalize()
		}
		return nil
	}
	closeFn := b.closeFn
	b.mu.Unlock()
	if err := b.waitPendingAsyncWrites(context.Background()); err != nil {
		return err
	}
	if closeFn != nil {
		if err := closeFn(context.Background(), b, full); err != nil && !errors.Is(err, errBulkNotFound) && !b.canIgnoreDedicatedCloseSendError(err) {
			return err
		}
	}
	b.bestEffortCloseDedicatedWriteHalf()
	b.mu.Lock()
	if b.localClosed {
		b.mu.Unlock()
		return nil
	}
	b.localClosed = true
	b.closeWriteStateLocked()
	if full {
		b.localReadClosed = true
		b.clearBufferedDataLocked()
	}
	shouldFinalize := b.shouldFinalizeLocked()
	b.mu.Unlock()
	if full {
		b.notifyReadable()
	}
	if shouldFinalize {
		b.finalize()
	}
	return nil
}

func (b *bulkHandle) Reset(err error) error {
	if b == nil {
		return nil
	}
	b.notifyAcceptStarted()
	resetErr := bulkResetError(err)
	b.mu.Lock()
	if b.resetErr != nil {
		err := b.resetErr
		b.mu.Unlock()
		return err
	}
	resetFn := b.resetFn
	b.mu.Unlock()
	if resetFn != nil {
		if sendErr := resetFn(context.Background(), b, bulkResetMessage(resetErr)); sendErr != nil {
			return sendErr
		}
	}
	b.markReset(resetErr)
	return nil
}

func (b *bulkHandle) Snapshot() BulkSnapshot {
	return b.snapshot()
}

func (b *bulkHandle) markRemoteClosed() {
	if b == nil {
		return
	}
	b.mu.Lock()
	b.remoteClosed = true
	shouldFinalize := b.shouldFinalizeLocked()
	b.mu.Unlock()
	b.notifyReadable()
	if shouldFinalize {
		b.finalize()
	}
}

func (b *bulkHandle) markPeerClosed() {
	if b == nil {
		return
	}
	b.mu.Lock()
	b.remoteClosed = true
	b.peerReadClosed = true
	b.closeWriteStateLocked()
	shouldFinalize := b.shouldFinalizeLocked()
	b.notifyFlowLocked()
	b.mu.Unlock()
	b.notifyReadable()
	if shouldFinalize {
		b.finalize()
	}
}

func (b *bulkHandle) markReset(err error) {
	if b == nil {
		return
	}
	resetErr := bulkResetError(err)
	b.mu.Lock()
	if b.resetErr == nil {
		b.resetErr = resetErr
		b.clearBufferedDataLocked()
		b.closeWriteStateLocked()
	}
	b.notifyFlowLocked()
	b.mu.Unlock()
	b.markAcceptReady(resetErr)
	b.notifyReadable()
	b.finalize()
}

func (b *bulkHandle) pushChunk(chunk []byte) error {
	return b.pushChunkWithOwnership(chunk, false)
}

func (b *bulkHandle) pushOwnedChunk(chunk []byte) error {
	return b.pushChunkWithOwnership(chunk, true)
}

func (b *bulkHandle) pushOwnedChunkNoReset(chunk []byte) error {
	return b.pushChunkWithOwnershipOptions(chunk, true, false)
}

func (b *bulkHandle) pushOwnedChunkWithReleaseNoReset(chunk []byte, release func()) error {
	return b.pushChunkWithOwnershipOptionsAndRelease(chunk, true, false, release)
}

func (b *bulkHandle) pushChunkWithOwnership(chunk []byte, owned bool) error {
	return b.pushChunkWithOwnershipOptions(chunk, owned, true)
}

func (b *bulkHandle) pushChunkWithOwnershipOptions(chunk []byte, owned bool, resetOnOverflow bool) error {
	return b.pushChunkWithOwnershipOptionsAndRelease(chunk, owned, resetOnOverflow, nil)
}

func (b *bulkHandle) pushChunkWithOwnershipOptionsAndRelease(chunk []byte, owned bool, resetOnOverflow bool, release func()) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if len(chunk) == 0 {
		if release != nil {
			release()
		}
		return nil
	}
	stored := bulkReadChunk{data: chunk, release: release}
	if !owned {
		stored.data = append([]byte(nil), chunk...)
		if stored.release != nil {
			stored.release()
			stored.release = nil
		}
	}
	b.mu.Lock()
	if b.resetErr != nil {
		err := b.resetErr
		b.mu.Unlock()
		stored.clear()
		return err
	}
	if b.inboundQueueLimit > 0 && b.bufferedChunkCountLocked() >= b.inboundQueueLimit {
		if !resetOnOverflow {
			b.mu.Unlock()
			stored.clear()
			return errBulkBackpressureExceeded
		}
		err := b.markResetLocked(errBulkBackpressureExceeded)
		b.mu.Unlock()
		stored.clear()
		b.notifyReadable()
		b.finalize()
		return err
	}
	if b.inboundBytesLimit > 0 && b.bufferedBytes+len(stored.data) > b.inboundBytesLimit {
		if !resetOnOverflow {
			b.mu.Unlock()
			stored.clear()
			return errBulkBackpressureExceeded
		}
		err := b.markResetLocked(errBulkBackpressureExceeded)
		b.mu.Unlock()
		stored.clear()
		b.notifyReadable()
		b.finalize()
		return err
	}
	b.readQueue = append(b.readQueue, stored)
	b.bufferedBytes += len(stored.data)
	b.notifyReadableLocked()
	b.mu.Unlock()
	return nil
}

func (b *bulkHandle) markResetLocked(err error) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if b.resetErr == nil {
		b.resetErr = bulkResetError(err)
		b.clearBufferedDataLocked()
		b.closeWriteStateLocked()
	}
	return b.resetErr
}

func (b *bulkHandle) clearBufferedDataLocked() {
	if b == nil {
		return
	}
	b.readBuf.clear()
	for i := range b.readQueue {
		b.readQueue[i].clear()
	}
	b.readQueue = nil
	b.readBuf = bulkReadChunk{}
	b.bufferedBytes = 0
}

func (b *bulkHandle) flowControlEnabled() bool {
	if b == nil {
		return false
	}
	return b.releaseFn != nil && (b.windowBytes > 0 || b.maxInFlight > 0)
}

func (b *bulkHandle) releaseThresholdBytes() int64 {
	if b == nil {
		return int64(defaultBulkChunkSize)
	}
	threshold := b.chunkSize
	if threshold <= 0 {
		threshold = defaultBulkChunkSize
	}
	if b.windowBytes > 0 && threshold > b.windowBytes {
		threshold = b.windowBytes
	}
	if threshold <= 0 {
		threshold = defaultBulkChunkSize
	}
	return int64(threshold)
}

func (b *bulkHandle) maybeSendWindowRelease(consumed int, force bool) {
	if b == nil || !b.flowControlEnabled() {
		return
	}
	b.mu.Lock()
	if consumed > 0 {
		b.pendingReleaseBytes += int64(consumed)
		b.pendingReleaseChunks++
	}
	if !force && b.pendingReleaseBytes < b.releaseThresholdBytes() {
		b.mu.Unlock()
		return
	}
	b.mu.Unlock()
	b.scheduleWindowRelease()
}

func (b *bulkHandle) scheduleWindowRelease() {
	if b == nil || b.releaseNotify == nil {
		return
	}
	select {
	case b.releaseNotify <- struct{}{}:
	default:
	}
}

func (b *bulkHandle) takePendingWindowRelease() (int64, int, bulkReleaseSender) {
	if b == nil {
		return 0, 0, nil
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	bytes := b.pendingReleaseBytes
	chunks := b.pendingReleaseChunks
	release := b.releaseFn
	b.pendingReleaseBytes = 0
	b.pendingReleaseChunks = 0
	return bytes, chunks, release
}

func (b *bulkHandle) runWindowReleaseLoop() {
	if b == nil {
		return
	}
	defer close(b.releaseWorkerDone)
	for {
		select {
		case <-b.Context().Done():
			return
		case <-b.releaseNotify:
		}
		for {
			bytes, chunks, release := b.takePendingWindowRelease()
			if release == nil || (bytes <= 0 && chunks <= 0) {
				break
			}
			_ = release(b, bytes, chunks)
		}
	}
}

func (b *bulkHandle) acquireOutboundWindow(ctx context.Context, size int, chunks int) error {
	if b == nil || size <= 0 || !b.flowControlEnabled() {
		return nil
	}
	if ctx == nil {
		ctx = context.Background()
	}
	need := int64(size)
	if chunks <= 0 {
		chunks = 1
	}
	for {
		b.mu.Lock()
		if b.resetErr != nil {
			err := b.resetErr
			b.mu.Unlock()
			return err
		}
		if b.localClosed || b.peerReadClosed {
			b.mu.Unlock()
			return io.ErrClosedPipe
		}
		bytesOK := true
		if b.windowBytes > 0 {
			bytesOK = b.outboundAvailBytes >= need
			if !bytesOK && need > int64(b.windowBytes) && b.outboundInFlight == 0 {
				bytesOK = true
			}
		}
		chunksOK := true
		if b.maxInFlight > 0 {
			chunksOK = b.outboundInFlight+chunks <= b.maxInFlight
		}
		if bytesOK && chunksOK {
			if b.windowBytes > 0 {
				b.outboundAvailBytes -= need
			}
			if b.maxInFlight > 0 {
				b.outboundInFlight += chunks
			}
			b.mu.Unlock()
			return nil
		}
		notify := b.flowNotify
		b.mu.Unlock()
		select {
		case <-notify:
		case <-ctx.Done():
			if stateErr := b.writeStateErrorSnapshot(); stateErr != nil {
				return stateErr
			}
			return normalizeStreamDeadlineError(ctx.Err())
		}
	}
}

func (b *bulkHandle) rollbackOutboundWindow(size int, chunks int) {
	if b == nil || size <= 0 || !b.flowControlEnabled() {
		return
	}
	if chunks <= 0 {
		chunks = 1
	}
	b.mu.Lock()
	if b.windowBytes > 0 {
		b.outboundAvailBytes += int64(size)
		maxAvail := int64(b.windowBytes)
		if b.outboundAvailBytes > maxAvail {
			b.outboundAvailBytes = maxAvail
		}
	}
	if b.maxInFlight > 0 && b.outboundInFlight > 0 {
		b.outboundInFlight -= chunks
		if b.outboundInFlight < 0 {
			b.outboundInFlight = 0
		}
	}
	b.notifyFlowLocked()
	b.mu.Unlock()
}

func (b *bulkHandle) releaseOutboundWindow(bytes int64, chunks int) {
	if b == nil || !b.flowControlEnabled() {
		return
	}
	b.mu.Lock()
	if b.windowBytes > 0 && bytes > 0 {
		b.outboundAvailBytes += bytes
		maxAvail := int64(b.windowBytes)
		if b.outboundAvailBytes > maxAvail {
			b.outboundAvailBytes = maxAvail
		}
	}
	if b.maxInFlight > 0 && chunks > 0 {
		b.outboundInFlight -= chunks
		if b.outboundInFlight < 0 {
			b.outboundInFlight = 0
		}
	}
	b.notifyFlowLocked()
	b.mu.Unlock()
}

func (b *bulkHandle) bufferedChunkCountLocked() int {
	if b == nil {
		return 0
	}
	count := len(b.readQueue)
	if len(b.readBuf.data) > 0 {
		count++
	}
	return count
}

func (b *bulkHandle) shouldFinalizeLocked() bool {
	if b == nil {
		return true
	}
	if b.resetErr != nil {
		return true
	}
	if b.dedicated {
		return b.localClosed && b.remoteClosed
	}
	return b.localReadClosed || (b.peerReadClosed && b.remoteClosed) || (b.localClosed && b.remoteClosed)
}

func (b *bulkHandle) snapshot() BulkSnapshot {
	if b == nil {
		return BulkSnapshot{}
	}
	dedicatedAttached := b.dedicatedAttachedSnapshot()
	dedicatedState, dedicatedAttempts, dedicatedLastCode, dedicatedDataStarted := b.dedicatedAttachDiagnosticsSnapshot()
	b.mu.Lock()
	defer b.mu.Unlock()
	snapshot := BulkSnapshot{
		ID:                b.id,
		DataID:            b.dataID,
		FastPathVersion:   normalizeBulkFastPathVersion(b.fastPathVersion),
		Scope:             normalizeFileScope(b.runtimeScope),
		Range:             b.rangeSpec,
		Metadata:          cloneBulkMetadata(b.metadata),
		Dedicated:         b.dedicated,
		DedicatedLaneID:   b.dedicatedLaneID,
		DedicatedAttached: dedicatedAttached,
		DedicatedAttachState: bulkDedicatedAttachStateName(
			dedicatedState,
		),
		DedicatedAttachAttempts: dedicatedAttempts,
		DedicatedAttachLastCode: dedicatedLastCode,
		DedicatedDataStarted:    dedicatedDataStarted,
		SessionEpoch:            b.sessionEpoch,
		TransportGeneration:     b.transportGeneration,
		LocalClosed:             b.localClosed,
		LocalReadClosed:         b.localReadClosed,
		RemoteClosed:            b.remoteClosed,
		PeerReadClosed:          b.peerReadClosed,
		BufferedChunks:          b.bufferedChunkCountLocked(),
		BufferedBytes:           b.bufferedBytes,
		ReadTimeout:             b.readTimeout,
		WriteTimeout:            b.writeTimeout,
		ChunkSize:               b.chunkSize,
		WindowBytes:             b.windowBytes,
		MaxInFlight:             b.maxInFlight,
		BytesRead:               b.bytesRead,
		BytesWritten:            b.bytesWritten,
		ReadCalls:               b.readCalls,
		WriteCalls:              b.writeCalls,
		OpenedAt:                b.createdAt,
		LastReadAt:              b.lastReadAt,
		LastWriteAt:             b.lastWriteAt,
	}
	if b.logical != nil {
		snapshot.LogicalClientID = b.logical.ID()
	}
	if b.resetErr != nil {
		snapshot.ResetError = b.resetErr.Error()
	}
	var diag snapshotBindingDiagnostics
	switch {
	case b.logical != nil || b.transport != nil:
		diag = snapshotBindingDiagnosticsFromLogical(b.logical, b.transport, b.transportGeneration)
	case b.client != nil:
		diag = snapshotBindingDiagnosticsFromClient(b.client, b.sessionEpoch)
	}
	snapshot.BindingOwner = diag.BindingOwner
	snapshot.BindingAlive = diag.BindingAlive
	snapshot.BindingCurrent = diag.BindingCurrent
	snapshot.BindingReason = diag.BindingReason
	snapshot.BindingError = diag.BindingError
	snapshot.BindingBulkAdaptiveSoftPayloadBytes = diag.BindingBulkAdaptiveSoftPayloadBytes
	snapshot.TransportAttached = diag.TransportAttached
	snapshot.TransportHasRuntimeConn = diag.TransportHasRuntimeConn
	snapshot.TransportCurrent = diag.TransportCurrent
	snapshot.TransportDetachReason = diag.TransportDetachReason
	snapshot.TransportDetachKind = diag.TransportDetachKind
	snapshot.TransportDetachGeneration = diag.TransportDetachGeneration
	snapshot.TransportDetachError = diag.TransportDetachError
	snapshot.TransportDetachedAt = diag.TransportDetachedAt
	snapshot.ReattachEligible = diag.ReattachEligible
	return snapshot
}

func (b *bulkHandle) finalize() {
	if b == nil {
		return
	}
	b.markDedicatedAttachClosed()
	b.maybeSendWindowRelease(0, true)
	if b.cancel != nil {
		b.cancel()
	}
	if b.writeCtxCancel != nil {
		b.writeCtxCancel()
	}
	if sender := b.clearDedicatedSender(); sender != nil {
		sender.stop()
	}
	if b.client != nil && b.releaseDedicatedActiveReserved() {
		b.client.releaseBulkDedicatedActiveSlot()
	}
	if b.client != nil {
		b.client.releaseBulkDedicatedLane(b.dedicatedLaneIDSnapshot())
	}
	if conn, owned := b.clearDedicatedConn(); conn != nil && owned {
		_ = conn.Close()
	}
	if b.runtime != nil {
		b.runtime.remove(b.runtimeScope, b.id)
	}
}

func (b *bulkHandle) recordReadLocked(n int, now time.Time) {
	if b == nil || n <= 0 {
		return
	}
	b.bytesRead += int64(n)
	b.readCalls++
	b.lastReadAt = now
}

func (b *bulkHandle) recordWrite(n int, now time.Time) {
	if b == nil || n <= 0 {
		return
	}
	b.mu.Lock()
	b.bytesWritten += int64(n)
	b.writeCalls++
	b.lastWriteAt = now
	b.mu.Unlock()
}

func (b *bulkHandle) waitReadable(ctx context.Context, notify <-chan struct{}, timeout time.Duration) error {
	if ctx == nil {
		ctx = context.Background()
	}
	deadline := streamEffectiveDeadline(time.Now(), timeout, time.Time{})
	if deadline.IsZero() {
		select {
		case <-notify:
			return nil
		case <-ctx.Done():
			if resetErr := b.resetErrSnapshot(); resetErr != nil {
				return resetErr
			}
			if b.localReadClosedSnapshot() {
				return io.ErrClosedPipe
			}
			if b.remoteClosedSnapshot() {
				return nil
			}
			return ctx.Err()
		}
	}
	if !deadline.After(time.Now()) {
		return normalizeStreamDeadlineError(context.DeadlineExceeded)
	}
	timer := time.NewTimer(time.Until(deadline))
	defer timer.Stop()
	select {
	case <-notify:
		return nil
	case <-ctx.Done():
		if resetErr := b.resetErrSnapshot(); resetErr != nil {
			return resetErr
		}
		if b.localReadClosedSnapshot() {
			return io.ErrClosedPipe
		}
		if b.remoteClosedSnapshot() {
			return nil
		}
		return normalizeStreamDeadlineError(ctx.Err())
	case <-timer.C:
		return normalizeStreamDeadlineError(context.DeadlineExceeded)
	}
}

func (b *bulkHandle) resetErrSnapshot() error {
	if b == nil {
		return io.ErrClosedPipe
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.resetErr
}

func (b *bulkHandle) remoteClosedSnapshot() bool {
	if b == nil {
		return true
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.remoteClosed
}

func (b *bulkHandle) localClosedSnapshot() bool {
	if b == nil {
		return true
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.localClosed
}

func (b *bulkHandle) localReadClosedSnapshot() bool {
	if b == nil {
		return true
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.localReadClosed
}

func (b *bulkHandle) writeStateErrorSnapshot() error {
	if b == nil {
		return io.ErrClosedPipe
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.resetErr != nil {
		return b.resetErr
	}
	if b.localClosed || b.peerReadClosed {
		return io.ErrClosedPipe
	}
	return nil
}

func (b *bulkHandle) notifyReadable() {
	if b == nil {
		return
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	b.notifyReadableLocked()
}

func (b *bulkHandle) notifyReadableLocked() {
	if b == nil || b.readNotify == nil {
		return
	}
	select {
	case b.readNotify <- struct{}{}:
	default:
	}
}

func (b *bulkHandle) notifyFlowLocked() {
	if b == nil || b.flowNotify == nil {
		return
	}
	select {
	case b.flowNotify <- struct{}{}:
	default:
	}
}

func (b *bulkHandle) closeWriteStateLocked() {
	if b == nil || b.writeStateClosed {
		return
	}
	b.writeStateClosed = true
	if b.writeStateDone != nil {
		close(b.writeStateDone)
	}
}

func bulkAsyncWriteQueueSize(maxInFlight int) int {
	if maxInFlight <= 0 {
		maxInFlight = defaultBulkOpenMaxInFlight
	}
	if maxInFlight < 8 {
		return 8
	}
	if maxInFlight > 128 {
		return 128
	}
	return maxInFlight
}

func getBulkAsyncWritePayload(size int) []byte {
	if size <= 0 {
		return nil
	}
	if pooled, ok := bulkAsyncWritePayloadPool.Get().([]byte); ok && cap(pooled) >= size {
		return pooled[:size]
	}
	return make([]byte, size)
}

func putBulkAsyncWritePayload(buf []byte) {
	if cap(buf) == 0 || cap(buf) > 8*1024*1024 {
		return
	}
	bulkAsyncWritePayloadPool.Put(buf[:0])
}

func (b *bulkHandle) beginPendingAsyncWriteLocked() {
	if b == nil {
		return
	}
	if b.pendingAsyncWrites == 0 {
		b.writeDrain = make(chan struct{})
	}
	b.pendingAsyncWrites++
}

func (b *bulkHandle) finishPendingAsyncWrite() {
	if b == nil {
		return
	}
	b.mu.Lock()
	if b.pendingAsyncWrites > 0 {
		b.pendingAsyncWrites--
		if b.pendingAsyncWrites == 0 && b.writeDrain != nil {
			close(b.writeDrain)
		}
	}
	b.mu.Unlock()
}

func (b *bulkHandle) waitPendingAsyncWrites(ctx context.Context) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if ctx == nil {
		ctx = context.Background()
	}
	b.mu.Lock()
	if b.pendingAsyncWrites == 0 {
		b.mu.Unlock()
		return nil
	}
	drain := b.writeDrain
	b.mu.Unlock()
	select {
	case <-ctx.Done():
		if err := b.writeStateErrorSnapshot(); err != nil {
			return err
		}
		return normalizeStreamDeadlineError(ctx.Err())
	case <-b.Context().Done():
		if err := b.writeStateErrorSnapshot(); err != nil {
			return err
		}
		return context.Canceled
	case <-drain:
		return b.writeStateErrorSnapshot()
	}
}

func (b *bulkHandle) enqueueAsyncWrite(ctx context.Context, req bulkAsyncWriteRequest) error {
	if b == nil {
		return io.ErrClosedPipe
	}
	if ctx == nil {
		ctx = context.Background()
	}
	b.mu.Lock()
	if b.resetErr != nil {
		err := b.resetErr
		b.mu.Unlock()
		return err
	}
	if b.localClosed || b.peerReadClosed {
		b.mu.Unlock()
		return io.ErrClosedPipe
	}
	queue := b.writeQueue
	if queue == nil {
		b.mu.Unlock()
		return errBulkDataPathNotReady
	}
	b.beginPendingAsyncWriteLocked()
	b.mu.Unlock()
	select {
	case queue <- req:
		return nil
	case <-ctx.Done():
		b.finishPendingAsyncWrite()
		return normalizeStreamDeadlineError(ctx.Err())
	case <-b.Context().Done():
		b.finishPendingAsyncWrite()
		if err := b.writeStateErrorSnapshot(); err != nil {
			return err
		}
		return context.Canceled
	}
}

func (b *bulkHandle) runAsyncWriteLoop() {
	if b == nil {
		return
	}
	defer close(b.writeWorkerDone)
	for {
		select {
		case <-b.Context().Done():
			b.drainPendingAsyncWrites()
			return
		case req := <-b.writeQueue:
			b.processAsyncWrite(req)
		}
	}
}

func (b *bulkHandle) drainPendingAsyncWrites() {
	if b == nil || b.writeQueue == nil {
		return
	}
	for {
		select {
		case req := <-b.writeQueue:
			b.rollbackOutboundWindow(len(req.payload), req.chunks)
			putBulkAsyncWritePayload(req.payload)
			b.finishPendingAsyncWrite()
		default:
			return
		}
	}
}

func (b *bulkHandle) processAsyncWrite(req bulkAsyncWriteRequest) {
	if b == nil {
		return
	}
	defer putBulkAsyncWritePayload(req.payload)
	defer b.finishPendingAsyncWrite()
	if len(req.payload) == 0 {
		return
	}
	if err := b.writeStateErrorSnapshot(); err != nil {
		b.rollbackOutboundWindow(len(req.payload), req.chunks)
		return
	}
	b.notifyAcceptStarted()
	b.mu.Lock()
	writeTimeout := b.writeTimeout
	bulkCtx := b.ctx
	b.mu.Unlock()
	sendCtx, cancel, err := b.newWriteContext(bulkCtx, writeTimeout)
	if err != nil {
		b.rollbackOutboundWindow(len(req.payload), req.chunks)
		if stateErr := b.writeStateErrorSnapshot(); stateErr == nil {
			b.markReset(err)
		}
		return
	}
	_, writeErr := b.executeSendWrite(sendCtx, req.startSeq, req.payload, req.chunks, true)
	cancel()
	if writeErr != nil {
		b.markReset(writeErr)
	}
}

func (b *bulkHandle) executeSendWrite(ctx context.Context, startSeq uint64, payload []byte, chunks int, payloadOwned bool) (int, error) {
	if b == nil {
		return 0, io.ErrClosedPipe
	}
	if len(payload) == 0 {
		return 0, nil
	}
	if chunks <= 0 {
		chunks = 1
	}
	if err := b.writeStateErrorSnapshot(); err != nil {
		b.rollbackOutboundWindow(len(payload), chunks)
		return 0, err
	}
	b.mu.Lock()
	sendWriteFn := b.sendWriteFn
	chunkSize := b.chunkSize
	b.mu.Unlock()
	if sendWriteFn == nil {
		b.rollbackOutboundWindow(len(payload), chunks)
		return 0, errBulkDataPathNotReady
	}
	written, err := sendWriteFn(ctx, b, startSeq, payload, payloadOwned)
	if written < 0 {
		written = 0
	}
	if written > len(payload) {
		written = len(payload)
	}
	if written > 0 {
		b.recordWrite(written, time.Now())
	}
	if written < len(payload) {
		remaining := len(payload) - written
		b.rollbackOutboundWindow(remaining, bulkPayloadChunkCount(remaining, chunkSize))
	}
	if err != nil {
		if b.canIgnoreDedicatedCloseSendError(err) {
			return written, nil
		}
		return written, b.normalizeWriteError(err)
	}
	if written != len(payload) {
		return written, io.ErrShortWrite
	}
	return written, nil
}

func (b *bulkHandle) normalizeWriteError(err error) error {
	if err == nil {
		return nil
	}
	if stateErr := b.writeStateErrorSnapshot(); stateErr != nil {
		return stateErr
	}
	return normalizeStreamDeadlineError(err)
}

func (b *bulkHandle) writeStateDoneSnapshot() <-chan struct{} {
	if b == nil {
		return nil
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.writeStateDone
}

func (b *bulkHandle) newWriteContext(parent context.Context, timeout time.Duration) (context.Context, func(), error) {
	baseParent := parent
	if b != nil && parent == b.ctx && b.writeCtx != nil {
		baseParent = b.writeCtx
	}
	ctx, cancel, err := bulkWriteContext(baseParent, timeout)
	if err != nil {
		return nil, func() {}, err
	}
	if b == nil {
		return ctx, cancel, nil
	}
	if stateErr := b.writeStateErrorSnapshot(); stateErr != nil {
		cancel()
		return nil, func() {}, stateErr
	}
	return ctx, cancel, nil
}

func (b *bulkHandle) canIgnoreDedicatedCloseSendError(err error) bool {
	if b == nil || !b.dedicated || err == nil {
		return false
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	if !(b.ctx.Err() != nil || b.remoteClosed || b.peerReadClosed || b.localClosed) {
		return false
	}
	if errors.Is(err, errTransportDetached) || errors.Is(err, net.ErrClosed) || errors.Is(err, io.ErrClosedPipe) {
		return true
	}
	message := strings.ToLower(err.Error())
	return strings.Contains(message, "broken pipe") || strings.Contains(message, "use of closed network connection")
}

func bulkWriteContext(parent context.Context, timeout time.Duration) (context.Context, func(), error) {
	if parent == nil {
		parent = context.Background()
	}
	deadline := streamEffectiveDeadline(time.Now(), timeout, time.Time{})
	if !deadline.IsZero() && !deadline.After(time.Now()) {
		return nil, func() {}, normalizeStreamDeadlineError(context.DeadlineExceeded)
	}
	if deadline.IsZero() {
		return parent, func() {}, nil
	}
	ctx, cancel := context.WithDeadline(parent, deadline)
	return ctx, cancel, nil
}

func normalizeBulkOpenRequest(req BulkOpenRequest) BulkOpenRequest {
	req.Range = normalizeBulkRange(req.Range)
	req.Metadata = cloneBulkMetadata(req.Metadata)
	req.FastPathVersion = normalizeBulkFastPathVersion(req.FastPathVersion)
	if req.Dedicated && req.DedicatedLaneID == 0 {
		req.DedicatedLaneID = 1
	}
	if req.ChunkSize <= 0 {
		req.ChunkSize = defaultBulkChunkSize
	}
	if req.WindowBytes <= 0 {
		req.WindowBytes = defaultBulkOpenWindowBytes
	}
	if req.MaxInFlight <= 0 {
		req.MaxInFlight = defaultBulkOpenMaxInFlight
	}
	if req.ReadTimeout < 0 {
		req.ReadTimeout = defaultBulkControlReadTimeout
	}
	if req.WriteTimeout < 0 {
		req.WriteTimeout = defaultBulkControlWriteTimeout
	}
	return req
}

func normalizeBulkOpenOptions(opt BulkOpenOptions) BulkOpenOptions {
	mode := normalizeBulkOpenMode(opt.Mode)
	switch mode {
	case BulkOpenModeDefault:
		// Preserve legacy behavior when Mode is not explicitly set.
		if opt.Dedicated {
			mode = BulkOpenModeDedicated
		} else {
			mode = BulkOpenModeShared
		}
	}
	readTimeout := opt.ReadTimeout
	if readTimeout < 0 {
		readTimeout = defaultBulkControlReadTimeout
	}
	writeTimeout := opt.WriteTimeout
	if writeTimeout < 0 {
		writeTimeout = defaultBulkControlWriteTimeout
	}
	return BulkOpenOptions{
		ID:           opt.ID,
		Range:        normalizeBulkRange(opt.Range),
		Metadata:     cloneBulkMetadata(opt.Metadata),
		ReadTimeout:  readTimeout,
		WriteTimeout: writeTimeout,
		Mode:         mode,
		Dedicated:    mode == BulkOpenModeDedicated,
		ChunkSize:    opt.ChunkSize,
		WindowBytes:  opt.WindowBytes,
		MaxInFlight:  opt.MaxInFlight,
	}
}

func normalizeBulkOpenMode(mode BulkOpenMode) BulkOpenMode {
	switch mode {
	case BulkOpenModeDefault, BulkOpenModeAuto, BulkOpenModeShared, BulkOpenModeDedicated:
		return mode
	default:
		return BulkOpenModeDefault
	}
}

func initialBulkDedicatedAttachState(dedicated bool) bulkDedicatedAttachState {
	if dedicated {
		return bulkDedicatedAttachStatePending
	}
	return bulkDedicatedAttachStateAttached
}

func bulkPayloadChunkCount(payloadLen int, chunkSize int) int {
	if payloadLen <= 0 {
		return 0
	}
	if chunkSize <= 0 {
		chunkSize = defaultBulkChunkSize
	}
	return (payloadLen + chunkSize - 1) / chunkSize
}

func bulkDedicatedAttachStateName(state bulkDedicatedAttachState) string {
	switch state {
	case bulkDedicatedAttachStatePending:
		return "pending"
	case bulkDedicatedAttachStateAttached:
		return "attached"
	case bulkDedicatedAttachStateDegraded:
		return "degraded"
	case bulkDedicatedAttachStateClosed:
		return "closed"
	default:
		return "unknown"
	}
}

func bulkOpenModeName(mode BulkOpenMode) string {
	switch normalizeBulkOpenMode(mode) {
	case BulkOpenModeAuto:
		return "auto"
	case BulkOpenModeShared:
		return "shared"
	case BulkOpenModeDedicated:
		return "dedicated"
	case BulkOpenModeDefault:
		fallthrough
	default:
		return "default"
	}
}

func normalizeBulkRange(r BulkRange) BulkRange {
	if r.Offset < 0 {
		r.Offset = -1
	}
	if r.Length < 0 {
		r.Length = -1
	}
	return r
}

func validBulkRange(r BulkRange) bool {
	return r.Offset >= 0 && r.Length >= 0
}

func cloneBulkMetadata(src BulkMetadata) BulkMetadata {
	if len(src) == 0 {
		return nil
	}
	dst := make(BulkMetadata, len(src))
	for key, value := range src {
		dst[key] = value
	}
	return dst
}

func bulkResetError(err error) error {
	if err == nil {
		return errBulkReset
	}
	return err
}

func bulkResetMessage(err error) string {
	if err == nil {
		return ""
	}
	return err.Error()
}