package notify

import (
	"context"
	"errors"
	"time"
)

const bulkOpenRecoveryTimeout = 2 * time.Second

func (c *ClientCommon) SetBulkHandler(fn func(BulkAcceptInfo) error) {
	runtime := c.getBulkRuntime()
	if runtime == nil {
		return
	}
	runtime.setHandler(fn)
}

func (c *ClientCommon) OpenSharedBulk(ctx context.Context, opt BulkOpenOptions) (Bulk, error) {
	opt.Mode = BulkOpenModeShared
	opt.Dedicated = false
	return c.OpenBulk(ctx, opt)
}

func (c *ClientCommon) OpenDedicatedBulk(ctx context.Context, opt BulkOpenOptions) (Bulk, error) {
	opt.Mode = BulkOpenModeDedicated
	opt.Dedicated = true
	return c.OpenBulk(ctx, opt)
}

func (c *ClientCommon) OpenBulk(ctx context.Context, opt BulkOpenOptions) (Bulk, error) {
	if normalizeBulkOpenMode(opt.Mode) == BulkOpenModeDefault && !opt.Dedicated {
		opt.Mode = c.bulkDefaultOpenModeSnapshot()
	}
	opt = normalizeBulkOpenOptions(opt)
	switch opt.Mode {
	case BulkOpenModeDedicated:
		opt.Dedicated = true
		return c.openBulkWithDedicatedMode(ctx, opt, false)
	case BulkOpenModeAuto:
		// Auto mode prefers dedicated path and falls back to shared if dedicated fails.
		if err := clientDedicatedBulkSupportError(c); err == nil {
			dedicatedOpt := opt
			dedicatedOpt.Mode = BulkOpenModeDedicated
			dedicatedOpt.Dedicated = true
			bulk, dedicatedErr := c.openBulkWithDedicatedMode(ctx, dedicatedOpt, true)
			if dedicatedErr == nil {
				return bulk, nil
			}
			sharedOpt := opt
			sharedOpt.Mode = BulkOpenModeShared
			sharedOpt.Dedicated = false
			sharedBulk, sharedErr := c.openBulkWithDedicatedMode(ctx, sharedOpt, false)
			if sharedErr == nil {
				c.bulkAttachFallbackCount.Add(1)
				return sharedBulk, nil
			}
			return nil, errors.Join(dedicatedErr, sharedErr)
		}
		opt.Mode = BulkOpenModeShared
		opt.Dedicated = false
		c.bulkAttachFallbackCount.Add(1)
		return c.openBulkWithDedicatedMode(ctx, opt, false)
	case BulkOpenModeShared, BulkOpenModeDefault:
		opt.Mode = BulkOpenModeShared
		opt.Dedicated = false
		return c.openBulkWithDedicatedMode(ctx, opt, false)
	default:
		opt.Mode = BulkOpenModeShared
		opt.Dedicated = false
		return c.openBulkWithDedicatedMode(ctx, opt, false)
	}
}

func (c *ClientCommon) openBulkWithDedicatedMode(ctx context.Context, opt BulkOpenOptions, waitForReset bool) (Bulk, error) {
	if c == nil {
		return nil, errBulkClientNil
	}
	route := c.clientSessionRouteSnapshot()
	if err := c.ensureClientSessionRouteSendReady(route); err != nil {
		return nil, err
	}
	opt = applyBulkOpenTuningDefaults(opt, c.bulkOpenTuningSnapshot())
	runtime := c.getBulkRuntime()
	if runtime == nil {
		return nil, errBulkRuntimeNil
	}
	req := clientBulkRequest(runtime, opt)
	if req.BulkID == "" {
		return nil, errBulkIDEmpty
	}
	if req.Dedicated {
		if err := clientDedicatedBulkSupportError(c); err != nil {
			return nil, err
		}
	}
	if !validBulkRange(req.Range) {
		return nil, errBulkRangeInvalid
	}
	if existing, exists := runtime.lookup(clientFileScope(), req.BulkID); exists {
		if existing.acceptsClientSessionRoute(route) {
			return nil, errBulkAlreadyExists
		}
		existing.markReset(errTransportDetached)
	}
	if req.DataID == 0 {
		var reserveErr error
		req.DataID, reserveErr = runtime.reserveDataID(clientFileScope(), 0)
		if reserveErr != nil {
			return nil, reserveErr
		}
	}
	if req.Dedicated {
		var laneErr error
		req.DedicatedLaneID, laneErr = c.reserveBulkDedicatedLaneAtRoute(route)
		if laneErr != nil {
			runtime.releaseDataID(clientFileScope(), req.DataID)
			return nil, laneErr
		}
		if req.AttachToken == "" {
			req.AttachToken = newBulkAttachToken()
		}
		bulk := newBulkHandle(clientSessionRouteContext(route), runtime, clientFileScope(), req, route.epoch, nil, nil, 0, clientBulkCloseSender(c), clientBulkResetSender(c), clientBulkDataSender(c, route), clientBulkWriteSender(c, route), clientBulkReleaseSender(c))
		bulk.setClientSnapshotOwner(c)
		bulk.setClientSessionRoute(route)
		bulk.markAcceptHandled()
		bulk.markDedicatedLaneReserved()
		if err := runtime.adoptReserved(clientFileScope(), bulk); err != nil {
			runtime.releaseDataID(clientFileScope(), req.DataID)
			return nil, err
		}
		resp, err := sendBulkOpenClientAtRoute(ctx, c, route, req)
		if err != nil {
			runtime.releaseDataID(clientFileScope(), req.DataID)
			cleanupErr := c.cleanupBulkResetAtRoute(ctx, route, BulkResetRequest{BulkID: req.BulkID, DataID: req.DataID, Error: err.Error()}, waitForReset)
			bulk.markReset(err)
			if cleanupErr != nil {
				return nil, errors.Join(err, cleanupErr)
			}
			return nil, err
		}
		if resp.DataID != 0 && resp.DataID != req.DataID {
			err = errBulkAlreadyExists
			cleanupErr := c.cleanupBulkResetAtRoute(ctx, route, BulkResetRequest{
				BulkID: req.BulkID,
				Error:  "bulk dedicated data id mismatch",
			}, waitForReset)
			bulk.markReset(err)
			if cleanupErr != nil {
				return nil, errors.Join(err, cleanupErr)
			}
			return nil, err
		}
		if resp.TransportGeneration != 0 {
			bulk.setTransportGeneration(resp.TransportGeneration)
		}
		if resp.FastPathVersion != 0 {
			bulk.setFastPathVersion(resp.FastPathVersion)
		}
		if resp.AttachToken != "" {
			req.AttachToken = resp.AttachToken
			bulk.setDedicatedAttachToken(resp.AttachToken)
		}
		if err := c.attachDedicatedBulkSidecar(ctx, bulk); err != nil {
			cleanupErr := c.cleanupBulkResetAtRoute(ctx, route, BulkResetRequest{
				BulkID: req.BulkID,
				DataID: req.DataID,
				Error:  err.Error(),
			}, waitForReset)
			bulk.markReset(err)
			if cleanupErr != nil {
				return nil, errors.Join(err, cleanupErr)
			}
			return nil, err
		}
		if err := bulk.waitAcceptReady(ctx); err != nil {
			var cleanupErr error
			if bulk.resetErrSnapshot() == nil {
				cleanupErr = c.cleanupBulkResetAtRoute(ctx, route, BulkResetRequest{
					BulkID: req.BulkID,
					DataID: req.DataID,
					Error:  err.Error(),
				}, waitForReset)
			} else {
				// A ready error already reset the remote handle. Keep the old
				// asynchronous cleanup for compatibility with that path and avoid
				// racing a concurrent dedicated attach teardown.
				c.bestEffortBulkResetAtRoute(route, BulkResetRequest{
					BulkID: req.BulkID,
					DataID: req.DataID,
					Error:  err.Error(),
				})
			}
			bulk.markReset(err)
			if cleanupErr != nil {
				return nil, errors.Join(err, cleanupErr)
			}
			return nil, err
		}
		return bulk, nil
	}
	bulk := newBulkHandle(clientSessionRouteContext(route), runtime, clientFileScope(), req, route.epoch, nil, nil, 0, clientBulkCloseSender(c), clientBulkResetSender(c), clientBulkDataSender(c, route), clientBulkWriteSender(c, route), clientBulkReleaseSender(c))
	bulk.setClientSnapshotOwner(c)
	bulk.setClientSessionRoute(route)
	bulk.markAcceptHandled()
	if err := runtime.adoptReserved(clientFileScope(), bulk); err != nil {
		runtime.releaseDataID(clientFileScope(), req.DataID)
		return nil, err
	}
	resp, err := sendBulkOpenClientAtRoute(ctx, c, route, req)
	if err != nil {
		c.bestEffortBulkResetAtRoute(route, BulkResetRequest{BulkID: req.BulkID, DataID: req.DataID, Error: err.Error()})
		bulk.markReset(err)
		return nil, err
	}
	if resp.DataID != 0 && resp.DataID != req.DataID {
		err = errBulkAlreadyExists
		c.bestEffortBulkResetAtRoute(route, BulkResetRequest{BulkID: req.BulkID, Error: "bulk data id mismatch"})
		bulk.markReset(err)
		return nil, err
	}
	if resp.FastPathVersion != 0 {
		bulk.setFastPathVersion(resp.FastPathVersion)
	}
	if resp.Dedicated {
		err = errBulkRejected
		c.bestEffortBulkResetAtRoute(route, BulkResetRequest{BulkID: req.BulkID, DataID: req.DataID, Error: "shared bulk upgraded to dedicated"})
		bulk.markReset(err)
		return nil, err
	}
	if resp.AttachToken != "" {
		bulk.setDedicatedAttachToken(resp.AttachToken)
	}
	bulk.setTransportGeneration(resp.TransportGeneration)
	return bulk, nil
}

func (c *ClientCommon) bestEffortBulkReset(req BulkResetRequest) {
	if c == nil {
		return
	}
	c.bestEffortBulkResetAtRoute(c.clientSessionRouteSnapshot(), req)
}

func (c *ClientCommon) bestEffortBulkResetAtEpoch(epoch uint64, req BulkResetRequest) {
	route := c.clientSessionRouteSnapshot()
	route.epoch = epoch
	c.bestEffortBulkResetAtRoute(route, req)
}

func (c *ClientCommon) bestEffortBulkResetAtRoute(route clientSessionRoute, req BulkResetRequest) {
	if c == nil {
		return
	}
	task := newClientBulkResetRecoveryTaskAtRoute(c, route, req)
	q := c.bulkRecoveryQueue()
	if !q.enqueue(task) {
		c.handleBulkRecoveryOverflowAtRoute(route, req)
	}
}

func (c *ClientCommon) bulkRecoveryQueue() *bulkRecoveryQueue {
	if c == nil {
		return nil
	}
	c.bulkRecoveryMu.Lock()
	defer c.bulkRecoveryMu.Unlock()
	if c.bulkRecovery == nil {
		c.bulkRecovery = newBulkRecoveryQueue(c.reportBulkRecoveryError)
	}
	return c.bulkRecovery
}

func newClientBulkResetRecoveryTask(c *ClientCommon, epoch uint64, req BulkResetRequest) bulkRecoveryTask {
	route := c.clientSessionRouteSnapshot()
	route.epoch = epoch
	return newClientBulkResetRecoveryTaskAtRoute(c, route, req)
}

func newClientBulkResetRecoveryTaskAtRoute(c *ClientCommon, route clientSessionRoute, req BulkResetRequest) bulkRecoveryTask {
	return func(ctx context.Context) error {
		if !c.clientSessionRouteCurrent(route) {
			return transportDetachedSessionEpochError()
		}
		_, err := sendBulkResetClientAtRoute(ctx, c, route, req)
		if errors.Is(err, errBulkNotFound) {
			return nil
		}
		return err
	}
}

func clientBulkRequest(runtime *bulkRuntime, opt BulkOpenOptions) BulkOpenRequest {
	opt = normalizeBulkOpenOptions(opt)
	id := opt.ID
	if id == "" && runtime != nil {
		id = runtime.nextID()
	}
	return normalizeBulkOpenRequest(BulkOpenRequest{
		BulkID:          id,
		FastPathVersion: bulkFastPathVersionCurrent,
		Range:           opt.Range,
		Metadata:        cloneBulkMetadata(opt.Metadata),
		ReadTimeout:     opt.ReadTimeout,
		WriteTimeout:    opt.WriteTimeout,
		Dedicated:       opt.Dedicated,
		ChunkSize:       opt.ChunkSize,
		WindowBytes:     opt.WindowBytes,
		MaxInFlight:     opt.MaxInFlight,
	})
}

func clientBulkCloseSender(c *ClientCommon) bulkCloseSender {
	return func(ctx context.Context, bulk *bulkHandle, full bool) error {
		if bulk != nil && bulk.Dedicated() {
			if err := bulk.waitDedicatedReady(ctx); err != nil {
				return err
			}
			return c.sendDedicatedBulkClose(ctx, bulk, full)
		}
		_, err := sendBulkCloseClientAtRoute(ctx, c, bulk.clientSessionRouteSnapshot(), BulkCloseRequest{
			BulkID: bulk.ID(),
			DataID: bulk.dataIDSnapshot(),
			Full:   full,
		})
		return err
	}
}

func clientBulkResetSender(c *ClientCommon) bulkResetSender {
	return func(ctx context.Context, bulk *bulkHandle, message string) error {
		if bulk != nil && bulk.Dedicated() {
			if err := bulk.waitDedicatedReady(ctx); err != nil {
				return err
			}
			return c.sendDedicatedBulkReset(ctx, bulk, message)
		}
		_, err := sendBulkResetClientAtRoute(ctx, c, bulk.clientSessionRouteSnapshot(), BulkResetRequest{
			BulkID: bulk.ID(),
			DataID: bulk.dataIDSnapshot(),
			Error:  message,
		})
		return err
	}
}

func clientBulkDataSender(c *ClientCommon, route clientSessionRoute) bulkDataSender {
	return func(ctx context.Context, bulk *bulkHandle, chunk []byte) error {
		if c == nil {
			return errBulkClientNil
		}
		if ctx != nil {
			select {
			case <-ctx.Done():
				return ctx.Err()
			default:
			}
		}
		if bulk != nil && bulk.Dedicated() {
			if err := bulk.waitDedicatedReady(ctx); err != nil {
				return err
			}
			return c.sendDedicatedBulkData(ctx, bulk, chunk)
		}
		if !c.clientSessionRouteCurrent(route) {
			return errTransportDetached
		}
		dataID := bulk.dataIDSnapshot()
		if dataID == 0 {
			return errBulkDataPathNotReady
		}
		return c.sendFastBulkDataAtRoute(ctx, route, dataID, bulk.nextOutboundDataSeq(), chunk, bulk.fastPathVersionSnapshot())
	}
}

func clientBulkWriteSender(c *ClientCommon, route clientSessionRoute) bulkWriteSender {
	return func(ctx context.Context, bulk *bulkHandle, startSeq uint64, payload []byte, payloadOwned bool) (int, error) {
		if c == nil {
			return 0, errBulkClientNil
		}
		if ctx != nil {
			select {
			case <-ctx.Done():
				return 0, ctx.Err()
			default:
			}
		}
		if bulk != nil && bulk.Dedicated() {
			if err := bulk.waitDedicatedReady(ctx); err != nil {
				return 0, err
			}
			return c.sendDedicatedBulkWrite(ctx, bulk, startSeq, payload, payloadOwned)
		}
		if !c.clientSessionRouteCurrent(route) {
			return 0, errTransportDetached
		}
		if bulk == nil {
			return 0, errBulkRuntimeNil
		}
		dataID := bulk.dataIDSnapshot()
		if dataID == 0 {
			return 0, errBulkDataPathNotReady
		}
		return c.sendFastBulkWriteAtRoute(ctx, route, dataID, startSeq, bulk.chunkSize, bulk.fastPathVersionSnapshot(), payload, payloadOwned)
	}
}

func clientBulkReleaseSender(c *ClientCommon) bulkReleaseSender {
	fallbackRoute := c.clientSessionRouteSnapshot()
	return func(bulk *bulkHandle, bytes int64, chunks int) error {
		if c == nil || bulk == nil {
			return errBulkClientNil
		}
		if bytes <= 0 && chunks <= 0 {
			return nil
		}
		ctx, cancel, err := bulk.newWriteContext(bulk.Context(), bulk.writeTimeout)
		if err != nil {
			return err
		}
		defer cancel()
		if bulk.Dedicated() {
			return c.sendDedicatedBulkRelease(ctx, bulk, bytes, chunks)
		}
		route := bulk.clientSessionRouteSnapshot()
		if !route.bound() {
			route = fallbackRoute
		}
		if bulk.fastPathVersionSnapshot() >= bulkFastPathVersionV2 {
			payload, err := encodeBulkDedicatedReleasePayload(bytes, chunks)
			if err != nil {
				return err
			}
			return c.sendFastBulkControlAtRoute(ctx, route, bulkFastPayloadTypeRelease, 0, bulk.dataIDSnapshot(), 0, bulk.fastPathVersionSnapshot(), payload)
		}
		return sendBulkReleaseClientAtRoute(ctx, c, route, BulkReleaseRequest{
			BulkID: bulk.ID(),
			DataID: bulk.dataIDSnapshot(),
			Bytes:  bytes,
			Chunks: chunks,
		})
	}
}