// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

package xexporterhelper // import "go.opentelemetry.io/collector/exporter/exporterhelper/xexporterhelper"

import (
	"context"
	"errors"

	"go.uber.org/zap"

	"go.opentelemetry.io/collector/component"
	"go.opentelemetry.io/collector/consumer/consumererror"
	"go.opentelemetry.io/collector/consumer/consumererror/xconsumererror"
	"go.opentelemetry.io/collector/consumer/xconsumer"
	"go.opentelemetry.io/collector/exporter"
	"go.opentelemetry.io/collector/exporter/exporterhelper"
	"go.opentelemetry.io/collector/exporter/exporterhelper/internal"
	"go.opentelemetry.io/collector/exporter/exporterhelper/internal/queue"
	"go.opentelemetry.io/collector/exporter/exporterhelper/internal/request"
	"go.opentelemetry.io/collector/exporter/exporterhelper/internal/sizer"
	"go.opentelemetry.io/collector/exporter/xexporter"
	"go.opentelemetry.io/collector/pdata/pprofile"
	"go.opentelemetry.io/collector/pdata/xpdata/pref"
	pdatareq "go.opentelemetry.io/collector/pdata/xpdata/request"
	"go.opentelemetry.io/collector/pipeline/xpipeline"
)

var (
	profilesMarshaler   = &pprofile.ProtoMarshaler{}
	profilesUnmarshaler = &pprofile.ProtoUnmarshaler{}
)

// NewProfilesQueueBatchSettings returns a new QueueBatchSettings to configure to WithQueueBatch when using pprofile.Profiles.
// Experimental: This API is at the early stage of development and may change without backward compatibility
// until https://github.com/open-telemetry/opentelemetry-collector/issues/8122 is resolved.
func NewProfilesQueueBatchSettings() QueueBatchSettings {
	return QueueBatchSettings{
		ReferenceCounter: profilesReferenceCounter{},
		Encoding:         profilesEncoding{},
	}
}

var (
	_ request.Request      = (*profilesRequest)(nil)
	_ request.ErrorHandler = (*profilesRequest)(nil)
)

type profilesRequest struct {
	pd         pprofile.Profiles
	cachedSize int
}

func newProfilesRequest(pd pprofile.Profiles) Request {
	return &profilesRequest{
		pd:         pd,
		cachedSize: -1,
	}
}

type profilesEncoding struct{}

var _ exporterhelper.QueueBatchEncoding[request.Request] = profilesEncoding{}

func (profilesEncoding) Unmarshal(bytes []byte) (context.Context, request.Request, error) {
	if queue.PersistRequestContextOnRead() {
		ctx, profiles, err := pdatareq.UnmarshalProfiles(bytes)
		if errors.Is(err, pdatareq.ErrInvalidFormat) {
			// fall back to unmarshaling without context
			profiles, err = profilesUnmarshaler.UnmarshalProfiles(bytes)
		}
		return ctx, newProfilesRequest(profiles), err
	}
	profiles, err := profilesUnmarshaler.UnmarshalProfiles(bytes)
	if err != nil {
		var req request.Request
		return context.Background(), req, err
	}
	return context.Background(), newProfilesRequest(profiles), nil
}

func (profilesEncoding) Marshal(ctx context.Context, req request.Request) ([]byte, error) {
	profiles := req.(*profilesRequest).pd
	if queue.PersistRequestContextOnWrite() {
		return pdatareq.MarshalProfiles(ctx, profiles)
	}
	return profilesMarshaler.MarshalProfiles(profiles)
}

var _ queue.ReferenceCounter[request.Request] = profilesReferenceCounter{}

type profilesReferenceCounter struct{}

func (profilesReferenceCounter) Ref(req request.Request) {
	pref.RefProfiles(req.(*profilesRequest).pd)
}

func (profilesReferenceCounter) Unref(req request.Request) {
	pref.UnrefProfiles(req.(*profilesRequest).pd)
}

func (req *profilesRequest) OnError(err error) Request {
	var profileError xconsumererror.Profiles
	if errors.As(err, &profileError) {
		// TODO: Add logic to unref the new request created here.
		return newProfilesRequest(profileError.Data())
	}
	return req
}

func (req *profilesRequest) ItemsCount() int {
	return req.pd.SampleCount()
}

func (req *profilesRequest) size(sizer sizer.ProfilesSizer) int {
	if req.cachedSize == -1 {
		req.cachedSize = sizer.ProfilesSize(req.pd)
	}
	return req.cachedSize
}

func (req *profilesRequest) setCachedSize(size int) {
	req.cachedSize = size
}

func (req *profilesRequest) BytesSize() int {
	return profilesMarshaler.ProfilesSize(req.pd)
}

type profileExporter struct {
	*internal.BaseExporter
	xconsumer.Profiles
}

// NewProfiles creates an xexporter.Profiles that records observability metrics and wraps every request with a Span.
func NewProfiles(
	ctx context.Context,
	set exporter.Settings,
	cfg component.Config,
	pusher xconsumer.ConsumeProfilesFunc,
	options ...exporterhelper.Option,
) (xexporter.Profiles, error) {
	if cfg == nil {
		return nil, errNilConfig
	}
	if pusher == nil {
		return nil, errNilPushProfileData
	}
	return NewProfilesRequest(ctx, set, requestFromProfiles(), requestConsumeFromProfiles(pusher),
		append([]exporterhelper.Option{internal.WithQueueBatchSettings(NewProfilesQueueBatchSettings())}, options...)...)
}

// requestConsumeFromProfiles returns a RequestConsumeFunc that consumes pprofile.Profiles.
func requestConsumeFromProfiles(pusher xconsumer.ConsumeProfilesFunc) RequestConsumeFunc {
	return func(ctx context.Context, request Request) error {
		return pusher.ConsumeProfiles(ctx, request.(*profilesRequest).pd)
	}
}

// requestFromProfiles returns a RequestFromProfilesFunc that converts pprofile.Profiles into a Request.
func requestFromProfiles() RequestConverterFunc[pprofile.Profiles] {
	return func(_ context.Context, profiles pprofile.Profiles) (Request, error) {
		return newProfilesRequest(profiles), nil
	}
}

// NewProfilesRequest creates a new profiles exporter based on a custom ProfilesConverter and Sender.
// Experimental: This API is at the early stage of development and may change without backward compatibility
// until https://github.com/open-telemetry/opentelemetry-collector/issues/8122 is resolved.
func NewProfilesRequest(
	_ context.Context,
	set exporter.Settings,
	converter RequestConverterFunc[pprofile.Profiles],
	pusher RequestConsumeFunc,
	options ...exporterhelper.Option,
) (xexporter.Profiles, error) {
	if set.Logger == nil {
		return nil, errNilLogger
	}

	if converter == nil {
		return nil, errNilProfilesConverter
	}

	if pusher == nil {
		return nil, errNilConsumeRequest
	}

	be, err := internal.NewBaseExporter(set, xpipeline.SignalProfiles, pusher, options...)
	if err != nil {
		return nil, err
	}

	tc, err := xconsumer.NewProfiles(newConsumeProfiles(converter, be, set.Logger), be.ConsumerOptions...)
	if err != nil {
		return nil, err
	}

	return &profileExporter{BaseExporter: be, Profiles: tc}, nil
}

func newConsumeProfiles(converter RequestConverterFunc[pprofile.Profiles], be *internal.BaseExporter, logger *zap.Logger) xconsumer.ConsumeProfilesFunc {
	return func(ctx context.Context, pd pprofile.Profiles) error {
		req, err := converter(ctx, pd)
		if err != nil {
			logger.Error("Failed to convert profiles. Dropping data.",
				zap.Int("dropped_samples", pd.SampleCount()),
				zap.Error(err))
			return consumererror.NewPermanent(err)
		}
		return be.Send(ctx, req)
	}
}