package shard

import (
	"context"
	"fmt"

	meta "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/metabase"
	"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
)

// SelectPrm groups the parameters of Select operation.
type SelectPrm struct {
	cnr     cid.ID
	filters objectSDK.SearchFilters
}

// SelectRes groups the resulting values of Select operation.
type SelectRes struct {
	addrList []oid.Address
}

// SetContainerID is a Select option to set the container id to search in.
func (p *SelectPrm) SetContainerID(cnr cid.ID) {
	p.cnr = cnr
}

// SetFilters is a Select option to set the object filters.
func (p *SelectPrm) SetFilters(fs objectSDK.SearchFilters) {
	p.filters = fs
}

// AddressList returns list of addresses of the selected objects.
func (r SelectRes) AddressList() []oid.Address {
	return r.addrList
}

// Select selects the objects from shard that match select parameters.
//
// Returns any error encountered that
// did not allow to completely select the objects.
func (s *Shard) Select(ctx context.Context, prm SelectPrm) (SelectRes, error) {
	ctx, span := tracing.StartSpanFromContext(ctx, "Shard.Select",
		trace.WithAttributes(
			attribute.String("shard_id", s.ID().String()),
			attribute.String("container_id", prm.cnr.EncodeToString()),
		))
	defer span.End()

	s.m.RLock()
	defer s.m.RUnlock()

	if s.info.Mode.NoMetabase() {
		return SelectRes{}, ErrDegradedMode
	}

	var selectPrm meta.SelectPrm
	selectPrm.SetFilters(prm.filters)
	selectPrm.SetContainerID(prm.cnr)

	mRes, err := s.metaBase.Select(ctx, selectPrm)
	if err != nil {
		return SelectRes{}, fmt.Errorf("could not select objects from metabase: %w", err)
	}

	return SelectRes{
		addrList: mRes.AddressList(),
	}, nil
}