package ingesterrf1

import (
	"context"
	"errors"

	"github.com/go-kit/log"
	"github.com/go-kit/log/level"
	"github.com/grafana/dskit/ring"
	"github.com/grafana/dskit/user"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"

	"github.com/grafana/loki/v3/pkg/distributor"
	"github.com/grafana/loki/v3/pkg/logproto"
)

type Tee struct {
	cfg        Config
	logger     log.Logger
	ringClient *RingClient

	ingesterAppends *prometheus.CounterVec
}

func NewTee(
	cfg Config,
	ringClient *RingClient,
	metricsNamespace string,
	registerer prometheus.Registerer,
	logger log.Logger,
) (*Tee, error) {
	registerer = prometheus.WrapRegistererWithPrefix(metricsNamespace+"_", registerer)

	t := &Tee{
		logger: log.With(logger, "component", "ingester-rf1-tee"),
		ingesterAppends: promauto.With(registerer).NewCounterVec(prometheus.CounterOpts{
			Name: "ingester_rf1_appends_total",
			Help: "The total number of batch appends sent to rf1 ingesters.",
		}, []string{"ingester", "status"}),
		cfg:        cfg,
		ringClient: ringClient,
	}

	return t, nil
}

// Duplicate Implements distributor.Tee which is used to tee distributor requests to pattern ingesters.
func (t *Tee) Duplicate(tenant string, streams []distributor.KeyedStream) {
	for idx := range streams {
		go func(stream distributor.KeyedStream) {
			if err := t.sendStream(tenant, stream); err != nil {
				level.Error(t.logger).Log("msg", "failed to send stream to ingester-rf1", "err", err)
			}
		}(streams[idx])
	}
}

func (t *Tee) sendStream(tenant string, stream distributor.KeyedStream) error {
	var descs [1]ring.InstanceDesc
	replicationSet, err := t.ringClient.ring.Get(stream.HashKey, ring.WriteNoExtend, descs[:0], nil, nil)
	if err != nil {
		return err
	}
	if replicationSet.Instances == nil {
		return errors.New("no instances found")
	}
	addr := replicationSet.Instances[0].Addr
	client, err := t.ringClient.pool.GetClientFor(addr)
	if err != nil {
		return err
	}
	req := &logproto.PushRequest{
		Streams: []logproto.Stream{
			stream.Stream,
		},
	}

	ctx, cancel := context.WithTimeout(user.InjectOrgID(context.Background(), tenant), t.cfg.ClientConfig.RemoteTimeout)
	defer cancel()
	_, err = client.(logproto.PusherRF1Client).Push(ctx, req)
	if err != nil {
		t.ingesterAppends.WithLabelValues(addr, "fail").Inc()
		return err
	}
	t.ingesterAppends.WithLabelValues(addr, "success").Inc()
	return nil
}