package service

import (
	"context"
	"fmt"

	"github.com/synapsecns/sanguine/services/rfq/relayer/reldb"

	"github.com/cornelk/hashmap"
	"github.com/synapsecns/sanguine/core/metrics"
	"github.com/synapsecns/sanguine/ethergo/signer/signer"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/metric"
)

const meterName = "github.com/synapsecns/sanguine/services/rfq/relayer/service"

// generate an interface for otelRecorder that exports the public method.
// this allows us to avoid using recordX externally anad makes the package less confusing.
//
// =============================================================================
// =============================================================================
// IMPORTANT: DO NOT REMOVE THIS COMMENT.
// NOTICE: PLEASE MAKE SURE YOU UPDATE BOTH THE DOCS AND THE GRAFANA DASHBOARD (IF NEEDED) AFTER UPDATING METRICS.
// =============================================================================
// =============================================================================
//
//go:generate go run github.com/vburenin/ifacemaker -f otel.go -s otelRecorder -i iOtelRecorder -p service -o otel_generated.go -c "autogenerated file"
type otelRecorder struct {
	metrics metrics.Handler
	// meter is the metrics meter.
	meter metric.Meter
	// db is the relayer database.
	db reldb.Service
	// statusCountGauge is the gauge for the status.
	statusCountGauge metric.Int64ObservableGauge
	// rebalanceCountGauge is the gauge for the rebalances.
	rebalanceCountGauge metric.Int64ObservableGauge
	// statusCounts is used for metrics.
	// status -> count
	statusCounts *hashmap.Map[reldb.QuoteRequestStatus, int]
	// signer is the signer for signing transactions.
	signer signer.Signer
}

func newOtelRecorder(meterHandler metrics.Handler, db reldb.Service, signer signer.Signer) (_ iOtelRecorder, err error) {
	or := otelRecorder{
		metrics:      meterHandler,
		db:           db,
		meter:        meterHandler.Meter(meterName),
		statusCounts: hashmap.New[reldb.QuoteRequestStatus, int](),
		signer:       signer,
	}

	or.statusCountGauge, err = or.meter.Int64ObservableGauge("status_count")
	if err != nil {
		return nil, fmt.Errorf("could not create status count gauge: %w", err)
	}

	or.rebalanceCountGauge, err = or.meter.Int64ObservableGauge("rebalance_count")
	if err != nil {
		return nil, fmt.Errorf("could not create rebalance count gauge: %w", err)
	}

	_, err = or.meter.RegisterCallback(or.recordStatusCounts, or.statusCountGauge)
	if err != nil {
		return nil, fmt.Errorf("could not register callback for status count gauge: %w", err)
	}

	_, err = or.meter.RegisterCallback(or.recordRebalanceCounts, or.rebalanceCountGauge)
	if err != nil {
		return nil, fmt.Errorf("could not register callback for rebalance count gauge: %w", err)
	}

	return &or, nil
}

func (o *otelRecorder) recordStatusCounts(_ context.Context, observer metric.Observer) (err error) {
	if o.metrics == nil || o.statusCountGauge == nil || o.statusCounts == nil {
		return nil
	}

	o.statusCounts.Range(func(status reldb.QuoteRequestStatus, count int) bool {
		opts := metric.WithAttributes(
			attribute.Int("status_int", int(status.Int())),
			attribute.String("status", status.String()),
			attribute.String("wallet", o.signer.Address().Hex()),
		)
		observer.ObserveInt64(o.statusCountGauge, int64(count), opts)

		return true
	})

	return nil
}

func (o *otelRecorder) recordRebalanceCounts(ctx context.Context, observer metric.Observer) (err error) {
	if o.metrics == nil || o.rebalanceCountGauge == nil || o.db == nil {
		return nil
	}

	rebalances, err := o.db.GetPendingRebalances(ctx)
	if err != nil {
		return fmt.Errorf("could not get pending rebalances: %w", err)
	}

	rebalanceIDs := []string{}
	for _, r := range rebalances {
		if r.RebalanceID != nil {
			rebalanceIDs = append(rebalanceIDs, *r.RebalanceID)
		}
	}

	opts := metric.WithAttributes(
		attribute.String("wallet", o.signer.Address().Hex()),
		attribute.StringSlice("rebalance_ids", rebalanceIDs),
	)
	observer.ObserveInt64(o.rebalanceCountGauge, int64(len(rebalances)), opts)

	return nil
}

// RecordStatusCount records the request status count.
func (o *otelRecorder) RecordStatusCount(status reldb.QuoteRequestStatus, count int) {
	o.statusCounts.Set(status, count)
}