package social

import (
	"context"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/metric"
	"go.opentelemetry.io/otel/metric/noop"
)

// meterName scopes the social domain's OpenTelemetry instruments.
const meterName = "scrabble/backend/social"

// socialMetrics holds the social domain's operational instruments. It defaults to
// no-ops (see defaultSocialMetrics); SetMetrics installs the real meter during
// startup wiring.
type socialMetrics struct {
	messages metric.Int64Counter
}

// defaultSocialMetrics returns instruments backed by a no-op meter.
func defaultSocialMetrics() *socialMetrics {
	return newSocialMetrics(noop.NewMeterProvider().Meter(meterName))
}

// newSocialMetrics builds the instruments on meter, falling back to a no-op
// counter on the (rare) construction error.
func newSocialMetrics(meter metric.Meter) *socialMetrics {
	c, err := meter.Int64Counter("chat_messages_total",
		metric.WithDescription("Per-game chat entries posted, labelled by kind (message/nudge)."))
	if err != nil {
		c, _ = noop.NewMeterProvider().Meter(meterName).Int64Counter("chat_messages_total")
	}
	return &socialMetrics{messages: c}
}

// SetMetrics installs the meter the social domain records to. It must be called
// during startup wiring; the default is a no-op meter.
func (svc *Service) SetMetrics(meter metric.Meter) {
	if meter == nil {
		return
	}
	svc.metrics = newSocialMetrics(meter)
}

// recordChat counts one posted chat entry of the given kind (message or nudge).
func (m *socialMetrics) recordChat(ctx context.Context, kind string) {
	m.messages.Add(ctx, 1, metric.WithAttributes(attribute.String("kind", kind)))
}