package shared

import (
	"context"
	"log/slog"

	"galaxy/user/internal/logging"
)

// LogServiceOutcome writes one structured service-level outcome log with a
// stable severity derived from err and with trace fields attached when ctx
// carries an active span.
func LogServiceOutcome(logger *slog.Logger, ctx context.Context, message string, err error, attrs ...any) {
	if logger == nil {
		logger = slog.Default()
	}

	attrs = append(attrs, logging.TraceAttrsFromContext(ctx)...)

	switch {
	case err == nil:
		logger.InfoContext(ctx, message, attrs...)
	case isExpectedServiceErrorCode(CodeOf(err)):
		logger.WarnContext(ctx, message, append(attrs, "error", err.Error())...)
	default:
		logger.ErrorContext(ctx, message, append(attrs, "error", err.Error())...)
	}
}

// MetricOutcome returns the stable low-cardinality outcome label derived from
// err for service metrics.
func MetricOutcome(err error) string {
	if err == nil {
		return "success"
	}

	code := CodeOf(err)
	if code == "" {
		return ErrorCodeInternalError
	}

	return code
}

// LogEventPublicationFailure writes one structured error log for an auxiliary
// post-commit event publication failure.
func LogEventPublicationFailure(logger *slog.Logger, ctx context.Context, eventType string, err error, attrs ...any) {
	if err == nil {
		return
	}
	if logger == nil {
		logger = slog.Default()
	}

	attrs = append(attrs,
		"event_type", eventType,
		"error", err.Error(),
	)
	attrs = append(attrs, logging.TraceAttrsFromContext(ctx)...)

	logger.ErrorContext(ctx, "auxiliary event publication failed", attrs...)
}

func isExpectedServiceErrorCode(code string) bool {
	switch code {
	case ErrorCodeInvalidRequest,
		ErrorCodeConflict,
		ErrorCodeSubjectNotFound:
		return true
	default:
		return false
	}
}