#pragma once

#include "envoy/extensions/tracers/opentelemetry/samplers/v3/cel_sampler.pb.h"

#include "envoy/server/factory_context.h"

#include "source/common/common/logger.h"

#include "source/common/config/datasource.h"

#include "source/extensions/filters/common/expr/evaluator.h"

#include "source/extensions/tracers/opentelemetry/samplers/sampler.h"

namespace Envoy {

namespace Extensions {

namespace Tracers {

namespace OpenTelemetry {

namespace Expr = Envoy::Extensions::Filters::Common::Expr;

/**

 * @brief A sampler which samples on CEL expression.

 *

 * - Returns RecordAndSample always.

 * - Description MUST be AlwaysOnSampler.

 *

 */

class CELSampler : public Sampler, Logger::Loggable<Logger::Id::tracing> {

public:

  CELSampler(const ::Envoy::LocalInfo::LocalInfo& local_info,

             Expr::BuilderInstanceSharedConstPtr builder, const xds::type::v3::CelExpression& expr);

  SamplingResult shouldSample(const StreamInfo::StreamInfo& stream_info,

                              const absl::optional<SpanContext> parent_context,

                              const std::string& trace_id, const std::string& name,

                              OTelSpanKind spankind,

                              OptRef<const Tracing::TraceContext> trace_context,

                              const std::vector<SpanContext>& links) override;

private:

  const ::Envoy::LocalInfo::LocalInfo& local_info_;

  const Extensions::Filters::Common::Expr::CompiledExpression compiled_expr_;

};

} // namespace OpenTelemetry

} // namespace Tracers

} // namespace Extensions

} // namespace Envoy