#pragma once

#include <map>

#include <memory>

#include <string>

#include "envoy/config/typed_config.h"

#include "envoy/server/tracer_config.h"

namespace Envoy {

namespace Extensions {

namespace Tracers {

namespace OpenTelemetry {

/**

 * @brief A string key-value map that stores the resource attributes.

 */

using ResourceAttributes = absl::flat_hash_map<std::string, std::string>;

/**

 * @brief A Resource represents the entity producing telemetry as Attributes.

 * For example, a process producing telemetry that is running in a container on Kubernetes

 * has a Pod name, it is in a namespace and possibly is part of a Deployment which also has a name.

 * See:

 * https://github.com/open-telemetry/opentelemetry-specification/blob/v1.26.0/specification/resource/sdk.md

 */

struct Resource {

  std::string schema_url_{""};

  ResourceAttributes attributes_{};

};

using ResourceConstSharedPtr = std::shared_ptr<const Resource>;

/**

 * @brief The base type for all resource detectors

 *

 */

class ResourceDetector {

public:

  /**

   * @brief Load attributes and returns a Resource object

   * populated with them and a possible SchemaUrl.

   * @return Resource

   */

  virtual Resource detect() PURE;

};

using ResourceDetectorPtr = std::unique_ptr<ResourceDetector>;

/*

 * A factory for creating resource detectors.

 */

class ResourceDetectorFactory : public Envoy::Config::TypedFactory {

public:

  /**

   * @brief Creates a resource detector based on the configuration type provided.

   *

   * @param message The resource detector configuration.

   * @param context The tracer factory context.

   * @return ResourceDetectorPtr A resource detector based on the configuration type provided.

   */

  virtual ResourceDetectorPtr

  createResourceDetector(const Protobuf::Message& message,

                         Server::Configuration::ServerFactoryContext& context) PURE;

};

using ResourceDetectorTypedFactoryPtr = std::unique_ptr<ResourceDetectorFactory>;

} // namespace OpenTelemetry

} // namespace Tracers

} // namespace Extensions

} // namespace Envoy