#pragma once

#include "envoy/extensions/filters/common/dependency/v3/dependency.pb.h"

#include "absl/status/status.h"

namespace Envoy {

namespace Http {

/**

 * Validation for an http filter chain based on the factory-level

 * FilterDependencies specification. @see NamedHttpFilterConfigFactory

 * Currently only validates decode dependencies.

 */

class DependencyManager {

public:

  /**

   * Register each filter in an http filter chain, using name and dependencies

   * from the filter factory. Filters must be registered in decode path order.

   */

  void registerFilter(

      const std::string& filter_name,

  /**

   * Returns StatusCode::kOk if the decode path of the filter chain is valid.

   * A filter chain is valid iff for each filter, every decode dependency has

   * been provided by a previous filter.

   * Returns StatusCode::kNotFoundError if the decode path is invalid, with

   * details of the first dependency violation found.

   *

   * TODO(auni53): Change this to a general valid() that checks decode and

   * encode path.

   */

  absl::Status validDecodeDependencies();

private:

  // Mapping of filter names to dependencies, in decode path order.

  std::vector<std::pair<std::string,

                        envoy::extensions::filters::common::dependency::v3::FilterDependencies>>

      filter_chain_;

};

} // namespace Http

} // namespace Envoy