// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_FLAT_RULESET_INDEXER_H_
#define EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_FLAT_RULESET_INDEXER_H_

#include <stddef.h>
#include <memory>
#include <set>
#include <vector>

#include "components/url_pattern_index/url_pattern_index.h"
#include "extensions/browser/api/declarative_net_request/flat/extension_ruleset_generated.h"
#include "extensions/common/api/declarative_net_request.h"
#include "third_party/flatbuffers/src/include/flatbuffers/flatbuffers.h"

namespace extensions::declarative_net_request {

struct IndexedRule;

// Helper class to index rules in the flatbuffer format for the Declarative Net
// Request API.
class FlatRulesetIndexer {
 public:
  FlatRulesetIndexer();

  FlatRulesetIndexer(const FlatRulesetIndexer&) = delete;
  FlatRulesetIndexer& operator=(const FlatRulesetIndexer&) = delete;

  ~FlatRulesetIndexer();

  // Adds `indexed_rule` to the ruleset.
  void AddUrlRule(const IndexedRule& indexed_rule);

  // Returns the number of rules added until now.
  size_t indexed_rules_count() const { return indexed_rules_count_; }

  // Finishes the ruleset construction and releases the underlying indexed data
  // buffer.
  flatbuffers::DetachedBuffer FinishAndReleaseBuffer();

 private:
  using UrlPatternIndexBuilder = url_pattern_index::UrlPatternIndexBuilder;

  std::vector<UrlPatternIndexBuilder*> GetBuilders(
      const IndexedRule& indexed_rule);

  flatbuffers::FlatBufferBuilder builder_;

  // Builders for the ruleset's URL pattern rules that are matched before the
  // request is initiated. This will consist of `flat::IndexType_count`
  // builders. We use unique_ptr since UrlPatternIndexBuilder is a non-copyable
  // and non-movable type.
  const std::vector<std::unique_ptr<UrlPatternIndexBuilder>>
      before_request_index_builders_;

  // Builders for the ruleset's URL pattern rules that are matched after the
  // request's headers have been received.
  const std::vector<std::unique_ptr<UrlPatternIndexBuilder>>
      headers_received_index_builders_;

  // The ruleset's indexed rule metadata, containing fields that are not
  // inherent to URL rules.
  std::vector<flatbuffers::Offset<flat::UrlRuleMetadata>> metadata_;

  // The ruleset's indexed regex rules that are matched before the request is
  // initiated.
  std::vector<flatbuffers::Offset<flat::RegexRule>> before_request_regex_rules_;

  // The ruleset's indexed regex rules that are matched after the request's
  // headers have been received.
  std::vector<flatbuffers::Offset<flat::RegexRule>>
      headers_received_regex_rules_;

  // Number of rules indexed until now.
  size_t indexed_rules_count_ = 0;

  // Whether Finish() has been called.
  bool finished_ = false;
};

}  // namespace extensions::declarative_net_request

#endif  // EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_FLAT_RULESET_INDEXER_H_