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#include "rewriter/version_rewriter.h"

#include <algorithm>
#include <string>

#include "base/const.h"
#include "base/logging.h"
#include "base/version.h"
#include "converter/segments.h"
#include "request/conversion_request.h"
#include "absl/container/flat_hash_map.h"
#include "absl/strings/string_view.h"

namespace mozc {
namespace {

constexpr struct {
  absl::string_view key;
  absl::string_view base_candidate;
} kKeyCandList[] = {
    {
        "う゛ぁーじょん",
        "ヴァージョン",
    },
    {
        "ゔぁーじょん",
        "ヴァージョン",
    },
    {
        "ばーじょん",
        "バージョン",
    },
    {
        "Version",
        "Version",
    },
};

}  // namespace

VersionRewriter::VersionRewriter(absl::string_view data_version) {
  std::string version_string =
      absl::StrCat(kVersionRewriterVersionPrefix, Version::GetMozcVersion(),
                   "+", data_version);
  for (const auto &[key, base_candidate] : kKeyCandList) {
    entries_.emplace(
        key, VersionEntry{std::string(base_candidate), version_string, 9});
  }
}

bool VersionRewriter::Rewrite(const ConversionRequest &request,
                              Segments *segments) const {
  bool result = false;
  for (size_t i = segments->history_segments_size();
       i < segments->segments_size(); ++i) {
    Segment *seg = segments->mutable_segment(i);
    DCHECK(seg);
    const auto it = entries_.find(seg->key());
    if (it != entries_.end()) {
      for (size_t j = 0; j < seg->candidates_size(); ++j) {
        const VersionEntry &ent = it->second;
        const Segment::Candidate &c = seg->candidate(static_cast<int>(j));
        if (c.value == ent.base_candidate) {
          Segment::Candidate *new_cand = seg->insert_candidate(
              std::min<int>(seg->candidates_size(), ent.rank));
          if (new_cand != nullptr) {
            new_cand->lid = c.lid;
            new_cand->rid = c.rid;
            new_cand->cost = c.cost;
            new_cand->value = ent.output;
            new_cand->content_value = ent.output;
            new_cand->key = seg->key();
            new_cand->content_key = seg->key();
            // we don't learn version
            new_cand->attributes |= Segment::Candidate::NO_LEARNING;
            result = true;
          }
          break;
        }
      }
    }
  }
  return result;
}

}  // namespace mozc
