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#include "rewriter/zipcode_rewriter.h"

#include <algorithm>
#include <string>

#include "base/logging.h"
#include "config/config_handler.h"
#include "converter/segments.h"
#include "dictionary/pos_matcher.h"
#include "protocol/config.pb.h"
#include "request/conversion_request.h"

namespace mozc {
namespace {
using dictionary::POSMatcher;
}  // namespace

bool ZipcodeRewriter::GetZipcodeCandidatePositions(const Segment &seg,
                                                   std::string *zipcode,
                                                   std::string *address,
                                                   size_t *insert_pos) const {
  DCHECK(zipcode);
  DCHECK(address);
  DCHECK(insert_pos);
  for (size_t i = 0; i < seg.candidates_size(); ++i) {
    const Segment::Candidate &c = seg.candidate(i);
    if (!pos_matcher_->IsZipcode(c.lid) || !pos_matcher_->IsZipcode(c.rid)) {
      continue;
    }
    *zipcode = c.content_key;
    *address = c.content_value;
    *insert_pos = i + 1;
    return true;
  }
  return false;
}

// Insert zipcode into the |segment|
bool ZipcodeRewriter::InsertCandidate(size_t insert_pos,
                                      const std::string &zipcode,
                                      const std::string &address,
                                      const ConversionRequest &request,
                                      Segment *segment) const {
  DCHECK(segment);
  if (segment->candidates_size() == 0) {
    LOG(WARNING) << "candidates_size is 0";
    return false;
  }

  const size_t offset = std::min(insert_pos, segment->candidates_size());
  Segment::Candidate *candidate = segment->insert_candidate(offset);
  if (candidate == nullptr) {
    LOG(ERROR) << "cannot insert candidate at " << offset;
    return false;
  }
  DCHECK_GE(offset, 1);
  const Segment::Candidate &base_candidate = segment->candidate(offset - 1);

  bool is_full_width = true;
  switch (request.config().space_character_form()) {
    case config::Config::FUNDAMENTAL_INPUT_MODE:
      is_full_width = true;
      break;
    case config::Config::FUNDAMENTAL_FULL_WIDTH:
      is_full_width = true;
      break;
    case config::Config::FUNDAMENTAL_HALF_WIDTH:
      is_full_width = false;
      break;
    default:
      LOG(WARNING) << "Unknown input mode";
      is_full_width = true;
      break;
  }

  std::string space;
  if (is_full_width) {
    space = "　";  // "　" (full-width space)
  } else {
    space = " ";
  }

  const std::string value = zipcode + space + address;

  candidate->Init();
  candidate->lid = pos_matcher_->GetZipcodeId();
  candidate->rid = pos_matcher_->GetZipcodeId();
  candidate->cost = base_candidate.cost;
  candidate->value = value;
  candidate->content_value = value;
  candidate->key = zipcode;
  candidate->content_key = zipcode;
  candidate->attributes |= Segment::Candidate::NO_VARIANTS_EXPANSION;
  candidate->attributes |= Segment::Candidate::NO_LEARNING;
  candidate->description = "郵便番号と住所";

  return true;
}

ZipcodeRewriter::ZipcodeRewriter(const POSMatcher *pos_matcher)
    : pos_matcher_(pos_matcher) {}

ZipcodeRewriter::~ZipcodeRewriter() = default;

bool ZipcodeRewriter::Rewrite(const ConversionRequest &request,
                              Segments *segments) const {
  if (segments->conversion_segments_size() != 1) {
    return false;
  }

  const Segment &segment = segments->conversion_segment(0);
  const std::string &key = segment.key();
  if (key.empty()) {
    LOG(ERROR) << "Key is empty";
    return false;
  }

  size_t insert_pos;
  std::string zipcode, address;
  if (!GetZipcodeCandidatePositions(segment, &zipcode, &address, &insert_pos)) {
    return false;
  }

  return InsertCandidate(insert_pos, zipcode, address, request,
                         segments->mutable_conversion_segment(0));
}

}  // namespace mozc