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#include "dictionary/dictionary_interface.h"

#include <vector>
#include <string>

#include "base/base.h"
#include "base/singleton.h"
#include "converter/node.h"
#include "dictionary/system/system_dictionary.h"
#include "dictionary/dictionary_preloader.h"
#include "dictionary/user_dictionary.h"

namespace mozc {

namespace {
#include "dictionary/embedded_dictionary_data.h"

class DictionaryImpl : public DictionaryInterface {
 public:
  DictionaryImpl();
  virtual ~DictionaryImpl();

  virtual Node *LookupPredictive(const char *str, int size,
                                 NodeAllocatorInterface *allocator) const;

  virtual Node *LookupExact(const char *str, int size,
                            NodeAllocatorInterface *allocator) const;

  virtual Node *LookupPrefix(const char *str, int size,
                             NodeAllocatorInterface *allocator) const;

  virtual Node *LookupReverse(const char *str, int size,
                              NodeAllocatorInterface *allocator) const;

 private:
  vector<DictionaryInterface *> dics_;
  enum LookupType {
    PREDICTIVE,
    EXACT,
    PREFIX,
    REVERSE,
  };

  Node *LookupInternal(const char *str, int size,
                       LookupType type,
                       NodeAllocatorInterface *allocator) const;
};

DictionaryImpl::DictionaryImpl() {
  {
    SystemDictionary *dic = SystemDictionary::GetSystemDictionary();
    CHECK(dic->OpenFromArray(kDictionaryData_data, kDictionaryData_size));
    DictionaryPreloader::PreloadIfApplicable(kDictionaryData_data,
                                             kDictionaryData_size);
    dics_.push_back(dic);
  }

  {
    UserDictionary *dic = UserDictionary::GetUserDictionary();
    dics_.push_back(dic);
  }
}

// since all sub-dictionaries are singleton, no need to delete them
DictionaryImpl::~DictionaryImpl() {
  dics_.clear();
}

Node *DictionaryImpl::LookupPredictive(const char *str, int size,
                                       NodeAllocatorInterface *allocator) const {
  return LookupInternal(str, size, PREDICTIVE, allocator);
}

Node *DictionaryImpl::LookupExact(const char *str, int size,
                                  NodeAllocatorInterface *allocator) const {
  return LookupInternal(str, size, EXACT, allocator);
}

Node *DictionaryImpl::LookupPrefix(const char *str, int size,
                                   NodeAllocatorInterface *allocator) const {
  return LookupInternal(str, size, PREFIX, allocator);
}

Node *DictionaryImpl::LookupReverse(const char *str, int size,
                                    NodeAllocatorInterface *allocator) const {
  return LookupInternal(str, size, REVERSE, allocator);
}

Node *DictionaryImpl::LookupInternal(const char *str, int size,
                                     LookupType type,
                                     NodeAllocatorInterface *allocator) const {
  Node *head = NULL;
  for (size_t i = 0; i < dics_.size(); ++i) {
    Node *nodes = NULL;
    switch (type) {
      case PREDICTIVE:
        nodes = dics_[i]->LookupPredictive(str, size, allocator);
        break;
      case EXACT:
        nodes = dics_[i]->LookupExact(str, size, allocator);
        break;
      case PREFIX:
        nodes = dics_[i]->LookupPrefix(str, size, allocator);
        break;
      case REVERSE:
        nodes = dics_[i]->LookupReverse(str, size, allocator);
        break;
    }
    if (head == NULL) {
      head = nodes;
    } else if (nodes != NULL) {
      Node *last = NULL;
      // TODO(taku)  this is O(n^2) algorithm. can be fixed.
      for (last = nodes; last->bnext != NULL; last = last->bnext) {}
      last->bnext = head;
      head = nodes;
    }
  }

  return head;
}

DictionaryInterface *g_dictionary = NULL;
}  // namespace

DictionaryInterface *DictionaryFactory::GetDictionary() {
  if (g_dictionary == NULL) {
    return Singleton<DictionaryImpl>::get();
  } else {
    return g_dictionary;
  }
}

void DictionaryFactory::SetDictionary(DictionaryInterface *dictionary) {
  g_dictionary = dictionary;
}
}  // namespace mozc