#ifndef CPPJIEBA_DICT_TRIE_HPP
#define CPPJIEBA_DICT_TRIE_HPP

#include <iostream>
#include <fstream>
#include <map>
#include <string>
#include <cstring>
#include <cstdlib>
#include <stdint.h>
#include <cmath>
#include <limits>
#include "limonp/StringUtil.hpp"
#include "limonp/Logging.hpp"
#include "Unicode.hpp"
#include "Trie.hpp"

namespace cppjieba {

using namespace limonp;

const double MIN_DOUBLE = -3.14e+100;
const double MAX_DOUBLE = 3.14e+100;
const size_t DICT_COLUMN_NUM = 3;
const char* const UNKNOWN_TAG = "";

class DictTrie {
 public:
  enum UserWordWeightOption {
    WordWeightMin,
    WordWeightMedian,
    WordWeightMax,
  }; // enum UserWordWeightOption

  DictTrie(const string& dict_path, const string& user_dict_paths = "", UserWordWeightOption user_word_weight_opt = WordWeightMedian) {
    Init(dict_path, user_dict_paths, user_word_weight_opt);
  }

  ~DictTrie() {
    delete trie_;
  }

  bool InsertUserWord(const string& word, const string& tag = UNKNOWN_TAG) {
    DictUnit node_info;
    if (!MakeNodeInfo(node_info, word, user_word_default_weight_, tag)) {
      return false;
    }
    active_node_infos_.push_back(node_info);
    trie_->InsertNode(node_info.word, &active_node_infos_.back());
    return true;
  }

  const DictUnit* Find(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end) const {
    return trie_->Find(begin, end);
  }

  void Find(RuneStrArray::const_iterator begin, 
        RuneStrArray::const_iterator end, 
        vector<struct Dag>&res,
        size_t max_word_len = MAX_WORD_LENGTH) const {
    trie_->Find(begin, end, res, max_word_len);
  }

  bool IsUserDictSingleChineseWord(const Rune& word) const {
    return IsIn(user_dict_single_chinese_word_, word);
  }

  double GetMinWeight() const {
    return min_weight_;
  }

 private:
  void Init(const string& dict_path, const string& user_dict_paths, UserWordWeightOption user_word_weight_opt) {
    LoadDict(dict_path);
    freq_sum_ = CalcFreqSum(static_node_infos_);
    CalculateWeight(static_node_infos_, freq_sum_);
    SetStaticWordWeights(user_word_weight_opt);

    if (user_dict_paths.size()) {
      LoadUserDict(user_dict_paths);
    }
    Shrink(static_node_infos_);
    CreateTrie(static_node_infos_);
  }
  
  void CreateTrie(const vector<DictUnit>& dictUnits) {
    assert(dictUnits.size());
    vector<Unicode> words;
    vector<const DictUnit*> valuePointers;
    for (size_t i = 0 ; i < dictUnits.size(); i ++) {
      words.push_back(dictUnits[i].word);
      valuePointers.push_back(&dictUnits[i]);
    }

    trie_ = new Trie(words, valuePointers);
  }

  void LoadUserDict(const string& filePaths) {
    vector<string> files = limonp::Split(filePaths, "|;");
    size_t lineno = 0;
    for (size_t i = 0; i < files.size(); i++) {
      ifstream ifs(files[i].c_str());
      XCHECK(ifs.is_open()) << "open " << files[i] << " failed"; 
      string line;
      DictUnit node_info;
      vector<string> buf;
      for (; getline(ifs, line); lineno++) {
        if (line.size() == 0) {
          continue;
        }
        buf.clear();
        Split(line, buf, " ");
        DictUnit node_info;
        if(buf.size() == 1){
          MakeNodeInfo(node_info, 
                buf[0], 
                user_word_default_weight_,
                UNKNOWN_TAG);
        } else if (buf.size() == 2) {
          MakeNodeInfo(node_info, 
                buf[0], 
                user_word_default_weight_,
                buf[1]);
        } else if (buf.size() == 3) {
          int freq = atoi(buf[1].c_str());
          assert(freq_sum_ > 0.0);
          double weight = log(1.0 * freq / freq_sum_);
          MakeNodeInfo(node_info, buf[0], weight, buf[2]);
        }
        static_node_infos_.push_back(node_info);
        if (node_info.word.size() == 1) {
          user_dict_single_chinese_word_.insert(node_info.word[0]);
        }
      }
    }
  }

  bool MakeNodeInfo(DictUnit& node_info,
        const string& word, 
        double weight, 
        const string& tag) {
    if (!DecodeRunesInString(word, node_info.word)) {
      XLOG(ERROR) << "Decode " << word << " failed.";
      return false;
    }
    node_info.weight = weight;
    node_info.tag = tag;
    return true;
  }

  void LoadDict(const string& filePath) {
    ifstream ifs(filePath.c_str());
    XCHECK(ifs.is_open()) << "open " << filePath << " failed.";
    string line;
    vector<string> buf;

    DictUnit node_info;
    for (size_t lineno = 0; getline(ifs, line); lineno++) {
      Split(line, buf, " ");
      XCHECK(buf.size() == DICT_COLUMN_NUM) << "split result illegal, line:" << line;
      MakeNodeInfo(node_info, 
            buf[0], 
            atof(buf[1].c_str()), 
            buf[2]);
      static_node_infos_.push_back(node_info);
    }
  }

  static bool WeightCompare(const DictUnit& lhs, const DictUnit& rhs) {
    return lhs.weight < rhs.weight;
  }

  void SetStaticWordWeights(UserWordWeightOption option) {
    XCHECK(!static_node_infos_.empty());
    vector<DictUnit> x = static_node_infos_;
    sort(x.begin(), x.end(), WeightCompare);
    min_weight_ = x[0].weight;
    max_weight_ = x[x.size() - 1].weight;
    median_weight_ = x[x.size() / 2].weight;
    switch (option) {
     case WordWeightMin:
       user_word_default_weight_ = min_weight_;
       break;
     case WordWeightMedian:
       user_word_default_weight_ = median_weight_;
       break;
     default:
       user_word_default_weight_ = max_weight_;
       break;
    }
  }

  double CalcFreqSum(const vector<DictUnit>& node_infos) const {
    double sum = 0.0;
    for (size_t i = 0; i < node_infos.size(); i++) {
      sum += node_infos[i].weight;
    }
    return sum;
  }

  void CalculateWeight(vector<DictUnit>& node_infos, double sum) const {
    assert(sum > 0.0);
    for (size_t i = 0; i < node_infos.size(); i++) {
      DictUnit& node_info = node_infos[i];
      assert(node_info.weight > 0.0);
      node_info.weight = log(double(node_info.weight)/sum);
    }
  }

  void Shrink(vector<DictUnit>& units) const {
    vector<DictUnit>(units.begin(), units.end()).swap(units);
  }

  vector<DictUnit> static_node_infos_;
  deque<DictUnit> active_node_infos_; // must not be vector
  Trie * trie_;

  double freq_sum_;
  double min_weight_;
  double max_weight_;
  double median_weight_;
  double user_word_default_weight_;
  unordered_set<Rune> user_dict_single_chinese_word_;
};
}

#endif