#include "lextrans.h"

#include <iostream>

#include "filelib.h"
#include "hg.h"
#include "tdict.h"
#include "grammar.h"
#include "sentence_metadata.h"

using namespace std;

struct LexicalTransImpl {
  LexicalTransImpl(const boost::program_options::variables_map& conf) :
      use_null(conf.count("lextrans_use_null") > 0),
      kXCAT(TD::Convert("X")*-1),
      kNULL(TD::Convert("<eps>")),
      kBINARY(new TRule("[X] ||| [X,1] [X,2] ||| [1] [2]")),
      kGOAL_RULE(new TRule("[Goal] ||| [X,1] ||| [1]")) {
    vector<string> gfiles = conf["grammar"].as<vector<string> >();
    assert(gfiles.size() == 1);
    ReadFile rf(gfiles.front());
    TextGrammar *tg = new TextGrammar;
    grammar.reset(tg);
    istream* in = rf.stream();
    int lc = 0;
    bool flag = false;
    while(*in) {
      string line;
      getline(*in, line);
      if (line.empty()) continue;
      ++lc;
      TRulePtr r(TRule::CreateRulePhrasetable(line));
      tg->AddRule(r);
      if (lc %   50000 == 0) { cerr << '.'; flag = true; }
      if (lc % 2000000 == 0) { cerr << " [" << lc << "]\n"; flag = false; }
    }
    if (flag) cerr << endl;
    cerr << "Loaded " << lc << " rules\n";
  }

  void BuildTrellis(const Lattice& lattice, const SentenceMetadata& smeta, Hypergraph* forest) {
    const int e_len = smeta.GetTargetLength();
    assert(e_len > 0);
    const int f_len = lattice.size();
    // hack to tell the feature function system how big the sentence pair is
    const int f_start = (use_null ? -1 : 0);
    int prev_node_id = -1;
    for (int i = 0; i < e_len; ++i) {  // for each word in the *target*
      Hypergraph::Node* node = forest->AddNode(kXCAT);
      const int new_node_id = node->id_;
      for (int j = f_start; j < f_len; ++j) { // for each word in the source
        const WordID src_sym = (j < 0 ? kNULL : lattice[j][0].label);
        const GrammarIter* gi = grammar->GetRoot()->Extend(src_sym);
        if (!gi) {
          cerr << "No translations found for: " << TD::Convert(src_sym) << "\n";
          abort();
        }
        const RuleBin* rb = gi->GetRules();
        assert(rb);
        for (int k = 0; k < rb->GetNumRules(); ++k) {
          TRulePtr rule = rb->GetIthRule(k);
          Hypergraph::Edge* edge = forest->AddEdge(rule, Hypergraph::TailNodeVector());
          edge->i_ = j;
          edge->j_ = j+1;
          edge->prev_i_ = i;
          edge->prev_j_ = i+1;
          edge->feature_values_ += edge->rule_->GetFeatureValues();
          forest->ConnectEdgeToHeadNode(edge->id_, new_node_id);
        }
      }
      if (prev_node_id >= 0) {
        const int comb_node_id = forest->AddNode(kXCAT)->id_;
        Hypergraph::TailNodeVector tail(2, prev_node_id);
        tail[1] = new_node_id;
        Hypergraph::Edge* edge = forest->AddEdge(kBINARY, tail);
        forest->ConnectEdgeToHeadNode(edge->id_, comb_node_id);
        prev_node_id = comb_node_id;
      } else {
        prev_node_id = new_node_id;
      }
    }
    Hypergraph::TailNodeVector tail(1, forest->nodes_.size() - 1);
    Hypergraph::Node* goal = forest->AddNode(TD::Convert("Goal")*-1);
    Hypergraph::Edge* hg_edge = forest->AddEdge(kGOAL_RULE, tail);
    forest->ConnectEdgeToHeadNode(hg_edge, goal);
  }

 private:
  const bool use_null;
  const WordID kXCAT;
  const WordID kNULL;
  const TRulePtr kBINARY;
  const TRulePtr kGOAL_RULE;
  GrammarPtr grammar;
};

LexicalTrans::LexicalTrans(const boost::program_options::variables_map& conf) :
  pimpl_(new LexicalTransImpl(conf)) {}

bool LexicalTrans::TranslateImpl(const string& input,
                      SentenceMetadata* smeta,
                      const vector<double>& weights,
                      Hypergraph* forest) {
  Lattice& lattice = smeta->src_lattice_;
  LatticeTools::ConvertTextOrPLF(input, &lattice);
  if (!lattice.IsSentence()) {
    // lexical models make independence assumptions
    // that don't work with lattices or conf nets
    cerr << "LexicalTrans: cannot deal with lattice source input!\n";
    abort();
  }
  smeta->SetSourceLength(lattice.size());
  pimpl_->BuildTrellis(lattice, *smeta, forest);
  forest->is_linear_chain_ = true;
  forest->Reweight(weights);
  return true;
}