/**************************************************************************/
/*                            File: build_lattice.cc                      */
/**************************************************************************/
/* Project: Continuous Speech Recognition Search Algorithms               */
/* Author: Neeraj Deshmukh, Aravind Ganapathiraju                         */
/* Class: EE 8993 Spring 1996                        Date: April 25, 1996 */
/**************************************************************************/

/*========================================================================
  This is the routine whihc builds the latice which has to be searched
  for the most probable hypothesis
  ========================================================================*/
/*------------------------------------------------------------------------
  system and ISIP include files
  ------------------------------------------------------------------------*/
#include "test.h"

void build_lattice_cc (FILE *file_in, Grammar *grammar,
		       HMM_Model **hmm_model, Score_Hyp *hypoth)
{
  HMM_State *temp_state  = NULL;
  Score_Hyp *temp_hyp    = NULL; 
  Score_Hyp *best_hyp    = new Score_Hyp (); 
  Score_Hyp *init_hyp    = NULL;
  Gram_State *state_ptr  = NULL;
  Trans_State *trans_ptr = NULL;
  String state_name      = "";
  String temp_symbol     = "";
  int_4 time_index       = 0;
  float_4 input_sample   = 0;
  float_4 score          = 1.0;
  
  hypoth->add_score_hyp_cc (NULL, NULL, 0, 0, 0);
  init_hyp = hypoth->get_next_hyp_cc ();

  int_2 num_vec_len      = ((hmm_model[0]->get_start_state_cc ())->get_mean_cc ())[0]->get_num_columns_cc ();
  
  // initialize the state_ptr to the first state in the language grammar
  //
  Gram_State *gram_states_ptr = grammar->get_states_ptr_cc ();
  
  // get the start state in the grammar
  //
  Gram_State *gram_start_state = grammar->get_start_state_cc ();
  for (trans_ptr = gram_start_state->get_transition_cc ();
       trans_ptr != NULL;
       trans_ptr = trans_ptr->get_next_transition_cc ())
    {
      // check all possible models that can start
      //
      for (int_2 ii = 0; ii < NUM_OF_MODELS; ii++)
	{
	  if (strcmp (trans_ptr->get_state_name_cc (), 
		      hmm_model[ii]->get_model_symbol_cc ()) == 0)
	    {
	      hypothesize_cc ( file_in, hmm_model[ii], hypoth, init_hyp, 
			       score, time_index , ii);
	      rewind (file_in);
	      break;
	    }
	}
    }
  
  // now read the inputs
  //
  while (fscanf (file_in, "%f", &input_sample) != EOF )
    {
      for (int_2 i = 1; i < num_vec_len; i++)
	fscanf ( file_in,"%f", &input_sample );

      // increment time index
      //
      time_index++;
      
      best_hyp->set_path_score_cc (0.0);
      
      // evaluate all hypotheses at this time frame
      //
      for (temp_hyp = hypoth->get_next_hyp_cc ();
	   temp_hyp != NULL;
	   temp_hyp = temp_hyp->get_next_hyp_cc ())
	{
	  if (temp_hyp->get_timestamp_cc () == time_index)
	    {
	      temp_state = (HMM_State *)(temp_hyp->get_element_cc());
	      
	      // check all models possible
	      //
	      for ( int_2 i = 0; i < NUM_OF_MODELS; i++)
		{
		  if (temp_state == hmm_model[i]->get_stop_state_cc ())
		    { 
		      // re-adjust best path so far
		      //
		      if ( temp_hyp->get_path_score_cc () > 
			   best_hyp->get_path_score_cc () )
			best_hyp = temp_hyp;
		    }
		}
	    }
	}
      
      // print the best path score
      //
      int_2 nn = best_hyp->get_word_index_cc ();
      
      // get to the new model states
      //
      state_ptr = gram_states_ptr->find_state_cc (hmm_model[nn]->get_model_symbol_cc ());
      
      // now write all possible transitions from here
      //
      for (trans_ptr = state_ptr->get_transition_cc ();
	   trans_ptr != NULL;
	   trans_ptr = trans_ptr->get_next_transition_cc ())
	{
	  state_name = trans_ptr->get_state_name_cc ();
	  
	  for (int_2 j = 0; j < NUM_OF_MODELS; j++)
	    {
	      temp_symbol = hmm_model[j]->get_model_symbol_cc ();
	      if (strcmp (temp_symbol, state_name) == 0)
		{
		  score = trans_ptr->get_transition_score_cc();
		  hypothesize_cc (file_in, hmm_model[j], hypoth,
				  best_hyp, score, time_index, j );
		}
	    }
	}
      fseek (file_in, num_vec_len * (sizeof(float_4)) * time_index, SEEK_SET); 
    }
}