/*
  collision.cc -- implement Collision

  source file of the GNU LilyPond music typesetter

  (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
*/
#include "debug.hh"
#include "collision.hh"
#include "note-column.hh"
#include "note-head.hh"
#include "paper-def.hh"

Collision::Collision()
{
    empty_b_ = transparent_b_ =true;
}

void
Collision::add(Note_column* ncol_l)
{
    clash_l_arr_.push(ncol_l);
    add_dependency(ncol_l);
}
/**
  should derive of Array.
 */
static 
int idx(int dir, bool h_shift_b)
{
    assert(abs (dir) == 1);
    int j = dir > 0 ? 0 : 3;
    if ( h_shift_b ) 
	j += dir;
    return j;
}

/** This complicated routine moves note columns around horizontally
  (and rests vertically) to ensure that notes don't clash. 

  This should be done better, probably.  

  This routine is dedicated to Stine Randmael :-)

  */
void
Collision::do_pre_processing()
{
    if (clash_l_arr_.size() <= 1)
	return;
    
    /*
      [stem up, stem up shifted, stem down shifted, stem down]
     */
    Array<Note_column*> clash_group_arr_a[4];
    
    for (int i=0; i < clash_l_arr_.size(); i++) {
	Note_column* c_l = clash_l_arr_[i];
	if (! c_l->dir_i_) {
	    warning ("No stem direction set. Ignoring column in clash. ");
	    continue;
	}
	int d = (c_l->dir_i_);
	
	clash_group_arr_a[idx(d, c_l->h_shift_b_)].push(c_l);
    }
    
    
    for (int j=0; j < 4; j++) {
	if (clash_group_arr_a[j].size() > 1) {
	    warning("Too many clashing notecolumns. Ignoring them.");
	    return;
	}
    }
    int d = 1;
    do {
	if (!clash_group_arr_a[idx(d, false)].size()){
	    clash_group_arr_a[idx(d,  false)] = clash_group_arr_a[idx(d, true)];
	    clash_group_arr_a[idx(d, true)].set_size(0);
	}
    } while ((d *= -1) != 1);
				  

    Interval_t<int> y_extent[4];
    Note_column * col_l_a[4];
    Real x_off [4];
    int y_off[4];
    
    for (int j =0 ; j < 4; j++) {
	if (clash_group_arr_a[j].size()) 
	    col_l_a[j] = clash_group_arr_a[j][0];
	else
	    col_l_a[j] = 0;
	
	if (col_l_a[j]) {
	    y_extent[j] = col_l_a[j]->head_positions_interval();
	}


	x_off [j] = 0.0;
	y_off[j] = 0;
    }
    
    do {
	x_off[idx(d, true)] = d*0.5;
    } while ((d *= -1) != 1);

  
    // y_extent: smallest y-pos noteball interval containing all balls
    // 4 (0..3) groups: stem up/down; shift on/off; 
    Interval_t<int> middle( y_extent[idx(-1,0)].max(),
			    y_extent[idx(1,0)].min() );
    Interval_t<int> open_middle( y_extent[idx(-1,0)].max()+1, y_extent[idx(1,0)].min()-1);
    do{
	if (!open_middle.contains_b(y_extent[idx(d,true)]))
	    x_off[idx(d, true)] = d *1.0 ;
    } while ((d *= -1) != 1);
   
    if (!middle.empty_b() 
	&& middle.length() < 2 && col_l_a[idx(1,0)] && col_l_a[idx(-1,0)]) {	
// reproduction of bugfix at 3am ?
	Note_head * nu_l= col_l_a[idx(1,0)]->head_l_arr_[0];
	Note_head * nd_l = col_l_a[idx(-1,0)]->head_l_arr_.top();
	if (! (nu_l->balltype_i_ == nd_l->balltype_i_ 
	       && nu_l->dots_i_ == nd_l->dots_i_  && middle.length() == 0 )) {
	    x_off[idx(1,0)] -= 0.5;
	    x_off[idx(1,1)] -= 0.5;
	    x_off[idx(-1,1)] += 0.5;
	    x_off[idx(-1,0)] += 0.5;
	}
	
    }    
    Real inter_f = paper()->internote_f();
    Real wid_f = paper()->note_width();
    for (int j=0; j < 4; j++) {
	if (col_l_a[j])
	    col_l_a[j]->translate(Offset(x_off[j] * wid_f,
					 y_off[j] * inter_f));
	
    }
}

IMPLEMENT_STATIC_NAME(Collision);
IMPLEMENT_IS_TYPE_B1(Collision, Item);

void
Collision::do_substitute_dependency(Score_elem*o_l,Score_elem*n_l)
{
    clash_l_arr_.substitute((Note_column*)o_l->item(), 
			    (Note_column*)(n_l?n_l->item():0));
}
