/*
  collision.cc -- implement Collision

  source file of the LilyPond music typesetter

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

Collision::Collision()
{
}

void
Collision::add(Note_column* ncol_l)
{
    clash_l_arr_.push(ncol_l);
    add_dependency(ncol_l);
}
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];
	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];
    bool rest_b_a[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();
	}

	rest_b_a[j] = (col_l_a[j]) ? col_l_a[j]->rest_b_ : false;	
	x_off [j] = 0.0;
	y_off[j] = 0;
    }
    
    do {
	x_off[idx(d, true)] = d*0.5;
    } while ((d *= -1) != 1);

   do {
	int i1 = idx(d, false);
	int i2 = idx(d,true);
	if (!intersection(y_extent[i1] , 
			  y_extent[i2]).empty_b()) {
	    if (rest_b_a[i1]) {
		y_off[i1] = -y_extent[i1][-d] + y_extent[1][d] + d*4; // ugh
		y_extent[i1] += y_off[i1];
	    }
	}
    } while ((d *= -1) != 1);

    do {
	int i1 = idx(d, false);
	int i2 = idx(-d,false);
	
	if (d*(y_extent[i1][-d] - y_extent[i2][d] )< 0&& rest_b_a[i1]) {
	    y_off[i1] = -y_extent[i1][-d] + y_extent[i2][d] +d* 4; // ugh
	    y_extent[i1] += y_off[i1];
	}
    } while ((d *= -1) != 1);
    
    Interval_t<int> middle( y_extent[0].min(), y_extent[3].max());
    Interval_t<int> open_middle( y_extent[3].max()+1, y_extent[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() <= 1 && col_l_a[idx(1,0)] && col_l_a[idx(-1,0)]
	&& !rest_b_a[idx(1,0)] && !rest_b_a[idx(-1,0)]) {
	
	Notehead * nu_l= col_l_a[idx(1,0)]->head_l_arr_[idx(1,0)];
	Notehead * nd_l = col_l_a[idx(-1,0)]->head_l_arr_[idx(1,0)];
	if (! (nu_l->balltype == nd_l->balltype && nu_l->dots == nd_l->dots)) {
	    x_off[idx(1,0)] -= 0.5;
	    x_off[1] -= 0.5;
	    x_off[2] += 0.5;
	    x_off[idx(-1,0)] += 0.5;
	}
    }    
    Real inter_f = paper()->internote();
    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);
