#include "spanner.hpp"

#include <stdlib.h>
#include <string.h>
#include <assert.h>
/*******************************************************************************
** InvalidateSpanArray
*******************************************************************************/
void
InvalidateSpanArray(SpanLine* dst, int x1, int x2)
{
   dst->nspans = 1;
   dst->spans[0].x1 = x1;
   dst->spans[0].x2 = x2;
}
/*******************************************************************************
** ValidateSpanArray
*******************************************************************************/
void
ValidateSpanArray(SpanLine* array, int x1, int x2)
{
   Span* span    = array->spans;
   Span* newspan = &array->spans[array->nspans];

   for (int n = array->nspans; n--; span++)
   {
      if (x1 < span->x2 && x2 > span->x1)
      {
         if (x1 > span->x1)
         {
            if (x2 < span->x2)
            {
               newspan->x1 = x2;
               newspan->x2 = span->x2;
               newspan++;
               array->nspans++;
            }
            span->x2 = x1;
         }
         else
         {
            if (x2 < span->x2)
            {
               span->x1 = x2;
            }
            else
            {
               for (Span* s = span; s != newspan; s[0] = s[1], s++);

               newspan--;
               span--;
               array->nspans--;            
            }
         }
      }
   }
   assert(array->nspans >= 0 && array->nspans < 60);
}
/*******************************************************************************
** SpannerInvalidate
*******************************************************************************/
void
SpannerInvalidate(Spanner* spanner)
{
   spanner->ngaps = spanner->height;
   
   for (int i = 0; i < spanner->height; i++)
   {
      InvalidateSpanArray(&spanner->lines[i], 0, spanner->width);
   }
}
/*******************************************************************************
** SpannerValidate
*******************************************************************************/
void
SpannerValidate(Spanner* spanner, int x1, int y1, int x2, int y2)
{
   for (int i = y1; i < y2; i++)
   {
      ValidateSpanArray(&spanner->lines[i], x1, x2);

      if (spanner->lines[i].nspans == 0) spanner->ngaps--;
   }
}
/*******************************************************************************
** SpannerCreate
*******************************************************************************/
void
SpannerCreate(Spanner* spanner, int width, int height)
{
   memset(spanner, 0, sizeof(Spanner));

   spanner->width    = width;
   spanner->height   = height;   
   spanner->lines    = (SpanLine*) calloc(height, sizeof(SpanLine));
}
/*******************************************************************************
** SpannerDelete
*******************************************************************************/
void
SpannerDelete(Spanner* spanner)
{
   free(spanner->lines);
}