#include <u.h>
#include <libc.h>
#include <draw.h>
#include <mouse.h>
#include <frame.h>

#define SLOP 25

void _fraddbox(Frame* f, int bn, int n) /* add n boxes after bn, shift the rest
                                         * up, box[bn+n]==box[bn] */
{
  int i;

  if (bn > f->nbox)
    drawerror(f->display, "_fraddbox");
  if (f->nbox + n > f->nalloc)
    _frgrowbox(f, n + SLOP);
  for (i = f->nbox; --i >= bn;)
    f->box[i + n] = f->box[i];
  f->nbox += n;
}

void _frclosebox(Frame* f, int n0, int n1) /* inclusive */
{
  int i;

  if (n0 >= f->nbox || n1 >= f->nbox || n1 < n0)
    drawerror(f->display, "_frclosebox");
  n1++;
  for (i = n1; i < f->nbox; i++)
    f->box[i - (n1 - n0)] = f->box[i];
  f->nbox -= n1 - n0;
}

void _frdelbox(Frame* f, int n0, int n1) /* inclusive */
{
  if (n0 >= f->nbox || n1 >= f->nbox || n1 < n0)
    drawerror(f->display, "_frdelbox");
  _frfreebox(f, n0, n1);
  _frclosebox(f, n0, n1);
}

void _frfreebox(Frame* f, int n0, int n1) /* inclusive */
{
  int i;

  if (n1 < n0)
    return;
  if (n0 >= f->nbox || n1 >= f->nbox)
    drawerror(f->display, "_frfreebox");
  n1++;
  for (i = n0; i < n1; i++)
    if (f->box[i].nrune >= 0)
      free(f->box[i].ptr);
}

void _frgrowbox(Frame* f, int delta) {
  f->nalloc += delta;
  f->box = realloc(f->box, f->nalloc * sizeof(Frbox));
  if (f->box == 0)
    drawerror(f->display, "_frgrowbox");
}

static void dupbox(Frame* f, int bn) {
  uchar* p;

  if (f->box[bn].nrune < 0)
    drawerror(f->display, "dupbox");
  _fraddbox(f, bn, 1);
  if (f->box[bn].nrune >= 0) {
    p = _frallocstr(f, NBYTE(&f->box[bn]) + 1);
    strcpy((char*)p, (char*)f->box[bn].ptr);
    f->box[bn + 1].ptr = p;
  }
}

static uchar* runeindex(uchar* p, int n) {
  int i, w;
  Rune rune;

  for (i = 0; i < n; i++, p += w)
    if (*p < Runeself)
      w = 1;
    else {
      w = chartorune(&rune, (char*)p);
      USED(rune);
    }
  return p;
}

static void truncatebox(
  Frame* f, Frbox* b, int n) /* drop last n chars; no allocation done */
{
  if (b->nrune < 0 || b->nrune < n)
    drawerror(f->display, "truncatebox");
  b->nrune -= n;
  runeindex(b->ptr, b->nrune)[0] = 0;
  b->wid = stringwidth(f->font, (char*)b->ptr);
}

static void chopbox(
  Frame* f, Frbox* b, int n) /* drop first n chars; no allocation done */
{
  char* p;

  if (b->nrune < 0 || b->nrune < n)
    drawerror(f->display, "chopbox");
  p = (char*)runeindex(b->ptr, n);
  memmove((char*)b->ptr, p, strlen(p) + 1);
  b->nrune -= n;
  b->wid = stringwidth(f->font, (char*)b->ptr);
}

void _frsplitbox(Frame* f, int bn, int n) {
  dupbox(f, bn);
  truncatebox(f, &f->box[bn], f->box[bn].nrune - n);
  chopbox(f, &f->box[bn + 1], n);
}

void _frmergebox(Frame* f, int bn) /* merge bn and bn+1 */
{
  Frbox* b;

  b = &f->box[bn];
  _frinsure(f, bn, NBYTE(&b[0]) + NBYTE(&b[1]) + 1);
  strcpy((char*)runeindex(b[0].ptr, b[0].nrune), (char*)b[1].ptr);
  b[0].wid += b[1].wid;
  b[0].nrune += b[1].nrune;
  _frdelbox(f, bn + 1, bn + 1);
}

int _frfindbox(
  Frame* f, int bn, ulong p,
  ulong q) /* find box containing q and put q on a box boundary */
{
  Frbox* b;

  for (b = &f->box[bn]; bn < f->nbox && p + NRUNE(b) <= q; bn++, b++)
    p += NRUNE(b);
  if (p != q)
    _frsplitbox(f, bn++, (int)(q - p));
  return bn;
}