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

void _frdrawtext(Frame* f, Point pt, Image* text, Image* back) {
  Frbox* b;
  int nb;

  for (nb = 0, b = f->box; nb < f->nbox; nb++, b++) {
    _frcklinewrap(f, &pt, b);
    if (!f->noredraw && b->nrune >= 0)
      stringbg(f->b, pt, text, ZP, f->font, (char*)b->ptr, back, ZP);
    pt.x += b->wid;
  }
}

static int nbytes(char* s0, int nr) {
  char* s;
  Rune r;

  s = s0;
  while (--nr >= 0)
    s += chartorune(&r, s);
  return s - s0;
}

void frdrawsel(Frame* f, Point pt, ulong p0, ulong p1, int issel) {
  Image *back, *text;

  if (f->ticked)
    frtick(f, frptofchar(f, f->p0), 0);

  if (p0 == p1) {
    frtick(f, pt, issel);
    return;
  }

  if (issel) {
    back = f->cols[HIGH];
    text = f->cols[HTEXT];
  } else {
    back = f->cols[BACK];
    text = f->cols[TEXT];
  }

  frdrawsel0(f, pt, p0, p1, back, text);
}

Point frdrawsel0(
  Frame* f, Point pt, ulong p0, ulong p1, Image* back, Image* text) {
  Frbox* b;
  int nb, nr, w, x, trim;
  Point qt;
  uint p;
  char* ptr;

  if (p0 > p1)
    sysfatal("libframe: frdrawsel0 p0=%lud > p1=%lud", p0, p1);

  p = 0;
  b = f->box;
  trim = 0;
  for (nb = 0; nb < f->nbox && p < p1; nb++) {
    nr = b->nrune;
    if (nr < 0)
      nr = 1;
    if (p + nr <= p0)
      goto Continue;
    if (p >= p0) {
      qt = pt;
      _frcklinewrap(f, &pt, b);
      /* fill in the end of a wrapped line */
      if (pt.y > qt.y)
        draw(f->b, Rect(qt.x, qt.y, f->r.max.x, pt.y), back, nil, qt);
    }
    ptr = (char*)b->ptr;
    if (p < p0) { /* beginning of region: advance into box */
      ptr += nbytes(ptr, p0 - p);
      nr -= (p0 - p);
      p = p0;
    }
    trim = 0;
    if (p + nr > p1) { /* end of region: trim box */
      nr -= (p + nr) - p1;
      trim = 1;
    }
    if (b->nrune < 0 || nr == b->nrune)
      w = b->wid;
    else
      w = stringnwidth(f->font, ptr, nr);
    x = pt.x + w;
    if (x > f->r.max.x)
      x = f->r.max.x;
    draw(f->b, Rect(pt.x, pt.y, x, pt.y + f->font->height), back, nil, pt);
    if (b->nrune >= 0)
      stringnbg(f->b, pt, text, ZP, f->font, ptr, nr, back, ZP);
    pt.x += w;
  Continue:
    b++;
    p += nr;
  }
  /* if this is end of last plain text box on wrapped line, fill to end of line
   */
  if (
    p1 > p0 && b > f->box && b < f->box + f->nbox && b[-1].nrune > 0 && !trim) {
    qt = pt;
    _frcklinewrap(f, &pt, b);
    if (pt.y > qt.y)
      draw(f->b, Rect(qt.x, qt.y, f->r.max.x, pt.y), back, nil, qt);
  }
  return pt;
}

void frredraw(Frame* f) {
  int ticked;
  Point pt;

  if (f->p0 == f->p1) {
    ticked = f->ticked;
    if (ticked)
      frtick(f, frptofchar(f, f->p0), 0);
    frdrawsel0(f, frptofchar(f, 0), 0, f->nchars, f->cols[BACK], f->cols[TEXT]);
    if (ticked)
      frtick(f, frptofchar(f, f->p0), 1);
    return;
  }

  pt = frptofchar(f, 0);
  pt = frdrawsel0(f, pt, 0, f->p0, f->cols[BACK], f->cols[TEXT]);
  pt = frdrawsel0(f, pt, f->p0, f->p1, f->cols[HIGH], f->cols[HTEXT]);
  pt = frdrawsel0(f, pt, f->p1, f->nchars, f->cols[BACK], f->cols[TEXT]);
}

static void _frtick(Frame* f, Point pt, int ticked) {
  Rectangle r;

  if (f->ticked == ticked || f->tick == 0 || !ptinrect(pt, f->r))
    return;
  pt.x -= f->tickscale; /* looks best just left of where requested */
  r = Rect(pt.x, pt.y, pt.x + FRTICKW * f->tickscale, pt.y + f->font->height);
  /* can go into left border but not right */
  if (r.max.x > f->r.max.x)
    r.max.x = f->r.max.x;
  if (ticked) {
    draw(f->tickback, f->tickback->r, f->b, nil, pt);
    draw(f->b, r, f->tick, nil, ZP);
  } else
    draw(f->b, r, f->tickback, nil, ZP);
  f->ticked = ticked;
}

void frtick(Frame* f, Point pt, int ticked) {
  if (f->tickscale != scalesize(f->display, 1)) {
    if (f->ticked)
      _frtick(f, pt, 0);
    frinittick(f);
  }
  _frtick(f, pt, ticked);
}

Point _frdraw(Frame* f, Point pt) {
  Frbox* b;
  int nb, n;

  for (b = f->box, nb = 0; nb < f->nbox; nb++, b++) {
    _frcklinewrap0(f, &pt, b);
    if (pt.y == f->r.max.y) {
      f->nchars -= _frstrlen(f, nb);
      _frdelbox(f, nb, f->nbox - 1);
      break;
    }
    if (b->nrune > 0) {
      n = _frcanfit(f, pt, b);
      if (n == 0)
        break;
      if (n != b->nrune) {
        _frsplitbox(f, nb, n);
        b = &f->box[nb];
      }
      pt.x += b->wid;
    } else {
      if (b->bc == '\n') {
        pt.x = f->r.min.x;
        pt.y += f->font->height;
      } else
        pt.x += _frnewwid(f, pt, b);
    }
  }
  return pt;
}

int _frstrlen(Frame* f, int nb) {
  int n;

  for (n = 0; nb < f->nbox; nb++)
    n += NRUNE(&f->box[nb]);
  return n;
}