/*

 * Copyright © 2022 Behdad Esfahbod

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

#ifndef HB_GEOMETRY_HH

#define HB_GEOMETRY_HH

#include "hb.hh"

struct hb_extents_t

{

  hb_extents_t () {}

  hb_extents_t (const hb_glyph_extents_t &extents) :

    xmin (hb_min (extents.x_bearing, extents.x_bearing + extents.width)),

    ymin (hb_min (extents.y_bearing, extents.y_bearing + extents.height)),

    xmax (hb_max (extents.x_bearing, extents.x_bearing + extents.width)),

    ymax (hb_max (extents.y_bearing, extents.y_bearing + extents.height)) {}

  hb_extents_t (float xmin, float ymin, float xmax, float ymax) :

    xmin (xmin), ymin (ymin), xmax (xmax), ymax (ymax) {}

  bool is_empty () const { return xmin >= xmax || ymin >= ymax; }

  bool is_void () const { return xmin > xmax; }

  void union_ (const hb_extents_t &o)

  {

    if (o.is_empty ()) return;

    if (is_empty ())

    {

      *this = o;

      return;

    }

    xmin = hb_min (xmin, o.xmin);

    ymin = hb_min (ymin, o.ymin);

    xmax = hb_max (xmax, o.xmax);

    ymax = hb_max (ymax, o.ymax);

  }

  void intersect (const hb_extents_t &o)

  {

    if (o.is_empty () || is_empty ())

    {

      *this = hb_extents_t {};

      return;

    }

    xmin = hb_max (xmin, o.xmin);

    ymin = hb_max (ymin, o.ymin);

    xmax = hb_min (xmax, o.xmax);

    ymax = hb_min (ymax, o.ymax);

  }

  void

  add_point (float x, float y)

  {

    if (unlikely (is_void ()))

    {

      xmin = xmax = x;

      ymin = ymax = y;

    }

    else

    {

      xmin = hb_min (xmin, x);

      ymin = hb_min (ymin, y);

      xmax = hb_max (xmax, x);

      ymax = hb_max (ymax, y);

    }

  }

  hb_glyph_extents_t to_glyph_extents (bool xneg = false, bool yneg = false) const

  {

    hb_position_t x0 = (hb_position_t) roundf (xmin);

    hb_position_t y0 = (hb_position_t) roundf (ymin);

    hb_position_t x1 = (hb_position_t) roundf (xmax);

    hb_position_t y1 = (hb_position_t) roundf (ymax);

    return hb_glyph_extents_t {xneg ? x1 : x0,

             yneg ? y0 : y1,

             xneg ? x0 - x1 : x1 - x0,

             yneg ? y1 - y0 : y0 - y1};

  }

  float xmin = 0.f;

  float ymin = 0.f;

  float xmax = -1.f;

  float ymax = -1.f;

};

struct hb_transform_t

{

  hb_transform_t () {}

  hb_transform_t (float xx, float yx,

      float xy, float yy,

      float x0, float y0) :

    xx (xx), yx (yx), xy (xy), yy (yy), x0 (x0), y0 (y0) {}

  bool is_identity () const

  {

    return xx == 1.f && yx == 0.f &&

     xy == 0.f && yy == 1.f &&

     x0 == 0.f && y0 == 0.f;

  }

  void multiply (const hb_transform_t &o)

  {

    /* Copied from cairo, with "o" being "a" there and "this" being "b" there. */

    hb_transform_t r;

    r.xx = o.xx * xx + o.yx * xy;

    r.yx = o.xx * yx + o.yx * yy;

    r.xy = o.xy * xx + o.yy * xy;

    r.yy = o.xy * yx + o.yy * yy;

    r.x0 = o.x0 * xx + o.y0 * xy + x0;

    r.y0 = o.x0 * yx + o.y0 * yy + y0;

    *this = r;

  }

  void transform_distance (float &dx, float &dy) const

  {

    float new_x = xx * dx + xy * dy;

    float new_y = yx * dx + yy * dy;

    dx = new_x;

    dy = new_y;

  }

  void transform_point (float &x, float &y) const

  {

    transform_distance (x, y);

    x += x0;

    y += y0;

  }

  void transform_extents (hb_extents_t &extents) const

  {

    float quad_x[4], quad_y[4];

    quad_x[0] = extents.xmin;

    quad_y[0] = extents.ymin;

    quad_x[1] = extents.xmin;

    quad_y[1] = extents.ymax;

    quad_x[2] = extents.xmax;

    quad_y[2] = extents.ymin;

    quad_x[3] = extents.xmax;

    quad_y[3] = extents.ymax;

    extents = hb_extents_t {};

    for (unsigned i = 0; i < 4; i++)

    {

      transform_point (quad_x[i], quad_y[i]);

      extents.add_point (quad_x[i], quad_y[i]);

    }

  }

  void transform (const hb_transform_t &o) { multiply (o); }

  void translate (float x, float y)

  {

    if (x == 0.f && y == 0.f)

      return;

    x0 += xx * x + xy * y;

    y0 += yx * x + yy * y;

  }

  void scale (float scaleX, float scaleY)

  {

    if (scaleX == 1.f && scaleY == 1.f)

      return;

    xx *= scaleX;

    yx *= scaleX;

    xy *= scaleY;

    yy *= scaleY;

  }

  void rotate (float rotation)

  {

    if (rotation == 0.f)

      return;

    // https://github.com/fonttools/fonttools/blob/f66ee05f71c8b57b5f519ee975e95edcd1466e14/Lib/fontTools/misc/transform.py#L240

    rotation = rotation * HB_PI;

    float c;

    float s;

#ifdef HAVE_SINCOSF

    sincosf (rotation, &s, &c);

#else

    c = cosf (rotation);

    s = sinf (rotation);

#endif

    auto other = hb_transform_t{c, s, -s, c, 0.f, 0.f};

    transform (other);

  }

  void skew (float skewX, float skewY)

  {

    if (skewX == 0.f && skewY == 0.f)

      return;

    // https://github.com/fonttools/fonttools/blob/f66ee05f71c8b57b5f519ee975e95edcd1466e14/Lib/fontTools/misc/transform.py#L255

    skewX = skewX * HB_PI;

    skewY = skewY * HB_PI;

    auto other = hb_transform_t{1.f,

        skewY ? tanf (skewY) : 0.f,

        skewX ? tanf (skewX) : 0.f,

        1.f,

        0.f, 0.f};

    transform (other);

  }

  float xx = 1.f;

  float yx = 0.f;

  float xy = 0.f;

  float yy = 1.f;

  float x0 = 0.f;

  float y0 = 0.f;

};

#define HB_TRANSFORM_IDENTITY hb_transform_t{1.f, 0.f, 0.f, 1.f, 0.f, 0.f}

struct hb_bounds_t

{

  enum status_t {

    UNBOUNDED,

    BOUNDED,

    EMPTY,

  };

  hb_bounds_t (status_t status = UNBOUNDED) : status (status) {}

  hb_bounds_t (const hb_extents_t &extents) :

    status (extents.is_empty () ? EMPTY : BOUNDED), extents (extents) {}

  void union_ (const hb_bounds_t &o)

  {

    if (o.status == UNBOUNDED)

      status = UNBOUNDED;

    else if (o.status == BOUNDED)

    {

      if (status == EMPTY)

  *this = o;

      else if (status == BOUNDED)

        extents.union_ (o.extents);

    }

  }

  void intersect (const hb_bounds_t &o)

  {

    if (o.status == EMPTY)

      status = EMPTY;

    else if (o.status == BOUNDED)

    {

      if (status == UNBOUNDED)

  *this = o;

      else if (status == BOUNDED)

      {

        extents.intersect (o.extents);

  if (extents.is_empty ())

    status = EMPTY;

      }

    }

  }

  status_t status;

  hb_extents_t extents;

};

struct hb_transform_decomposed_t

{

  float translateX = 0;

  float translateY = 0;

  float rotation = 0;  // in degrees, counter-clockwise

  float scaleX = 1;

  float scaleY = 1;

  float skewX = 0;  // in degrees, counter-clockwise

  float skewY = 0;  // in degrees, counter-clockwise

  float tCenterX = 0;

  float tCenterY = 0;

  operator bool () const

  {

    return translateX || translateY ||

     rotation ||

     scaleX != 1 || scaleY != 1 ||

     skewX || skewY ||

     tCenterX || tCenterY;

  }

  hb_transform_t to_transform () const

  {

    hb_transform_t t;

    t.translate (translateX + tCenterX, translateY + tCenterY);

    t.rotate (rotation);

    t.scale (scaleX, scaleY);

    t.skew (-skewX, skewY);

    t.translate (-tCenterX, -tCenterY);

    return t;

  }

};

#endif /* HB_GEOMETRY_HH */