/* Haiku window system support.  Hey, Emacs, this is -*- C++ -*-
   Copyright (C) 2021 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#include <Font.h>
#include <Rect.h>
#include <AffineTransform.h>

#include <cstring>
#include <cmath>

#include "haiku_support.h"

/* Haiku doesn't expose font language data in BFont objects.  Thus, we
   select a few representative characters for each supported `:lang'
   (currently Chinese, Korean and Japanese,) and test for those
   instead.  */

static uint32_t language_code_points[MAX_LANGUAGE][4] =
  {{20154, 20754, 22996, 0}, /* Chinese.  */
   {51312, 49440, 44544, 0}, /* Korean.  */
   {26085, 26412, 12371, 0}, /* Japanese.  */};

static void
estimate_font_ascii (BFont *font, int *max_width,
		     int *min_width, int *avg_width)
{
  char ch[2];
  bool tems[1];
  int total = 0;
  int count = 0;
  int min = 0;
  int max = 0;

  std::memset (ch, 0, sizeof ch);
  for (ch[0] = 32; ch[0] < 127; ++ch[0])
    {
      tems[0] = false;
      font->GetHasGlyphs (ch, 1, tems);
      if (tems[0])
	{
	  int w = font->StringWidth (ch);
	  ++count;
	  total += w;

	  if (!min || min > w)
	    min = w;
	  if (max < w)
	    max = w;
	}
    }

  *min_width = min;
  *max_width = max;
  *avg_width = total / count;
}

void
BFont_close (void *font)
{
  if (font != (void *) be_fixed_font &&
      font != (void *) be_plain_font &&
      font != (void *) be_bold_font)
    delete (BFont *) font;
}

void
BFont_dat (void *font, int *px_size, int *min_width, int *max_width,
	   int *avg_width, int *height, int *space_width, int *ascent,
	   int *descent, int *underline_position, int *underline_thickness)
{
  BFont *ft = (BFont *) font;
  struct font_height fheight;
  bool have_space_p;

  char atem[1];
  bool otem[1];

  ft->GetHeight (&fheight);
  atem[0] = ' ';
  otem[0] = false;
  ft->GetHasGlyphs (atem, 1, otem);
  have_space_p = otem[0];

  estimate_font_ascii (ft, max_width, min_width, avg_width);
  *ascent = std::lrint (fheight.ascent);
  *descent = std::lrint (fheight.descent);
  *height = *ascent + *descent;

  *space_width = have_space_p ? ft->StringWidth (" ") : 0;

  *px_size = std::lrint (ft->Size ());
  *underline_position = 0;
  *underline_thickness = 0;
}

/* Return non-null if FONT contains CHR, a Unicode code-point.  */
int
BFont_have_char_p (void *font, int32_t chr)
{
  BFont *ft = (BFont *) font;
  return ft->IncludesBlock (chr, chr);
}

/* Return non-null if font contains a block from BEG to END.  */
int
BFont_have_char_block (void *font, int32_t beg, int32_t end)
{
  BFont *ft = (BFont *) font;
  return ft->IncludesBlock (beg, end);
}

/* Compute bounds for MB_STR, a character in multibyte encoding,
   used with font.  The width (in pixels) is returned in ADVANCE,
   the left bearing in LB, and the right bearing in RB.  */
void
BFont_char_bounds (void *font, const char *mb_str, int *advance,
		   int *lb, int *rb)
{
  BFont *ft = (BFont *) font;
  edge_info edge_info;
  float size, escapement;
  size = ft->Size ();

  ft->GetEdges (mb_str, 1, &edge_info);
  ft->GetEscapements (mb_str, 1, &escapement);
  *advance = std::lrint (escapement * size);
  *lb = std::lrint (edge_info.left * size);
  *rb = *advance + std::lrint (edge_info.right * size);
}

/* The same, but for a variable amount of chars.  */
void
BFont_nchar_bounds (void *font, const char *mb_str, int *advance,
		    int *lb, int *rb, int32_t n)
{
  BFont *ft = (BFont *) font;
  edge_info edge_info[n];
  float size;
  float escapement[n];

  size = ft->Size ();

  ft->GetEdges (mb_str, n, edge_info);
  ft->GetEscapements (mb_str, n, (float *) escapement);

  for (int32_t i = 0; i < n; ++i)
    {
      advance[i] = std::lrint (escapement[i] * size);
      lb[i] = advance[i] - std::lrint (edge_info[i].left * size);
      rb[i] = advance[i] + std::lrint (edge_info[i].right * size);
    }
}

static void
font_style_to_flags (char *st, struct haiku_font_pattern *pattern)
{
  char *style = strdup (st);
  char *token;
  pattern->weight = -1;
  pattern->width = NO_WIDTH;
  pattern->slant = NO_SLANT;
  int tok = 0;

  while ((token = std::strtok (!tok ? style : NULL, " ")) && tok < 3)
    {
      if (token && !strcmp (token, "Thin"))
	pattern->weight = HAIKU_THIN;
      else if (token && !strcmp (token, "UltraLight"))
	pattern->weight = HAIKU_ULTRALIGHT;
      else if (token && !strcmp (token, "ExtraLight"))
	pattern->weight = HAIKU_EXTRALIGHT;
      else if (token && !strcmp (token, "Light"))
	pattern->weight = HAIKU_LIGHT;
      else if (token && !strcmp (token, "SemiLight"))
	pattern->weight = HAIKU_SEMI_LIGHT;
      else if (token && !strcmp (token, "Regular"))
	{
	  if (pattern->slant == NO_SLANT)
	    pattern->slant = SLANT_REGULAR;

	  if (pattern->width == NO_WIDTH)
	    pattern->width = NORMAL_WIDTH;

	  if (pattern->weight == -1)
	    pattern->weight = HAIKU_REGULAR;
	}
      else if (token && !strcmp (token, "SemiBold"))
	pattern->weight = HAIKU_SEMI_BOLD;
      else if (token && !strcmp (token, "Bold"))
	pattern->weight = HAIKU_BOLD;
      else if (token && (!strcmp (token, "ExtraBold") ||
			 /* This has actually been seen in the wild.  */
			 !strcmp (token, "Extrabold")))
	pattern->weight = HAIKU_EXTRA_BOLD;
      else if (token && !strcmp (token, "UltraBold"))
	pattern->weight = HAIKU_ULTRA_BOLD;
      else if (token && !strcmp (token, "Book"))
	pattern->weight = HAIKU_BOOK;
      else if (token && !strcmp (token, "Heavy"))
	pattern->weight = HAIKU_HEAVY;
      else if (token && !strcmp (token, "UltraHeavy"))
	pattern->weight = HAIKU_ULTRA_HEAVY;
      else if (token && !strcmp (token, "Black"))
	pattern->weight = HAIKU_BLACK;
      else if (token && !strcmp (token, "Medium"))
	pattern->weight = HAIKU_MEDIUM;
      else if (token && !strcmp (token, "Oblique"))
	pattern->slant = SLANT_OBLIQUE;
      else if (token && !strcmp (token, "Italic"))
	pattern->slant = SLANT_ITALIC;
      else if (token && !strcmp (token, "UltraCondensed"))
	pattern->width = ULTRA_CONDENSED;
      else if (token && !strcmp (token, "ExtraCondensed"))
	pattern->width = EXTRA_CONDENSED;
      else if (token && !strcmp (token, "Condensed"))
	pattern->width = CONDENSED;
      else if (token && !strcmp (token, "SemiCondensed"))
	pattern->width = SEMI_CONDENSED;
      else if (token && !strcmp (token, "SemiExpanded"))
	pattern->width = SEMI_EXPANDED;
      else if (token && !strcmp (token, "Expanded"))
	pattern->width = EXPANDED;
      else if (token && !strcmp (token, "ExtraExpanded"))
	pattern->width = EXTRA_EXPANDED;
      else if (token && !strcmp (token, "UltraExpanded"))
	pattern->width = ULTRA_EXPANDED;
      else
	{
	  tok = 1000;
	  break;
	}
      tok++;
    }

  if (pattern->weight != -1)
    pattern->specified |= FSPEC_WEIGHT;
  if (pattern->slant != NO_SLANT)
    pattern->specified |= FSPEC_SLANT;
  if (pattern->width != NO_WIDTH)
    pattern->specified |= FSPEC_WIDTH;

  if (tok > 3)
    {
      pattern->specified &= ~FSPEC_SLANT;
      pattern->specified &= ~FSPEC_WEIGHT;
      pattern->specified &= ~FSPEC_WIDTH;
      pattern->specified |= FSPEC_STYLE;
      std::strncpy ((char *) &pattern->style, st,
		    sizeof pattern->style - 1);
    }

  free (style);
}

static bool
font_check_wanted_chars (struct haiku_font_pattern *pattern, font_family family,
			 char *style)
{
  BFont ft;

  if (ft.SetFamilyAndStyle (family, style) != B_OK)
    return false;

  for (int i = 0; i < pattern->want_chars_len; ++i)
    if (!ft.IncludesBlock (pattern->wanted_chars[i],
			   pattern->wanted_chars[i]))
      return false;

  return true;
}

static bool
font_check_one_of (struct haiku_font_pattern *pattern, font_family family,
		   char *style)
{
  BFont ft;

  if (ft.SetFamilyAndStyle (family, style) != B_OK)
    return false;

  for (int i = 0; i < pattern->need_one_of_len; ++i)
    if (ft.IncludesBlock (pattern->need_one_of[i],
			  pattern->need_one_of[i]))
      return true;

  return false;
}

static bool
font_check_language (struct haiku_font_pattern *pattern, font_family family,
		     char *style)
{
  BFont ft;

  if (ft.SetFamilyAndStyle (family, style) != B_OK)
    return false;

  if (pattern->language == MAX_LANGUAGE)
    return false;

  for (uint32_t *ch = (uint32_t *)
	 &language_code_points[pattern->language]; *ch; ch++)
    if (!ft.IncludesBlock (*ch, *ch))
      return false;

  return true;
}

static bool
font_family_style_matches_p (font_family family, char *style, uint32_t flags,
			     struct haiku_font_pattern *pattern,
			     int ignore_flags_p = 0)
{
  struct haiku_font_pattern m;
  m.specified = 0;

  if (style)
    font_style_to_flags (style, &m);

  if ((pattern->specified & FSPEC_FAMILY) &&
      strcmp ((char *) &pattern->family, family))
    return false;

  if (!ignore_flags_p && (pattern->specified & FSPEC_SPACING) &&
      !(pattern->mono_spacing_p) != !(flags & B_IS_FIXED))
    return false;

  if (pattern->specified & FSPEC_STYLE)
    return style && !strcmp (style, pattern->style);

  if ((pattern->specified & FSPEC_WEIGHT)
      && (pattern->weight
	  != ((m.specified & FSPEC_WEIGHT) ? m.weight : HAIKU_REGULAR)))
    return false;

  if ((pattern->specified & FSPEC_SLANT)
      && (pattern->slant
	  != ((m.specified & FSPEC_SLANT) ? m.slant : SLANT_REGULAR)))
    return false;

  if ((pattern->specified & FSPEC_WANTED)
      && !font_check_wanted_chars (pattern, family, style))
    return false;

  if ((pattern->specified & FSPEC_WIDTH)
      && (pattern->width !=
	  ((m.specified & FSPEC_WIDTH) ? m.width : NORMAL_WIDTH)))
    return false;

  if ((pattern->specified & FSPEC_NEED_ONE_OF)
      && !font_check_one_of (pattern, family, style))
    return false;

  if ((pattern->specified & FSPEC_LANGUAGE)
      && !font_check_language (pattern, family, style))
    return false;

  return true;
}

static void
haiku_font_fill_pattern (struct haiku_font_pattern *pattern,
			 font_family family, char *style,
			 uint32_t flags)
{
  if (style)
    font_style_to_flags (style, pattern);

  pattern->specified |= FSPEC_FAMILY;
  std::strncpy (pattern->family, family,
		sizeof pattern->family - 1);
  pattern->specified |= FSPEC_SPACING;
  pattern->mono_spacing_p = flags & B_IS_FIXED;
}

/* Delete every element of the font pattern PT.  */
void
haiku_font_pattern_free (struct haiku_font_pattern *pt)
{
  struct haiku_font_pattern *tem = pt;
  while (tem)
    {
      struct haiku_font_pattern *t = tem;
      tem = t->next;
      delete t;
    }
}

/* Find all fonts matching the font pattern PT.  */
struct haiku_font_pattern *
BFont_find (struct haiku_font_pattern *pt)
{
  struct haiku_font_pattern *r = NULL;
  font_family name;
  font_style sname;
  uint32 flags;
  int sty_count;
  int fam_count = count_font_families ();

  for (int fi = 0; fi < fam_count; ++fi)
    {
      if (get_font_family (fi, &name, &flags) == B_OK)
	{
	  sty_count = count_font_styles (name);
	  if (!sty_count &&
	      font_family_style_matches_p (name, NULL, flags, pt))
	    {
	      struct haiku_font_pattern *p = new struct haiku_font_pattern;
	      p->specified = 0;
	      p->oblique_seen_p = 1;
	      haiku_font_fill_pattern (p, name, NULL, flags);
	      p->next = r;
	      if (p->next)
		p->next->last = p;
	      p->last = NULL;
	      p->next_family = r;
	      r = p;
	    }
	  else if (sty_count)
	    {
	      for (int si = 0; si < sty_count; ++si)
		{
		  int oblique_seen_p = 0;
		  struct haiku_font_pattern *head = r;
		  struct haiku_font_pattern *p = NULL;

		  if (get_font_style (name, si, &sname, &flags) == B_OK)
		    {
		      if (font_family_style_matches_p (name, (char *) &sname, flags, pt))
			{
			  p = new struct haiku_font_pattern;
			  p->specified = 0;
			  haiku_font_fill_pattern (p, name, (char *) &sname, flags);
			  if (p->specified & FSPEC_SLANT &&
			      ((p->slant == SLANT_OBLIQUE) || (p->slant == SLANT_ITALIC)))
			    oblique_seen_p = 1;

			  p->next = r;
			  if (p->next)
			    p->next->last = p;
			  r = p;
			  p->next_family = head;
			}
		    }

		  if (p)
		    p->last = NULL;

		  for (; head; head = head->last)
		    {
		      head->oblique_seen_p = oblique_seen_p;
		    }
		}
	    }
	}
    }

  /* There's a very good chance that this result will get cached if no
     slant is specified.  Thus, we look through each font that hasn't
     seen an oblique style, and add one.  */

  if (!(pt->specified & FSPEC_SLANT))
    {
      /* r->last is invalid from here onwards.  */
      for (struct haiku_font_pattern *p = r; p;)
	{
	  if (!p->oblique_seen_p)
	    {
	      struct haiku_font_pattern *n = new haiku_font_pattern;
	      *n = *p;
	      n->slant = SLANT_OBLIQUE;
	      p->next = n;
	      p = p->next_family;
	    }
	  else
	    p = p->next_family;
	}
    }

  return r;
}

/* Find and open a font matching the pattern PAT, which must have its
   family set.  */
int
BFont_open_pattern (struct haiku_font_pattern *pat, void **font, float size)
{
  int sty_count;
  font_family name;
  font_style sname;
  uint32 flags = 0;
  if (!(pat->specified & FSPEC_FAMILY))
    return 1;
  strncpy (name, pat->family, sizeof name - 1);
  sty_count = count_font_styles (name);

  if (!sty_count &&
      font_family_style_matches_p (name, NULL, flags, pat, 1))
    {
      BFont *ft = new BFont;
      if (ft->SetFamilyAndStyle (name, NULL) != B_OK)
	{
	  delete ft;
	  return 1;
	}
      ft->SetSize (size);
      ft->SetEncoding (B_UNICODE_UTF8);
      ft->SetSpacing (B_BITMAP_SPACING);
      *font = (void *) ft;
      return 0;
    }
  else if (sty_count)
    {
      for (int si = 0; si < sty_count; ++si)
	{
	  if (get_font_style (name, si, &sname, &flags) == B_OK &&
	      font_family_style_matches_p (name, (char *) &sname, flags, pat))
	    {
	      BFont *ft = new BFont;
	      if (ft->SetFamilyAndStyle (name, sname) != B_OK)
		{
		  delete ft;
		  return 1;
		}
	      ft->SetSize (size);
	      ft->SetEncoding (B_UNICODE_UTF8);
	      ft->SetSpacing (B_BITMAP_SPACING);
	      *font = (void *) ft;
	      return 0;
	    }
	}
    }

  if (pat->specified & FSPEC_SLANT && pat->slant == SLANT_OBLIQUE)
    {
      struct haiku_font_pattern copy = *pat;
      copy.slant = SLANT_REGULAR;
      int code = BFont_open_pattern (&copy, font, size);
      if (code)
	return code;
      BFont *ft = (BFont *) *font;
      /* XXX Font measurements don't respect shear.  Haiku bug?
	 This apparently worked in BeOS.
	 ft->SetShear (100.0); */
      ft->SetFace (B_ITALIC_FACE);
      return 0;
    }

  return 1;
}

/* Query the family of the default fixed font.  */
void
BFont_populate_fixed_family (struct haiku_font_pattern *ptn)
{
  font_family f;
  font_style s;
  be_fixed_font->GetFamilyAndStyle (&f, &s);

  ptn->specified |= FSPEC_FAMILY;
  strncpy (ptn->family, f, sizeof ptn->family - 1);
}

void
BFont_populate_plain_family (struct haiku_font_pattern *ptn)
{
  font_family f;
  font_style s;
  be_plain_font->GetFamilyAndStyle (&f, &s);

  ptn->specified |= FSPEC_FAMILY;
  strncpy (ptn->family, f, sizeof ptn->family - 1);
}

int
BFont_string_width (void *font, const char *utf8)
{
  return ((BFont *) font)->StringWidth (utf8);
}