/*
 * Copyright © 2009  Red Hat, Inc.
 * Copyright © 2011  Google, Inc.
 *
 *  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.
 *
 * Red Hat Author(s): Behdad Esfahbod
 * Google Author(s): Behdad Esfahbod
 */

#include "hb-private.hh"

#include "hb-glib.h"

#include "hb-unicode-private.hh"


#if !GLIB_CHECK_VERSION(2,29,14)
static const hb_script_t
glib_script_to_script[] =
{
  HB_SCRIPT_COMMON,
  HB_SCRIPT_INHERITED,
  HB_SCRIPT_ARABIC,
  HB_SCRIPT_ARMENIAN,
  HB_SCRIPT_BENGALI,
  HB_SCRIPT_BOPOMOFO,
  HB_SCRIPT_CHEROKEE,
  HB_SCRIPT_COPTIC,
  HB_SCRIPT_CYRILLIC,
  HB_SCRIPT_DESERET,
  HB_SCRIPT_DEVANAGARI,
  HB_SCRIPT_ETHIOPIC,
  HB_SCRIPT_GEORGIAN,
  HB_SCRIPT_GOTHIC,
  HB_SCRIPT_GREEK,
  HB_SCRIPT_GUJARATI,
  HB_SCRIPT_GURMUKHI,
  HB_SCRIPT_HAN,
  HB_SCRIPT_HANGUL,
  HB_SCRIPT_HEBREW,
  HB_SCRIPT_HIRAGANA,
  HB_SCRIPT_KANNADA,
  HB_SCRIPT_KATAKANA,
  HB_SCRIPT_KHMER,
  HB_SCRIPT_LAO,
  HB_SCRIPT_LATIN,
  HB_SCRIPT_MALAYALAM,
  HB_SCRIPT_MONGOLIAN,
  HB_SCRIPT_MYANMAR,
  HB_SCRIPT_OGHAM,
  HB_SCRIPT_OLD_ITALIC,
  HB_SCRIPT_ORIYA,
  HB_SCRIPT_RUNIC,
  HB_SCRIPT_SINHALA,
  HB_SCRIPT_SYRIAC,
  HB_SCRIPT_TAMIL,
  HB_SCRIPT_TELUGU,
  HB_SCRIPT_THAANA,
  HB_SCRIPT_THAI,
  HB_SCRIPT_TIBETAN,
  HB_SCRIPT_CANADIAN_ABORIGINAL,
  HB_SCRIPT_YI,
  HB_SCRIPT_TAGALOG,
  HB_SCRIPT_HANUNOO,
  HB_SCRIPT_BUHID,
  HB_SCRIPT_TAGBANWA,

  /* Unicode-4.0 additions */
  HB_SCRIPT_BRAILLE,
  HB_SCRIPT_CYPRIOT,
  HB_SCRIPT_LIMBU,
  HB_SCRIPT_OSMANYA,
  HB_SCRIPT_SHAVIAN,
  HB_SCRIPT_LINEAR_B,
  HB_SCRIPT_TAI_LE,
  HB_SCRIPT_UGARITIC,

  /* Unicode-4.1 additions */
  HB_SCRIPT_NEW_TAI_LUE,
  HB_SCRIPT_BUGINESE,
  HB_SCRIPT_GLAGOLITIC,
  HB_SCRIPT_TIFINAGH,
  HB_SCRIPT_SYLOTI_NAGRI,
  HB_SCRIPT_OLD_PERSIAN,
  HB_SCRIPT_KHAROSHTHI,

  /* Unicode-5.0 additions */
  HB_SCRIPT_UNKNOWN,
  HB_SCRIPT_BALINESE,
  HB_SCRIPT_CUNEIFORM,
  HB_SCRIPT_PHOENICIAN,
  HB_SCRIPT_PHAGS_PA,
  HB_SCRIPT_NKO,

  /* Unicode-5.1 additions */
  HB_SCRIPT_KAYAH_LI,
  HB_SCRIPT_LEPCHA,
  HB_SCRIPT_REJANG,
  HB_SCRIPT_SUNDANESE,
  HB_SCRIPT_SAURASHTRA,
  HB_SCRIPT_CHAM,
  HB_SCRIPT_OL_CHIKI,
  HB_SCRIPT_VAI,
  HB_SCRIPT_CARIAN,
  HB_SCRIPT_LYCIAN,
  HB_SCRIPT_LYDIAN,

  /* Unicode-5.2 additions */
  HB_SCRIPT_AVESTAN,
  HB_SCRIPT_BAMUM,
  HB_SCRIPT_EGYPTIAN_HIEROGLYPHS,
  HB_SCRIPT_IMPERIAL_ARAMAIC,
  HB_SCRIPT_INSCRIPTIONAL_PAHLAVI,
  HB_SCRIPT_INSCRIPTIONAL_PARTHIAN,
  HB_SCRIPT_JAVANESE,
  HB_SCRIPT_KAITHI,
  HB_SCRIPT_TAI_THAM,
  HB_SCRIPT_LISU,
  HB_SCRIPT_MEETEI_MAYEK,
  HB_SCRIPT_OLD_SOUTH_ARABIAN,
  HB_SCRIPT_OLD_TURKIC,
  HB_SCRIPT_SAMARITAN,
  HB_SCRIPT_TAI_VIET,

  /* Unicode-6.0 additions */
  HB_SCRIPT_BATAK,
  HB_SCRIPT_BRAHMI,
  HB_SCRIPT_MANDAIC,

  /* Unicode-6.1 additions */
  HB_SCRIPT_CHAKMA,
  HB_SCRIPT_MEROITIC_CURSIVE,
  HB_SCRIPT_MEROITIC_HIEROGLYPHS,
  HB_SCRIPT_MIAO,
  HB_SCRIPT_SHARADA,
  HB_SCRIPT_SORA_SOMPENG,
  HB_SCRIPT_TAKRI
};
#endif

hb_script_t
hb_glib_script_to_script (GUnicodeScript script)
{
#if GLIB_CHECK_VERSION(2,29,14)
  return (hb_script_t) g_unicode_script_to_iso15924 (script);
#else
  if (likely ((unsigned int) script < ARRAY_LENGTH (glib_script_to_script)))
    return glib_script_to_script[script];

  if (unlikely (script == G_UNICODE_SCRIPT_INVALID_CODE))
    return HB_SCRIPT_INVALID;

  return HB_SCRIPT_UNKNOWN;
#endif
}

GUnicodeScript
hb_glib_script_from_script (hb_script_t script)
{
#if GLIB_CHECK_VERSION(2,29,14)
  return g_unicode_script_from_iso15924 (script);
#else
  unsigned int count = ARRAY_LENGTH (glib_script_to_script);
  for (unsigned int i = 0; i < count; i++)
    if (glib_script_to_script[i] == script)
      return (GUnicodeScript) i;

  if (unlikely (script == HB_SCRIPT_INVALID))
    return G_UNICODE_SCRIPT_INVALID_CODE;

  return G_UNICODE_SCRIPT_UNKNOWN;
#endif
}


static hb_unicode_combining_class_t
hb_glib_unicode_combining_class (hb_unicode_funcs_t *ufuncs HB_UNUSED,
				 hb_codepoint_t      unicode,
				 void               *user_data HB_UNUSED)

{
  return (hb_unicode_combining_class_t) g_unichar_combining_class (unicode);
}

static unsigned int
hb_glib_unicode_eastasian_width (hb_unicode_funcs_t *ufuncs HB_UNUSED,
				 hb_codepoint_t      unicode,
				 void               *user_data HB_UNUSED)
{
  return g_unichar_iswide (unicode) ? 2 : 1;
}

static hb_unicode_general_category_t
hb_glib_unicode_general_category (hb_unicode_funcs_t *ufuncs HB_UNUSED,
				  hb_codepoint_t      unicode,
				  void               *user_data HB_UNUSED)

{
  /* hb_unicode_general_category_t and GUnicodeType are identical */
  return (hb_unicode_general_category_t) g_unichar_type (unicode);
}

static hb_codepoint_t
hb_glib_unicode_mirroring (hb_unicode_funcs_t *ufuncs HB_UNUSED,
			   hb_codepoint_t      unicode,
			   void               *user_data HB_UNUSED)
{
  g_unichar_get_mirror_char (unicode, &unicode);
  return unicode;
}

static hb_script_t
hb_glib_unicode_script (hb_unicode_funcs_t *ufuncs HB_UNUSED,
			hb_codepoint_t      unicode,
			void               *user_data HB_UNUSED)
{
  return hb_glib_script_to_script (g_unichar_get_script (unicode));
}

static hb_bool_t
hb_glib_unicode_compose (hb_unicode_funcs_t *ufuncs HB_UNUSED,
			 hb_codepoint_t      a,
			 hb_codepoint_t      b,
			 hb_codepoint_t     *ab,
			 void               *user_data HB_UNUSED)
{
#if GLIB_CHECK_VERSION(2,29,12)
  return g_unichar_compose (a, b, ab);
#endif

  /* We don't ifdef-out the fallback code such that compiler always
   * sees it and makes sure it's compilable. */

  gchar utf8[12];
  gchar *normalized;
  int len;
  hb_bool_t ret;

  len = g_unichar_to_utf8 (a, utf8);
  len += g_unichar_to_utf8 (b, utf8 + len);
  normalized = g_utf8_normalize (utf8, len, G_NORMALIZE_NFC);
  len = g_utf8_strlen (normalized, -1);
  if (unlikely (!len))
    return false;

  if (len == 1) {
    *ab = g_utf8_get_char (normalized);
    ret = true;
  } else {
    ret = false;
  }

  g_free (normalized);
  return ret;
}

static hb_bool_t
hb_glib_unicode_decompose (hb_unicode_funcs_t *ufuncs HB_UNUSED,
			   hb_codepoint_t      ab,
			   hb_codepoint_t     *a,
			   hb_codepoint_t     *b,
			   void               *user_data HB_UNUSED)
{
#if GLIB_CHECK_VERSION(2,29,12)
  return g_unichar_decompose (ab, a, b);
#endif

  /* We don't ifdef-out the fallback code such that compiler always
   * sees it and makes sure it's compilable. */

  gchar utf8[6];
  gchar *normalized;
  int len;
  hb_bool_t ret;

  len = g_unichar_to_utf8 (ab, utf8);
  normalized = g_utf8_normalize (utf8, len, G_NORMALIZE_NFD);
  len = g_utf8_strlen (normalized, -1);
  if (unlikely (!len))
    return false;

  if (len == 1) {
    *a = g_utf8_get_char (normalized);
    *b = 0;
    ret = *a != ab;
  } else if (len == 2) {
    *a = g_utf8_get_char (normalized);
    *b = g_utf8_get_char (g_utf8_next_char (normalized));
    /* Here's the ugly part: if ab decomposes to a single character and
     * that character decomposes again, we have to detect that and undo
     * the second part :-(. */
    gchar *recomposed = g_utf8_normalize (normalized, -1, G_NORMALIZE_NFC);
    hb_codepoint_t c = g_utf8_get_char (recomposed);
    if (c != ab && c != *a) {
      *a = c;
      *b = 0;
    }
    g_free (recomposed);
    ret = true;
  } else {
    /* If decomposed to more than two characters, take the last one,
     * and recompose the rest to get the first component. */
    gchar *end = g_utf8_offset_to_pointer (normalized, len - 1);
    gchar *recomposed;
    *b = g_utf8_get_char (end);
    recomposed = g_utf8_normalize (normalized, end - normalized, G_NORMALIZE_NFC);
    /* We expect that recomposed has exactly one character now. */
    *a = g_utf8_get_char (recomposed);
    g_free (recomposed);
    ret = true;
  }

  g_free (normalized);
  return ret;
}

static unsigned int
hb_glib_unicode_decompose_compatibility (hb_unicode_funcs_t *ufuncs,
					 hb_codepoint_t      u,
					 hb_codepoint_t     *decomposed,
					 void               *user_data HB_UNUSED)
{
#if GLIB_CHECK_VERSION(2,29,12)
  return g_unichar_fully_decompose (u, TRUE, decomposed, HB_UNICODE_MAX_DECOMPOSITION_LEN);
#endif

  /* If the user doesn't have GLib >= 2.29.12 we have to perform
   * a round trip to UTF-8 and the associated memory management dance. */
  gchar utf8[6];
  gchar *utf8_decomposed, *c;
  gsize utf8_len, utf8_decomposed_len, i;

  /* Convert @u to UTF-8 and normalise it in NFKD mode. This performs the compatibility decomposition. */
  utf8_len = g_unichar_to_utf8 (u, utf8);
  utf8_decomposed = g_utf8_normalize (utf8, utf8_len, G_NORMALIZE_NFKD);
  utf8_decomposed_len = g_utf8_strlen (utf8_decomposed, -1);

  assert (utf8_decomposed_len <= HB_UNICODE_MAX_DECOMPOSITION_LEN);

  for (i = 0, c = utf8_decomposed; i < utf8_decomposed_len; i++, c = g_utf8_next_char (c))
    *decomposed++ = g_utf8_get_char (c);

  g_free (utf8_decomposed);

  return utf8_decomposed_len;
}

hb_unicode_funcs_t *
hb_glib_get_unicode_funcs (void)
{
  static const hb_unicode_funcs_t _hb_glib_unicode_funcs = {
    HB_OBJECT_HEADER_STATIC,

    NULL, /* parent */
    true, /* immutable */
    {
#define HB_UNICODE_FUNC_IMPLEMENT(name) hb_glib_unicode_##name,
      HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_UNICODE_FUNC_IMPLEMENT
    }
  };

  return const_cast<hb_unicode_funcs_t *> (&_hb_glib_unicode_funcs);
}