/*
 * 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.
 *
 * Google Author(s): Behdad Esfahbod
 */

#include "options.hh"


view_options_t view_opts[1];
shape_options_t shape_opts[1];
font_options_t font_opts[1];

const char *out_file = "/dev/stdout";
hb_bool_t debug = FALSE;


static gboolean
parse_margin (const char *name G_GNUC_UNUSED,
	      const char *arg,
	      gpointer    data G_GNUC_UNUSED,
	      GError    **error G_GNUC_UNUSED)
{
  view_options_t::margin_t &m = view_opts->margin;
  switch (sscanf (arg, "%lf %lf %lf %lf", &m.t, &m.r, &m.b, &m.l)) {
    case 1: m.r = m.t;
    case 2: m.b = m.t;
    case 3: m.l = m.r;
    case 4: return TRUE;
    default:
      g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
		   "%s argument should be one to four space-separated numbers",
		   name);
      return FALSE;
  }
}


static gboolean
parse_shapers (const char *name G_GNUC_UNUSED,
	       const char *arg,
	       gpointer    data G_GNUC_UNUSED,
	       GError    **error G_GNUC_UNUSED)
{
  shape_opts->shapers = g_strsplit (arg, ",", 0);
  return TRUE;
}


static void
parse_space (char **pp)
{
  char c;
#define ISSPACE(c) ((c)==' '||(c)=='\f'||(c)=='\n'||(c)=='\r'||(c)=='\t'||(c)=='\v')
  while (c = **pp, ISSPACE (c))
    (*pp)++;
#undef ISSPACE
}

static hb_bool_t
parse_char (char **pp, char c)
{
  parse_space (pp);

  if (**pp != c)
    return FALSE;

  (*pp)++;
  return TRUE;
}

static hb_bool_t
parse_uint (char **pp, unsigned int *pv)
{
  char *p = *pp;
  unsigned int v;

  v = strtol (p, pp, 0);

  if (p == *pp)
    return FALSE;

  *pv = v;
  return TRUE;
}


static hb_bool_t
parse_feature_value_prefix (char **pp, hb_feature_t *feature)
{
  if (parse_char (pp, '-'))
    feature->value = 0;
  else {
    parse_char (pp, '+');
    feature->value = 1;
  }

  return TRUE;
}

static hb_bool_t
parse_feature_tag (char **pp, hb_feature_t *feature)
{
  char *p = *pp, c;

  parse_space (pp);

#define ISALNUM(c) (('a' <= (c) && (c) <= 'z') || ('A' <= (c) && (c) <= 'Z') || ('0' <= (c) && (c) <= '9'))
  while (c = **pp, ISALNUM(c))
    (*pp)++;
#undef ISALNUM

  if (p == *pp)
    return FALSE;

  feature->tag = hb_tag_from_string (p, *pp - p);
  return TRUE;
}

static hb_bool_t
parse_feature_indices (char **pp, hb_feature_t *feature)
{
  hb_bool_t has_start;

  feature->start = 0;
  feature->end = (unsigned int) -1;

  if (!parse_char (pp, '['))
    return TRUE;

  has_start = parse_uint (pp, &feature->start);

  if (parse_char (pp, ':')) {
    parse_uint (pp, &feature->end);
  } else {
    if (has_start)
      feature->end = feature->start + 1;
  }

  return parse_char (pp, ']');
}

static hb_bool_t
parse_feature_value_postfix (char **pp, hb_feature_t *feature)
{
  return !parse_char (pp, '=') || parse_uint (pp, &feature->value);
}


static hb_bool_t
parse_one_feature (char **pp, hb_feature_t *feature)
{
  return parse_feature_value_prefix (pp, feature) &&
	 parse_feature_tag (pp, feature) &&
	 parse_feature_indices (pp, feature) &&
	 parse_feature_value_postfix (pp, feature) &&
	 (parse_char (pp, ',') || **pp == '\0');
}

static void
skip_one_feature (char **pp)
{
  char *e;
  e = strchr (*pp, ',');
  if (e)
    *pp = e + 1;
  else
    *pp = *pp + strlen (*pp);
}

static gboolean
parse_features (const char *name G_GNUC_UNUSED,
	        const char *arg,
	        gpointer    data G_GNUC_UNUSED,
	        GError    **error G_GNUC_UNUSED)
{
  char *s = (char *) arg;
  char *p;

  shape_opts->num_features = 0;
  shape_opts->features = NULL;

  if (!*s)
    return TRUE;

  /* count the features first, so we can allocate memory */
  p = s;
  do {
    shape_opts->num_features++;
    p = strchr (p, ',');
    if (p)
      p++;
  } while (p);

  shape_opts->features = (hb_feature_t *) calloc (shape_opts->num_features, sizeof (*shape_opts->features));

  /* now do the actual parsing */
  p = s;
  shape_opts->num_features = 0;
  while (*p) {
    if (parse_one_feature (&p, &shape_opts->features[shape_opts->num_features]))
      shape_opts->num_features++;
    else
      skip_one_feature (&p);
  }

  return TRUE;
}


static gchar *
shapers_to_string (void)
{
  GString *shapers = g_string_new (NULL);
  const char **shaper_list = hb_shape_list_shapers ();

  for (; *shaper_list; shaper_list++) {
    g_string_append (shapers, *shaper_list);
    g_string_append_c (shapers, ',');
  }
  g_string_truncate (shapers, MAX (0, (gint)shapers->len - 1));

  return g_string_free (shapers, FALSE);
}

static G_GNUC_NORETURN gboolean
show_version (const char *name G_GNUC_UNUSED,
	      const char *arg G_GNUC_UNUSED,
	      gpointer    data G_GNUC_UNUSED,
	      GError    **error G_GNUC_UNUSED)
{
  g_printf ("%s (%s) %s\n", g_get_prgname (), PACKAGE_NAME, PACKAGE_VERSION);

  char *shapers = shapers_to_string ();
  g_printf ("Available shapers: %s\n", shapers);
  g_free (shapers);
  if (strcmp (HB_VERSION_STRING, hb_version_string ()))
    g_printf ("Linked HarfBuzz library has a different version: %s\n", hb_version_string ());

  exit(0);
}


void
parse_options (int argc, char *argv[])
{
  GOptionEntry entries[] =
  {
    {"version",		0, G_OPTION_FLAG_NO_ARG,
			      G_OPTION_ARG_CALLBACK,	(gpointer) &show_version,	"Show version numbers",			NULL},
    {"debug",		0, 0, G_OPTION_ARG_NONE,	&debug,				"Free all resources before exit",	NULL},
    {"output",		0, 0, G_OPTION_ARG_STRING,	&out_file,			"Set output file name",			"filename"},

    {"annotate",	0, 0, G_OPTION_ARG_NONE,	&view_opts->annotate,		"Annotate output rendering",		NULL},
    {"background",	0, 0, G_OPTION_ARG_STRING,	&view_opts->back,		"Set background color",			"red/#rrggbb/#rrggbbaa"},
    {"foreground",	0, 0, G_OPTION_ARG_STRING,	&view_opts->fore,		"Set foreground color",			"red/#rrggbb/#rrggbbaa"},
    {"line-space",	0, 0, G_OPTION_ARG_DOUBLE,	&view_opts->line_space,		"Set space between lines (default: 0)",	"units"},
    {"margin",		0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_margin,	"Margin around output",			"one to four numbers"},

    {"shapers",		0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_shapers,	"Comma-separated list of shapers",	"list"},
    {"direction",	0, 0, G_OPTION_ARG_STRING,	&shape_opts->direction,		"Set text direction (default: auto)",	"ltr/rtl/ttb/btt"},
    {"language",	0, 0, G_OPTION_ARG_STRING,	&shape_opts->language,		"Set text language (default: $LANG)",	"langstr"},
    {"script",		0, 0, G_OPTION_ARG_STRING,	&shape_opts->script,		"Set text script (default: auto)",	"ISO-15924 tag"},
    {"features",	0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_features,	"Font features to apply to text",	"TODO"},

    {"face-index",	0, 0, G_OPTION_ARG_INT,		&font_opts->face_index,		"Face index (default: 0)",		"index"},
    {"font-size",	0, 0, G_OPTION_ARG_DOUBLE,	&font_opts->font_size,		"Font size",				"size"},

    {NULL}
  };
  GError *parse_error = NULL;
  GOptionContext *context;

  context = g_option_context_new ("- FONT-FILE TEXT");

  g_option_context_add_main_entries (context, entries, NULL);

  if (!g_option_context_parse (context, &argc, &argv, &parse_error))
  {
    if (parse_error != NULL)
      fail ("%s", parse_error->message);
    else
      fail ("Option parse error");
    exit(1);
  }
  g_option_context_free(context);

  if (argc != 3) {
    g_printerr ("Usage: %s [OPTION...] FONT-FILE TEXT\n", g_get_prgname ());
    exit (1);
  }

  font_opts->font_file = argv[1];
  shape_opts->text = argv[2];
}