/* footnote.c -- footnotes for Texinfo.
   $Id: footnote.c,v 1.12 2007/12/03 01:38:43 karl Exp $

   Copyright (C) 1998, 1999, 2002, 2007 Free Software Foundation, Inc.

   This program 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.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "system.h"
#include "footnote.h"
#include "macro.h"
#include "makeinfo.h"
#include "node.h"
#include "xml.h"
#include "xref.h"

/* Nonzero means that the footnote style for this document was set on
   the command line, which overrides any other settings. */
int footnote_style_preset = 0;

/* The current footnote number in this node.  Each time a new node is
   started this is reset to 1. */
int current_footnote_number = 1;

/* Nonzero means we automatically number footnotes with no specified marker. */
int number_footnotes = 1;

/* Nonzero means we are currently outputting footnotes. */
int already_outputting_pending_notes = 0;


/* Footnotes can be handled in one of two ways:

   separate_node:
        Make them look like followed references, with the reference
        destinations in a makeinfo manufactured node or,
   end_node:
        Make them appear at the bottom of the node that they originally
        appeared in. */

#define separate_node 0
#define end_node 1

int footnote_style = end_node;
int first_footnote_this_node = 1;
int footnote_count = 0;

/* Set the footnote style based on the style identifier in STRING. */
int
set_footnote_style (char *string)
{
  if (mbscasecmp (string, "separate") == 0)
    footnote_style = separate_node;
  else if (mbscasecmp (string, "end") == 0)
    footnote_style = end_node;
  else
    return -1;

 return 0;
}

void
cm_footnotestyle (void)
{
  char *arg;

  get_rest_of_line (1, &arg);

  /* If set on command line, do not change the footnote style.  */
  if (!footnote_style_preset && set_footnote_style (arg) != 0)
    line_error (_("Bad argument to %c%s"), COMMAND_PREFIX, command);

  free (arg);
}

typedef struct fn
{
  struct fn *next;
  char *marker;
  char *note;
  int number;
}  FN;

FN *pending_notes = NULL;

/* A method for remembering footnotes.  Note that this list gets output
   at the end of the current node. */
static void
remember_note (char *marker, char *note)
{
  FN *temp = xmalloc (sizeof (FN));

  temp->marker = xstrdup (marker);
  temp->note = xstrdup (note);
  temp->next = pending_notes;
  temp->number = current_footnote_number;
  pending_notes = temp;
  footnote_count++;
}

/* How to get rid of existing footnotes. */
static void
free_pending_notes (void)
{
  FN *temp;

  while ((temp = pending_notes))
    {
      free (temp->marker);
      free (temp->note);
      pending_notes = pending_notes->next;
      free (temp);
    }
  first_footnote_this_node = 1;
  footnote_count = 0;
  current_footnote_number = 1;	/* for html */
}

/* What to do when you see a @footnote construct. */

 /* Handle a "footnote".
    footnote *{this is a footnote}
    where "*" is the (optional) marker character for this note. */
void
cm_footnote (void)
{
  char *marker;
  char *note;

  get_until ("{", &marker);
  canon_white (marker);

  if (macro_expansion_output_stream && !executing_string)
    append_to_expansion_output (input_text_offset + 1); /* include the { */

  /* Read the argument in braces. */
  if (curchar () != '{')
    {
      line_error (_("`%c%s' needs an argument `{...}', not just `%s'"),
                  COMMAND_PREFIX, command, marker);
      free (marker);
      return;
    }
  else
    {
      int len;
      int braces = 1;
      int loc = ++input_text_offset;

      while (braces)
        {
          if (loc == input_text_length)
            {
              line_error (_("No closing brace for footnote `%s'"), marker);
              return;
            }

          if (input_text[loc] == '{')
            braces++;
          else if (input_text[loc] == '}')
            braces--;
          else if (input_text[loc] == '\n')
            line_number++;

          loc++;
        }

      len = (loc - input_text_offset) - 1;
      note = xmalloc (len + 1);
      memcpy (note, &input_text[input_text_offset], len);
      note[len] = 0;
      input_text_offset = loc;
    }

  /* Must write the macro-expanded argument to the macro expansion
     output stream.  This is like the case in index_add_arg.  */
  if (macro_expansion_output_stream && !executing_string)
    {
      /* Calling me_execute_string on a lone } provokes an error, since
         as far as the reader knows there is no matching {.  We wrote
         the { above in the call to append_to_expansion_output. */
      me_execute_string_keep_state (note, "}");
    }

  if (!current_node || !*current_node)
    {
      line_error (_("Footnote defined without parent node"));
      free (marker);
      free (note);
      return;
    }

  /* output_pending_notes is non-reentrant (it uses a global data
     structure pending_notes, which it frees before it returns), and
     TeX doesn't grok footnotes inside footnotes anyway.  Disallow
     that.  */
  if (already_outputting_pending_notes)
    {
      line_error (_("Footnotes inside footnotes are not allowed"));
      free (marker);
      free (note);
      return;
    }

  if (!*marker)
    {
      free (marker);

      if (number_footnotes)
        {
          marker = xmalloc (10);
          sprintf (marker, "%d", current_footnote_number);
        }
      else
        marker = xstrdup ("*");
    }

  if (xml)
    xml_insert_footnote (note);
  else 
    {
  remember_note (marker, note);

  /* fixme: html: footnote processing needs work; we currently ignore
     the style requested; we could clash with a node name of the form
     `fn-<n>', though that's unlikely. */
  if (html)
    {
      /* Hyperlink also serves as an anchor (mnemonic: fnd is footnote
         definition.)  */
      add_html_elt ("<a rel=\"footnote\" href=");
      add_word_args ("\"#fn-%d\" name=\"fnd-%d\"><sup>%s</sup></a>",
		     current_footnote_number, current_footnote_number,
                     marker);
    }
  else
    /* Your method should at least insert MARKER. */
    switch (footnote_style)
      {
      case separate_node:
        add_word_args ("(%s)", marker);
        execute_string (" (*note %s-Footnote-%d::)",
                        current_node, current_footnote_number);
        if (first_footnote_this_node)
          {
            char *temp_string, *expanded_ref;

            temp_string = xmalloc (strlen (current_node)
                                   + strlen ("-Footnotes") + 1);

            strcpy (temp_string, current_node);
            strcat (temp_string, "-Footnotes");
            expanded_ref = expansion (temp_string, 0);
            remember_node_reference (expanded_ref, line_number,
                                     followed_reference);
            free (temp_string);
            free (expanded_ref);
            first_footnote_this_node = 0;
          }
        break;

      case end_node:
        add_word_args ("(%s)", marker);
        break;

      default:
        break;
      }
  current_footnote_number++;
    }
  free (marker);
  free (note);
}

/* Output the footnotes.  We are at the end of the current node. */
void
output_pending_notes (void)
{
  FN *footnote = pending_notes;

  if (!pending_notes)
    return;

  if (html)
    {
      add_html_block_elt ("<div class=\"footnote\">\n<hr>\n");
      /* We add an anchor here so @printindex can refer to this point
         (as the node name) for entries defined in footnotes.  */
      if (!splitting)
        add_word ("<a name=\"texinfo-footnotes-in-document\"></a>");
      add_word_args ("<h4>%s</h4>", (char *) _("Footnotes"));
    }
  else
    switch (footnote_style)
      {
      case separate_node:
        {
          char *old_current_node = current_node;
          char *old_command = xstrdup (command);

          already_outputting_pending_notes++;
          execute_string ("%cnode %s-Footnotes,,,%s\n",
                          COMMAND_PREFIX, current_node, current_node);
          already_outputting_pending_notes--;
          current_node = old_current_node;
          free (command);
          command = old_command;
        }
      break;

      case end_node:
        close_paragraph ();
        in_fixed_width_font++;
        /* This string should be translated according to the
           @documentlanguage, not the current LANG.  We can't do that
           yet, so leave it in English.  */
        execute_string ("---------- Footnotes ----------\n\n");
        in_fixed_width_font--;
        break;
      }

  /* Handle the footnotes in reverse order. */
  {
    int save_in_fixed_width_font = in_fixed_width_font;
    FN **array = xmalloc ((footnote_count + 1) * sizeof (FN *));
    array[footnote_count] = NULL;

    while (--footnote_count > -1)
      {
        array[footnote_count] = footnote;
        footnote = footnote->next;
      }

    filling_enabled = 1;
    indented_fill = 1;
    in_fixed_width_font = 0;

    while ((footnote = array[++footnote_count]))
      {
        if (html)
          {
	    /* Make the text of every footnote begin a separate paragraph.  */
            add_html_block_elt ("<p class=\"footnote\"><small>");
            /* Make footnote number a link to its definition.  */
            add_word_args ("[<a name=\"fn-%d\" href=\"#fnd-%d\">%d</a>]",
			   footnote->number, footnote->number, footnote->number);
            add_word ("</small> ");
            already_outputting_pending_notes++;
            execute_string ("%s", footnote->note);
            already_outputting_pending_notes--;
            add_word ("</p>\n");
          }
        else
          {
            char *old_current_node = current_node;
            char *old_command = xstrdup (command);

            already_outputting_pending_notes++;
            execute_string ("%canchor{%s-Footnote-%d}(%s) %s",
                            COMMAND_PREFIX, current_node, footnote->number,
                            footnote->marker, footnote->note);
            already_outputting_pending_notes--;
            current_node = old_current_node;
            free (command);
            command = old_command;
          }

        close_paragraph ();
      }

    if (html)
      add_html_block_elt ("<hr></div>");
    close_paragraph ();
    free (array);

    in_fixed_width_font = save_in_fixed_width_font;
  }

  free_pending_notes ();
}
