/* Message list header manipulation.
   Copyright (C) 2007, 2015-2016 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2007.

   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/>.  */


#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

/* Specification.  */
#include "msgl-header.h"

#include <string.h>

#include "xalloc.h"

#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))


void
msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
                                 const char *field, const char *value)
{
  /* The known fields in their usual order.  */
  static const struct
    {
      const char *name;
      size_t len;
    }
  known_fields[] =
    {
      { "Project-Id-Version:", sizeof ("Project-Id-Version:") - 1 },
      { "Report-Msgid-Bugs-To:", sizeof ("Report-Msgid-Bugs-To:") - 1 },
      { "POT-Creation-Date:", sizeof ("POT-Creation-Date:") - 1 },
      { "PO-Revision-Date:", sizeof ("PO-Revision-Date:") - 1 },
      { "Last-Translator:", sizeof ("Last-Translator:") - 1 },
      { "Language-Team:", sizeof ("Language-Team:") - 1 },
      { "Language:", sizeof ("Language:") - 1 },
      { "MIME-Version:", sizeof ("MIME-Version:") - 1 },
      { "Content-Type:", sizeof ("Content-Type:") - 1 },
      { "Content-Transfer-Encoding:",
        sizeof ("Content-Transfer-Encoding:") - 1 }
    };
  size_t field_len;
  int field_index;
  size_t k, i;

  field_len = strlen (field);

  /* Search the field in known_fields[].  */
  field_index = -1;
  for (k = 0; k < SIZEOF (known_fields); k++)
    if (strcmp (known_fields[k].name, field) == 0)
      {
        field_index = k;
        break;
      }

  for (i = 0; i < mdlp->nitems; i++)
    {
      message_list_ty *mlp = mdlp->item[i]->messages;
      size_t j;

      /* Search the header entry.  */
      for (j = 0; j < mlp->nitems; j++)
        if (is_header (mlp->item[j]) && !mlp->item[j]->obsolete)
          {
            message_ty *mp = mlp->item[j];

            /* Modify the header entry.  */
            const char *header = mp->msgstr;
            char *new_header =
              XNMALLOC (strlen (header) + 1
                        + strlen (field) + 1 + strlen (value) + 1 + 1,
                        char);

            /* Test whether the field already occurs in the header entry.  */
            const char *h;

            for (h = header; *h != '\0'; )
              {
                if (strncmp (h, field, field_len) == 0)
                  break;
                h = strchr (h, '\n');
                if (h == NULL)
                  break;
                h++;
              }
            if (h != NULL && *h != '\0')
              {
                /* Replace the field.  */
                char *p = new_header;
                memcpy (p, header, h - header);
                p += h - header;
                p = stpcpy (p, field);
                p = stpcpy (stpcpy (stpcpy (p, " "), value), "\n");
                h = strchr (h, '\n');
                if (h != NULL)
                  {
                    h++;
                    stpcpy (p, h);
                  }
              }
            else if (field_index < 0)
              {
                /* An unknown field.  Append it at the end.  */
                char *p = new_header;
                p = stpcpy (p, header);
                if (p > new_header && p[-1] != '\n')
                  *p++ = '\n';
                p = stpcpy (p, field);
                stpcpy (stpcpy (stpcpy (p, " "), value), "\n");
              }
            else
              {
                /* Find the appropriate position for inserting the field.  */
                for (h = header; *h != '\0'; )
                  {
                    /* Test whether h starts with a field name whose index is
                       > field_index.  */
                    for (k = field_index + 1; k < SIZEOF (known_fields); k++)
                      if (strncmp (h, known_fields[k].name, known_fields[k].len)
                          == 0)
                        break;
                    if (k < SIZEOF (known_fields))
                      break;
                    h = strchr (h, '\n');
                    if (h == NULL)
                      break;
                    h++;
                  }
                if (h != NULL && *h != '\0')
                  {
                    /* Insert the field at position h.  */
                    char *p = new_header;
                    memcpy (p, header, h - header);
                    p += h - header;
                    p = stpcpy (p, field);
                    p = stpcpy (stpcpy (stpcpy (p, " "), value), "\n");
                    stpcpy (p, h);
                  }
                else
                  {
                    /* Append it at the end.  */
                    char *p = new_header;
                    p = stpcpy (p, header);
                    if (p > new_header && p[-1] != '\n')
                      *p++ = '\n';
                    p = stpcpy (p, field);
                    stpcpy (stpcpy (stpcpy (p, " "), value), "\n");
                  }
              }

            mp->msgstr = new_header;
          }
    }
}