/* cfg_driver.c -- Main driver for Mailutils configuration files
   Copyright (C) 2007 Free Software Foundation, Inc.

   GNU Mailutils 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, 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
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <ctype.h>
#include <mailutils/argcv.h>
#include <mailutils/nls.h>
#include <mailutils/cfg.h>
#include <mailutils/errno.h>
#include <mailutils/error.h>
#include <mailutils/mutil.h>
#include <mailutils/monitor.h>
#include <mailutils/refcount.h>
#include <mailutils/list.h>
#include <mailutils/iterator.h>
#include <mailutils/stream.h>
#include <mailutils/assoc.h>


static mu_assoc_t section_tab;

static void
alloc_section_tab ()
{
  if (!section_tab)
    mu_assoc_create (&section_tab, sizeof (struct mu_cfg_cont **),
		     MU_ASSOC_COPY_KEY);
}

int
mu_create_canned_section (char *name, struct mu_cfg_section **psection)
{
  int rc;
  struct mu_cfg_cont **pcont;
  alloc_section_tab ();
  rc = mu_assoc_ref_install (section_tab, name, (void **)&pcont);
  if (rc == 0 || rc == MU_ERR_EXISTS)
    {
      mu_config_create_container (pcont, mu_cfg_cont_section);
      *psection = &(*pcont)->v.section;
      (*psection)->ident = name;
    }
  return rc;
}

int
mu_create_canned_param (char *name, struct mu_cfg_param **pparam)
{
  int rc;
  struct mu_cfg_cont **pcont;
  alloc_section_tab ();
  rc = mu_assoc_ref_install (section_tab, name, (void **)&pcont);
  if (rc == 0 || rc == MU_ERR_EXISTS)
    {
      mu_config_create_container (pcont, mu_cfg_cont_param);
      *pparam = &(*pcont)->v.param;
      (*pparam)->ident = name;
    }
  return rc;
}

struct mu_cfg_cont *
mu_get_canned_container (const char *name)
{
  struct mu_cfg_cont **pcont = mu_assoc_ref (section_tab, name);
  return pcont ? *pcont : NULL;
}


static struct mu_cfg_cont *root_container;

int
mu_config_create_container (struct mu_cfg_cont **pcont,
			    enum mu_cfg_cont_type type)
{
  struct mu_cfg_cont *cont;
  int rc;
  
  cont = calloc (1, sizeof (*cont));
  if (!cont)
    return ENOMEM;
  rc = mu_refcount_create (&cont->refcount);
  if (rc)
    free (cont);
  else
    {
      cont->type = type;
      *pcont = cont;
    }
  return rc; 
}  


struct dup_data
{
  struct mu_cfg_cont *cont;
};

static int dup_container (struct mu_cfg_cont **pcont);

static int
_dup_cont_action (void *item, void *cbdata)
{
  int rc;
  struct mu_cfg_cont *cont = item;
  struct dup_data *pdd = cbdata;

  rc = dup_container (&cont);
  if (rc)
    return rc;

  if (!pdd->cont->v.section.children)
    {
      int rc = mu_list_create (&pdd->cont->v.section.children);
      if (rc)
	return rc;
    }
  return mu_list_append (pdd->cont->v.section.children, cont);
}

static int
dup_container (struct mu_cfg_cont **pcont)
{
  int rc;
  struct mu_cfg_cont *newcont, *oldcont = *pcont;
  struct dup_data dd;

  rc = mu_config_create_container (&newcont, oldcont->type);
  if (rc)
    return rc;

  dd.cont = newcont;
  switch (oldcont->type)
    {
    case mu_cfg_cont_section:
      newcont->v.section.ident = oldcont->v.section.ident;
      newcont->v.section.label = oldcont->v.section.label;
      newcont->v.section.parser = oldcont->v.section.parser;
      newcont->v.section.target = oldcont->v.section.target;
      newcont->v.section.docstring = oldcont->v.section.docstring;
      newcont->v.section.children = NULL;
      mu_list_do (oldcont->v.section.children, _dup_cont_action, &dd);
      break;

    case mu_cfg_cont_param:
      newcont->v.param = oldcont->v.param;
      break;
    }
  *pcont = newcont;
  return 0;
}


static void
destroy_list (mu_list_t *plist)
{
  mu_list_t list = *plist;
  mu_iterator_t itr = NULL;
  
  if (!list)
    return;

  mu_list_get_iterator (list, &itr);
  for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
       mu_iterator_next (itr))
    {
      struct mu_cfg_cont *cont, *p;
      mu_iterator_current (itr, (void**)&cont);
      p = cont;
      mu_config_destroy_container (&p);
      if (!p)
	mu_list_remove (list, cont);
    }
  mu_iterator_destroy (&itr);
  if (mu_list_is_empty (list))
    mu_list_destroy (plist);
}

void
mu_config_destroy_container (struct mu_cfg_cont **pcont)
{
  struct mu_cfg_cont *cont = *pcont;
  unsigned refcount = mu_refcount_dec (cont->refcount);
  /* printf ("destr %p-%s: %d\n", cont, cont->v.section.ident, refcount); */
  switch (cont->type)
    {
    case mu_cfg_cont_section:
      destroy_list (&cont->v.section.children);
      break;

    case mu_cfg_cont_param:
      break;
    }

  if (refcount == 0)
    {
      free (cont);
      *pcont = 0;
    }
}
     

int
mu_cfg_section_add_container (struct mu_cfg_section *sect,
			      struct mu_cfg_cont *cont)
{
  if (!cont)
    return 0;
  if (!sect->children)
    mu_list_create (&sect->children);
  return mu_list_append (sect->children, cont);
}

int
mu_cfg_section_add_params (struct mu_cfg_section *sect,
			   struct mu_cfg_param *param)
{
  if (!param)
    return 0;

  for (; param->ident; param++)
    {
      int rc;
      struct mu_cfg_cont *container;

      if (param->type == mu_cfg_section)
	{
	  container = mu_get_canned_container (param->ident);
	  if (!container)
	    {
	      mu_error (_("INTERNAL ERROR: Requested unknown canned "
			  "section %s"),
			param->ident);
	      abort ();
	    }
	  mu_config_clone_container (container);
	}
      else
	{
	  rc = mu_config_create_container (&container, mu_cfg_cont_param);
	  if (rc)
	    return rc;
	  container->v.param = *param;
	}
      mu_cfg_section_add_container (sect, container);
    }
  return 0;
}

static int
_clone_action (void *item, void *cbdata)
{
  struct mu_cfg_cont *cont = item;
  return mu_config_clone_container (cont);
}

int
mu_config_clone_container (struct mu_cfg_cont *cont)
{
  mu_refcount_inc (cont->refcount);
  /* printf("clone %p-%s: %d\n", cont, cont->v.section.ident, n); */
  switch (cont->type)
    {
    case mu_cfg_cont_section:
      mu_list_do (cont->v.section.children, _clone_action, NULL);
      break;

    case mu_cfg_cont_param:
      break;
    }
  return 0;
}  


int
_mu_config_register_section (struct mu_cfg_cont **proot,
			     const char *parent_path,
			     const char *ident,
			     const char *label,
			     mu_cfg_section_fp parser,
			     struct mu_cfg_param *param,
			     struct mu_cfg_section **psection)
{
  int rc;
  struct mu_cfg_section *root_section;
  struct mu_cfg_section *parent;
  
  if (!*proot)
    {
      rc = mu_config_create_container (proot, mu_cfg_cont_section);
      if (rc)
	return rc;
      memset (&(*proot)->v.section, 0, sizeof (*proot)->v.section);
    }
  
  root_section = &(*proot)->v.section;
  
  if (parent_path)
    {
      if (mu_cfg_find_section (root_section, parent_path, &parent))
	return MU_ERR_NOENT;
    }
  else  
    parent = root_section;

  if (mu_refcount_value ((*proot)->refcount) > 1)
    {
      /* It is a clone, do copy-on-write */
      rc = dup_container (proot);
      if (rc)
	return rc;

      root_section = &(*proot)->v.section;
      
      if (parent_path)
	{
	  if (mu_cfg_find_section (root_section, parent_path, &parent))
	    return MU_ERR_NOENT;
	}
      else  
	parent = root_section;
    }

  if (ident)
    {
      struct mu_cfg_cont *container;
      struct mu_cfg_section *s;
      
      if (!parent->children)
	mu_list_create (&parent->children);
      mu_config_create_container (&container, mu_cfg_cont_section);
      mu_list_append (parent->children, container); 
      s = &container->v.section;

      s->ident = strdup (ident);
      s->label = label ? strdup (label) : NULL;
      s->parser = parser;
      s->children = NULL;
      mu_cfg_section_add_params (s, param);
      if (psection)
	*psection = s;
    }
  else
    {
      mu_cfg_section_add_params (parent, param);
      /* FIXME: */
      if (!parent->parser)
	parent->parser = parser;
      if (psection)
	*psection = parent;
    }
  return 0;
}
  
int
mu_config_register_section (const char *parent_path,
			    const char *ident,
			    const char *label,
			    mu_cfg_section_fp parser,
			    struct mu_cfg_param *param)
{
  return _mu_config_register_section (&root_container,
				      parent_path,
				      ident, label,
				      parser, param, NULL);
}

int
mu_config_register_plain_section (const char *parent_path, const char *ident,
				  struct mu_cfg_param *params)
{
  return mu_config_register_section (parent_path, ident, NULL, NULL, params);
}

static int
prog_parser (enum mu_cfg_section_stage stage,
	     const mu_cfg_node_t *node,
	     const char *label, void **section_data,
	     void *call_data,
	     mu_cfg_tree_t *tree)
{
  if (stage == mu_cfg_section_start)
    return strcmp (node->tag_label, label);

  return 0;
}

static char *
make_file_name (const char *dir, const char *file)
{
  char *tmp;
  size_t len = strlen (dir) + 1 + strlen (file);
  tmp = malloc (len + 1);
  if (!tmp)
    {
      mu_error ("%s", mu_strerror (errno));
      exit (1);
    }
  strcpy (tmp, dir);
  strcat (tmp, "/");
  strcat (tmp, file);
  return tmp;
}

struct include_data
{
  const char *progname;
  struct mu_cfg_param *progparam;
  int flags;
  void *target;
};

static int
_cb_include (mu_debug_t debug, void *data, char *arg)
{
  int ret = 0;
  struct stat sb;
  char *dirname = arg;
  struct include_data *idp = data;
  char *tmp = NULL;
  
  if (dirname[0] != '/')
    dirname = tmp = make_file_name (SYSCONFDIR, dirname);
  
  if (stat (dirname, &sb) == 0)
    {
      if (S_ISDIR (sb.st_mode))
	{
	  char *file = make_file_name (dirname, idp->progname);
	  ret = mu_get_config (file, idp->progname, idp->progparam, 0,
			       idp->target);
	}
      else
	ret = mu_get_config (dirname, idp->progname, idp->progparam,
			     idp->flags, idp->target);
    }
  else if (errno == ENOENT)
    {
      mu_cfg_format_error (debug, MU_DEBUG_ERROR,
			   _("include file or directory does not exist"));
      ret = 1;
    }
  else
    {
      mu_cfg_format_error (debug, MU_DEBUG_ERROR,
			   _("cannot stat include file or directory: %s"),
			   mu_strerror (errno));
      ret = 1;
    }
  free (tmp);
  return ret;
}

struct mu_cfg_cont *
mu_build_container (const char *progname,
		    struct mu_cfg_param *progparam, int flags, void *target)
{
  struct mu_cfg_cont *cont = root_container;
  struct include_data idata;
  struct mu_cfg_param mu_include_param[] = {
    { "include", mu_cfg_callback, &idata, 0, _cb_include,
      N_("Include contents of the given file.  If a directory is given, "
	 "include contents of the file <file>/<program>, where <program> is "
	 "the name of the program.  This latter form is allowed only in "
	 "the site-wide configuration file."),
      N_("file-or-directory") },
    { NULL }
  };
      
  mu_config_clone_container (cont);
  idata.progname = progname;
  idata.progparam = progparam;
  idata.flags = flags & MU_PARSE_CONFIG_GLOBAL;
  idata.target = target;
  _mu_config_register_section (&cont, NULL, NULL, NULL,
			       (void*) progname, mu_include_param, NULL);
  if (flags & MU_PARSE_CONFIG_GLOBAL)
    {
      mu_iterator_t iter;
      struct mu_cfg_section *prog_sect;
      struct mu_cfg_cont *old_root = root_container;
      static struct mu_cfg_param empty_param = { NULL };
      if (!progparam)
	progparam = &empty_param;
      
      _mu_config_register_section (&cont, NULL, "program", progname,
				   prog_parser, progparam, &prog_sect);
      
      if (old_root->v.section.children)
	{
	  if (!prog_sect->children)
	    mu_list_create (&prog_sect->children);
	  mu_list_get_iterator (old_root->v.section.children, &iter);
	  for (mu_iterator_first (iter); !mu_iterator_is_done (iter);
	       mu_iterator_next (iter))
	    {
	      struct mu_cfg_cont *c;
	      mu_iterator_current (iter, (void**)&c);
	      mu_list_append (prog_sect->children, c);
	    }
	  mu_iterator_destroy (&iter);
	}
    }
  else if (progparam)
    _mu_config_register_section (&cont, NULL, NULL, NULL, NULL,
				 progparam, NULL);
  return cont;
}

int
mu_cfg_tree_reduce (mu_cfg_tree_t *parse_tree, const char *progname,
		    struct mu_cfg_param *progparam, int flags,
		    void *target_ptr)
{
  int rc = 1;
  
  if (root_container)
    {
      struct mu_cfg_cont *cont = mu_build_container (progname, progparam,
						     flags, target_ptr);
      rc = mu_cfg_scan_tree (parse_tree, &cont->v.section, target_ptr,
			     (void*) progname);
      mu_config_destroy_container (&cont);
    }

  if (flags & MU_PARSE_CONFIG_DUMP)
    {
      mu_stream_t stream;
      mu_stdio_stream_create (&stream, stderr,
 			      MU_STREAM_NO_CHECK|MU_STREAM_NO_CLOSE);
      mu_stream_open (stream);
      mu_cfg_format_parse_tree (stream, parse_tree);
      mu_stream_destroy (&stream, NULL);
    }

  return rc;
}

void
mu_format_config_tree (mu_stream_t stream, const char *progname,
		       struct mu_cfg_param *progparam, int flags)
{
  struct mu_cfg_cont *cont = mu_build_container (progname, progparam, flags,
						 NULL);
  mu_cfg_format_container (stream, cont);
  mu_config_destroy_container (&cont);
}

int
mu_parse_config (const char *file, const char *progname,
		 struct mu_cfg_param *progparam, int flags,
		 void *target_ptr)
{
  int rc;
  char *full_name = mu_tilde_expansion (file, "/", NULL);
  if (full_name)
    {
      if (access (full_name, R_OK) == 0)
	{
	  rc = mu_get_config (full_name, progname, progparam, flags,
				 target_ptr);
	  free (full_name);
	}
      else
	rc = ENOENT;
    }
  else
    rc = ENOMEM;
  return rc;
}