/********************************************************************\
 * qofobject.c -- the Core Object Registration/Lookup Interface     *
 * 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 2 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, contact:                        *
 *                                                                  *
 * Free Software Foundation           Voice:  +1-617-542-5942       *
 * 59 Temple Place - Suite 330        Fax:    +1-617-542-2652       *
 * Boston, MA  02111-1307,  USA       gnu@gnu.org                   *
 *                                                                  *
\********************************************************************/
/*
 * qofobject.c -- the Core Object Object Registry
 * Copyright (C) 2001 Derek Atkins
 * Author: Derek Atkins <warlord@MIT.EDU>
 */

#include "config.h"

#include <glib.h>

#include "gnc-engine-util.h"
#include "gnc-trace.h"
#include "qofobject.h"
#include "qofobject-p.h"
#include "qofbook.h"

static short module = MOD_QUERY;

static gboolean object_is_initialized = FALSE;
static GList *object_modules = NULL;
static GList *book_list = NULL;
static GHashTable *backend_data = NULL;

gpointer
qof_object_new_instance (QofIdTypeConst type_name, QofBook *book)
{
  const QofObject *obj;

  if (!type_name) return NULL;

  obj = qof_object_lookup (type_name);
  if (!obj) return NULL;

  if (obj->new) 
    return (obj->new (book));

  return NULL;
}

void qof_object_book_begin (QofBook *book)
{
  GList *l;

  if (!book) return;
  ENTER (" ");
  for (l = object_modules; l; l = l->next) {
    QofObject *obj = l->data;
    if (obj->book_begin)
      obj->book_begin (book);
  }

  /* Remember this book for later */
  book_list = g_list_prepend (book_list, book);
  LEAVE (" ");
}

void qof_object_book_end (QofBook *book)
{
  GList *l;

  if (!book) return;
  ENTER (" ");
  for (l = object_modules; l; l = l->next) {
    QofObject *obj = l->data;
    if (obj->book_end)
      obj->book_end (book);
  }

  /* Remove it from the list */
  book_list = g_list_remove (book_list, book);
  LEAVE (" ");
}

gboolean 
qof_object_is_dirty (QofBook *book)
{
  GList *l;

  if (!book) return FALSE;
  for (l = object_modules; l; l = l->next) 
  {
    QofObject *obj = l->data;
    if (obj->is_dirty)
    {
      QofCollection *col;
      col = qof_book_get_collection (book, obj->e_type);
      if (obj->is_dirty (col)) return TRUE;
    }
  }
  return FALSE;
}

void 
qof_object_mark_clean (QofBook *book)
{
  GList *l;

  if (!book) return;
  for (l = object_modules; l; l = l->next) 
  {
    QofObject *obj = l->data;
    if (obj->mark_clean)
    {
      QofCollection *col;
      col = qof_book_get_collection (book, obj->e_type);
      (obj->mark_clean) (col);
    }
  }
}

void qof_object_foreach_type (QofForeachTypeCB cb, gpointer user_data)
{
  GList *l;

  if (!cb) return;

  for (l = object_modules; l; l = l->next) {
    QofObject *obj = l->data;
    (cb) (obj, user_data);
  }
}

void 
qof_object_foreach (QofIdTypeConst type_name, QofBook *book, 
                    QofEntityForeachCB cb, gpointer user_data)
{
  QofCollection *col;
  const QofObject *obj;

  if (!book || !type_name) return;
  ENTER ("type=%s", type_name);

  obj = qof_object_lookup (type_name);
  if (!obj)
  {
    PERR ("No object of type %s", type_name);
    return;
  }
  col = qof_book_get_collection (book, obj->e_type);
  PINFO ("lookup obj=%p for type=%s", obj, type_name);
  if (!obj) return;

  PINFO ("type=%s foreach=%p", type_name, obj->foreach);
  if (obj->foreach) 
  {
    obj->foreach (col, cb, user_data);
  }
  LEAVE ("type=%s", type_name);

  return;
}

const char *
qof_object_printable (QofIdTypeConst type_name, gpointer obj)
{
  const QofObject *b_obj;

  if (!type_name || !obj) return NULL;

  b_obj = qof_object_lookup (type_name);
  if (!b_obj) return NULL;

  if (b_obj->printable)
    return (b_obj->printable (obj));

  return NULL;
}

const char * qof_object_get_type_label (QofIdTypeConst type_name)
{
  const QofObject *obj;

  if (!type_name) return NULL;

  obj = qof_object_lookup (type_name);
  if (!obj) return NULL;

  return (obj->type_label);
}

static gboolean clear_table (gpointer key, gpointer value, gpointer user_data)
{
  g_hash_table_destroy (value);
  return TRUE;
}

/* INITIALIZATION and PRIVATE FUNCTIONS */

void qof_object_initialize (void)
{
  if (object_is_initialized) return;
  backend_data = g_hash_table_new (g_str_hash, g_str_equal);
  object_is_initialized = TRUE;
}

void qof_object_shutdown (void)
{
  g_return_if_fail (object_is_initialized == TRUE);

  g_hash_table_foreach_remove (backend_data, clear_table, NULL);
  g_hash_table_destroy (backend_data);
  backend_data = NULL;

  g_list_free (object_modules);
  object_modules = NULL;
  g_list_free (book_list);
  book_list = NULL;
  object_is_initialized = FALSE;
}

/* Register new types of object objects.
 * Return TRUE if successful,
 * return FALSE if it fails, invalid arguments, or if the object
 * already exists
 */
gboolean qof_object_register (const QofObject *object)
{
  g_return_val_if_fail (object_is_initialized, FALSE);

  if (!object) return FALSE;
  g_return_val_if_fail (object->interface_version == QOF_OBJECT_VERSION, FALSE);

  if (g_list_index (object_modules, (gpointer)object) == -1)
    object_modules = g_list_prepend (object_modules, (gpointer)object);
  else
    return FALSE;

  /* Now initialize all the known books */
  if (object->book_begin && book_list) {
    GList *node;
    for (node = book_list; node; node = node->next)
      object->book_begin (node->data);
  }

  return TRUE;
}

const QofObject * qof_object_lookup (QofIdTypeConst name)
{
  GList *iter;
  const QofObject *obj;

  g_return_val_if_fail (object_is_initialized, NULL);

  if (!name) return NULL;

  for (iter = object_modules; iter; iter = iter->next) {
    obj = iter->data;
    if (!safe_strcmp (obj->e_type, name))
      return obj;
  }
  return NULL;
}

gboolean qof_object_register_backend (QofIdTypeConst type_name,
                                   const char *backend_name,
                                   gpointer be_data)
{
  GHashTable *ht;
  g_return_val_if_fail (object_is_initialized, FALSE);

  if (!type_name || *type_name == '\0' ||
      !backend_name || *backend_name == '\0' ||
      !be_data)
    return FALSE;

  ht = g_hash_table_lookup (backend_data, backend_name);

  /* If it doesn't already exist, create a new table for this backend */
  if (!ht) {
    ht = g_hash_table_new (g_str_hash, g_str_equal);
    g_hash_table_insert (backend_data, (char *)backend_name, ht);
  }

  /* Now insert the data */
  g_hash_table_insert (ht, (char *)type_name, be_data);

  return TRUE;
}

gpointer qof_object_lookup_backend (QofIdTypeConst type_name,
                                 const char *backend_name)
{
  GHashTable *ht;

  if (!type_name || *type_name == '\0' ||
      !backend_name || *backend_name == '\0')
    return NULL;

  ht = g_hash_table_lookup (backend_data, (char *)backend_name);
  if (!ht)
    return NULL;

  return g_hash_table_lookup (ht, (char *)type_name);
}

struct foreach_data {
  QofForeachBackendTypeCB        cb;
  gpointer                 user_data;
};

static void foreach_backend (gpointer key, gpointer be_item, gpointer arg)
{
  char *data_type = key;
  struct foreach_data *cb_data = arg;

  g_return_if_fail (key && be_item && arg);

  /* Call the callback for this data type */
  (cb_data->cb) (data_type, be_item, cb_data->user_data);
}

void qof_object_foreach_backend (const char *backend_name,
                                 QofForeachBackendTypeCB cb,
                                 gpointer user_data)
{
  GHashTable *ht;
  struct foreach_data cb_data;

  if (!backend_name || *backend_name == '\0' || !cb)
    return;

  ht = g_hash_table_lookup (backend_data, (char *)backend_name);
  if (!ht)
    return;

  cb_data.cb = cb;
  cb_data.user_data = user_data;

  g_hash_table_foreach (ht, foreach_backend, &cb_data);
}

/* ========================= END OF FILE =================== */