gnucash/libgnucash/engine/gncTaxTable.c

/********************************************************************\
 * gncTaxTable.c -- the Gnucash Tax Table 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       *
 * 51 Franklin Street, Fifth Floor    Fax:    +1-617-542-2652       *
 * Boston, MA  02110-1301,  USA       gnu@gnu.org                   *
 *                                                                  *
\********************************************************************/

/*
 * Copyright (C) 2002 Derek Atkins
 * Copyright (C) 2003 Linas Vepstas <linas@linas.org>
 * Author: Derek Atkins <warlord@MIT.EDU>
 */

#include <config.h>

#include <glib.h>
#include <qofinstance-p.h>

#include "gnc-features.h"
#include "gncTaxTableP.h"

struct _gncTaxTable
{
    QofInstance     inst;
    const char *    name;
    GncTaxTableEntryList*  entries;
    time64          modtime;      /* internal date of last modtime */

    /* See libgnucash/engine/TaxTableBillTermImmutability.txt for an explanation of the following */
    /* Code that handles this is *identical* to that in gncBillTerm */
    gint64          refcount;
    GncTaxTable *   parent;       /* if non-null, we are an immutable child */
    GncTaxTable *   child;        /* if non-null, we have not changed */
    gboolean        invisible;
    GList *         children;     /* list of children for disconnection */
};

struct _gncTaxTableClass
{
    QofInstanceClass parent_class;
};

struct _gncTaxTableEntry
{
    GncTaxTable *   table;
    Account *       account;
    GncAmountType   type;
    gnc_numeric     amount;
};

struct _book_info
{
    GList *         tables;          /* visible tables */
};

static QofLogModule log_module = GNC_MOD_BUSINESS;

/* =============================================================== */
/* You must edit the functions in this block in tandem.  KEEP THEM IN
   SYNC! */

#define GNC_RETURN_ENUM_AS_STRING(x,s) case (x): return (s);
const char *
gncAmountTypeToString (GncAmountType type)
{
    switch (type)
    {
        GNC_RETURN_ENUM_AS_STRING(GNC_AMT_TYPE_VALUE, "VALUE");
        GNC_RETURN_ENUM_AS_STRING(GNC_AMT_TYPE_PERCENT, "PERCENT");
    default:
        g_warning ("asked to translate unknown amount type %d.\n", type);
        break;
    }
    return(NULL);
}

const char *
gncTaxIncludedTypeToString (GncTaxIncluded type)
{
    switch (type)
    {
        GNC_RETURN_ENUM_AS_STRING(GNC_TAXINCLUDED_YES, "YES");
        GNC_RETURN_ENUM_AS_STRING(GNC_TAXINCLUDED_NO, "NO");
        GNC_RETURN_ENUM_AS_STRING(GNC_TAXINCLUDED_USEGLOBAL, "USEGLOBAL");
    default:
        g_warning ("asked to translate unknown taxincluded type %d.\n", type);
        break;
    }
    return(NULL);
}
#undef GNC_RETURN_ENUM_AS_STRING
#define GNC_RETURN_ON_MATCH(s,x) \
  if(g_strcmp0((s), (str)) == 0) { *type = x; return(TRUE); }
gboolean
gncAmountStringToType (const char *str, GncAmountType *type)
{
    GNC_RETURN_ON_MATCH ("VALUE", GNC_AMT_TYPE_VALUE);
    GNC_RETURN_ON_MATCH ("PERCENT", GNC_AMT_TYPE_PERCENT);
    g_warning ("asked to translate unknown amount type string %s.\n",
               str ? str : "(null)");

    return(FALSE);
}

gboolean
gncTaxIncludedStringToType (const char *str, GncTaxIncluded *type)
{
    GNC_RETURN_ON_MATCH ("YES", GNC_TAXINCLUDED_YES);
    GNC_RETURN_ON_MATCH ("NO", GNC_TAXINCLUDED_NO);
    GNC_RETURN_ON_MATCH ("USEGLOBAL", GNC_TAXINCLUDED_USEGLOBAL);
    g_warning ("asked to translate unknown taxincluded type string %s.\n",
               str ? str : "(null)");

    return(FALSE);
}
#undef GNC_RETURN_ON_MATCH

/* =============================================================== */
/* Misc inline functions */

#define _GNC_MOD_NAME        GNC_ID_TAXTABLE

#define SET_STR(obj, member, str) { \
        if (!g_strcmp0 (member, str)) return; \
        gncTaxTableBeginEdit (obj); \
        CACHE_REPLACE (member, str); \
        }

static inline void
mark_table (GncTaxTable *table)
{
    qof_instance_set_dirty(&table->inst);
    qof_event_gen (&table->inst, QOF_EVENT_MODIFY, NULL);
}

static inline void
maybe_resort_list (GncTaxTable *table)
{
    struct _book_info *bi;

    if (table->parent || table->invisible) return;
    bi = qof_book_get_data (qof_instance_get_book(table), _GNC_MOD_NAME);
    bi->tables = g_list_sort (bi->tables, (GCompareFunc)gncTaxTableCompare);
}

static inline void
mod_table (GncTaxTable *table)
{
    table->modtime = gnc_time (NULL);
}

static inline void addObj (GncTaxTable *table)
{
    struct _book_info *bi;
    bi = qof_book_get_data (qof_instance_get_book(table), _GNC_MOD_NAME);
    bi->tables = g_list_insert_sorted (bi->tables, table,
                                       (GCompareFunc)gncTaxTableCompare);
}

static inline void remObj (GncTaxTable *table)
{
    struct _book_info *bi;
    bi = qof_book_get_data (qof_instance_get_book(table), _GNC_MOD_NAME);
    bi->tables = g_list_remove (bi->tables, table);
}

static inline void
gncTaxTableAddChild (GncTaxTable *table, GncTaxTable *child)
{
    g_return_if_fail(table);
    g_return_if_fail(child);
    g_return_if_fail(qof_instance_get_destroying(table) == FALSE);

    table->children = g_list_prepend(table->children, child);
}

static inline void
gncTaxTableRemoveChild (GncTaxTable *table, const GncTaxTable *child)
{
    g_return_if_fail(table);
    g_return_if_fail(child);

    if (qof_instance_get_destroying(table)) return;

    table->children = g_list_remove(table->children, child);
}

/* =============================================================== */

enum
{
    PROP_0,
    PROP_NAME,		/* Table */
    PROP_INVISIBLE,	/* Table */
    PROP_REFCOUNT,	/* Table */
//  PROP_PARENT,	/* Table */
};

/* GObject Initialization */
G_DEFINE_TYPE(GncTaxTable, gnc_taxtable, QOF_TYPE_INSTANCE)

static void
gnc_taxtable_init(GncTaxTable* tt)
{
}

static void
gnc_taxtable_dispose(GObject *ttp)
{
    G_OBJECT_CLASS(gnc_taxtable_parent_class)->dispose(ttp);
}

static void
gnc_taxtable_finalize(GObject* ttp)
{
    G_OBJECT_CLASS(gnc_taxtable_parent_class)->dispose(ttp);
}

static void
gnc_taxtable_get_property (GObject         *object,
                           guint            prop_id,
                           GValue          *value,
                           GParamSpec      *pspec)
{
    GncTaxTable *tt;

    g_return_if_fail(GNC_IS_TAXTABLE(object));

    tt = GNC_TAXTABLE(object);
    switch (prop_id)
    {
    case PROP_NAME:
        g_value_set_string(value, tt->name);
        break;
    case PROP_INVISIBLE:
        g_value_set_boolean(value, tt->invisible);
        break;
    case PROP_REFCOUNT:
        g_value_set_uint64(value, tt->refcount);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

static void
gnc_taxtable_set_property (GObject         *object,
                           guint            prop_id,
                           const GValue          *value,
                           GParamSpec      *pspec)
{
    GncTaxTable *tt;

    g_return_if_fail(GNC_IS_TAXTABLE(object));

    tt = GNC_TAXTABLE(object);
    g_assert (qof_instance_get_editlevel(tt));

    switch (prop_id)
    {
    case PROP_NAME:
        gncTaxTableSetName(tt, g_value_get_string(value));
        break;
    case PROP_INVISIBLE:
        if (g_value_get_boolean(value))
        {
            gncTaxTableMakeInvisible(tt);
        }
        break;
    case PROP_REFCOUNT:
        gncTaxTableSetRefcount(tt, g_value_get_uint64(value));
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

/** Return displayable name */
static gchar*
impl_get_display_name(const QofInstance* inst)
{
    GncTaxTable* tt;

    g_return_val_if_fail(inst != NULL, FALSE);
    g_return_val_if_fail(GNC_IS_TAXTABLE(inst), FALSE);

    tt = GNC_TAXTABLE(inst);
    return g_strdup_printf("Tax table %s", tt->name);
}

/** Does this object refer to a specific object */
static gboolean
impl_refers_to_object(const QofInstance* inst, const QofInstance* ref)
{
    GncTaxTable* tt;

    g_return_val_if_fail(inst != NULL, FALSE);
    g_return_val_if_fail(GNC_IS_TAXTABLE(inst), FALSE);

    tt = GNC_TAXTABLE(inst);

    if (GNC_IS_ACCOUNT(ref))
    {
        GList* node;

        for (node = tt->entries; node != NULL; node = node->next)
        {
            GncTaxTableEntry* tte = node->data;

            if (tte->account == GNC_ACCOUNT(ref))
            {
                return TRUE;
            }
        }
    }

    return FALSE;
}

/** Returns a list of my type of object which refers to an object.  For example, when called as
        qof_instance_get_typed_referring_object_list(taxtable, account);
    it will return the list of taxtables which refer to a specific account.  The result should be the
    same regardless of which taxtable object is used.  The list must be freed by the caller but the
    objects on the list must not.
 */
static GList*
impl_get_typed_referring_object_list(const QofInstance* inst, const QofInstance* ref)
{
    if (!GNC_IS_ACCOUNT(ref))
    {
        return NULL;
    }

    return qof_instance_get_referring_object_list_from_collection(qof_instance_get_collection(inst), ref);
}

static void
gnc_taxtable_class_init (GncTaxTableClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
    QofInstanceClass* qof_class = QOF_INSTANCE_CLASS(klass);

    gobject_class->dispose = gnc_taxtable_dispose;
    gobject_class->finalize = gnc_taxtable_finalize;
    gobject_class->set_property = gnc_taxtable_set_property;
    gobject_class->get_property = gnc_taxtable_get_property;

    qof_class->get_display_name = impl_get_display_name;
    qof_class->refers_to_object = impl_refers_to_object;
    qof_class->get_typed_referring_object_list = impl_get_typed_referring_object_list;

    g_object_class_install_property
    (gobject_class,
     PROP_NAME,
     g_param_spec_string ("name",
                          "TaxTable Name",
                          "The accountName is an arbitrary string "
                          "assigned by the user.  It is intended to "
                          "a short, 10 to 30 character long string "
                          "that is displayed by the GUI as the "
                          "tax table mnemonic.",
                          NULL,
                          G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_INVISIBLE,
     g_param_spec_boolean ("invisible",
                           "Invisible",
                           "TRUE if the tax table is invisible.  FALSE if visible.",
                           FALSE,
                           G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_REFCOUNT,
     g_param_spec_uint64("ref-count",
                         "Reference count",
                         "The ref-count property contains number of times this tax table "
                         "is referenced.",
                         0,           /* min */
                         G_MAXUINT64, /* max */
                         0,           /* default */
                         G_PARAM_READWRITE));
}

/* Create/Destroy Functions */
GncTaxTable *
gncTaxTableCreate (QofBook *book)
{
    GncTaxTable *table;
    if (!book) return NULL;

    table = g_object_new (GNC_TYPE_TAXTABLE, NULL);
    qof_instance_init_data (&table->inst, _GNC_MOD_NAME, book);
    table->name = CACHE_INSERT ("");
    addObj (table);
    qof_event_gen (&table->inst, QOF_EVENT_CREATE, NULL);
    return table;
}

void
gncTaxTableDestroy (GncTaxTable *table)
{
    if (!table) return;
    qof_instance_set_destroying(table, TRUE);
    qof_instance_set_dirty (&table->inst);
    gncTaxTableCommitEdit (table);
}

static void
gncTaxTableFree (GncTaxTable *table)
{
    GList *list;
    GncTaxTable *child;

    if (!table) return;

    qof_event_gen (&table->inst, QOF_EVENT_DESTROY, NULL);
    CACHE_REMOVE (table->name);
    remObj (table);

    /* destroy the list of entries */
    for (list = table->entries; list; list = list->next)
        gncTaxTableEntryDestroy (list->data);
    g_list_free (table->entries);

    if (!qof_instance_get_destroying(table))
        PERR("free a taxtable without do_free set!");

    /* disconnect from parent */
    if (table->parent)
        gncTaxTableRemoveChild(table->parent, table);

    /* disconnect from the children */
    for (list = table->children; list; list = list->next)
    {
        child = list->data;
        gncTaxTableSetParent(child, NULL);
    }
    g_list_free(table->children);

    /* qof_instance_release (&table->inst); */
    g_object_unref (table);
}

/* =============================================================== */

GncTaxTableEntry * gncTaxTableEntryCreate (void)
{
    GncTaxTableEntry *entry;
    entry = g_new0 (GncTaxTableEntry, 1);
    entry->amount = gnc_numeric_zero ();
    return entry;
}

void gncTaxTableEntryDestroy (GncTaxTableEntry *entry)
{
    if (!entry) return;
    g_free (entry);
}

/* =============================================================== */
/* Set Functions */

void gncTaxTableSetName (GncTaxTable *table, const char *name)
{
    if (!table || !name) return;
    SET_STR (table, table->name, name);
    mark_table (table);
    maybe_resort_list (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableSetParent (GncTaxTable *table, GncTaxTable *parent)
{
    if (!table) return;
    gncTaxTableBeginEdit (table);
    if (table->parent)
        gncTaxTableRemoveChild(table->parent, table);
    table->parent = parent;
    if (parent)
        gncTaxTableAddChild(parent, table);
    table->refcount = 0;
    gncTaxTableMakeInvisible (table);
    mark_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableSetChild (GncTaxTable *table, GncTaxTable *child)
{
    if (!table) return;
    gncTaxTableBeginEdit (table);
    table->child = child;
    mark_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableIncRef (GncTaxTable *table)
{
    if (!table) return;
    if (table->parent || table->invisible) return;        /* children dont need refcounts */
    gncTaxTableBeginEdit (table);
    table->refcount++;
    mark_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableDecRef (GncTaxTable *table)
{
    if (!table) return;
    if (table->parent || table->invisible) return;        /* children dont need refcounts */
    g_return_if_fail (table->refcount > 0);
    gncTaxTableBeginEdit (table);
    table->refcount--;
    mark_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableSetRefcount (GncTaxTable *table, gint64 refcount)
{
    if (!table) return;
    g_return_if_fail (refcount >= 0);
    gncTaxTableBeginEdit (table);
    table->refcount = refcount;
    mark_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableMakeInvisible (GncTaxTable *table)
{
    struct _book_info *bi;
    if (!table) return;
    gncTaxTableBeginEdit (table);
    table->invisible = TRUE;
    bi = qof_book_get_data (qof_instance_get_book(table), _GNC_MOD_NAME);
    bi->tables = g_list_remove (bi->tables, table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableEntrySetAccount (GncTaxTableEntry *entry, Account *account)
{
    if (!entry || !account) return;
    if (entry->account == account) return;
    entry->account = account;
    if (entry->table)
    {
        mark_table (entry->table);
        mod_table (entry->table);
    }
}

void gncTaxTableEntrySetType (GncTaxTableEntry *entry, GncAmountType type)
{
    if (!entry) return;
    if (entry->type == type) return;
    entry->type = type;
    if (entry->table)
    {
        mark_table (entry->table);
        mod_table (entry->table);
    }
}

void gncTaxTableEntrySetAmount (GncTaxTableEntry *entry, gnc_numeric amount)
{
    if (!entry) return;
    if (gnc_numeric_eq (entry->amount, amount)) return;
    entry->amount = amount;
    if (entry->table)
    {
        mark_table (entry->table);
        mod_table (entry->table);
    }
}

void gncTaxTableAddEntry (GncTaxTable *table, GncTaxTableEntry *entry)
{
    if (!table || !entry) return;
    if (entry->table == table) return; /* already mine */

    gncTaxTableBeginEdit (table);
    if (entry->table)
        gncTaxTableRemoveEntry (entry->table, entry);

    entry->table = table;
    table->entries = g_list_insert_sorted (table->entries, entry,
                                           (GCompareFunc)gncTaxTableEntryCompare);
    mark_table (table);
    mod_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableRemoveEntry (GncTaxTable *table, GncTaxTableEntry *entry)
{
    if (!table || !entry) return;
    gncTaxTableBeginEdit (table);
    entry->table = NULL;
    table->entries = g_list_remove (table->entries, entry);
    mark_table (table);
    mod_table (table);
    gncTaxTableCommitEdit (table);
}

void gncTaxTableChanged (GncTaxTable *table)
{
    if (!table) return;
    gncTaxTableBeginEdit (table);
    table->child = NULL;
    gncTaxTableCommitEdit (table);
}

/* =============================================================== */

void gncTaxTableBeginEdit (GncTaxTable *table)
{
    qof_begin_edit(&table->inst);
}

static void gncTaxTableOnError (QofInstance *inst, QofBackendError errcode)
{
    PERR("TaxTable QofBackend Failure: %d", errcode);
    gnc_engine_signal_commit_error( errcode );
}

static void gncTaxTableOnDone (QofInstance *inst) {}

static void table_free (QofInstance *inst)
{
    GncTaxTable *table = (GncTaxTable *) inst;
    gncTaxTableFree (table);
}

void gncTaxTableCommitEdit (GncTaxTable *table)
{
    /* GnuCash 2.6.3 and earlier didn't handle taxtable kvp's... */
     if (qof_instance_has_kvp (QOF_INSTANCE (table)))
          gnc_features_set_used (qof_instance_get_book (QOF_INSTANCE (table)),
                                 GNC_FEATURE_KVP_EXTRA_DATA);

    if (!qof_commit_edit (QOF_INSTANCE(table))) return;
    qof_commit_edit_part2 (&table->inst, gncTaxTableOnError,
                           gncTaxTableOnDone, table_free);
}


/* =============================================================== */
/* Get Functions */

GncTaxTable *gncTaxTableLookupByName (QofBook *book, const char *name)
{
    GList *list = gncTaxTableGetTables (book);

    for ( ; list; list = list->next)
    {
        GncTaxTable *table = list->data;
        if (!g_strcmp0 (table->name, name))
            return list->data;
    }
    return NULL;
}

GncTaxTable*
gncTaxTableGetDefault (QofBook *book, GncOwnerType type)
{
    GSList *path = NULL;
    const GncGUID *guid = NULL;
    const char *vendor = "Default Vendor TaxTable";
    const char *customer = "Default Customer TaxTable";
    const char *section = "Business";

    g_return_val_if_fail (book != NULL, NULL);
    g_return_val_if_fail (type == GNC_OWNER_CUSTOMER || \
                          type == GNC_OWNER_VENDOR, NULL);
    path = g_slist_prepend (path, type == GNC_OWNER_CUSTOMER ? (void*)customer : (void*)vendor);
    path = g_slist_prepend (path, (void*)section);

    guid = qof_book_get_guid_option (book, path);
    g_slist_free (path);

    return gncTaxTableLookup (book, guid);
}

GncTaxTableList * gncTaxTableGetTables (QofBook *book)
{
    struct _book_info *bi;
    if (!book) return NULL;

    bi = qof_book_get_data (book, _GNC_MOD_NAME);
    return bi ? bi->tables : NULL;
}

const char *gncTaxTableGetName (const GncTaxTable *table)
{
    if (!table) return NULL;
    return table->name;
}

static GncTaxTableEntry *gncTaxTableEntryCopy (const GncTaxTableEntry *entry)
{
    GncTaxTableEntry *e;
    if (!entry) return NULL;

    e = gncTaxTableEntryCreate ();
    gncTaxTableEntrySetAccount (e, entry->account);
    gncTaxTableEntrySetType (e, entry->type);
    gncTaxTableEntrySetAmount (e, entry->amount);

    return e;
}

static GncTaxTable *gncTaxTableCopy (const GncTaxTable *table)
{
    GncTaxTable *t;
    GList *list;

    if (!table) return NULL;
    t = gncTaxTableCreate (qof_instance_get_book(table));
    gncTaxTableSetName (t, table->name);
    for (list = table->entries; list; list = list->next)
    {
        GncTaxTableEntry *entry, *e;
        entry = list->data;
        e = gncTaxTableEntryCopy (entry);
       /* Clang static analyzer thinks we're leaking e, but we're not.
        * We're transferring it to table. */
        gncTaxTableAddEntry (t, e);
    }
    return t;
}

GncTaxTable *gncTaxTableReturnChild (GncTaxTable *table, gboolean make_new)
{
    GncTaxTable *child = NULL;

    if (!table) return NULL;
    if (table->child) return table->child;
    if (table->parent || table->invisible) return table;
    if (make_new)
    {
        child = gncTaxTableCopy (table);
        gncTaxTableSetChild (table, child);
        gncTaxTableSetParent (child, table);
    }
    return child;
}

GncTaxTable *gncTaxTableGetParent (const GncTaxTable *table)
{
    if (!table) return NULL;
    return table->parent;
}

GncTaxTableEntryList* gncTaxTableGetEntries (const GncTaxTable *table)
{
    if (!table) return NULL;
    return table->entries;
}

gint64 gncTaxTableGetRefcount (const GncTaxTable *table)
{
    if (!table) return 0;
    return table->refcount;
}

time64 gncTaxTableLastModifiedSecs (const GncTaxTable *table)
{
    if (!table) return 0;
    return table->modtime;
}

gboolean gncTaxTableGetInvisible (const GncTaxTable *table)
{
    if (!table) return FALSE;
    return table->invisible;
}

Account * gncTaxTableEntryGetAccount (const GncTaxTableEntry *entry)
{
    if (!entry) return NULL;
    return entry->account;
}

GncAmountType gncTaxTableEntryGetType (const GncTaxTableEntry *entry)
{
    if (!entry) return 0;
    return entry->type;
}

gnc_numeric gncTaxTableEntryGetAmount (const GncTaxTableEntry *entry)
{
    if (!entry) return gnc_numeric_zero();
    return entry->amount;
}

/* This is a semi-private function (meaning that it's not declared in
 * the header) used for SQL Backend testing. */
GncTaxTable* gncTaxTableEntryGetTable( const GncTaxTableEntry* entry )
{
    if (!entry) return NULL;
    return entry->table;
}

int gncTaxTableEntryCompare (const GncTaxTableEntry *a, const GncTaxTableEntry *b)
{
    char *name_a, *name_b;
    int retval;

    if (!a && !b) return 0;
    if (!a) return -1;
    if (!b) return 1;

    name_a = gnc_account_get_full_name (a->account);
    name_b = gnc_account_get_full_name (b->account);
    retval = g_strcmp0(name_a, name_b);
    g_free(name_a);
    g_free(name_b);

    if (retval)
        return retval;

    return gnc_numeric_compare (a->amount, b->amount);
}

int gncTaxTableCompare (const GncTaxTable *a, const GncTaxTable *b)
{
    if (!a && !b) return 0;
    if (!a) return -1;
    if (!b) return 1;
    return g_strcmp0 (a->name, b->name);
}

gboolean gncTaxTableEntryEqual(const GncTaxTableEntry *a, const GncTaxTableEntry *b)
{
    if (a == NULL && b == NULL) return TRUE;
    if (a == NULL || b == NULL) return FALSE;

    if (!xaccAccountEqual(a->account, b->account, TRUE))
    {
        PWARN("accounts differ");
        return FALSE;
    }

    if (a->type != b->type)
    {
        PWARN("types differ");
        return FALSE;
    }

    if (!gnc_numeric_equal(a->amount, b->amount))
    {
        PWARN("amounts differ");
        return FALSE;
    }

    return TRUE;
}

gboolean gncTaxTableEqual(const GncTaxTable *a, const GncTaxTable *b)
{
    if (a == NULL && b == NULL) return TRUE;
    if (a == NULL || b == NULL) return FALSE;

    g_return_val_if_fail(GNC_IS_TAXTABLE(a), FALSE);
    g_return_val_if_fail(GNC_IS_TAXTABLE(b), FALSE);

    if (g_strcmp0(a->name, b->name) != 0)
    {
        PWARN("Names differ: %s vs %s", a->name, b->name);
        return FALSE;
    }

    if (a->invisible != b->invisible)
    {
        PWARN("invisible flags differ");
        return FALSE;
    }

    if ((a->entries != NULL) != (b->entries != NULL))
    {
        PWARN("only one has entries");
        return FALSE;
    }

    if (a->entries != NULL && b->entries != NULL)
    {
        GncTaxTableEntryList* a_node;
        GncTaxTableEntryList* b_node;

        for (a_node = a->entries, b_node = b->entries;
                a_node != NULL && b_node != NULL;
                a_node = a_node->next, b_node = b_node->next)
        {
            if (!gncTaxTableEntryEqual((GncTaxTableEntry*)a_node->data,
                                       (GncTaxTableEntry*)b_node->data))
            {
                PWARN("entries differ");
                return FALSE;
            }
        }

        if (a_node != NULL || b_node != NULL)
        {
            PWARN("Unequal number of entries");
            return FALSE;
        }
    }

#if 0
    /* See libgnucash/engine/TaxTableBillTermImmutability.txt for an explanation of the following */
    /* Code that handles this is *identical* to that in gncBillTerm */
    gint64          refcount;
    GncTaxTable *   parent;       /* if non-null, we are an immutable child */
    GncTaxTable *   child;        /* if non-null, we have not changed */
    GList *         children;     /* list of children for disconnection */
#endif

    return TRUE;
}

/*
 * This will add value to the account-value for acc, creating a new
 * list object if necessary
 */
GList *gncAccountValueAdd (GList *list, Account *acc, gnc_numeric value)
{
    GList *li;
    GncAccountValue *res = NULL;

    g_return_val_if_fail (acc, list);
    g_return_val_if_fail (gnc_numeric_check (value) == GNC_ERROR_OK, list);

    /* Try to find the account in the list */
    for (li = list; li; li = li->next)
    {
        res = li->data;
        if (res->account == acc)
        {
            res->value = gnc_numeric_add (res->value, value, GNC_DENOM_AUTO,
                                          GNC_HOW_DENOM_REDUCE | GNC_HOW_RND_ROUND_HALF_UP);
            return list;
        }
    }
    /* Nope, didn't find it. */

    res = g_new0 (GncAccountValue, 1);
    res->account = acc;
    res->value = value;
    return g_list_prepend (list, res);
}

/* Merge l2 into l1.  l2 is not touched. */
GList *gncAccountValueAddList (GList *l1, GList *l2)
{
    GList *li;

    for (li = l2; li; li = li->next )
    {
        GncAccountValue *val = li->data;
        l1 = gncAccountValueAdd (l1, val->account, val->value);
    }

    return l1;
}

/* return the total for this list */
gnc_numeric gncAccountValueTotal (GList *list)
{
    gnc_numeric total = gnc_numeric_zero ();

    for ( ; list ; list = list->next)
    {
        GncAccountValue *val = list->data;
        total = gnc_numeric_add (total, val->value, GNC_DENOM_AUTO, GNC_HOW_DENOM_REDUCE | GNC_HOW_RND_ROUND_HALF_UP);
    }
    return total;
}

/* Destroy a list of accountvalues */
void gncAccountValueDestroy (GList *list)
{
    GList *node;
    for ( node = list; node ; node = node->next)
        g_free (node->data);

    g_list_free (list);
}

/* Package-Private functions */

static void _gncTaxTableCreate (QofBook *book)
{
    struct _book_info *bi;

    if (!book) return;

    bi = g_new0 (struct _book_info, 1);
    qof_book_set_data (book, _GNC_MOD_NAME, bi);
}

static void
destroy_taxtable_on_book_close (QofInstance *ent, gpointer data)
{
    GncTaxTable *table = GNC_TAXTABLE(ent);

    gncTaxTableBeginEdit (table);
    gncTaxTableDestroy (table);
}

static void _gncTaxTableDestroy (QofBook *book)
{
    struct _book_info *bi;
    QofCollection *col;

    if (!book) return;

    bi = qof_book_get_data (book, _GNC_MOD_NAME);

    col = qof_book_get_collection (book, GNC_ID_TAXTABLE);
    qof_collection_foreach (col, destroy_taxtable_on_book_close, NULL);

    g_list_free (bi->tables);
    g_free (bi);
}

static QofObject gncTaxTableDesc =
{
    DI(.interface_version = ) QOF_OBJECT_VERSION,
    DI(.e_type            = ) _GNC_MOD_NAME,
    DI(.type_label        = ) "Tax Table",
    DI(.create            = ) (gpointer)gncTaxTableCreate,
    DI(.book_begin        = ) _gncTaxTableCreate,
    DI(.book_end          = ) _gncTaxTableDestroy,
    DI(.is_dirty          = ) qof_collection_is_dirty,
    DI(.mark_clean        = ) qof_collection_mark_clean,
    DI(.foreach           = ) qof_collection_foreach,
    DI(.printable         = ) NULL,
    DI(.version_cmp       = ) (int (*)(gpointer, gpointer)) qof_instance_version_cmp,
};

gboolean gncTaxTableRegister (void)
{
    static QofParam params[] =
    {
        { GNC_TT_NAME, 		QOF_TYPE_STRING, 	(QofAccessFunc)gncTaxTableGetName, 		(QofSetterFunc)gncTaxTableSetName },
        { GNC_TT_REFCOUNT, 	QOF_TYPE_INT64, 	(QofAccessFunc)gncTaxTableGetRefcount, 	(QofSetterFunc)gncTaxTableSetRefcount },
        { QOF_PARAM_BOOK, 	QOF_ID_BOOK, 		(QofAccessFunc)qof_instance_get_book, 	NULL },
        { QOF_PARAM_GUID, 	QOF_TYPE_GUID, 		(QofAccessFunc)qof_instance_get_guid, 	NULL },
        { NULL },
    };

    qof_class_register (_GNC_MOD_NAME, (QofSortFunc)gncTaxTableCompare, params);

    return qof_object_register (&gncTaxTableDesc);
}

/* need a QOF tax table entry object */
//gncTaxTableEntrySetType_q int32
//gint gncTaxTableEntryGetType_q (GncTaxTableEntry *entry);