/********************************************************************
 * gnc-pricedb.c -- a simple price database for gnucash.            *
 * Copyright (C) 2001 Rob Browning                                  *
 * Copyright (C) 2001,2003 Linas Vepstas <linas@linas.org>          *
 *                                                                  *
 * 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                   *
 *                                                                  *
 *******************************************************************/

#include "config.h"

#include <glib.h>
#include <string.h>
#include "gnc-pricedb-p.h"
#include "qofbackend-p.h"

/* This static indicates the debugging module that this .o belongs to.  */
static QofLogModule log_module = GNC_MOD_PRICE;

static gboolean add_price(GNCPriceDB *db, GNCPrice *p);
static gboolean remove_price(GNCPriceDB *db, GNCPrice *p, gboolean cleanup);
static GNCPrice *lookup_nearest_in_time(GNCPriceDB *db, const gnc_commodity *c,
                                        const gnc_commodity *currency,
                                        Timespec t, gboolean sameday);

enum
{
    PROP_0,
    PROP_COMMODITY,
    PROP_CURRENCY,
    PROP_DATE,
    PROP_SOURCE,
    PROP_TYPE,
    PROP_VALUE
};

/* GObject Initialization */
G_DEFINE_TYPE(GNCPrice, gnc_price, QOF_TYPE_INSTANCE);

static void
gnc_price_init(GNCPrice* price)
{
    price->refcount = 1;
    price->value = gnc_numeric_zero();
    price->type = NULL;
    price->source = PRICE_SOURCE_INVALID;
}

/* Array of char constants for converting price-source enums. Be sure to keep in
 * sync with the enum values in gnc-pricedb.h The string user:price-editor is
 * explicitly used by price_to_gui() in dialog-price-editor.c and the string
 * Finance::Quote is explicitly used by fq-results->commod-tz-quote-triples in
 * price-quotes.scm. Take care to keep them in sync if you make changes. Beware
 * that the strings are used to store the enum values in the backends so any
 * changes will affect backward data compatibility.
 */
static const char* source_names[] =
{
    /* sync with price_to_gui in dialog-price-editor.c */
    "user:price-editor",
    /* sync with commidity-tz-quote->price in price-quotes.scm */
    "Finance::Quote",
    "user:price",
    /* String retained for backwards compatibility. */
    "user:xfer-dialog",
    "user:split-register",
    "user:stock-split",
    "user:invoice-post",
    "invalid"
};

static void
gnc_price_dispose(GObject *pricep)
{
    G_OBJECT_CLASS(gnc_price_parent_class)->dispose(pricep);
}

static void
gnc_price_finalize(GObject* pricep)
{
    G_OBJECT_CLASS(gnc_price_parent_class)->finalize(pricep);
}

/* Note that g_value_set_object() refs the object, as does
 * g_object_get(). But g_object_get() only unrefs once when it disgorges
 * the object, leaving an unbalanced ref, which leaks. So instead of
 * using g_value_set_object(), use g_value_take_object() which doesn't
 * ref the object when used in get_property().
 */
static void
gnc_price_get_property(GObject* object, guint prop_id, GValue* value, GParamSpec* pspec)
{
    GNCPrice* price;

    g_return_if_fail(GNC_IS_PRICE(object));

    price = GNC_PRICE(object);
    switch (prop_id)
    {
    case PROP_SOURCE:
        g_value_set_string(value, gnc_price_get_source_string(price));
        break;
    case PROP_TYPE:
        g_value_set_string(value, price->type);
        break;
    case PROP_VALUE:
        g_value_set_boxed(value, &price->value);
        break;
    case PROP_COMMODITY:
        g_value_take_object(value, price->commodity);
        break;
    case PROP_CURRENCY:
        g_value_take_object(value, price->currency);
        break;
    case PROP_DATE:
        g_value_set_boxed(value, &price->tmspec);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

static void
gnc_price_set_property(GObject* object, guint prop_id, const GValue* value, GParamSpec* pspec)
{
    GNCPrice* price;
    gnc_numeric* number;
    Timespec* ts;

    g_return_if_fail(GNC_IS_PRICE(object));

    price = GNC_PRICE(object);
    switch (prop_id)
    {
    case PROP_SOURCE:
        gnc_price_set_source_string(price, g_value_get_string(value));
        break;
    case PROP_TYPE:
        gnc_price_set_typestr(price, g_value_get_string(value));
        break;
    case PROP_VALUE:
        number = g_value_get_boxed(value);
        gnc_price_set_value(price, *number);
        break;
    case PROP_COMMODITY:
        gnc_price_set_commodity(price, g_value_get_object(value));
        break;
    case PROP_CURRENCY:
        gnc_price_set_currency(price, g_value_get_object(value));
        break;
    case PROP_DATE:
        ts = g_value_get_boxed(value);
        gnc_price_set_time(price, *ts);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

static void
gnc_price_class_init(GNCPriceClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

    gobject_class->dispose = gnc_price_dispose;
    gobject_class->finalize = gnc_price_finalize;
    gobject_class->set_property = gnc_price_set_property;
    gobject_class->get_property = gnc_price_get_property;

    g_object_class_install_property
    (gobject_class,
     PROP_COMMODITY,
     g_param_spec_object ("commodity",
                          "Commodity",
                          "The commodity field denotes the base kind of "
                          "'stuff' for the units of this quote, whether "
                          "it is USD, gold, stock, etc.",
                          GNC_TYPE_COMMODITY,
                          G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_CURRENCY,
     g_param_spec_object ("currency",
                          "Currency",
                          "The currency field denotes the external kind "
                          "'stuff' for the units of this quote, whether "
                          "it is USD, gold, stock, etc.",
                          GNC_TYPE_COMMODITY,
                          G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_SOURCE,
     g_param_spec_string ("source",
                          "Price source",
                          "The price source is PriceSource enum describing how"
                          " the price was created. This property works on the"
                          " string values in source_names for SQL database"
                          " compatibility.",
                          NULL,
                          G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_TYPE,
     g_param_spec_string ("type",
                          "Quote type",
                          "The quote type is a string describing the "
                          "type of a price quote.  Types possible now "
                          "are 'bid', 'ask', 'last', 'nav', 'transaction', "
                          "and 'unknown'.",
                          NULL,
                          G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_DATE,
     g_param_spec_boxed("date",
                        "Date",
                        "The date of the price quote.",
                        GNC_TYPE_NUMERIC,
                        G_PARAM_READWRITE));

    g_object_class_install_property
    (gobject_class,
     PROP_VALUE,
     g_param_spec_boxed("value",
                        "Value",
                        "The value of the price quote.",
                        GNC_TYPE_NUMERIC,
                        G_PARAM_READWRITE));
}

/* ==================================================================== */
/* GNCPrice functions
 */

/* allocation */
GNCPrice *
gnc_price_create (QofBook *book)
{
    GNCPrice *p;

    g_return_val_if_fail (book, NULL);

    p = g_object_new(GNC_TYPE_PRICE, NULL);

    qof_instance_init_data (&p->inst, GNC_ID_PRICE, book);
    qof_event_gen (&p->inst, QOF_EVENT_CREATE, NULL);

    return p;
}

static void
gnc_price_destroy (GNCPrice *p)
{
    ENTER(" ");
    qof_event_gen (&p->inst, QOF_EVENT_DESTROY, NULL);

    if (p->type) CACHE_REMOVE(p->type);

    /* qof_instance_release (&p->inst); */
    g_object_unref(p);
    LEAVE (" ");
}

void
gnc_price_ref(GNCPrice *p)
{
    if (!p) return;
    p->refcount++;
}

void
gnc_price_unref(GNCPrice *p)
{
    if (!p) return;
    if (p->refcount == 0)
    {
        return;
    }

    p->refcount--;

    if (p->refcount <= 0)
    {
        if (NULL != p->db)
        {
            PERR("last unref while price in database");
        }
        gnc_price_destroy (p);
    }
}

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

GNCPrice *
gnc_price_clone (GNCPrice* p, QofBook *book)
{
    /* the clone doesn't belong to a PriceDB */
    GNCPrice *new_p;

    g_return_val_if_fail (book, NULL);

    ENTER ("pr=%p", p);

    if (!p)
    {
        LEAVE (" ");
        return NULL;
    }

    new_p = gnc_price_create(book);
    if (!new_p)
    {
        LEAVE (" ");
        return NULL;
    }

    qof_instance_copy_version(new_p, p);

    gnc_price_begin_edit(new_p);
    /* never ever clone guid's */
    gnc_price_set_commodity(new_p, gnc_price_get_commodity(p));
    gnc_price_set_time(new_p, gnc_price_get_time(p));
    gnc_price_set_source(new_p, gnc_price_get_source(p));
    gnc_price_set_typestr(new_p, gnc_price_get_typestr(p));
    gnc_price_set_value(new_p, gnc_price_get_value(p));
    gnc_price_set_currency(new_p, gnc_price_get_currency(p));
    gnc_price_commit_edit(new_p);
    LEAVE (" ");
    return(new_p);
}

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

void
gnc_price_begin_edit (GNCPrice *p)
{
    qof_begin_edit(&p->inst);
}

static void commit_err (QofInstance *inst, QofBackendError errcode)
{
    PERR ("Failed to commit: %d", errcode);
    gnc_engine_signal_commit_error( errcode );
}

static void noop (QofInstance *inst) {}

void
gnc_price_commit_edit (GNCPrice *p)
{
    if (!qof_commit_edit (QOF_INSTANCE(p))) return;
    qof_commit_edit_part2 (&p->inst, commit_err, noop, noop);
}

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

void
gnc_pricedb_begin_edit (GNCPriceDB *pdb)
{
    qof_begin_edit(&pdb->inst);
}

void
gnc_pricedb_commit_edit (GNCPriceDB *pdb)
{
    if (!qof_commit_edit (QOF_INSTANCE(pdb))) return;
    qof_commit_edit_part2 (&pdb->inst, commit_err, noop, noop);
}

/* ==================================================================== */
/* setters */

static void
gnc_price_set_dirty (GNCPrice *p)
{
    qof_instance_set_dirty(&p->inst);
    qof_event_gen(&p->inst, QOF_EVENT_MODIFY, NULL);
}

void
gnc_price_set_commodity(GNCPrice *p, gnc_commodity *c)
{
    if (!p) return;

    if (!gnc_commodity_equiv(p->commodity, c))
    {
        /* Changing the commodity requires the hash table
         * position to be modified. The easiest way of doing
         * this is to remove and reinsert. */
        gnc_price_ref (p);
        remove_price (p->db, p, TRUE);
        gnc_price_begin_edit (p);
        p->commodity = c;
        gnc_price_set_dirty(p);
        gnc_price_commit_edit (p);
        add_price (p->db, p);
        gnc_price_unref (p);
    }
}


void
gnc_price_set_currency(GNCPrice *p, gnc_commodity *c)
{
    if (!p) return;

    if (!gnc_commodity_equiv(p->currency, c))
    {
        /* Changing the currency requires the hash table
         * position to be modified. The easiest way of doing
         * this is to remove and reinsert. */
        gnc_price_ref (p);
        remove_price (p->db, p, TRUE);
        gnc_price_begin_edit (p);
        p->currency = c;
        gnc_price_set_dirty(p);
        gnc_price_commit_edit (p);
        add_price (p->db, p);
        gnc_price_unref (p);
    }
}

void
gnc_price_set_time(GNCPrice *p, Timespec t)
{
    if (!p) return;
    if (!timespec_equal(&(p->tmspec), &t))
    {
        /* Changing the datestamp requires the hash table
         * position to be modified. The easiest way of doing
         * this is to remove and reinsert. */
        gnc_price_ref (p);
        remove_price (p->db, p, FALSE);
        gnc_price_begin_edit (p);
        p->tmspec = t;
        gnc_price_set_dirty(p);
        gnc_price_commit_edit (p);
        add_price (p->db, p);
        gnc_price_unref (p);
    }
}

void
gnc_price_set_source(GNCPrice *p, PriceSource s)
{
    if (!p) return;
    gnc_price_begin_edit (p);
    p->source = s;
    gnc_price_set_dirty(p);
    gnc_price_commit_edit(p);
}

void
gnc_price_set_source_string(GNCPrice *p, const char* str)
{
    if (!p) return;
    for (PriceSource s = PRICE_SOURCE_EDIT_DLG;
         s < PRICE_SOURCE_INVALID; ++s)
        if (strcmp(source_names[s], str) == 0)
        {
            gnc_price_set_source(p, s);
            return;
        }


}
void
gnc_price_set_typestr(GNCPrice *p, const char* type)
{
    if (!p) return;
    if (g_strcmp0(p->type, type) != 0)
    {
        gchar *tmp;

        gnc_price_begin_edit (p);
        tmp = CACHE_INSERT((gpointer) type);
        if (p->type) CACHE_REMOVE(p->type);
        p->type = tmp;
        gnc_price_set_dirty(p);
        gnc_price_commit_edit (p);
    }
}

void
gnc_price_set_value(GNCPrice *p, gnc_numeric value)
{
    if (!p) return;
    if (!gnc_numeric_eq(p->value, value))
    {
        gnc_price_begin_edit (p);
        p->value = value;
        gnc_price_set_dirty(p);
        gnc_price_commit_edit (p);
    }
}

/* ==================================================================== */
/* getters */

GNCPrice *
gnc_price_lookup (const GncGUID *guid, QofBook *book)
{
    QofCollection *col;

    if (!guid || !book) return NULL;
    col = qof_book_get_collection (book, GNC_ID_PRICE);
    return (GNCPrice *) qof_collection_lookup_entity (col, guid);
}

gnc_commodity *
gnc_price_get_commodity(const GNCPrice *p)
{
    if (!p) return NULL;
    return p->commodity;
}

Timespec
gnc_price_get_time(const GNCPrice *p)
{
    if (!p)
    {
        Timespec result;
        result.tv_sec = 0;
        result.tv_nsec = 0;
        return result;
    }
    return p->tmspec;
}

PriceSource
gnc_price_get_source(const GNCPrice *p)
{
    if (!p) return PRICE_SOURCE_INVALID;
    return p->source;
}

const char*
gnc_price_get_source_string(const GNCPrice *p)
{
    if (!p) return NULL;
    return source_names[p->source];
}

const char *
gnc_price_get_typestr(const GNCPrice *p)
{
    if (!p) return NULL;
    return p->type;
}

gnc_numeric
gnc_price_get_value(const GNCPrice *p)
{
    if (!p)
    {
        PERR("price NULL.\n");
        return gnc_numeric_zero();
    }
    return p->value;
}

gnc_commodity *
gnc_price_get_currency(const GNCPrice *p)
{
    if (!p) return NULL;
    return p->currency;
}

gboolean
gnc_price_equal (const GNCPrice *p1, const GNCPrice *p2)
{
    Timespec ts1;
    Timespec ts2;

    if (p1 == p2) return TRUE;
    if (!p1 || !p2) return FALSE;

    if (!gnc_commodity_equiv (gnc_price_get_commodity (p1),
                              gnc_price_get_commodity (p2)))
        return FALSE;

    if (!gnc_commodity_equiv (gnc_price_get_currency (p1),
                              gnc_price_get_currency (p2)))
        return FALSE;

    ts1 = gnc_price_get_time (p1);
    ts2 = gnc_price_get_time (p2);

    if (!timespec_equal (&ts1, &ts2))
        return FALSE;

    if (gnc_price_get_source (p1) != gnc_price_get_source (p2))
        return FALSE;

    if (g_strcmp0 (gnc_price_get_typestr (p1),
                   gnc_price_get_typestr (p2)) != 0)
        return FALSE;

    if (!gnc_numeric_eq (gnc_price_get_value (p1),
                         gnc_price_get_value (p2)))
        return FALSE;

    return TRUE;
}

/* ==================================================================== */
/* price list manipulation functions */

static gint
compare_prices_by_date(gconstpointer a, gconstpointer b)
{
    Timespec time_a;
    Timespec time_b;
    gint result;

    if (!a && !b) return 0;
    /* nothing is always less than something */
    if (!a) return -1;

    time_a = gnc_price_get_time((GNCPrice *) a);
    time_b = gnc_price_get_time((GNCPrice *) b);

    result = -timespec_cmp(&time_a, &time_b);
    if (result) return result;

    /* For a stable sort */
    return guid_compare (gnc_price_get_guid((GNCPrice *) a),
                         gnc_price_get_guid((GNCPrice *) b));
}

typedef struct
{
    GNCPrice* pPrice;
    gboolean isDupl;
} PriceListIsDuplStruct;

static void
price_list_is_duplicate( gpointer data, gpointer user_data )
{
    GNCPrice* pPrice = (GNCPrice*)data;
    PriceListIsDuplStruct* pStruct = (PriceListIsDuplStruct*)user_data;
    Timespec time_a, time_b;

    time_a = timespecCanonicalDayTime( gnc_price_get_time( pPrice ) );
    time_b = timespecCanonicalDayTime( gnc_price_get_time( pStruct->pPrice ) );

    /* If the date, currency, commodity and price match, it's a duplicate */
    if ( !gnc_numeric_equal( gnc_price_get_value( pPrice ),  gnc_price_get_value( pStruct->pPrice ) ) ) return;
    if ( gnc_price_get_commodity( pPrice ) != gnc_price_get_commodity( pStruct->pPrice ) ) return;
    if ( gnc_price_get_currency( pPrice ) != gnc_price_get_currency( pStruct->pPrice ) ) return;

    if ( timespec_cmp( &time_a, &time_b ) != 0 ) return;

    pStruct->isDupl = TRUE;
}

gboolean
gnc_price_list_insert(PriceList **prices, GNCPrice *p, gboolean check_dupl)
{
    GList *result_list;
    PriceListIsDuplStruct* pStruct;
    gboolean isDupl;

    if (!prices || !p) return FALSE;
    gnc_price_ref(p);

    if (check_dupl)
    {
        pStruct = g_new0( PriceListIsDuplStruct, 1 );
        pStruct->pPrice = p;
        pStruct->isDupl = FALSE;
        g_list_foreach( *prices, price_list_is_duplicate, pStruct );
        isDupl = pStruct->isDupl;
        g_free( pStruct );

        if ( isDupl )
        {
            return TRUE;
        }
    }

    result_list = g_list_insert_sorted(*prices, p, compare_prices_by_date);
    if (!result_list) return FALSE;
    *prices = result_list;
    return TRUE;
}

gboolean
gnc_price_list_remove(PriceList **prices, GNCPrice *p)
{
    GList *result_list;
    GList *found_element;

    if (!prices || !p) return FALSE;

    found_element = g_list_find(*prices, p);
    if (!found_element) return TRUE;

    result_list = g_list_remove_link(*prices, found_element);
    gnc_price_unref((GNCPrice *) found_element->data);
    g_list_free(found_element);

    *prices = result_list;
    return TRUE;
}

static void
price_list_destroy_helper(gpointer data, gpointer user_data)
{
    gnc_price_unref((GNCPrice *) data);
}

void
gnc_price_list_destroy(PriceList *prices)
{
    g_list_foreach(prices, price_list_destroy_helper, NULL);
    g_list_free(prices);
}

gboolean
gnc_price_list_equal(PriceList *prices1, PriceList *prices2)
{
    GList *n1, *n2;

    if (prices1 == prices2) return TRUE;

    if (g_list_length (prices1) < g_list_length (prices2))
    {
        PWARN ("prices2 has extra prices");
        return FALSE;
    }

    if (g_list_length (prices1) > g_list_length (prices2))
    {
        PWARN ("prices1 has extra prices");
        return FALSE;
    }

    for (n1 = prices1, n2 = prices2; n1 ; n1 = n1->next, n2 = n2->next)
        if (!gnc_price_equal (n1->data, n2->data))
            return FALSE;

    return TRUE;
}

/* ==================================================================== */
/* GNCPriceDB functions

   Structurally a GNCPriceDB contains a hash mapping price commodities
   (of type gnc_commodity*) to hashes mapping price currencies (of
   type gnc_commodity*) to GNCPrice lists (see gnc-pricedb.h for a
   description of GNCPrice lists).  The top-level key is the commodity
   you want the prices for, and the second level key is the commodity
   that the value is expressed in terms of.
 */

/* GObject Initialization */
QOF_GOBJECT_IMPL(gnc_pricedb, GNCPriceDB, QOF_TYPE_INSTANCE);

static void
gnc_pricedb_init(GNCPriceDB* pdb)
{
}

static void
gnc_pricedb_dispose_real (GObject *pdbp)
{
}

static void
gnc_pricedb_finalize_real(GObject* pdbp)
{
}

static GNCPriceDB *
gnc_pricedb_create(QofBook * book)
{
    GNCPriceDB * result;
    QofCollection *col;

    g_return_val_if_fail (book, NULL);

    /* There can only be one pricedb per book.  So if one exits already,
     * then use that.  Warn user, they shouldn't be creating two ...
     */
    col = qof_book_get_collection (book, GNC_ID_PRICEDB);
    result = qof_collection_get_data (col);
    if (result)
    {
        PWARN ("A price database already exists for this book!");
        return result;
    }

    result = g_object_new(GNC_TYPE_PRICEDB, NULL);
    qof_instance_init_data (&result->inst, GNC_ID_PRICEDB, book);
    qof_collection_mark_clean(col);

    /** \todo This leaks result when the collection is destroyed.  When
       qofcollection is fixed to allow a destroy notifier, we'll need to
       provide one here. */
    qof_collection_set_data (col, result);

    result->commodity_hash = g_hash_table_new(NULL, NULL);
    g_return_val_if_fail (result->commodity_hash, NULL);
    return result;
}

static void
destroy_pricedb_currency_hash_data(gpointer key,
                                   gpointer data,
                                   gpointer user_data)
{
    GList *price_list = (GList *) data;
    GList *node;
    GNCPrice *p;

    for (node = price_list; node; node = node->next)
    {
        p = node->data;

        p->db = NULL;
    }

    gnc_price_list_destroy(price_list);
}

static void
destroy_pricedb_commodity_hash_data(gpointer key,
                                    gpointer data,
                                    gpointer user_data)
{
    GHashTable *currency_hash = (GHashTable *) data;
    if (!currency_hash) return;
    g_hash_table_foreach (currency_hash,
                          destroy_pricedb_currency_hash_data,
                          NULL);
    g_hash_table_destroy(currency_hash);
}

void
gnc_pricedb_destroy(GNCPriceDB *db)
{
    if (!db) return;
    if (db->commodity_hash)
    {
        g_hash_table_foreach (db->commodity_hash,
                              destroy_pricedb_commodity_hash_data,
                              NULL);
    }
    g_hash_table_destroy (db->commodity_hash);
    db->commodity_hash = NULL;
    /* qof_instance_release (&db->inst); */
    g_object_unref(db);
}

void
gnc_pricedb_set_bulk_update(GNCPriceDB *db, gboolean bulk_update)
{
    db->bulk_update = bulk_update;
}

/* ==================================================================== */
/* This is kind of weird, the way its done.  Each collection of prices
 * for a given commodity should get its own guid, be its own entity, etc.
 * We really shouldn't be using the collection data.  But, hey I guess its OK,
 * yeah? Umm, possibly not. (NW). See TODO below.
*/
/** \todo Collections of prices are not destroyed fully.

    \par
    gnc_pricedb_destroy does not clean up properly because
    gnc_pricedb_create reports an existing PriceDB after
    running gnc_pricedb_destroy. To change the pricedb, we need to
    destroy and recreate the book. Yuk.
 */

GNCPriceDB *
gnc_collection_get_pricedb(QofCollection *col)
{
    if (!col) return NULL;
    return qof_collection_get_data (col);
}

GNCPriceDB *
gnc_pricedb_get_db(QofBook *book)
{
    QofCollection *col;

    if (!book) return NULL;
    col = qof_book_get_collection (book, GNC_ID_PRICEDB);
    return gnc_collection_get_pricedb (col);
}

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

static gboolean
num_prices_helper (GNCPrice *p, gpointer user_data)
{
    guint *count = user_data;

    *count += 1;

    return TRUE;
}

guint
gnc_pricedb_get_num_prices(GNCPriceDB *db)
{
    guint count;

    if (!db) return 0;

    count = 0;

    gnc_pricedb_foreach_price(db, num_prices_helper, &count, FALSE);

    return count;
}

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

typedef struct
{
    gboolean equal;
    GNCPriceDB *db2;
    gnc_commodity *commodity;
} GNCPriceDBEqualData;

static void
pricedb_equal_foreach_pricelist(gpointer key, gpointer val, gpointer user_data)
{
    GNCPriceDBEqualData *equal_data = user_data;
    gnc_commodity *currency = key;
    GList *price_list1 = val;
    GList *price_list2;

    price_list2 = gnc_pricedb_get_prices (equal_data->db2,
                                          equal_data->commodity,
                                          currency);

    if (!gnc_price_list_equal (price_list1, price_list2))
        equal_data->equal = FALSE;

    gnc_price_list_destroy (price_list2);
}

static void
pricedb_equal_foreach_currencies_hash (gpointer key, gpointer val,
                                       gpointer user_data)
{
    GHashTable *currencies_hash = val;
    GNCPriceDBEqualData *equal_data = user_data;

    equal_data->commodity = key;

    g_hash_table_foreach (currencies_hash,
                          pricedb_equal_foreach_pricelist,
                          equal_data);
}

gboolean
gnc_pricedb_equal (GNCPriceDB *db1, GNCPriceDB *db2)
{
    GNCPriceDBEqualData equal_data;

    if (db1 == db2) return TRUE;

    if (!db1 || !db2)
    {
        PWARN ("one is NULL");
        return FALSE;
    }

    equal_data.equal = TRUE;
    equal_data.db2 = db2;

    g_hash_table_foreach (db1->commodity_hash,
                          pricedb_equal_foreach_currencies_hash,
                          &equal_data);

    return equal_data.equal;
}

/* ==================================================================== */
/* The add_price() function is a utility that only manages the
 * dual hash table instertion */

static gboolean
add_price(GNCPriceDB *db, GNCPrice *p)
{
    /* This function will use p, adding a ref, so treat p as read-only
       if this function succeeds. */
    GList *price_list;
    gnc_commodity *commodity;
    gnc_commodity *currency;
    GHashTable *currency_hash;
    GNCPrice *old_price;

    if (!db || !p) return FALSE;
    ENTER ("db=%p, pr=%p dirty=%d destroying=%d",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p));

    if (!qof_instance_books_equal(db, p))
    {
        PERR ("attempted to mix up prices across different books");
        LEAVE (" ");
        return FALSE;
    }

    commodity = gnc_price_get_commodity(p);
    if (!commodity)
    {
        PWARN("no commodity");
        LEAVE (" ");
        return FALSE;
    }
    currency = gnc_price_get_currency(p);
    if (!currency)
    {
        PWARN("no currency");
        LEAVE (" ");
        return FALSE;
    }
    if (!db->commodity_hash)
    {
        LEAVE ("no commodity hash found ");
        return FALSE;
    }
/* Check for an existing price on the same day. If there is no existing price,
 * add this one. If this price is of equal or better precedence than the old
 * one, copy this one over the old one.
 */
    old_price = gnc_pricedb_lookup_day (db, p->commodity, p->currency,
                                        p->tmspec);
    if (!db->bulk_update && old_price != NULL)
    {
        if (p->source > old_price->source)
        {
            gnc_price_unref(p);
            LEAVE ("Better price already in DB.");
            return FALSE;
        }
        gnc_pricedb_remove_price(db, old_price);
    }

    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        currency_hash = g_hash_table_new(NULL, NULL);
        g_hash_table_insert(db->commodity_hash, commodity, currency_hash);
    }

    price_list = g_hash_table_lookup(currency_hash, currency);
    if (!gnc_price_list_insert(&price_list, p, !db->bulk_update))
    {
        LEAVE ("gnc_price_list_insert failed");
        return FALSE;
    }

    if (!price_list)
    {
        LEAVE (" no price list");
        return FALSE;
    }

    g_hash_table_insert(currency_hash, currency, price_list);
    p->db = db;

    qof_event_gen (&p->inst, QOF_EVENT_ADD, NULL);

    LEAVE ("db=%p, pr=%p dirty=%d dextroying=%d commodity=%s/%s currency_hash=%p",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p),
           gnc_commodity_get_namespace(p->commodity),
           gnc_commodity_get_mnemonic(p->commodity),
           currency_hash);
    return TRUE;
}

/* If gnc_pricedb_add_price() succeeds, it takes ownership of the
   passed-in GNCPrice and inserts it into the pricedb. Writing to this
   pointer afterwards will have interesting results, so don't.
 */
gboolean
gnc_pricedb_add_price(GNCPriceDB *db, GNCPrice *p)
{
    if (!db || !p) return FALSE;

    ENTER ("db=%p, pr=%p dirty=%d destroying=%d",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p));

    if (FALSE == add_price(db, p))
    {
        LEAVE (" failed to add price");
        return FALSE;
    }

    gnc_pricedb_begin_edit(db);
    qof_instance_set_dirty(&db->inst);
    gnc_pricedb_commit_edit(db);

    LEAVE ("db=%p, pr=%p dirty=%d destroying=%d",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p));

    return TRUE;
}

/* remove_price() is a utility; its only function is to remove the price
 * from the double-hash tables.
 */

static gboolean
remove_price(GNCPriceDB *db, GNCPrice *p, gboolean cleanup)
{
    GList *price_list;
    gnc_commodity *commodity;
    gnc_commodity *currency;
    GHashTable *currency_hash;

    if (!db || !p) return FALSE;
    ENTER ("db=%p, pr=%p dirty=%d destroying=%d",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p));

    commodity = gnc_price_get_commodity(p);
    if (!commodity)
    {
        LEAVE (" no commodity");
        return FALSE;
    }
    currency = gnc_price_get_currency(p);
    if (!currency)
    {
        LEAVE (" no currency");
        return FALSE;
    }
    if (!db->commodity_hash)
    {
        LEAVE (" no commodity hash");
        return FALSE;
    }

    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return FALSE;
    }

    qof_event_gen (&p->inst, QOF_EVENT_REMOVE, NULL);
    price_list = g_hash_table_lookup(currency_hash, currency);
    gnc_price_ref(p);
    if (!gnc_price_list_remove(&price_list, p))
    {
        gnc_price_unref(p);
        LEAVE (" cannot remove price list");
        return FALSE;
    }

    /* if the price list is empty, then remove this currency from the
       commodity hash */
    if (price_list)
    {
        g_hash_table_insert(currency_hash, currency, price_list);
    }
    else
    {
        g_hash_table_remove(currency_hash, currency);

        if (cleanup)
        {
            /* chances are good that this commodity had only one currency.
             * If there are no currencies, we may as well destroy the
             * commodity too. */
            guint num_currencies = g_hash_table_size (currency_hash);
            if (0 == num_currencies)
            {
                g_hash_table_remove (db->commodity_hash, commodity);
                g_hash_table_destroy (currency_hash);
            }
        }
    }

    gnc_price_unref(p);
    LEAVE ("db=%p, pr=%p", db, p);
    return TRUE;
}

gboolean
gnc_pricedb_remove_price(GNCPriceDB *db, GNCPrice *p)
{
    gboolean rc;
    if (!db || !p) return FALSE;
    ENTER ("db=%p, pr=%p dirty=%d destroying=%d",
           db, p, qof_instance_get_dirty_flag(p),
           qof_instance_get_destroying(p));

    gnc_price_ref(p);
    rc = remove_price (db, p, TRUE);
    gnc_pricedb_begin_edit(db);
    qof_instance_set_dirty(&db->inst);
    gnc_pricedb_commit_edit(db);

    /* invoke the backend to delete this price */
    gnc_price_begin_edit (p);
    qof_instance_set_destroying(p, TRUE);
    gnc_price_commit_edit (p);
    p->db = NULL;
    gnc_price_unref(p);
    LEAVE ("db=%p, pr=%p", db, p);
    return rc;
}

typedef struct
{
    GNCPriceDB *db;
    Timespec cutoff;
    gboolean delete_user;
    gboolean delete_last;
    GSList *list;
} remove_info;

static gboolean
check_one_price_date (GNCPrice *price, gpointer user_data)
{
    remove_info *data = user_data;
    PriceSource source;
    Timespec pt;

    ENTER("price %p (%s), data %p", price,
          gnc_commodity_get_mnemonic(gnc_price_get_commodity(price)),
          user_data);
    if (!data->delete_user)
    {
        source = gnc_price_get_source (price);
        if (source != PRICE_SOURCE_FQ)
        {
            LEAVE("Not an automatic quote");
            return TRUE;
        }
    }

    pt = gnc_price_get_time (price);
    {
        gchar buf[40];
        gnc_timespec_to_iso8601_buff(pt , buf);
        DEBUG("checking date %s", buf);
    }
    if (timespec_cmp (&pt, &data->cutoff) < 0)
    {
        data->list = g_slist_prepend(data->list, price);
        DEBUG("will delete");
    }
    LEAVE(" ");
    return TRUE;
}

static void
pricedb_remove_foreach_pricelist (gpointer key,
                                  gpointer val,
                                  gpointer user_data)
{
    GList *price_list = (GList *) val;
    GList *node = price_list;
    remove_info *data = (remove_info *) user_data;

    ENTER("key %p, value %p, data %p", key, val, user_data);

    /* The most recent price is the first in the list */
    if (!data->delete_last)
        node = g_list_next(node);

    /* now check each item in the list */
    g_list_foreach(node, (GFunc)check_one_price_date, data);

    LEAVE(" ");
}

static void
pricedb_remove_foreach_currencies_hash (gpointer key,
                                        gpointer val,
                                        gpointer user_data)
{
    GHashTable *currencies_hash = (GHashTable *) val;

    ENTER("key %p, value %p, data %p", key, val, user_data);
    g_hash_table_foreach(currencies_hash,
                         pricedb_remove_foreach_pricelist, user_data);
    LEAVE(" ");
}


gboolean
gnc_pricedb_remove_old_prices(GNCPriceDB *db,
                              Timespec cutoff,
                              gboolean delete_user,
                              gboolean delete_last)
{
    remove_info data;
    GSList *item;

    data.db = db;
    data.cutoff = cutoff;
    data.delete_user = delete_user;
    data.delete_last = delete_last;
    data.list = NULL;

    ENTER("db %p, delet_user %d, delete_last %d", db, delete_user, delete_last);
    {
        gchar buf[40];
        gnc_timespec_to_iso8601_buff(cutoff, buf);
        DEBUG("checking date %s", buf);
    }

    /* Traverse the database once building up an external list of prices
     * to be deleted */
    g_hash_table_foreach(db->commodity_hash,
                         pricedb_remove_foreach_currencies_hash,
                         &data);

    if (data.list == NULL)
        return FALSE;

    /* Now run this external list deleting prices */
    for (item = data.list; item; item = g_slist_next(item))
    {
        gnc_pricedb_remove_price(db, item->data);
    }

    g_slist_free(data.list);
    LEAVE(" ");
    return TRUE;
}

/* ==================================================================== */
/* lookup/query functions */

GNCPrice *
gnc_pricedb_lookup_latest(GNCPriceDB *db,
                          const gnc_commodity *commodity,
                          const gnc_commodity *currency)
{
    GList *price_list;
    GNCPrice *result;
    GHashTable *currency_hash;

    if (!db || !commodity || !currency) return NULL;
    ENTER ("db=%p commodity=%p currency=%p", db, commodity, currency);

    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return NULL;
    }

    price_list = g_hash_table_lookup(currency_hash, currency);
    if (!price_list)
    {
        LEAVE (" no price list");
        return NULL;
    }

    /* This works magically because prices are inserted in date-sorted
     * order, and the latest date always comes first. So return the
     * first in the list.  */
    result = price_list->data;
    gnc_price_ref(result);
    LEAVE(" ");
    return result;
}


static void
lookup_latest(gpointer key, gpointer val, gpointer user_data)
{
    //gnc_commodity *currency = (gnc_commodity *)key;
    GList *price_list = (GList *)val;
    GList **return_list = (GList **)user_data;

    if (!price_list) return;

    /* the latest price is the first in list */
    gnc_price_list_insert(return_list, price_list->data, FALSE);
}

PriceList *
gnc_pricedb_lookup_latest_any_currency(GNCPriceDB *db,
                                       const gnc_commodity *commodity)
{
    GList *result;
    GHashTable *currency_hash;

    result = NULL;

    if (!db || !commodity) return NULL;
    ENTER ("db=%p commodity=%p", db, commodity);
    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return NULL;
    }

    g_hash_table_foreach(currency_hash, lookup_latest, &result);

    if (!result)
    {
        LEAVE (" ");
        return NULL;
    }

    result = g_list_sort(result, compare_prices_by_date);

    LEAVE(" ");
    return result;
}


static void
hash_values_helper(gpointer key, gpointer value, gpointer data)
{
    GList ** l = data;
    *l = g_list_concat(*l, g_list_copy (value));
}

gboolean
gnc_pricedb_has_prices(GNCPriceDB *db,
                       const gnc_commodity *commodity,
                       const gnc_commodity *currency)
{
    GList *price_list;
    GHashTable *currency_hash;
    gint size;

    if (!db || !commodity) return FALSE;
    ENTER ("db=%p commodity=%p currency=%p", db, commodity, currency);
    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        LEAVE("no, no currency_hash table");
        return FALSE;
    }

    if (currency)
    {
        price_list = g_hash_table_lookup(currency_hash, currency);
        if (price_list)
        {
            LEAVE("yes");
            return TRUE;
        }
        LEAVE("no, no price list");
        return FALSE;
    }

    size = g_hash_table_size (currency_hash);
    LEAVE("%s", size > 0 ? "yes" : "no");
    return size > 0;
}


PriceList *
gnc_pricedb_get_prices(GNCPriceDB *db,
                       const gnc_commodity *commodity,
                       const gnc_commodity *currency)
{
    GList *price_list;
    GList *result;
    GList *node;
    GHashTable *currency_hash;

    if (!db || !commodity) return NULL;
    ENTER ("db=%p commodity=%p currency=%p", db, commodity, currency);
    currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
    if (!currency_hash)
    {
        currency_hash = g_hash_table_lookup(db->commodity_hash, commodity);
        LEAVE (" no currency hash");
        return NULL;
    }

    if (currency)
    {
        price_list = g_hash_table_lookup(currency_hash, currency);
        if (!price_list)
        {
            LEAVE (" no price list");
            return NULL;
        }
        result = g_list_copy (price_list);
    }
    else
    {
        result = NULL;
        g_hash_table_foreach(currency_hash, hash_values_helper, (gpointer)&result);
    }
    for (node = result; node; node = node->next)
        gnc_price_ref (node->data);

    LEAVE (" ");
    return result;
}


GNCPrice *
gnc_pricedb_lookup_day(GNCPriceDB *db,
                       const gnc_commodity *c,
                       const gnc_commodity *currency,
                       Timespec t)
{
    return lookup_nearest_in_time(db, c, currency, t, TRUE);
}

PriceList *
gnc_pricedb_lookup_at_time(GNCPriceDB *db,
                           const gnc_commodity *c,
                           const gnc_commodity *currency,
                           Timespec t)
{
    GList *price_list;
    GList *result = NULL;
    GList *item = NULL;
    GHashTable *currency_hash;

    if (!db || !c || !currency) return NULL;
    ENTER ("db=%p commodity=%p currency=%p", db, c, currency);
    currency_hash = g_hash_table_lookup(db->commodity_hash, c);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return NULL;
    }

    price_list = g_hash_table_lookup(currency_hash, currency);
    if (!price_list)
    {
        LEAVE (" no price list");
        return NULL;
    }

    item = price_list;
    while (item)
    {
        GNCPrice *p = item->data;
        Timespec price_time = gnc_price_get_time(p);
        if (timespec_equal(&price_time, &t))
        {
            result = g_list_prepend(result, p);
            gnc_price_ref(p);
        }
        item = item->next;
    }
    LEAVE (" ");
    return result;
}

static GNCPrice *
lookup_nearest_in_time(GNCPriceDB *db,
                       const gnc_commodity *c,
                       const gnc_commodity *currency,
                       Timespec t,
                       gboolean sameday)
{
    GList *price_list;
    GNCPrice *current_price = NULL;
    GNCPrice *next_price = NULL;
    GNCPrice *result = NULL;
    GList *item = NULL;
    GHashTable *currency_hash;

    if (!db || !c || !currency) return NULL;
    ENTER ("db=%p commodity=%p currency=%p", db, c, currency);
    currency_hash = g_hash_table_lookup(db->commodity_hash, c);
    if (!currency_hash)
    {
        LEAVE ("no currency hash");
        return NULL;
    }

    price_list = g_hash_table_lookup(currency_hash, currency);
    if (!price_list)
    {
        LEAVE ("no price list");
        return NULL;
    }

    item = price_list;

    /* default answer */
    current_price = item->data;

    /* find the first candidate past the one we want.  Remember that
       prices are in most-recent-first order. */
    while (!next_price && item)
    {
        GNCPrice *p = item->data;
        Timespec price_time = gnc_price_get_time(p);
        if (timespec_cmp(&price_time, &t) <= 0)
        {
            next_price = item->data;
            break;
        }
        current_price = item->data;
        item = item->next;
    }

    if (current_price)      /* How can this be null??? */
    {
        if (!next_price)
        {
            /* It's earlier than the last price on the list */
            result = current_price;
            if (sameday)
            {
                /* Must be on the same day. */
                Timespec price_day;
                Timespec t_day;
                price_day = timespecCanonicalDayTime(gnc_price_get_time(current_price));
                t_day = timespecCanonicalDayTime(t);
                if (!timespec_equal(&price_day, &t_day))
                    result = NULL;
            }
        }
        else
        {
            /* If the requested time is not earlier than the first price on the
               list, then current_price and next_price will be the same. */
            Timespec current_t = gnc_price_get_time(current_price);
            Timespec next_t = gnc_price_get_time(next_price);
            Timespec diff_current = timespec_diff(&current_t, &t);
            Timespec diff_next = timespec_diff(&next_t, &t);
            Timespec abs_current = timespec_abs(&diff_current);
            Timespec abs_next = timespec_abs(&diff_next);

            if (sameday)
            {
                /* Result must be on same day, see if either of the two isn't */
                Timespec t_day = timespecCanonicalDayTime(t);
                Timespec current_day = timespecCanonicalDayTime(current_t);
                Timespec next_day = timespecCanonicalDayTime(next_t);
                if (timespec_equal(&current_day, &t_day))
                {
                    if (timespec_equal(&next_day, &t_day))
                    {
                        /* Both on same day, return nearest */
                        if (timespec_cmp(&abs_current, &abs_next) < 0)
                            result = current_price;
                        else
                            result = next_price;
                    }
                    else
                        /* current_price on same day, next_price not */
                        result = current_price;
                }
                else if (timespec_equal(&next_day, &t_day))
                    /* next_price on same day, current_price not */
                    result = next_price;
            }
            else
            {
                /* Choose the price that is closest to the given time. In case of
                 * a tie, prefer the older price since it actually existed at the
                 * time. (This also fixes bug #541970.) */
                if (timespec_cmp(&abs_current, &abs_next) < 0)
                {
                    result = current_price;
                }
                else
                {
                    result = next_price;
                }
            }
        }
    }

    gnc_price_ref(result);
    LEAVE (" ");
    return result;
}

GNCPrice *
gnc_pricedb_lookup_nearest_in_time(GNCPriceDB *db,
                                   const gnc_commodity *c,
                                   const gnc_commodity *currency,
                                   Timespec t)
{
    return lookup_nearest_in_time(db, c, currency, t, FALSE);
}

GNCPrice *
gnc_pricedb_lookup_latest_before (GNCPriceDB *db,
                                  gnc_commodity *c,
                                  gnc_commodity *currency,
                                  Timespec t)
{
    GList *price_list;
    GNCPrice *current_price = NULL;
    /*  GNCPrice *next_price = NULL;
        GNCPrice *result = NULL;*/
    GList *item = NULL;
    GHashTable *currency_hash;
    Timespec price_time;

    if (!db || !c || !currency) return NULL;
    ENTER ("db=%p commodity=%p currency=%p", db, c, currency);
    currency_hash = g_hash_table_lookup(db->commodity_hash, c);
    if (!currency_hash)
    {
        LEAVE ("no currency hash");
        return NULL;
    }

    price_list = g_hash_table_lookup(currency_hash, currency);
    if (!price_list)
    {
        LEAVE ("no price list");
        return NULL;
    }

    item = price_list;
    do
    {
        price_time = gnc_price_get_time (item->data);
        if (timespec_cmp(&price_time, &t) <= 0)
            current_price = item->data;
        item = item->next;
    }
    while (timespec_cmp(&price_time, &t) > 0 && item);
    gnc_price_ref(current_price);
    LEAVE (" ");
    return current_price;
}


static void
lookup_nearest(gpointer key, gpointer val, gpointer user_data)
{
    //gnc_commodity *currency = (gnc_commodity *)key;
    GList *price_list = (GList *)val;
    GNCPrice *current_price = NULL;
    GNCPrice *next_price = NULL;
    GNCPrice *result = NULL;
    GList *item = NULL;
    GNCPriceLookupHelper *lookup_helper = (GNCPriceLookupHelper *)user_data;
    GList **return_list = lookup_helper->return_list;
    Timespec t = lookup_helper->time;

    item = price_list;

    /* default answer */
    current_price = item->data;

    /* find the first candidate past the one we want.  Remember that
       prices are in most-recent-first order. */
    while (!next_price && item)
    {
        GNCPrice *p = item->data;
        Timespec price_time = gnc_price_get_time(p);
        if (timespec_cmp(&price_time, &t) <= 0)
        {
            next_price = item->data;
            break;
        }
        current_price = item->data;
        item = item->next;
    }

    if (current_price)
    {
        if (!next_price)
        {
            result = current_price;
        }
        else
        {
            Timespec current_t = gnc_price_get_time(current_price);
            Timespec next_t = gnc_price_get_time(next_price);
            Timespec diff_current = timespec_diff(&current_t, &t);
            Timespec diff_next = timespec_diff(&next_t, &t);
            Timespec abs_current = timespec_abs(&diff_current);
            Timespec abs_next = timespec_abs(&diff_next);

            if (timespec_cmp(&abs_current, &abs_next) <= 0)
            {
                result = current_price;
            }
            else
            {
                result = next_price;
            }
        }
    }

    gnc_price_list_insert(return_list, result, FALSE);
}


static void
lookup_latest_before(gpointer key, gpointer val, gpointer user_data)
{
    //gnc_commodity *currency = (gnc_commodity *)key;
    GList *price_list = (GList *)val;
    GNCPrice *current_price = NULL;
    /*  GNCPrice *next_price = NULL;
        GNCPrice *result = NULL;*/
    GList *item = NULL;
    GNCPriceLookupHelper *lookup_helper = (GNCPriceLookupHelper *)user_data;
    GList **return_list = lookup_helper->return_list;
    Timespec t = lookup_helper->time;
    Timespec price_time;

    if (price_list)
    {
        item = price_list;
        do
        {
            price_time = gnc_price_get_time (item->data);
            if (timespec_cmp(&price_time, &t) <= 0)
                current_price = item->data;
            item = item->next;
        }
        while (timespec_cmp(&price_time, &t) > 0 && item);
    }

    gnc_price_list_insert(return_list, current_price, FALSE);
}


PriceList *
gnc_pricedb_lookup_nearest_in_time_any_currency(GNCPriceDB *db,
        const gnc_commodity *c,
        Timespec t)
{
    GList *result = NULL;
    GHashTable *currency_hash;
    GNCPriceLookupHelper lookup_helper;

    if (!db || !c) return NULL;
    ENTER ("db=%p commodity=%p", db, c);
    currency_hash = g_hash_table_lookup(db->commodity_hash, c);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return NULL;
    }

    lookup_helper.return_list = &result;
    lookup_helper.time = t;
    g_hash_table_foreach(currency_hash, lookup_nearest, &lookup_helper);

    if (!result)
    {
        LEAVE (" ");
        return NULL;
    }

    result = g_list_sort(result, compare_prices_by_date);

    LEAVE (" ");
    return result;
}


PriceList *
gnc_pricedb_lookup_latest_before_any_currency(GNCPriceDB *db,
        gnc_commodity *c,
        Timespec t)
{
    GList *result = NULL;
    GHashTable *currency_hash;
    GNCPriceLookupHelper lookup_helper;

    if (!db || !c) return NULL;
    ENTER ("db=%p commodity=%p", db, c);
    currency_hash = g_hash_table_lookup(db->commodity_hash, c);
    if (!currency_hash)
    {
        LEAVE (" no currency hash");
        return NULL;
    }

    lookup_helper.return_list = &result;
    lookup_helper.time = t;
    g_hash_table_foreach(currency_hash, lookup_latest_before, &lookup_helper);

    if (!result)
    {
        LEAVE (" ");
        return NULL;
    }

    result = g_list_sort(result, compare_prices_by_date);

    LEAVE (" ");
    return result;
}


/*
 * Convert a balance from one currency to another.
 */
gnc_numeric
gnc_pricedb_convert_balance_latest_price(GNCPriceDB *pdb,
        gnc_numeric balance,
        const gnc_commodity *balance_currency,
        const gnc_commodity *new_currency)
{
    GNCPrice *price, *currency_price;
    GList *price_list, *list_helper;
    gnc_numeric currency_price_value;
    gnc_commodity *intermediate_currency;

    if (gnc_numeric_zero_p (balance) ||
            gnc_commodity_equiv (balance_currency, new_currency))
        return balance;

    /* Look for a direct price. */
    price = gnc_pricedb_lookup_latest (pdb, balance_currency, new_currency);
    if (price)
    {
        balance = gnc_numeric_mul (balance, gnc_price_get_value (price),
                                   gnc_commodity_get_fraction (new_currency),
                                   GNC_HOW_RND_ROUND);
        gnc_price_unref (price);
        return balance;
    }

    /* Look for a price of the new currency in the balance currency and use
     * the reciprocal if we find it
     */
    price = gnc_pricedb_lookup_latest (pdb, new_currency, balance_currency);
    if (price)
    {
        balance = gnc_numeric_div (balance, gnc_price_get_value (price),
                                   gnc_commodity_get_fraction (new_currency),
                                   GNC_HOW_RND_ROUND);
        gnc_price_unref (price);
        return balance;
    }

    /*
     * no direct price found, try if we find a price in another currency
     * and convert in two stages
     */
    price_list = gnc_pricedb_lookup_latest_any_currency(pdb, balance_currency);
    if (!price_list)
    {
        balance =  gnc_numeric_zero ();
        return balance;
    }

    list_helper = price_list;
    currency_price_value = gnc_numeric_zero();

    do
    {
        price = (GNCPrice *)(list_helper->data);

        intermediate_currency = gnc_price_get_currency(price);
        currency_price = gnc_pricedb_lookup_latest(pdb, intermediate_currency,
                         new_currency);
        if (currency_price)
        {
            currency_price_value = gnc_price_get_value(currency_price);
            gnc_price_unref(currency_price);
        }
        else
        {
            currency_price = gnc_pricedb_lookup_latest(pdb, new_currency,
                             intermediate_currency);
            if (currency_price)
            {
                /* here we need the reciprocal */
                currency_price_value = gnc_numeric_div(gnc_numeric_create(1, 1),
                                                       gnc_price_get_value(currency_price),
                                                       GNC_DENOM_AUTO,
                                                       GNC_HOW_DENOM_EXACT | GNC_HOW_RND_NEVER);
                gnc_price_unref(currency_price);
            }
        }

        list_helper = list_helper->next;
    }
    while ((list_helper != NULL) &&
            (gnc_numeric_zero_p(currency_price_value)));

    balance = gnc_numeric_mul (balance, currency_price_value,
                               GNC_DENOM_AUTO,
                               GNC_HOW_DENOM_EXACT | GNC_HOW_RND_NEVER);
    balance = gnc_numeric_mul (balance, gnc_price_get_value (price),
                               gnc_commodity_get_fraction (new_currency),
                               GNC_HOW_RND_ROUND);

    gnc_price_list_destroy(price_list);
    return balance;
}

gnc_numeric
gnc_pricedb_convert_balance_nearest_price(GNCPriceDB *pdb,
        gnc_numeric balance,
        const gnc_commodity *balance_currency,
        const gnc_commodity *new_currency,
        Timespec t)
{
    GNCPrice *price, *currency_price;
    GList *price_list, *list_helper;
    gnc_numeric currency_price_value;
    gnc_commodity *intermediate_currency;

    if (gnc_numeric_zero_p (balance) ||
            gnc_commodity_equiv (balance_currency, new_currency))
        return balance;

    /* Look for a direct price. */
    price = gnc_pricedb_lookup_nearest_in_time (pdb, balance_currency, new_currency, t);
    if (price)
    {
        balance = gnc_numeric_mul (balance, gnc_price_get_value (price),
                                   gnc_commodity_get_fraction (new_currency),
                                   GNC_HOW_RND_ROUND);
        gnc_price_unref (price);
        return balance;
    }

    /* Look for a price of the new currency in the balance currency and use
     * the reciprocal if we find it
     */
    price = gnc_pricedb_lookup_nearest_in_time (pdb, new_currency, balance_currency, t);
    if (price)
    {
        balance = gnc_numeric_div (balance, gnc_price_get_value (price),
                                   gnc_commodity_get_fraction (new_currency),
                                   GNC_HOW_RND_ROUND);
        gnc_price_unref (price);
        return balance;
    }

    /*
     * no direct price found, try if we find a price in another currency
     * and convert in two stages
     */
    price_list = gnc_pricedb_lookup_nearest_in_time_any_currency(pdb, balance_currency, t);
    if (!price_list)
    {
        balance =  gnc_numeric_zero ();
        return balance;
    }

    list_helper = price_list;
    currency_price_value = gnc_numeric_zero();

    do
    {
        price = (GNCPrice *)(list_helper->data);

        intermediate_currency = gnc_price_get_currency(price);
        currency_price = gnc_pricedb_lookup_nearest_in_time(pdb, intermediate_currency,
                         new_currency, t);
        if (currency_price)
        {
            currency_price_value = gnc_price_get_value(currency_price);
            gnc_price_unref(currency_price);
        }
        else
        {
            currency_price = gnc_pricedb_lookup_nearest_in_time(pdb, new_currency,
                             intermediate_currency, t);
            if (currency_price)
            {
                /* here we need the reciprocal */
                currency_price_value = gnc_numeric_div(gnc_numeric_create(1, 1),
                                                       gnc_price_get_value(currency_price),
                                                       GNC_DENOM_AUTO,
                                                       GNC_HOW_DENOM_EXACT | GNC_HOW_RND_NEVER);
                gnc_price_unref(currency_price);
            }
        }

        list_helper = list_helper->next;
    }
    while ((list_helper != NULL) &&
            (gnc_numeric_zero_p(currency_price_value)));

    balance = gnc_numeric_mul (balance, currency_price_value,
                               GNC_DENOM_AUTO,
                               GNC_HOW_DENOM_EXACT | GNC_HOW_RND_NEVER);

    balance = gnc_numeric_mul (balance, gnc_price_get_value (price),
                               gnc_commodity_get_fraction (new_currency),
                               GNC_HOW_RND_ROUND);

    gnc_price_list_destroy(price_list);
    return balance;
}


/* ==================================================================== */
/* gnc_pricedb_foreach_price infrastructure
 */

typedef struct
{
    gboolean ok;
    gboolean (*func)(GNCPrice *p, gpointer user_data);
    gpointer user_data;
} GNCPriceDBForeachData;

static void
pricedb_foreach_pricelist(gpointer key, gpointer val, gpointer user_data)
{
    GList *price_list = (GList *) val;
    GList *node = price_list;
    GNCPriceDBForeachData *foreach_data = (GNCPriceDBForeachData *) user_data;

    /* stop traversal when func returns FALSE */
    while (foreach_data->ok && node)
    {
        GNCPrice *p = (GNCPrice *) node->data;
        foreach_data->ok = foreach_data->func(p, foreach_data->user_data);
        node = node->next;
    }
}

static void
pricedb_foreach_currencies_hash(gpointer key, gpointer val, gpointer user_data)
{
    GHashTable *currencies_hash = (GHashTable *) val;
    g_hash_table_foreach(currencies_hash, pricedb_foreach_pricelist, user_data);
}

static gboolean
unstable_price_traversal(GNCPriceDB *db,
                         gboolean (*f)(GNCPrice *p, gpointer user_data),
                         gpointer user_data)
{
    GNCPriceDBForeachData foreach_data;

    if (!db || !f) return FALSE;
    foreach_data.ok = TRUE;
    foreach_data.func = f;
    foreach_data.user_data = user_data;
    if (db->commodity_hash == NULL)
    {
        return FALSE;
    }
    g_hash_table_foreach(db->commodity_hash,
                         pricedb_foreach_currencies_hash,
                         &foreach_data);

    return foreach_data.ok;
}

static gint
compare_kvpairs_by_commodity_key(gconstpointer a, gconstpointer b)
{
    GHashTableKVPair *kvpa = (GHashTableKVPair *) a;
    GHashTableKVPair *kvpb = (GHashTableKVPair *) b;
    gnc_commodity *ca;
    gnc_commodity *cb;
    int cmp_result;

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

    ca = (gnc_commodity *) kvpa->key;
    cb = (gnc_commodity *) kvpb->key;

    cmp_result = g_strcmp0(gnc_commodity_get_namespace(ca),
                           gnc_commodity_get_namespace(cb));

    if (cmp_result != 0) return cmp_result;

    return g_strcmp0(gnc_commodity_get_mnemonic(ca),
                     gnc_commodity_get_mnemonic(cb));
}

static gboolean
stable_price_traversal(GNCPriceDB *db,
                       gboolean (*f)(GNCPrice *p, gpointer user_data),
                       gpointer user_data)
{
    GSList *currency_hashes = NULL;
    gboolean ok = TRUE;
    GSList *i = NULL;

    if (!db || !f) return FALSE;

    currency_hashes = g_hash_table_key_value_pairs(db->commodity_hash);
    currency_hashes = g_slist_sort(currency_hashes,
                                   compare_kvpairs_by_commodity_key);

    for (i = currency_hashes; i; i = i->next)
    {
        GHashTableKVPair *kv_pair = (GHashTableKVPair *) i->data;
        GHashTable *currency_hash = (GHashTable *) kv_pair->value;
        GSList *price_lists = g_hash_table_key_value_pairs(currency_hash);
        GSList *j;

        price_lists = g_slist_sort(price_lists, compare_kvpairs_by_commodity_key);
        for (j = price_lists; j; j = j->next)
        {
            GHashTableKVPair *pricelist_kvp = (GHashTableKVPair *) j->data;
            GList *price_list = (GList *) pricelist_kvp->value;
            GList *node;

            for (node = (GList *) price_list; node; node = node->next)
            {
                GNCPrice *price = (GNCPrice *) node->data;

                /* stop traversal when f returns FALSE */
                if (FALSE == ok) break;
                if (!f(price, user_data)) ok = FALSE;
            }
        }
        if (price_lists)
        {
            g_slist_foreach(price_lists, g_hash_table_kv_pair_free_gfunc, NULL);
            g_slist_free(price_lists);
            price_lists = NULL;
        }
    }

    if (currency_hashes)
    {
        g_slist_foreach(currency_hashes, g_hash_table_kv_pair_free_gfunc, NULL);
        g_slist_free(currency_hashes);
    }
    return ok;
}

gboolean
gnc_pricedb_foreach_price(GNCPriceDB *db,
                          gboolean (*f)(GNCPrice *p, gpointer user_data),
                          gpointer user_data,
                          gboolean stable_order)
{
    ENTER ("db=%p f=%p", db, f);
    if (stable_order)
    {
        LEAVE (" stable order found");
        return stable_price_traversal(db, f, user_data);
    }
    LEAVE (" use unstable order");
    return unstable_price_traversal(db, f, user_data);
}

/* ==================================================================== */
/* commodity substitution */

typedef struct
{
    gnc_commodity *old_c;
    gnc_commodity *new_c;
} GNCPriceFixupData;

static gboolean
add_price_to_list (GNCPrice *p, gpointer data)
{
    GList **list = data;

    *list = g_list_prepend (*list, p);

    return TRUE;
}

static void
gnc_price_fixup_legacy_commods(gpointer data, gpointer user_data)
{
    GNCPrice *p = data;
    GNCPriceFixupData *fixup_data = user_data;
    gnc_commodity *price_c;

    if (!p) return;

    price_c = gnc_price_get_commodity(p);
    if (gnc_commodity_equiv(price_c, fixup_data->old_c))
    {
        gnc_price_set_commodity (p, fixup_data->new_c);
    }
    price_c = gnc_price_get_currency(p);
    if (gnc_commodity_equiv(price_c, fixup_data->old_c))
    {
        gnc_price_set_currency (p, fixup_data->new_c);
    }
}

void
gnc_pricedb_substitute_commodity(GNCPriceDB *db,
                                 gnc_commodity *old_c,
                                 gnc_commodity *new_c)
{
    GNCPriceFixupData data;
    GList *prices = NULL;

    if (!db || !old_c || !new_c) return;

    data.old_c = old_c;
    data.new_c = new_c;

    gnc_pricedb_foreach_price (db, add_price_to_list, &prices, FALSE);

    g_list_foreach (prices, gnc_price_fixup_legacy_commods, &data);

    g_list_free (prices);
}

/***************************************************************************/

/* Semi-lame debugging code */

void
gnc_price_print(GNCPrice *p, FILE *f, int indent)
{
    gnc_commodity *commodity;
    gnc_commodity *currency;
    gchar *istr = NULL;           /* indent string */
    const char *str;

    if (!p) return;
    if (!f) return;

    commodity = gnc_price_get_commodity(p);
    currency = gnc_price_get_currency(p);

    if (!commodity) return;
    if (!currency) return;

    istr = g_strnfill(indent, ' ');

    fprintf(f, "%s<pdb:price>\n", istr);
    fprintf(f, "%s  <pdb:commodity pointer=%p>\n", istr, commodity);
    str = gnc_commodity_get_namespace(commodity);
    str = str ? str : "(null)";
    fprintf(f, "%s    <cmdty:ref-space>%s</gnc:cmdty:ref-space>\n", istr, str);
    str = gnc_commodity_get_mnemonic(commodity);
    str = str ? str : "(null)";
    fprintf(f, "%s    <cmdty:ref-id>%s</cmdty:ref-id>\n", istr, str);
    fprintf(f, "%s  </pdb:commodity>\n", istr);
    fprintf(f, "%s  <pdb:currency pointer=%p>\n", istr, currency);
    str = gnc_commodity_get_namespace(currency);
    str = str ? str : "(null)";
    fprintf(f, "%s    <cmdty:ref-space>%s</gnc:cmdty:ref-space>\n", istr, str);
    str = gnc_commodity_get_mnemonic(currency);
    str = str ? str : "(null)";
    fprintf(f, "%s    <cmdty:ref-id>%s</cmdty:ref-id>\n", istr, str);
    fprintf(f, "%s  </pdb:currency>\n", istr);
    str = source_names[gnc_price_get_source(p)];
    str = str ? str : "invalid";
    fprintf(f, "%s  %s\n", istr, str);
    str = gnc_price_get_typestr(p);
    str = str ? str : "(null)";
    fprintf(f, "%s  %s\n", istr, str);
    fprintf(f, "%s  %g\n", istr, gnc_numeric_to_double(gnc_price_get_value(p)));
    fprintf(f, "%s</pdb:price>\n", istr);

    g_free(istr);
}

static gboolean
print_pricedb_adapter(GNCPrice *p, gpointer user_data)
{
    FILE *f = (FILE *) user_data;
    gnc_price_print(p, f, 1);
    return TRUE;
}

void
gnc_pricedb_print_contents(GNCPriceDB *db, FILE *f)
{
    if (!db)
    {
        PERR("NULL PriceDB\n");
        return;
    }
    if (!f)
    {
        PERR("NULL FILE*\n");
        return;
    }

    fprintf(f, "<gnc:pricedb>\n");
    gnc_pricedb_foreach_price(db, print_pricedb_adapter, f, FALSE);
    fprintf(f, "</gnc:pricedb>\n");
}

/* ==================================================================== */
/* gncObject function implementation and registration */

static void
pricedb_book_begin (QofBook *book)
{
    gnc_pricedb_create(book);
}

static void
pricedb_book_end (QofBook *book)
{
    GNCPriceDB *db;
    QofCollection *col;

    if (!book)
        return;
    col = qof_book_get_collection(book, GNC_ID_PRICEDB);
    db = qof_collection_get_data(col);
    qof_collection_set_data(col, NULL);
    gnc_pricedb_destroy(db);
}

static gpointer
price_create (QofBook *book)
{
    return gnc_price_create(book);
}

/* ==================================================================== */
/* a non-boolean foreach. Ugh */

typedef struct
{
    void (*func)(GNCPrice *p, gpointer user_data);
    gpointer user_data;
}
VoidGNCPriceDBForeachData;

static void
void_pricedb_foreach_pricelist(gpointer key, gpointer val, gpointer user_data)
{
    GList *price_list = (GList *) val;
    GList *node = price_list;
    VoidGNCPriceDBForeachData *foreach_data = (VoidGNCPriceDBForeachData *) user_data;

    while (node)
    {
        GNCPrice *p = (GNCPrice *) node->data;
        foreach_data->func(p, foreach_data->user_data);
        node = node->next;
    }
}

static void
void_pricedb_foreach_currencies_hash(gpointer key, gpointer val, gpointer user_data)
{
    GHashTable *currencies_hash = (GHashTable *) val;
    g_hash_table_foreach(currencies_hash, void_pricedb_foreach_pricelist, user_data);
}

static void
void_unstable_price_traversal(GNCPriceDB *db,
                              void (*f)(GNCPrice *p, gpointer user_data),
                              gpointer user_data)
{
    VoidGNCPriceDBForeachData foreach_data;

    if (!db || !f) return;
    foreach_data.func = f;
    foreach_data.user_data = user_data;

    g_hash_table_foreach(db->commodity_hash,
                         void_pricedb_foreach_currencies_hash,
                         &foreach_data);
}

static void
price_foreach(const QofCollection *col, QofInstanceForeachCB cb, gpointer data)
{
    GNCPriceDB *db;

    db = qof_collection_get_data(col);
    void_unstable_price_traversal(db,
                                  (void (*)(GNCPrice *, gpointer)) cb,
                                  data);
}

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

static const char *
price_printable(gpointer obj)
{
    GNCPrice *pr = obj;
    gnc_commodity *commodity;
    gnc_commodity *currency;
    static char buff[2048];  /* nasty static OK for printing */
    char *val, *da;

    if (!pr) return "";

    val = gnc_numeric_to_string (pr->value);
    da = qof_print_date (pr->tmspec.tv_sec);

    commodity = gnc_price_get_commodity(pr);
    currency = gnc_price_get_currency(pr);

    g_snprintf (buff, 2048, "%s %s / %s on %s", val,
                gnc_commodity_get_unique_name(commodity),
                gnc_commodity_get_unique_name(currency),
                da);
    g_free (val);
    g_free (da);
    return buff;
}

#ifdef _MSC_VER
/* MSVC compiler doesn't have C99 "designated initializers"
 * so we wrap them in a macro that is empty on MSVC. */
# define DI(x) /* */
#else
# define DI(x) x
#endif
static QofObject price_object_def =
{
    DI(.interface_version = ) QOF_OBJECT_VERSION,
    DI(.e_type            = ) GNC_ID_PRICE,
    DI(.type_label        = ) "Price",
    DI(.create            = ) price_create,
    DI(.book_begin        = ) NULL,
    DI(.book_end          = ) NULL,
    DI(.is_dirty          = ) qof_collection_is_dirty,
    DI(.mark_clean        = ) qof_collection_mark_clean,
    DI(.foreach           = ) price_foreach,
    DI(.printable         = ) price_printable,
    DI(.version_cmp       = ) NULL,
};

static QofObject pricedb_object_def =
{
    DI(.interface_version = ) QOF_OBJECT_VERSION,
    DI(.e_type            = ) GNC_ID_PRICEDB,
    DI(.type_label        = ) "PriceDB",
    DI(.create            = ) NULL,
    DI(.book_begin        = ) pricedb_book_begin,
    DI(.book_end          = ) pricedb_book_end,
    DI(.is_dirty          = ) qof_collection_is_dirty,
    DI(.mark_clean        = ) qof_collection_mark_clean,
    DI(.foreach           = ) NULL,
    DI(.printable         = ) NULL,
    DI(.version_cmp       = ) NULL,
};

gboolean
gnc_pricedb_register (void)
{
    static QofParam params[] =
    {
        { PRICE_COMMODITY, GNC_ID_COMMODITY, (QofAccessFunc)gnc_price_get_commodity, (QofSetterFunc)gnc_price_set_commodity },
        { PRICE_CURRENCY, GNC_ID_COMMODITY, (QofAccessFunc)gnc_price_get_currency, (QofSetterFunc)gnc_price_set_currency },
        { PRICE_DATE, QOF_TYPE_DATE, (QofAccessFunc)gnc_price_get_time, (QofSetterFunc)gnc_price_set_time },
        { PRICE_SOURCE, QOF_TYPE_STRING, (QofAccessFunc)gnc_price_get_source, (QofSetterFunc)gnc_price_set_source },
        { PRICE_TYPE, QOF_TYPE_STRING, (QofAccessFunc)gnc_price_get_typestr, (QofSetterFunc)gnc_price_set_typestr },
        { PRICE_VALUE, QOF_TYPE_NUMERIC, (QofAccessFunc)gnc_price_get_value, (QofSetterFunc)gnc_price_set_value },
        { NULL },
    };

    qof_class_register (GNC_ID_PRICE, NULL, params);

    if (!qof_object_register (&price_object_def))
        return FALSE;
    return qof_object_register (&pricedb_object_def);
}

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