gncInvoice.c

/********************************************************************\
 * gncInvoice.c -- the Core Business Invoice                        *
 *                                                                  *
 * 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) 2001,2002,2006 Derek Atkins
 * Copyright (C) 2003 Linas Vepstas <linas@linas.org>
 * Copyright (c) 2005 Neil Williams <linux@codehelp.co.uk>
 * Author: Derek Atkins <warlord@MIT.EDU>
 */

#include "config.h"

#include <glib.h>
#include <glib/gi18n.h>

#include "Transaction.h"
#include "Account.h"
#include "gncBillTermP.h"
#include "gncEntry.h"
#include "gncEntryP.h"
#include "gnc-features.h"
#include "gncJobP.h"
#include "gncInvoice.h"
#include "gncInvoiceP.h"
#include "gncOwnerP.h"

struct _gncInvoice
{
    QofInstance   inst;

    char          *id;
    char          *notes;
    gboolean      active;

    char          *billing_id;
    char          *printname;
    GncBillTerm   *terms;
    GList         *entries;
    GList         *prices;
    GncOwner      owner;
    GncOwner      billto;
    GncJob        *job;
    Timespec      date_opened;
    Timespec      date_posted;

    gnc_numeric   to_charge_amount;

    gnc_commodity *currency;

    Account       *posted_acc;
    Transaction   *posted_txn;
    GNCLot        *posted_lot;
};

struct _gncInvoiceClass
{
    QofInstanceClass parent_class;
};

static QofLogModule log_module = GNC_MOD_BUSINESS;

#define _GNC_MOD_NAME     GNC_ID_INVOICE

#define GNC_INVOICE_ID    "gncInvoice"
#define GNC_INVOICE_GUID  "invoice-guid"
#define GNC_INVOICE_IS_CN "credit-note"

#define SET_STR(obj, member, str) { \
        char * tmp; \
        \
        if (!safe_strcmp (member, str)) return; \
        gncInvoiceBeginEdit (obj); \
        tmp = CACHE_INSERT (str); \
        CACHE_REMOVE (member); \
        member = tmp; \
        }

static void mark_invoice (GncInvoice *invoice);
static void
mark_invoice (GncInvoice *invoice)
{
    qof_instance_set_dirty(&invoice->inst);
    qof_event_gen (&invoice->inst, QOF_EVENT_MODIFY, NULL);
}

QofBook * gncInvoiceGetBook(GncInvoice *x)
{
    return qof_instance_get_book(QOF_INSTANCE(x));
}

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

enum
{
    PROP_0,
    PROP_NOTES
};

/* GObject Initialization */
G_DEFINE_TYPE(GncInvoice, gnc_invoice, QOF_TYPE_INSTANCE);

static void
gnc_invoice_init(GncInvoice* inv)
{
}

static void
gnc_invoice_dispose(GObject *invp)
{
    G_OBJECT_CLASS(gnc_invoice_parent_class)->dispose(invp);
}

static void
gnc_invoice_finalize(GObject* invp)
{
    G_OBJECT_CLASS(gnc_invoice_parent_class)->finalize(invp);
}

static void
gnc_invoice_get_property (GObject         *object,
                          guint            prop_id,
                          GValue          *value,
                          GParamSpec      *pspec)
{
    GncInvoice *inv;

    g_return_if_fail(GNC_IS_INVOICE(object));

    inv = GNC_INVOICE(object);
    switch (prop_id)
    {
    case PROP_NOTES:
        g_value_set_string(value, inv->notes);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

static void
gnc_invoice_set_property (GObject         *object,
                          guint            prop_id,
                          const GValue          *value,
                          GParamSpec      *pspec)
{
    GncInvoice *inv;

    g_return_if_fail(GNC_IS_INVOICE(object));

    inv = GNC_INVOICE(object);
    switch (prop_id)
    {
    case PROP_NOTES:
        gncInvoiceSetNotes(inv, g_value_get_string(value));
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

static gchar*
impl_get_display_name(const QofInstance* inst)
{
    GncInvoice* inv;
    QofInstance* owner;
    gchar* s;

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

    inv = GNC_INVOICE(inst);
    owner = qofOwnerGetOwner(&inv->owner);
    if (owner != NULL)
    {
        gchar* display_name;

        display_name = qof_instance_get_display_name(owner);
        s = g_strdup_printf("Invoice %s (%s)", inv->id, display_name);
        g_free(display_name);
    }
    else
    {
        s = g_strdup_printf("Invoice %s", inv->id);
    }

    return s;
}

static gboolean
impl_refers_to_object(const QofInstance* inst, const QofInstance* ref)
{
    GncInvoice* inv;

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

    inv = GNC_INVOICE(inst);

    if (GNC_IS_BILLTERM(ref))
    {
        return (inv->terms == GNC_BILLTERM(ref));
    }
    else if (GNC_IS_JOB(ref))
    {
        return (inv->job == GNC_JOB(ref));
    }
    else if (GNC_IS_COMMODITY(ref))
    {
        return (inv->currency == GNC_COMMODITY(ref));
    }
    else if (GNC_IS_ACCOUNT(ref))
    {
        return (inv->posted_acc == GNC_ACCOUNT(ref));
    }
    else if (GNC_IS_TRANSACTION(ref))
    {
        return (inv->posted_txn == GNC_TRANSACTION(ref));
    }
    else if (GNC_IS_LOT(ref))
    {
        return (inv->posted_lot == GNC_LOT(ref));
    }

    return FALSE;
}

static GList*
impl_get_typed_referring_object_list(const QofInstance* inst, const QofInstance* ref)
{
    if (!GNC_IS_BILLTERM(ref) && !GNC_IS_JOB(ref) && !GNC_IS_COMMODITY(ref) && !GNC_IS_ACCOUNT(ref)
            && !GNC_IS_TRANSACTION(ref) && !GNC_IS_LOT(ref))
    {
        return NULL;
    }

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

static void
gnc_invoice_class_init (GncInvoiceClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
    QofInstanceClass* qof_class = QOF_INSTANCE_CLASS(klass);

    gobject_class->dispose = gnc_invoice_dispose;
    gobject_class->finalize = gnc_invoice_finalize;
    gobject_class->set_property = gnc_invoice_set_property;
    gobject_class->get_property = gnc_invoice_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_NOTES,
     g_param_spec_string ("notes",
                          "Invoice Notes",
                          "The invoice notes is an arbitrary string "
                          "assigned by the user to provide notes regarding "
                          "this invoice.",
                          NULL,
                          G_PARAM_READWRITE));
}

/* Create/Destroy Functions */
GncInvoice *gncInvoiceCreate (QofBook *book)
{
    GncInvoice *invoice;

    if (!book) return NULL;

    invoice = g_object_new (GNC_TYPE_INVOICE, NULL);
    qof_instance_init_data (&invoice->inst, _GNC_MOD_NAME, book);

    invoice->id = CACHE_INSERT ("");
    invoice->notes = CACHE_INSERT ("");
    invoice->billing_id = CACHE_INSERT ("");

    invoice->billto.type = GNC_OWNER_CUSTOMER;
    invoice->active = TRUE;

    invoice->to_charge_amount = gnc_numeric_zero();

    qof_event_gen (&invoice->inst, QOF_EVENT_CREATE, NULL);

    return invoice;
}

GncInvoice *gncInvoiceCopy (const GncInvoice *from)
{
    GncInvoice *invoice;
    QofBook* book;
    GList *node;
    gint64 is_cn;

    g_assert(from);
    book = qof_instance_get_book(from);
    g_assert(book);

    invoice = g_object_new (GNC_TYPE_INVOICE, NULL);
    qof_instance_init_data (&invoice->inst, _GNC_MOD_NAME, book);

    gncInvoiceBeginEdit(invoice);

    invoice->id = CACHE_INSERT (from->id);
    invoice->notes = CACHE_INSERT (from->notes);
    invoice->billing_id = CACHE_INSERT (from->billing_id);
    invoice->active = from->active;

    is_cn = kvp_frame_get_gint64(from->inst.kvp_data, GNC_INVOICE_IS_CN);
    kvp_frame_set_gint64(invoice->inst.kvp_data, GNC_INVOICE_IS_CN, is_cn);

    invoice->terms = from->terms;
    gncBillTermIncRef (invoice->terms);

    gncOwnerCopy(&from->billto, &invoice->billto);
    gncOwnerCopy(&from->owner, &invoice->owner);
    invoice->job = from->job; // FIXME: Need IncRef or similar here?!?

    invoice->to_charge_amount = from->to_charge_amount;
    invoice->date_opened = from->date_opened;

    // Oops. Do not forget to copy the pointer to the correct currency here.
    invoice->currency = from->currency;

    // Copy all invoice->entries
    for (node = from->entries; node; node = node->next)
    {
        GncEntry *from_entry = node->data;
        GncEntry *to_entry = gncEntryCreate(book);
        gncEntryCopy(from_entry, to_entry);

        switch (gncInvoiceGetOwnerType (invoice))
        {
        case GNC_OWNER_VENDOR:
        case GNC_OWNER_EMPLOYEE:
            // this is a vendor bill, or an expense voucher
            gncBillAddEntry(invoice, to_entry);
            break;
        case GNC_OWNER_CUSTOMER:
        default:
            // this is an invoice
            gncInvoiceAddEntry(invoice, to_entry);
            break;
        }
    }

    // FIXME: The prices are not (yet) copied; is this a problem?

    // Posted-date and the posted Txn is intentionally not copied; the
    // copy isn't "posted" but needs to be posted by the user.

    gncInvoiceCommitEdit(invoice);

    return invoice;
}

void gncInvoiceDestroy (GncInvoice *invoice)
{
    if (!invoice) return;
    qof_instance_set_destroying(invoice, TRUE);
    gncInvoiceCommitEdit (invoice);
}

static void gncInvoiceFree (GncInvoice *invoice)
{
    if (!invoice) return;

    qof_event_gen (&invoice->inst, QOF_EVENT_DESTROY, NULL);

    CACHE_REMOVE (invoice->id);
    CACHE_REMOVE (invoice->notes);
    CACHE_REMOVE (invoice->billing_id);
    g_list_free (invoice->entries);
    g_list_free (invoice->prices);

    if (invoice->printname) g_free (invoice->printname);

    if (invoice->terms)
        gncBillTermDecRef (invoice->terms);

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

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

void gncInvoiceSetID (GncInvoice *invoice, const char *id)
{
    if (!invoice || !id) return;
    SET_STR (invoice, invoice->id, id);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetOwner (GncInvoice *invoice, GncOwner *owner)
{
    if (!invoice || !owner) return;
    if (gncOwnerEqual (&invoice->owner, owner)) return;
    gncInvoiceBeginEdit (invoice);
    gncOwnerCopy (owner, &invoice->owner);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

static void
qofInvoiceSetOwner (GncInvoice *invoice, QofInstance *ent)
{
    if (!invoice || !ent)
    {
        return;
    }
    gncInvoiceBeginEdit (invoice);
    qofOwnerSetEntity(&invoice->owner, ent);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

static void
qofInvoiceSetBillTo (GncInvoice *invoice, QofInstance *ent)
{
    if (!invoice || !ent)
    {
        return;
    }
    gncInvoiceBeginEdit (invoice);
    qofOwnerSetEntity(&invoice->billto, ent);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetDateOpenedGDate (GncInvoice *invoice, const GDate *date)
{
    g_assert (date);
    gncInvoiceSetDateOpened(invoice, timespecCanonicalDayTime(gdate_to_timespec(*date)));
}

void gncInvoiceSetDateOpened (GncInvoice *invoice, Timespec date)
{
    if (!invoice) return;
    if (timespec_equal (&invoice->date_opened, &date)) return;
    gncInvoiceBeginEdit (invoice);
    invoice->date_opened = date;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetDatePosted (GncInvoice *invoice, Timespec date)
{
    if (!invoice) return;
    if (timespec_equal (&invoice->date_posted, &date)) return;
    gncInvoiceBeginEdit (invoice);
    invoice->date_posted = date;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetTerms (GncInvoice *invoice, GncBillTerm *terms)
{
    if (!invoice) return;
    if (invoice->terms == terms) return;
    gncInvoiceBeginEdit (invoice);
    if (invoice->terms)
        gncBillTermDecRef (invoice->terms);
    invoice->terms = terms;
    if (invoice->terms)
        gncBillTermIncRef (invoice->terms);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetBillingID (GncInvoice *invoice, const char *billing_id)
{
    if (!invoice) return;
    SET_STR (invoice, invoice->billing_id, billing_id);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetNotes (GncInvoice *invoice, const char *notes)
{
    if (!invoice || !notes) return;
    SET_STR (invoice, invoice->notes, notes);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetActive (GncInvoice *invoice, gboolean active)
{
    if (!invoice) return;
    if (invoice->active == active) return;
    gncInvoiceBeginEdit (invoice);
    invoice->active = active;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetIsCreditNote (GncInvoice *invoice, gboolean credit_note)
{
    if (!invoice) return;
    gncInvoiceBeginEdit (invoice);
    kvp_frame_set_gint64(invoice->inst.kvp_data, GNC_INVOICE_IS_CN,
                         credit_note ? 1 : 0);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);

    /* If this is a credit note, set a feature flag for it in the book
     * This will prevent older GnuCash versions that don't support
     * credit notes to open this file. */
    if (credit_note)
        gnc_features_set_used (gncInvoiceGetBook (invoice), GNC_FEATURE_CREDIT_NOTES);
}

void gncInvoiceSetCurrency (GncInvoice *invoice, gnc_commodity *currency)
{
    if (!invoice || !currency) return;
    if (invoice->currency &&
            gnc_commodity_equal (invoice->currency, currency))
        return;
    gncInvoiceBeginEdit (invoice);
    invoice->currency = currency;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetBillTo (GncInvoice *invoice, GncOwner *billto)
{
    if (!invoice || !billto) return;
    if (gncOwnerEqual (&invoice->billto, billto)) return;

    gncInvoiceBeginEdit (invoice);
    gncOwnerCopy (billto, &invoice->billto);
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetToChargeAmount (GncInvoice *invoice, gnc_numeric amount)
{
    if (!invoice) return;
    if (gnc_numeric_equal (invoice->to_charge_amount, amount)) return;
    gncInvoiceBeginEdit (invoice);
    invoice->to_charge_amount = amount;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetPostedTxn (GncInvoice *invoice, Transaction *txn)
{
    if (!invoice) return;
    g_return_if_fail (invoice->posted_txn == NULL);

    gncInvoiceBeginEdit (invoice);
    invoice->posted_txn = txn;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetPostedLot (GncInvoice *invoice, GNCLot *lot)
{
    if (!invoice) return;
    g_return_if_fail (invoice->posted_lot == NULL);

    gncInvoiceBeginEdit (invoice);
    invoice->posted_lot = lot;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceSetPostedAcc (GncInvoice *invoice, Account *acc)
{
    if (!invoice) return;
    g_return_if_fail (invoice->posted_acc == NULL);

    gncInvoiceBeginEdit (invoice);
    invoice->posted_acc = acc;
    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);
}

void gncInvoiceAddEntry (GncInvoice *invoice, GncEntry *entry)
{
    GncInvoice *old;

    g_assert(invoice);
    g_assert(entry);
    if (!invoice || !entry) return;

    old = gncEntryGetInvoice (entry);
    if (old == invoice) return; /* I already own this one */
    if (old) gncInvoiceRemoveEntry (old, entry);

    gncEntrySetInvoice (entry, invoice);
    invoice->entries = g_list_insert_sorted (invoice->entries, entry,
                       (GCompareFunc)gncEntryCompare);
    mark_invoice (invoice);
}

void gncInvoiceRemoveEntry (GncInvoice *invoice, GncEntry *entry)
{
    if (!invoice || !entry) return;

    gncEntrySetInvoice (entry, NULL);
    invoice->entries = g_list_remove (invoice->entries, entry);
    mark_invoice (invoice);
}

void gncInvoiceAddPrice (GncInvoice *invoice, GNCPrice *price)
{
    if (!invoice || !price) return;

    invoice->prices = g_list_prepend(invoice->prices, price);
    mark_invoice (invoice);
}

void gncBillAddEntry (GncInvoice *bill, GncEntry *entry)
{
    GncInvoice *old;

    g_assert(bill);
    g_assert(entry);
    if (!bill || !entry) return;

    old = gncEntryGetBill (entry);
    if (old == bill) return;    /* I already own this one */
    if (old) gncBillRemoveEntry (old, entry);

    gncEntrySetBill (entry, bill);
    bill->entries = g_list_insert_sorted (bill->entries, entry,
                                          (GCompareFunc)gncEntryCompare);
    mark_invoice (bill);
}

void gncBillRemoveEntry (GncInvoice *bill, GncEntry *entry)
{
    if (!bill || !entry) return;

    gncEntrySetBill (entry, NULL);
    bill->entries = g_list_remove (bill->entries, entry);
    mark_invoice (bill);
}

void gncInvoiceSortEntries (GncInvoice *invoice)
{
    if (!invoice) return;
    invoice->entries = g_list_sort(invoice->entries,
                                   (GCompareFunc)gncEntryCompare);
    mark_invoice(invoice);
}

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

const char * gncInvoiceGetID (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->id;
}

const GncOwner * gncInvoiceGetOwner (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return &invoice->owner;
}

static QofInstance*
qofInvoiceGetOwner (GncInvoice *invoice)
{
    GncOwner *owner;

    if (!invoice)
    {
        return NULL;
    }
    owner = &invoice->owner;
    return QOF_INSTANCE(owner);
}

static QofInstance*
qofInvoiceGetBillTo (GncInvoice *invoice)
{
    GncOwner *billto;

    if (!invoice)
    {
        return NULL;
    }
    billto = &invoice->billto;
    return QOF_INSTANCE(billto);
}

Timespec gncInvoiceGetDateOpened (const GncInvoice *invoice)
{
    Timespec ts;
    ts.tv_sec = 0;
    ts.tv_nsec = 0;
    if (!invoice) return ts;
    return invoice->date_opened;
}

Timespec gncInvoiceGetDatePosted (const GncInvoice *invoice)
{
    Timespec ts;
    ts.tv_sec = 0;
    ts.tv_nsec = 0;
    if (!invoice) return ts;
    return invoice->date_posted;
}

Timespec gncInvoiceGetDateDue (const GncInvoice *invoice)
{
    Transaction *txn;
    Timespec ts;
    ts.tv_sec = 0;
    ts.tv_nsec = 0;
    if (!invoice) return ts;
    txn = gncInvoiceGetPostedTxn (invoice);
    if (!txn) return ts;
    return xaccTransRetDateDueTS (txn);
}

GncBillTerm * gncInvoiceGetTerms (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->terms;
}

const char * gncInvoiceGetBillingID (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->billing_id;
}

const char * gncInvoiceGetNotes (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->notes;
}

GncOwnerType gncInvoiceGetOwnerType (const GncInvoice *invoice)
{
    const GncOwner *owner;
    g_return_val_if_fail (invoice, GNC_OWNER_NONE);

    owner = gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice));
    return (gncOwnerGetType (owner));
}

static gnc_numeric
gncInvoiceGetTotalInternal (GncInvoice *invoice, gboolean use_value,
                            gboolean use_tax,
                            gboolean use_payment_type, GncEntryPaymentType type)
{
    GList *node;
    gnc_numeric total = gnc_numeric_zero();
    gboolean is_cust_doc, is_cn;

    g_return_val_if_fail (invoice, total);

    /* Is the current document an invoice/credit note related to a customer or a vendor/employee ?
     * The GncEntry code needs to know to return the proper entry amounts
     */
    is_cust_doc = (gncInvoiceGetOwnerType (invoice) == GNC_OWNER_CUSTOMER);
    is_cn = gncInvoiceGetIsCreditNote (invoice);

    for (node = gncInvoiceGetEntries(invoice); node; node = node->next)
    {
        GncEntry *entry = node->data;
        gnc_numeric value, tax;

        if (use_payment_type && gncEntryGetBillPayment (entry) != type)
            continue;

        value = gncEntryGetDocValue (entry, FALSE, is_cust_doc, is_cn);
        if (gnc_numeric_check (value) == GNC_ERROR_OK)
        {
            if (use_value)
                total = gnc_numeric_add (total, value, GNC_DENOM_AUTO, GNC_HOW_DENOM_LCD);
        }
        else
            g_warning ("bad value in our entry");

        if (use_tax)
        {
            tax = gncEntryGetDocTaxValue (entry, FALSE, is_cust_doc, is_cn);
            if (gnc_numeric_check (tax) == GNC_ERROR_OK)
                total = gnc_numeric_add (total, tax, GNC_DENOM_AUTO, GNC_HOW_DENOM_LCD);
            else
                g_warning ("bad tax-value in our entry");
        }
    }
    return total;
}

gnc_numeric gncInvoiceGetTotal (GncInvoice *invoice)
{
    if (!invoice) return gnc_numeric_zero();
    return gncInvoiceGetTotalInternal(invoice, TRUE, TRUE, FALSE, 0);
}

gnc_numeric gncInvoiceGetTotalSubtotal (GncInvoice *invoice)
{
    if (!invoice) return gnc_numeric_zero();
    return gncInvoiceGetTotalInternal(invoice, TRUE, FALSE, FALSE, 0);
}

gnc_numeric gncInvoiceGetTotalTax (GncInvoice *invoice)
{
    if (!invoice) return gnc_numeric_zero();
    return gncInvoiceGetTotalInternal(invoice, FALSE, TRUE, FALSE, 0);
}

gnc_numeric gncInvoiceGetTotalOf (GncInvoice *invoice, GncEntryPaymentType type)
{
    if (!invoice) return gnc_numeric_zero();
    return gncInvoiceGetTotalInternal(invoice, TRUE, TRUE, TRUE, type);
}

GList * gncInvoiceGetTypeListForOwnerType (GncOwnerType type)
{
    GList *type_list = NULL;
    switch (type)
    {
    case GNC_OWNER_CUSTOMER:
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_CUST_INVOICE));
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_CUST_CREDIT_NOTE));
        return type_list;
    case GNC_OWNER_VENDOR:
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_VEND_INVOICE));
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_VEND_CREDIT_NOTE));
        return type_list;
    case GNC_OWNER_EMPLOYEE:
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_EMPL_INVOICE));
        type_list = g_list_append (type_list, GINT_TO_POINTER(GNC_INVOICE_EMPL_CREDIT_NOTE));
        return type_list;
    default:
        return NULL;
    }

}

GncInvoiceType gncInvoiceGetType (const GncInvoice *invoice)
{
    if (!invoice) return GNC_INVOICE_UNDEFINED;
    switch (gncInvoiceGetOwnerType (invoice))
    {
    case GNC_OWNER_CUSTOMER:
        return (gncInvoiceGetIsCreditNote(invoice) ?
                GNC_INVOICE_CUST_CREDIT_NOTE :
                GNC_INVOICE_CUST_INVOICE);
    case GNC_OWNER_VENDOR:
        return (gncInvoiceGetIsCreditNote(invoice) ?
                GNC_INVOICE_VEND_CREDIT_NOTE :
                GNC_INVOICE_VEND_INVOICE);
    case GNC_OWNER_EMPLOYEE:
        return (gncInvoiceGetIsCreditNote(invoice) ?
                GNC_INVOICE_EMPL_CREDIT_NOTE :
                GNC_INVOICE_EMPL_INVOICE);
    default:
        PWARN ("No invoice types defined for owner %d",
               gncInvoiceGetOwnerType (invoice));
        return GNC_INVOICE_UNDEFINED;
    }
}

const char * gncInvoiceGetTypeString (const GncInvoice *invoice)
{
    GncInvoiceType type = gncInvoiceGetType(invoice);
    switch (type)
    {
    case GNC_INVOICE_CUST_INVOICE:
        return _("Invoice");
    case GNC_INVOICE_VEND_INVOICE:
        return _("Bill");
    case GNC_INVOICE_EMPL_INVOICE:
        return _("Expense");
    case GNC_INVOICE_CUST_CREDIT_NOTE:
        return _("Customer Credit Note");
    case GNC_INVOICE_VEND_CREDIT_NOTE:
        return _("Vendor Credit Note");
    case GNC_INVOICE_EMPL_CREDIT_NOTE:
        return _("Employee Credit Note");
    default:
        PWARN("Unknown invoice type");
        return NULL;
    }
}

gnc_commodity * gncInvoiceGetCurrency (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->currency;
}

GncOwner * gncInvoiceGetBillTo (GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return &invoice->billto;
}

GNCLot * gncInvoiceGetPostedLot (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->posted_lot;
}

Transaction * gncInvoiceGetPostedTxn (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->posted_txn;
}

Account * gncInvoiceGetPostedAcc (const GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->posted_acc;
}

gboolean gncInvoiceGetActive (const GncInvoice *invoice)
{
    if (!invoice) return FALSE;
    return invoice->active;
}

gboolean gncInvoiceGetIsCreditNote (const GncInvoice *invoice)
{
    gint64 is_cn;
    if (!invoice) return FALSE;
    if (kvp_frame_get_gint64(invoice->inst.kvp_data, GNC_INVOICE_IS_CN))
        return TRUE;
    else
        return FALSE;
}


gnc_numeric gncInvoiceGetToChargeAmount (const GncInvoice *invoice)
{
    if (!invoice) return gnc_numeric_zero();
    return invoice->to_charge_amount;
}

EntryList * gncInvoiceGetEntries (GncInvoice *invoice)
{
    if (!invoice) return NULL;
    return invoice->entries;
}

GNCPrice * gncInvoiceGetPrice(GncInvoice *invoice, gnc_commodity *commodity)
{
    GList *node = g_list_first(invoice->prices);

    while (node != NULL)
    {
        GNCPrice *curr = (GNCPrice*)node->data;

        if (gnc_commodity_equal(commodity, gnc_price_get_commodity(curr)))
            return curr;

        node = g_list_next(node);
    }

    return NULL;
}

static QofCollection*
qofInvoiceGetEntries (GncInvoice *invoice)
{
    QofCollection *entry_coll;
    GList         *list;
    QofInstance     *entry;

    entry_coll = qof_collection_new(GNC_ID_ENTRY);
    for (list = gncInvoiceGetEntries(invoice); list != NULL; list = list->next)
    {
        entry = QOF_INSTANCE(list->data);
        qof_collection_add_entity(entry_coll, entry);
    }
    return entry_coll;
}

static void
qofInvoiceEntryCB (QofInstance *ent, gpointer user_data)
{
    GncInvoice *invoice;

    invoice = (GncInvoice*)user_data;
    if (!invoice || !ent)
    {
        return;
    }
    switch (gncInvoiceGetOwnerType (invoice))
    {
    case GNC_OWNER_VENDOR:
    {
        gncBillAddEntry (invoice, (GncEntry*) ent);
        break;
    }
    default :
    {
        gncInvoiceAddEntry(invoice, (GncEntry*)ent);
        break;
    }
    }
}

static void
qofInvoiceSetEntries(GncInvoice *invoice, QofCollection *entry_coll)
{
    if (!entry_coll)
    {
        return;
    }
    if (0 == safe_strcmp(qof_collection_get_type(entry_coll), GNC_ID_ENTRY))
    {
        qof_collection_foreach(entry_coll, qofInvoiceEntryCB, invoice);
    }
}

static GncJob*
qofInvoiceGetJob (const GncInvoice *invoice)
{
    if (!invoice)
    {
        return NULL;
    }
    return invoice->job;
}

static void
qofInvoiceSetJob (GncInvoice *invoice, GncJob *job)
{
    if (!invoice)
    {
        return;
    }
    invoice->job = job;
}

static void
gncInvoiceDetachFromLot (GNCLot *lot)
{
    KvpFrame *kvp;

    if (!lot) return;
    gnc_lot_begin_edit (lot);
    kvp = gnc_lot_get_slots (lot);
    kvp_frame_set_slot_path (kvp, NULL, GNC_INVOICE_ID, GNC_INVOICE_GUID, NULL);
    qof_instance_set_dirty (QOF_INSTANCE (lot));
    gnc_lot_commit_edit (lot);
}

static void
gncInvoiceAttachToLot (GncInvoice *invoice, GNCLot *lot)
{
    KvpFrame *kvp;
    KvpValue *value;

    if (!invoice || !lot)
        return;

    if (invoice->posted_lot) return;    /* Cannot reset invoice's lot */

    gnc_lot_begin_edit (lot);
    kvp = gnc_lot_get_slots (lot);
    value = kvp_value_new_guid (qof_instance_get_guid (QOF_INSTANCE(invoice)));
    kvp_frame_set_slot_path (kvp, value, GNC_INVOICE_ID, GNC_INVOICE_GUID, NULL);
    qof_instance_set_dirty (QOF_INSTANCE (lot));
    gnc_lot_commit_edit (lot);
    kvp_value_delete (value);
    gncInvoiceSetPostedLot (invoice, lot);
}

GncInvoice * gncInvoiceGetInvoiceFromLot (GNCLot *lot)
{
    KvpFrame *kvp;
    KvpValue *value;
    GncGUID *guid;
    QofBook *book;

    if (!lot) return NULL;

    book = gnc_lot_get_book (lot);
    kvp = gnc_lot_get_slots (lot);
    value = kvp_frame_get_slot_path (kvp, GNC_INVOICE_ID, GNC_INVOICE_GUID, NULL);
    if (!value) return NULL;

    guid = kvp_value_get_guid (value);
    return gncInvoiceLookup(book, guid);
}

static void
gncInvoiceAttachToTxn (GncInvoice *invoice, Transaction *txn)
{
    KvpFrame *kvp;
    KvpValue *value;

    if (!invoice || !txn)
        return;

    if (invoice->posted_txn) return;    /* Cannot reset invoice's txn */

    xaccTransBeginEdit (txn);
    kvp = xaccTransGetSlots (txn);
    value = kvp_value_new_guid (qof_instance_get_guid(QOF_INSTANCE(invoice)));
    kvp_frame_set_slot_path (kvp, value, GNC_INVOICE_ID, GNC_INVOICE_GUID, NULL);
    kvp_value_delete (value);
    xaccTransSetTxnType (txn, TXN_TYPE_INVOICE);
    xaccTransCommitEdit (txn);
    gncInvoiceSetPostedTxn (invoice, txn);
}

GncInvoice *
gncInvoiceGetInvoiceFromTxn (const Transaction *txn)
{
    KvpFrame *kvp;
    KvpValue *value;
    GncGUID *guid;
    QofBook *book;

    if (!txn) return NULL;

    book = xaccTransGetBook (txn);
    kvp = xaccTransGetSlots (txn);
    value = kvp_frame_get_slot_path (kvp, GNC_INVOICE_ID, GNC_INVOICE_GUID, NULL);
    if (!value) return NULL;

    guid = kvp_value_get_guid (value);
    return gncInvoiceLookup(book, guid);
}

gboolean gncInvoiceAmountPositive (const GncInvoice *invoice)
{
    switch (gncInvoiceGetType (invoice))
    {
    case GNC_INVOICE_CUST_INVOICE:
    case GNC_INVOICE_VEND_CREDIT_NOTE:
    case GNC_INVOICE_EMPL_CREDIT_NOTE:
        return TRUE;
    case GNC_INVOICE_CUST_CREDIT_NOTE:
    case GNC_INVOICE_VEND_INVOICE:
    case GNC_INVOICE_EMPL_INVOICE:
        return FALSE;
    case GNC_INVOICE_UNDEFINED:
    default:
        /* Should never be reached.
         * If it is, perhaps a new value is added to GncInvoiceType ? */
        g_assert_not_reached();
        return FALSE;
    }
}

static gboolean gncInvoicePostAddSplit (QofBook *book,
                                        Account *acc,
                                        Transaction *txn,
                                        gnc_numeric value,
                                        const gchar *memo,
                                        const gchar *type,
                                        GncInvoice *invoice)
{
    Split *split;

    split = xaccMallocSplit (book);
    /* set action and memo? */

    xaccSplitSetMemo (split, memo);
    xaccSplitSetAction (split, type);

    /* Need to insert this split into the account AND txn before
     * we set the Base Value.  Otherwise SetBaseValue complains
     * that we don't have an account and fails to set the value.
     */
    xaccAccountBeginEdit (acc);
    xaccAccountInsertSplit (acc, split);
    xaccAccountCommitEdit (acc);
    xaccTransAppendSplit (txn, split);

    /* General note on the split creations below:
     * Invoice and bill amounts are always stored as positive values in entries
     * So to convert them to proper splits, the amounts may have to be reverted
     * to have the proper effect on the account balance.
     * Credit notes have the opposite effect of invoices/bills, but their amounts
     * are stored as negative values as well. So to convert them into splits
     * they can be treated exactly the same as their invoice/bill counter parts.
     * The net effect is that the owner type is sufficient to determine whether a
     * value has to be reverted when converting an invoice/bill/cn amount to a split.
     */
    if (gnc_commodity_equal(xaccAccountGetCommodity(acc), invoice->currency))
    {
        xaccSplitSetBaseValue (split, value,
                               invoice->currency);
    }
    else
    {
        /*need to do conversion */
        GNCPrice *price = gncInvoiceGetPrice(invoice, xaccAccountGetCommodity(acc));

        if (price == NULL)
        {
            /*This is an error, which shouldn't even be able to happen.
              We can't really do anything sensible about it, and this is
                        a user-interface free zone so we can't try asking the user
              again either, have to return NULL*/
            return FALSE;
        }
        else
        {
            gnc_numeric converted_amount;
            xaccSplitSetValue(split, value);
            converted_amount = gnc_numeric_div(value, gnc_price_get_value(price), GNC_DENOM_AUTO, GNC_HOW_RND_ROUND_HALF_UP);
            DEBUG("converting from %f to %f\n", gnc_numeric_to_double(value), gnc_numeric_to_double(converted_amount));
            xaccSplitSetAmount(split, converted_amount);
        }
    }

    return TRUE;
}

Transaction * gncInvoicePostToAccount (GncInvoice *invoice, Account *acc,
                                       Timespec *post_date, Timespec *due_date,
                                       const char * memo, gboolean accumulatesplits)
{
    Transaction *txn;
    QofBook *book;
    GNCLot *lot = NULL;
    GList *iter;
    GList *splitinfo = NULL;
    gnc_numeric total;
    gboolean is_cust_doc;
    gboolean is_cn;
    const char *name, *type;
    char *lot_title;
    Account *ccard_acct = NULL;
    const GncOwner *owner;
    gboolean autopay = TRUE; /* FIXME this will have to become a user selectable option at some point */

    if (!invoice || !acc) return NULL;

    gncInvoiceBeginEdit (invoice);
    book = qof_instance_get_book(invoice);

    /* Stabilize the Billing Terms of this invoice */
    if (invoice->terms)
        gncInvoiceSetTerms (invoice,
                            gncBillTermReturnChild (invoice->terms, TRUE));

    /* GncEntry functions need to know if the invoice/credit note is for a customer or a vendor/employee. */
    is_cust_doc = (gncInvoiceGetOwnerType (invoice) == GNC_OWNER_CUSTOMER);
    is_cn = gncInvoiceGetIsCreditNote (invoice);

    /* Figure out if we need to separate out "credit-card" items */
    owner = gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice));
    if (gncInvoiceGetOwnerType (invoice) == GNC_OWNER_EMPLOYEE)
        ccard_acct = gncEmployeeGetCCard (gncOwnerGetEmployee (owner));

    /* Create a new lot for this invoice */
    lot = gnc_lot_new (book);
    gnc_lot_begin_edit (lot);

    type = gncInvoiceGetTypeString (invoice);

    /* Set the lot title */
    lot_title = g_strdup_printf ("%s %s", type, gncInvoiceGetID (invoice));
    gnc_lot_set_title (lot, lot_title);
    g_free (lot_title);

    /* Create a new transaction */
    txn = xaccMallocTransaction (book);
    xaccTransBeginEdit (txn);

    name = gncOwnerGetName (gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice)));

    /* Set Transaction Description (Owner Name) , Num (invoice ID), Currency */
    xaccTransSetDescription (txn, name ? name : "");
    xaccTransSetNum (txn, gncInvoiceGetID (invoice));
    xaccTransSetCurrency (txn, invoice->currency);

    /* Entered and Posted at date */
    xaccTransSetDateEnteredSecs (txn, time(NULL));
    if (post_date)
    {
        xaccTransSetDatePostedTS (txn, post_date);
        gncInvoiceSetDatePosted (invoice, *post_date);
    }

    if (due_date)
        xaccTransSetDateDueTS (txn, due_date);

    /* Iterate through the entries; sum up everything for each account.
     * then create the appropriate splits in this txn.
     */
    total = gnc_numeric_zero();
    for (iter = gncInvoiceGetEntries(invoice); iter; iter = iter->next)
    {
        gnc_numeric value, tax;
        GList *taxes;
        GncEntry * entry = iter->data;
        Account *this_acc;

        /* Stabilize the TaxTable in this entry */
        gncEntryBeginEdit (entry);
        if (is_cust_doc)
            gncEntrySetInvTaxTable
            (entry, gncTaxTableReturnChild (gncEntryGetInvTaxTable (entry), TRUE));
        else
        {
            gncEntrySetBillTaxTable
            (entry, gncTaxTableReturnChild (gncEntryGetBillTaxTable (entry), TRUE));

            /* If this is a bill, and the entry came from an invoice originally, copy the price */
            if (gncEntryGetBillable (entry))
                gncEntrySetInvPrice (entry, gncEntryGetBillPrice (entry));
        }
        gncEntryCommitEdit (entry);

        /* Obtain the Entry's Value and TaxValues */
        value = gncEntryGetBalValue (entry, FALSE, is_cust_doc);
        tax   = gncEntryGetBalTaxValue (entry, FALSE, is_cust_doc);
        taxes = gncEntryGetBalTaxValues (entry, is_cust_doc);

        /* add the value for the account split */
        this_acc = (is_cust_doc ? gncEntryGetInvAccount (entry) :
                    gncEntryGetBillAccount (entry));
        if (this_acc)
        {
            if (gnc_numeric_check (value) == GNC_ERROR_OK)
            {
                if (accumulatesplits)
                    splitinfo = gncAccountValueAdd (splitinfo, this_acc, value);
                else if (!gncInvoicePostAddSplit (book, this_acc, txn, value,
                                                  gncEntryGetDescription (entry),
                                                  type, invoice))
                {
                    /*This is an error, which shouldn't even be able to happen.
                      We can't really do anything sensible about it, and this is
                      a user-interface free zone so we can't try asking the user
                      again either, have to return NULL*/
                    return NULL;
                }

                /* If there is a credit-card account, and this is a CCard
                 * payment type, the don't add it to the total, and instead
                 * create a split to the CC Acct with a memo of the entry
                 * description instead of the provided memo.  Note that the
                 * value reversal is the same as the post account.
                 *
                 * Note: we don't have to worry about the tax values --
                 * expense vouchers don't have them.
                 */
                if (ccard_acct && gncEntryGetBillPayment (entry) == GNC_PAYMENT_CARD)
                {
                    Split *split;

                    split = xaccMallocSplit (book);
                    /* set action? */
                    xaccSplitSetMemo (split, gncEntryGetDescription (entry));
                    xaccSplitSetAction (split, type);
                    xaccAccountBeginEdit (ccard_acct);
                    xaccAccountInsertSplit (ccard_acct, split);
                    xaccAccountCommitEdit (ccard_acct);
                    xaccTransAppendSplit (txn, split);
                    xaccSplitSetBaseValue (split, gnc_numeric_neg (value),
                                           invoice->currency);

                }
                else
                    total = gnc_numeric_add (total, value, GNC_DENOM_AUTO, GNC_HOW_DENOM_LCD);

            }
            else
                g_warning ("bad value in our entry");
        }

        /* now merge in the TaxValues */
        splitinfo = gncAccountValueAddList (splitinfo, taxes);

        /* ... and add the tax total */
        if (gnc_numeric_check (tax) == GNC_ERROR_OK)
            total = gnc_numeric_add (total, tax, GNC_DENOM_AUTO, GNC_HOW_DENOM_LCD);
        else
            g_warning ("bad tax in our entry");

        gncAccountValueDestroy (taxes);
    } /* for */

    /* Iterate through the splitinfo list and generate the splits */
    for (iter = splitinfo; iter; iter = iter->next)
    {
        GncAccountValue *acc_val = iter->data;
        if (!gncInvoicePostAddSplit (book, acc_val->account, txn, acc_val->value,
                                     memo, type, invoice))
        {
            /*This is an error, which shouldn't even be able to happen.
              We can't really do anything sensible about it, and this is
              a user-interface free zone so we can't try asking the user
              again either, have to return NULL*/
            return NULL;
        }
    }

    /* If there is a ccard account, we may have an additional "to_card" payment.
     * we should make that now.
     */
    if (ccard_acct && !gnc_numeric_zero_p (invoice->to_charge_amount))
    {
        Split *split = xaccMallocSplit (book);

        /* To charge amount is stored in document value. We need balance value here
         * so convert if necessary. */
        gnc_numeric to_charge_bal_amount = (is_cn ? gnc_numeric_neg (invoice->to_charge_amount)
                                            : invoice->to_charge_amount);

        /* Set memo.  action? */
        xaccSplitSetMemo (split, _("Extra to Charge Card"));
        xaccSplitSetAction (split, type);

        xaccAccountBeginEdit (ccard_acct);
        xaccAccountInsertSplit (ccard_acct, split);
        xaccAccountCommitEdit (ccard_acct);
        xaccTransAppendSplit (txn, split);
        xaccSplitSetBaseValue (split, gnc_numeric_neg (to_charge_bal_amount),
                               invoice->currency);

        total = gnc_numeric_sub (total, to_charge_bal_amount,
                                 GNC_DENOM_AUTO, GNC_HOW_DENOM_LCD);
    }

    /* Now create the Posted split (which is the opposite sign of the above splits) */
    {
        Split *split = xaccMallocSplit (book);

        /* Set action/memo */
        xaccSplitSetMemo (split, memo);
        xaccSplitSetAction (split, type);

        xaccAccountBeginEdit (acc);
        xaccAccountInsertSplit (acc, split);
        xaccAccountCommitEdit (acc);
        xaccTransAppendSplit (txn, split);
        xaccSplitSetBaseValue (split, gnc_numeric_neg (total),
                               invoice->currency);

        /* add this split to the lot */
        gnc_lot_add_split (lot, split);
    }

    /* Now attach this invoice to the txn, lot, and account */
    gncInvoiceAttachToLot (invoice, lot);
    gncInvoiceAttachToTxn (invoice, txn);
    gncInvoiceSetPostedAcc (invoice, acc);

    xaccTransSetReadOnly (txn, _("Generated from an invoice.  Try unposting the invoice."));
    xaccTransCommitEdit (txn);

    gncAccountValueDestroy (splitinfo);

    gnc_lot_commit_edit (lot);
    gncInvoiceCommitEdit (invoice);

    /* If requested, attempt to automatically apply open payments
     * and reverse documents to this lot to close it (or at least
     * reduce its balance) */
    if (autopay)
        gncInvoiceAutoApplyPayments (invoice);

    return txn;
}

gboolean
gncInvoiceUnpost (GncInvoice *invoice, gboolean reset_tax_tables)
{
    Transaction *txn;
    GNCLot *lot;
    GList *lot_split_list, *lot_split_iter;

    if (!invoice) return FALSE;
    if (!gncInvoiceIsPosted (invoice)) return FALSE;

    txn = gncInvoiceGetPostedTxn (invoice);
    g_return_val_if_fail (txn, FALSE);

    lot = gncInvoiceGetPostedLot (invoice);
    g_return_val_if_fail (lot, FALSE);

    /* Destroy the Posted Transaction */
    xaccTransClearReadOnly (txn);
    xaccTransBeginEdit (txn);
    xaccTransDestroy (txn);
    xaccTransCommitEdit (txn);

    /* Disconnect the lot from the invoice; re-attach to the invoice owner */
    gncInvoiceDetachFromLot (lot);
    gncOwnerAttachToLot (&invoice->owner, lot);

    /* Check if this invoice was linked to other lots (payments/inverse signed
     * invoices).
     * If this is the case, recreate the link transaction between all the remaining lots.
     *
     * Note that before GnuCash 2.6 payments were not stored in separate lots, but
     * always ended up in invoice lots when matched to an invoice. Over-payments
     * were copied to a new lot, to which later an invoice was added again and so on.
     * These over-payments were handled with automatic payment forward transactions.
     * You could consider these transactions to be links between lots as well, but
     * to avoid some unexpected behavior, these will not be altered here.
     */

    // Note: make a copy of the lot list here, when splits are deleted from the lot,
    //       the original list may be destroyed by the lot code.
    lot_split_list = g_list_copy (gnc_lot_get_split_list (lot));
    for (lot_split_iter = lot_split_list; lot_split_iter; lot_split_iter = lot_split_iter->next)
    {
        Split *split = lot_split_iter->data;
        GList *other_split_list, *list_iter;
        Transaction *other_txn = xaccSplitGetParent (split);
        GList *lot_list = NULL;

        /* Only work with transactions that link invoices and payments.
         * Note: this check also catches the possible case of NULL splits. */
        if (xaccTransGetTxnType (other_txn) != TXN_TYPE_LINK)
            continue;

        /* Save a list of lots this linking transaction linked to */
        other_split_list = xaccTransGetSplitList (other_txn);
        for (list_iter = other_split_list; list_iter; list_iter = list_iter->next)
        {
            Split *other_split = list_iter->data;
            GNCLot *other_lot = xaccSplitGetLot (other_split);

            /* Omit the lot we are about to delete */
            if (other_lot == lot)
                continue;

            lot_list = g_list_prepend (lot_list, other_lot);
        }
        /* Maintain original split order */
        lot_list = g_list_reverse (lot_list);

        /* Now remove this link transaction. */
        xaccTransClearReadOnly (other_txn);
        xaccTransBeginEdit (other_txn);
        xaccTransDestroy (other_txn);
        xaccTransCommitEdit (other_txn);

        /* Re-balance the saved lots as well as is possible */
        gncOwnerAutoApplyPaymentsWithLots (&invoice->owner, lot_list);

        /* If any of the saved lots has no more splits, then destroy it.
         * Otherwise if any has an invoice associated with it,
         * send it a modified event to reset its paid status */
        for (list_iter = lot_list; list_iter; list_iter = list_iter->next)
        {
            GNCLot *other_lot = list_iter->data;
            GncInvoice *other_invoice = gncInvoiceGetInvoiceFromLot (other_lot);

            if (!gnc_lot_count_splits (other_lot))
                gnc_lot_destroy (other_lot);
            else if (other_invoice)
                qof_event_gen (QOF_INSTANCE(other_invoice), QOF_EVENT_MODIFY, NULL);
        }
    }
    g_list_free (lot_split_list);

    /* If the lot has no splits, then destroy it */
    if (!gnc_lot_count_splits (lot))
        gnc_lot_destroy (lot);

    /* Clear out the invoice posted information */
    gncInvoiceBeginEdit (invoice);

    invoice->posted_acc = NULL;
    invoice->posted_txn = NULL;
    invoice->posted_lot = NULL;
    invoice->date_posted.tv_sec = invoice->date_posted.tv_nsec = 0;

    /* if we've been asked to reset the tax tables, then do so */
    if (reset_tax_tables)
    {
        gboolean is_cust_doc = (gncInvoiceGetOwnerType(invoice) == GNC_OWNER_CUSTOMER);
        GList *iter;

        for (iter = gncInvoiceGetEntries(invoice); iter; iter = iter->next)
        {
            GncEntry *entry = iter->data;

            gncEntryBeginEdit(entry);
            if (is_cust_doc)
                gncEntrySetInvTaxTable(entry,
                                       gncTaxTableGetParent(gncEntryGetInvTaxTable(entry)));
            else
                gncEntrySetBillTaxTable(entry,
                                        gncTaxTableGetParent(gncEntryGetBillTaxTable(entry)));
            gncEntryCommitEdit(entry);
        }
    }

    mark_invoice (invoice);
    gncInvoiceCommitEdit (invoice);

    return TRUE;
}

struct lotmatch
{
    const GncOwner *owner;
    gboolean positive_balance;
};

static gboolean
gnc_lot_match_owner_balancing (GNCLot *lot, gpointer user_data)
{
    struct lotmatch *lm = user_data;
    GncOwner owner_def;
    const GncOwner *owner;
    gnc_numeric balance = gnc_lot_get_balance (lot);

    /* Could (part of) this lot serve to balance the lot
     * for which this query was run ?*/
    if (lm->positive_balance == gnc_numeric_positive_p (balance))
        return FALSE;

    /* Is it ours? Either the lot owner or the lot invoice owner should match */
    if (!gncOwnerGetOwnerFromLot (lot, &owner_def))
    {
        const GncInvoice *invoice = gncInvoiceGetInvoiceFromLot (lot);
        if (!invoice)
            return FALSE;
        owner = gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice));
    }
    else
        owner = gncOwnerGetEndOwner (&owner_def);

    return gncOwnerEqual (owner, lm->owner);
}

void gncInvoiceAutoApplyPayments (GncInvoice *invoice)
{
    GNCLot *inv_lot;
    Account *acct;
    const GncOwner *owner;
    GList *lot_list;
    struct lotmatch lm;

    /* General note: "paying" in this context means balancing
     * a lot, by linking opposite signed lots together. So below the term
     * "payment" can both mean a true payment or it can mean a document of
     * the opposite sign (invoice vs credit note). It just
     * depends on what type of document was given as parameter
     * to this function. */

    /* Payments can only be applied to posted invoices */
    g_return_if_fail (invoice);
    g_return_if_fail (invoice->posted_lot);

    inv_lot = invoice->posted_lot;
    acct = invoice->posted_acc;
    owner = gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice));

    /* Find all lots whose balance (or part of their balance) could be
     * used to close this lot.
     * To be eligible, the lots have to have an opposite signed balance
     * and be for the same owner.
     * For example, for an invoice lot, payment lots and credit note lots
     * could be used. */
    lm.positive_balance =  gnc_numeric_positive_p (gnc_lot_get_balance (inv_lot));
    lm.owner = owner;
    lot_list = xaccAccountFindOpenLots (acct, gnc_lot_match_owner_balancing,
                                        &lm, NULL);

    lot_list = g_list_prepend (lot_list, inv_lot);
    gncOwnerAutoApplyPaymentsWithLots (owner, lot_list);
    g_list_free (lot_list);
}

/*
 * Create a payment of "amount" for the invoice owner and attempt
 * to balance it with the given invoice.
 */
void
gncInvoiceApplyPayment (const GncInvoice *invoice, Transaction *txn,
                        Account *xfer_acc, gnc_numeric amount,
                        gnc_numeric exch, Timespec date,
                        const char *memo, const char *num)
{
    GNCLot *payment_lot, *invoice_lot;
    GList *selected_lots = NULL;
    const GncOwner *owner;

    /* Verify our arguments */
    if (!invoice || !gncInvoiceIsPosted (invoice) || !xfer_acc) return;

    owner = gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice));
    g_return_if_fail (owner->owner.undefined);

    /* Create a lot for this payment */
    payment_lot = gncOwnerCreatePaymentLot (owner, txn, invoice->posted_acc, xfer_acc,
                                            amount, exch, date, memo, num);

    /* Select the invoice as only payment candidate */
    selected_lots = g_list_prepend (selected_lots, invoice->posted_lot);

    /* And link the invoice lot and the payment lot together as well as possible. */
    if (payment_lot)
        selected_lots = g_list_prepend (selected_lots, payment_lot);
    gncOwnerAutoApplyPaymentsWithLots (owner, selected_lots);
}

static gboolean gncInvoiceDateExists (const Timespec *date)
{
    g_return_val_if_fail (date, FALSE);
    if (date->tv_sec || date->tv_nsec) return TRUE;
    return FALSE;
}

gboolean gncInvoiceIsPosted (const GncInvoice *invoice)
{
    if (!invoice) return FALSE;
    return gncInvoiceDateExists (&(invoice->date_posted));
}

gboolean gncInvoiceIsPaid (const GncInvoice *invoice)
{
    if (!invoice) return FALSE;
    if (!invoice->posted_lot) return FALSE;
    return gnc_lot_is_closed(invoice->posted_lot);
}

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

void gncInvoiceBeginEdit (GncInvoice *invoice)
{
    qof_begin_edit(&invoice->inst);
}

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

static void gncInvoiceOnDone (QofInstance *invoice) { }

static void invoice_free (QofInstance *inst)
{
    GncInvoice *invoice = (GncInvoice *) inst;
    gncInvoiceFree (invoice);
}

void gncInvoiceCommitEdit (GncInvoice *invoice)
{
    if (!qof_commit_edit (QOF_INSTANCE(invoice))) return;
    qof_commit_edit_part2 (&invoice->inst, gncInvoiceOnError,
                           gncInvoiceOnDone, invoice_free);
}

int gncInvoiceCompare (const GncInvoice *a, const GncInvoice *b)
{
    int compare;

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

    compare = safe_strcmp (a->id, b->id);
    if (compare) return compare;

    compare = timespec_cmp (&(a->date_opened), &(b->date_opened));
    if (compare) return compare;

    compare = timespec_cmp (&(a->date_posted), &(b->date_posted));
    if (compare) return compare;

    return qof_instance_guid_compare(a, b);
}

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

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

    if (safe_strcmp(a->id, b->id) != 0)
    {
        PWARN("IDs differ: %s vs %s", a->id, b->id);
        return FALSE;
    }

    if (safe_strcmp(a->notes, b->notes) != 0)
    {
        PWARN("Notes differ: %s vs %s", a->notes, b->notes);
        return FALSE;
    }

    if (safe_strcmp(a->billing_id, b->billing_id) != 0)
    {
        PWARN("Billing IDs differ: %s vs %s", a->billing_id, b->billing_id);
        return FALSE;
    }

    if (safe_strcmp(a->printname, b->printname) != 0)
    {
        PWARN("Printnames differ: %s vs %s", a->printname, b->printname);
        return FALSE;
    }

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

    if (!gncBillTermEqual(a->terms, b->terms))
    {
        PWARN("Billterms differ");
        return FALSE;
    }

    if (!gncJobEqual(a->job, b->job))
    {
        PWARN("Jobs differ");
        return FALSE;
    }

    if (!gnc_commodity_equal(a->currency, b->currency))
    {
        PWARN("Currencies differ");
        return FALSE;
    }

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

    if (!xaccTransEqual(a->posted_txn, b->posted_txn, TRUE, TRUE, TRUE, FALSE))
    {
        PWARN("Posted tx differ");
        return FALSE;
    }

#if 0
    if (!gncLotEqual(a->posted_lot, b->posted_lot))
    {
        PWARN("Posted lots differ");
        return FALSE;
    }
#endif

    /* FIXME: Need real checks */
#if 0
    GList       *entries;
    GList       *prices;
    GncOwner    owner;
    GncOwner    billto;
    Timespec    date_opened;
    Timespec    date_posted;

    gnc_numeric to_charge_amount;
#endif

    return TRUE;
}

/* ============================================================= */
/* Package-Private functions */

static const char * _gncInvoicePrintable (gpointer obj)
{
    GncInvoice *invoice = obj;

    g_return_val_if_fail (invoice, NULL);

    if (qof_instance_get_dirty_flag(invoice) || invoice->printname == NULL)
    {
        if (invoice->printname) g_free (invoice->printname);

        invoice->printname =
            g_strdup_printf ("%s%s", invoice->id,
                             gncInvoiceIsPosted (invoice) ? _(" (posted)") : "");
    }

    return invoice->printname;
}

static void
destroy_invoice_on_book_close(QofInstance *ent, gpointer data)
{
    GncInvoice* invoice = GNC_INVOICE(ent);

    gncInvoiceBeginEdit(invoice);
    gncInvoiceDestroy(invoice);
}

static void
gnc_invoice_book_end(QofBook* book)
{
    QofCollection *col;

    col = qof_book_get_collection(book, GNC_ID_INVOICE);
    qof_collection_foreach(col, destroy_invoice_on_book_close, NULL);
}

static QofObject gncInvoiceDesc =
{
    DI(.interface_version = ) QOF_OBJECT_VERSION,
    DI(.e_type            = ) _GNC_MOD_NAME,
    DI(.type_label        = ) "Invoice",
    DI(.create            = ) (gpointer)gncInvoiceCreate,
    DI(.book_begin        = ) NULL,
    DI(.book_end          = ) gnc_invoice_book_end,
    DI(.is_dirty          = ) qof_collection_is_dirty,
    DI(.mark_clean        = ) qof_collection_mark_clean,
    DI(.foreach           = ) qof_collection_foreach,
    DI(.printable         = ) _gncInvoicePrintable,
    DI(.version_cmp       = ) (int (*)(gpointer, gpointer)) qof_instance_version_cmp,
};

static void
reg_lot (void)
{
    static QofParam params[] =
    {
        {
            INVOICE_FROM_LOT, _GNC_MOD_NAME,
            (QofAccessFunc)gncInvoiceGetInvoiceFromLot, NULL
        },
        { NULL },
    };

    qof_class_register (GNC_ID_LOT, NULL, params);
}

static void
reg_txn (void)
{
    static QofParam params[] =
    {
        {
            INVOICE_FROM_TXN, _GNC_MOD_NAME,
            (QofAccessFunc)gncInvoiceGetInvoiceFromTxn, NULL
        },
        { NULL },
    };

    qof_class_register (GNC_ID_TRANS, NULL, params);
}

gboolean gncInvoiceRegister (void)
{
    static QofParam params[] =
    {
        { INVOICE_ID,        QOF_TYPE_STRING,  (QofAccessFunc)gncInvoiceGetID,     (QofSetterFunc)gncInvoiceSetID },
        { INVOICE_OWNER,     GNC_ID_OWNER,     (QofAccessFunc)gncInvoiceGetOwner, NULL },
        { INVOICE_OPENED,    QOF_TYPE_DATE,    (QofAccessFunc)gncInvoiceGetDateOpened, (QofSetterFunc)gncInvoiceSetDateOpened },
        { INVOICE_DUE,       QOF_TYPE_DATE,    (QofAccessFunc)gncInvoiceGetDateDue, NULL },
        { INVOICE_POSTED,    QOF_TYPE_DATE,    (QofAccessFunc)gncInvoiceGetDatePosted, (QofSetterFunc)gncInvoiceSetDatePosted },
        { INVOICE_IS_POSTED, QOF_TYPE_BOOLEAN, (QofAccessFunc)gncInvoiceIsPosted, NULL },
        { INVOICE_IS_PAID,   QOF_TYPE_BOOLEAN, (QofAccessFunc)gncInvoiceIsPaid,    NULL },
        { INVOICE_BILLINGID, QOF_TYPE_STRING,  (QofAccessFunc)gncInvoiceGetBillingID, (QofSetterFunc)gncInvoiceSetBillingID },
        { INVOICE_NOTES,     QOF_TYPE_STRING,  (QofAccessFunc)gncInvoiceGetNotes,   (QofSetterFunc)gncInvoiceSetNotes },
        { INVOICE_ACC,       GNC_ID_ACCOUNT,   (QofAccessFunc)gncInvoiceGetPostedAcc, (QofSetterFunc)gncInvoiceSetPostedAcc },
        { INVOICE_POST_TXN,  GNC_ID_TRANS,     (QofAccessFunc)gncInvoiceGetPostedTxn, (QofSetterFunc)gncInvoiceSetPostedTxn },
        { INVOICE_POST_LOT,  GNC_ID_LOT,       (QofAccessFunc)gncInvoiceGetPostedLot, NULL/*(QofSetterFunc)gncInvoiceSetPostedLot*/ },
        { INVOICE_TYPE,      QOF_TYPE_INT32,   (QofAccessFunc)gncInvoiceGetType,    NULL },
        { INVOICE_TYPE_STRING, QOF_TYPE_STRING, (QofAccessFunc)gncInvoiceGetTypeString,    NULL },
        { INVOICE_TERMS,     GNC_ID_BILLTERM,  (QofAccessFunc)gncInvoiceGetTerms,   (QofSetterFunc)gncInvoiceSetTerms },
        { INVOICE_BILLTO,    GNC_ID_OWNER,     (QofAccessFunc)gncInvoiceGetBillTo, NULL  },
        { INVOICE_ENTRIES,   QOF_TYPE_COLLECT, (QofAccessFunc)qofInvoiceGetEntries, (QofSetterFunc)qofInvoiceSetEntries },
        { INVOICE_JOB,       GNC_ID_JOB,       (QofAccessFunc)qofInvoiceGetJob,     (QofSetterFunc)qofInvoiceSetJob },
        { QOF_PARAM_ACTIVE,  QOF_TYPE_BOOLEAN, (QofAccessFunc)gncInvoiceGetActive, (QofSetterFunc)gncInvoiceSetActive },
        { INVOICE_IS_CN,     QOF_TYPE_BOOLEAN, (QofAccessFunc)gncInvoiceGetIsCreditNote, (QofSetterFunc)gncInvoiceSetIsCreditNote },
        { 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)gncInvoiceCompare, params);
    reg_lot ();
    reg_txn ();

    /* Make the compiler happy... */
    if (0)
    {
        qofInvoiceSetEntries(NULL, NULL);
        qofInvoiceGetEntries(NULL);
        qofInvoiceSetOwner(NULL, NULL);
        qofInvoiceGetOwner(NULL);
        qofInvoiceSetBillTo(NULL, NULL);
        qofInvoiceGetBillTo(NULL);
    }
    if (!qof_choice_create(GNC_ID_INVOICE))
    {
        return FALSE;
    }
    return qof_object_register (&gncInvoiceDesc);
}

gchar *gncInvoiceNextID (QofBook *book, const GncOwner *owner)
{
    gchar *nextID;
    switch (gncOwnerGetType(gncOwnerGetEndOwner(owner)))
    {
    case GNC_OWNER_CUSTOMER:
        nextID = qof_book_increment_and_format_counter (book, "gncInvoice");
        break;
    case GNC_OWNER_VENDOR:
        nextID = qof_book_increment_and_format_counter (book, "gncBill");
        break;
    case GNC_OWNER_EMPLOYEE:
        nextID = qof_book_increment_and_format_counter (book, "gncExpVoucher");
        break;
    default:
        nextID = qof_book_increment_and_format_counter (book, _GNC_MOD_NAME);
        break;
    }
    return nextID;
}