Factor out some code from gnc-budget into Recurrence so that the budget

estimation code can use stand-alone recurrences to estimate budget values.
  Also, tweak the initial budget so that it begins at the beginning of the 
  current month.


git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@13092 57a11ea4-9604-0410-9ed3-97b8803252fd

src/engine/Recurrence.c

@@ -27,6 +27,8 @@
 #include "gnc-date.h"
 #include "qof.h"
 #include "gnc-engine.h"
+#include "gnc-gdate-utils.h"
+#include "Account.h"
 
 static QofLogModule log_module = GNC_MOD_ENGINE;
 
@@ -228,6 +230,36 @@ recurrenceNthInstance(const Recurrence *r, guint n, GDate *date)
     }
 }
 
+time_t
+recurrenceGetPeriodTime(const Recurrence *r, guint period_num, gboolean end)
+{
+    GDate date;
+    recurrenceNthInstance(r, period_num + (end ? 1 : 0), &date);
+    if (end) {
+        g_date_subtract_days(&date, 1);
+        return gnc_timet_get_day_end_gdate(&date);
+    } else {
+        return gnc_timet_get_day_start_gdate(&date);
+    }
+}
+
+gnc_numeric
+recurrenceGetAccountPeriodValue(const Recurrence *r, Account *acc, guint n)
+{
+    gnc_numeric num1, num2;
+    time_t t1, t2;
+
+    // FIXME: maybe zero is not best error return val.
+    g_return_val_if_fail(r && acc, gnc_numeric_zero());
+    t1 = recurrenceGetPeriodTime(r, n, FALSE);
+    t2 = recurrenceGetPeriodTime(r, n, TRUE);
+
+    num1 = xaccAccountGetBalanceAsOfDateInCurrency(acc, t1, NULL, TRUE);
+    num2 = xaccAccountGetBalanceAsOfDateInCurrency(acc, t2, NULL, TRUE);
+
+    return gnc_numeric_sub(num2, num1, GNC_DENOM_AUTO, GNC_HOW_DENOM_FIXED);
+}
+
 void
 recurrenceListNextInstance(const GList *rlist, const GDate *ref, GDate *next)
 {

src/engine/Recurrence.h

@@ -45,6 +45,8 @@
 #define RECURRENCE_H
 
 #include <glib.h>
+#include "Account.h"
+#include "gnc-numeric.h"
 
 typedef enum {
     PERIOD_ONCE,         /* Not a true period at all, but convenient here. */
@@ -69,7 +71,7 @@ typedef struct {
 
 
 /* recurrenceSet() will enforce internal consistency by overriding
-   inconsistent inputs so that 'r' will _always_ end up being valid
+   inconsistent inputs so that 'r' will _always_ end up being a valid 
    recurrence.
 
      - if the period type is invalid, PERIOD_MONTH is used.
@@ -122,6 +124,15 @@ void recurrenceNextInstance(const Recurrence *r, const GDate *refDate,
 /* Zero-based.  n == 1 gets the instance after the start date. */
 void recurrenceNthInstance(const Recurrence *r, guint n, GDate *date);
 
+/* Get a time coresponding to the beginning (or end if 'end' is true)
+   of the nth instance of the recurrence. Also zero-based. */
+time_t recurrenceGetPeriodTime(const Recurrence *r, guint n, gboolean end);
+
+/* Get the amount that an Account's value changed between the
+   beginning and end of the nth instance of the recurrence. */
+gnc_numeric recurrenceGetAccountPeriodValue(const Recurrence *r, 
+                                            Account *acct, guint n);
+
 /* Get the earliest of the next occurances -- a "composite" recurrence */
 void recurrenceListNextInstance(const GList *r, const GDate *refDate,
                                 GDate *nextDate);

src/engine/gnc-budget.c

@@ -25,7 +25,7 @@
 #include <glib.h>
 #include <glib/gprintf.h>
 #include <glib/gi18n.h>
-
+#include <time.h>
 #include "qof.h"
 
 #include "Account.h"
@@ -50,14 +50,16 @@ GncBudget*
 gnc_budget_new(QofBook *book)
 {
     GncBudget* budget;
-
+    GDate date;
     g_return_val_if_fail(book, NULL);
 
     ENTER(" ");
     budget = g_new0(GncBudget, 1);
     qof_instance_init (&budget->inst, GNC_ID_BUDGET, book);
 
-    recurrenceSet(&budget->recurrence, 1, PERIOD_MONTH, NULL);
+    g_date_set_time(&date, time(NULL));
+    g_date_subtract_days(&date, g_date_get_day(&date)-1);
+    recurrenceSet(&budget->recurrence, 1, PERIOD_MONTH, &date);
 
     gnc_budget_set_name(budget, _("Unnamed Budget"));
     gnc_budget_set_description(budget, "");
@@ -249,52 +251,24 @@ gnc_budget_get_account_period_value(GncBudget *budget, Account *account,
     return numeric;
 }
 
-/* If 'end' is true, then get a time just before the beginning of the
-   next period */
-static time_t
-gnc_budget_get_period_time(GncBudget *budget, guint period_num, gboolean end)
-{
-    GDate date;
-    recurrenceNthInstance(&(budget->recurrence),
-                          period_num + (end ? 1 : 0), &date);
-    if (end) {
-        g_date_subtract_days(&date, 1);
-        return gnc_timet_get_day_end_gdate(&date);
-    } else {
-        return gnc_timet_get_day_start_gdate(&date);
-    }
-
-}
 
 Timespec
 gnc_budget_get_period_start_date(GncBudget *budget, guint period_num)
 {
     Timespec ts;
     timespecFromTime_t(
-        &ts,  gnc_budget_get_period_time(budget, period_num, FALSE));
+        &ts,  recurrenceGetPeriodTime(&budget->recurrence, period_num, FALSE));
     return ts;
 }
 
 gnc_numeric
 gnc_budget_get_account_period_actual_value(
-    GncBudget *budget, Account *account, guint period_num)
+    GncBudget *budget, Account *acc, guint period_num)
 {
-    gnc_numeric numeric, num1, num2;
-    time_t t1, t2;
-
     // FIXME: maybe zero is not best error return val.
-    g_return_val_if_fail(GNC_IS_BUDGET(budget) && account, gnc_numeric_zero());
-    t1 = gnc_budget_get_period_time(budget, period_num, FALSE);
-    t2 = gnc_budget_get_period_time(budget, period_num, TRUE);
-
-    num1 = xaccAccountGetBalanceAsOfDateInCurrency(
-        account, t1, NULL, TRUE);
-    num2 = xaccAccountGetBalanceAsOfDateInCurrency(
-        account, t2, NULL, TRUE);
-
-    numeric = gnc_numeric_sub(num2, num1, GNC_DENOM_AUTO,
-                              GNC_HOW_DENOM_FIXED);
-    return numeric;
+    g_return_val_if_fail(GNC_IS_BUDGET(budget) && acc, gnc_numeric_zero());
+    return recurrenceGetAccountPeriodValue(&budget->recurrence, 
+                                           acc, period_num);
 }
 
 QofBook*