Add get method to have an account at a specific date or for a range.

accountant/api/models/accounts.py

@@ -14,11 +14,15 @@
     You should have received a copy of the GNU Affero General Public License
     along with Accountant.  If not, see <http://www.gnu.org/licenses/>.
 """
+from datetime import date
+
 from sqlalchemy import func, case, cast
+from sqlalchemy.orm import validates
 
 from accountant import db
 
 from .entries import Entry
+from .operations import Operation
 
 
 class Account(db.Model):
@@ -46,5 +50,57 @@ class Account(db.Model):
         return query
 
     @classmethod
-    def get(cls, session, id):
-        return session.query(cls).filter(cls.id == id).one()
+    def get(cls, session, account, begin=date.today(), end=None):
+        if isinstance(account, int) or isinstance(account, str):
+            account_id = account
+        else:
+            account_id = account.id
+
+        current = begin if end is None else end
+
+        query = session.query(
+            cls,
+            func.sum(Operation.value).label("future"),
+            func.sum(case([(Operation.pointed,
+                            Operation.value,)],
+                          else_=0)).label("pointed"),
+            func.sum(case([(Operation.operation_date <= str(current),
+                            Operation.value,)],
+                          else_=0)).label("current")
+        ).group_by(cls.id)
+
+        if end:
+            subquery = session.query(
+                Operation.account_id,
+                func.sum(case([(func.sign(Operation.value) == -1,
+                                Operation.value)],
+                              else_=0)).label("expenses"),
+                func.sum(case([(func.sign(Operation.value) == 1,
+                                Operation.value)],
+                              else_=0)).label("revenues"),
+                func.sum(Operation.value).label("balance")
+            ).filter(
+                Operation.operation_date >= begin,
+                Operation.operation_date <= end
+            ).group_by(
+                Operation.account_id
+            ).subquery()
+
+            base_subquery = query.subquery()
+
+            query = session.query(
+                base_subquery, subquery
+            ).select_from(base_subquery, subquery).filter(
+                base_subquery.c.id == subquery.c.account_id,
+                base_subquery.c.id == account_id,
+            )
+        else:
+            query = query.filter(cls.id == account_id)
+
+        return query.one()
+
+    @validates('authorized_overdraft')
+    def validate_authorized_overdraft(self, key, authorized_overdraft):
+        assert authorized_overdraft > 0
+
+        return authorized_overdraft