Moved the pagination and the page number out of range error from the accounting application to the Mia core application.

mia_core/utils.py

@@ -125,3 +125,45 @@ class UrlBuilder:
             return "%s=%s" % (
                 urllib.parse.quote(self.name),
                 urllib.parse.quote(self.value))
+
+
+class Pagination:
+    """The pagination.
+
+    Args:
+        count (int): The total number of records
+        page_no (int): The specified page number
+        page_size (int): The specified number of records per page
+        is_reverse (bool): Whether we should display the last
+                           page first
+
+    Raises:
+        PageNoOutOfRangeError: if the specified page number is out
+            of range or is redundant.
+
+    Attributes:
+        page_no (int): The current page number
+        page_size (int): The page size
+    """
+    page_no = None
+    page_size = None
+
+    DEFAULT_PAGE_SIZE = 10
+
+    def __init__(self, count, page_no, page_size, is_reverse=False):
+        self.page_size = page_size \
+            if page_size is not None \
+            else self.DEFAULT_PAGE_SIZE
+        total_pages = int((count - 1) / self.page_size) + 1
+        default_page = 1 if not is_reverse else total_pages
+        if page_no == default_page:
+            raise PageNoOutOfRangeError()
+        self.page_no = page_no \
+            if page_no is not None \
+            else default_page
+        if self.page_no > total_pages:
+            raise PageNoOutOfRangeError()
+
+
+class PageNoOutOfRangeError(Exception):
+    pass