Show 10 pages at most in pagination

sapl/crud.py

@@ -10,28 +10,26 @@ from django.views.generic import (
 from sapl.layout import SaplFormLayout
 
 
-def makePagination(current_page, total_pages):
-    current = current_page
-    total = total_pages
+def from_to(start, end):
+    return list(range(start, end + 1))
 
-    if total_pages > 10:
-
-        if current <= 3:
-            return [1, 2, 3, 4, 5, None, total - 1, total]
-        elif current >= total - 3:
-            return [1, 2, None, total - 4, total - 3,
-                    total - 2, total - 1, total]
-        else:
-            return [1, 2, None, current - 1, current, current + 1,
-                    None, total - 1, total]
 
+def make_pagination(index, num_pages):
+    PAGINATION_LENGTH = 10
+    if num_pages <= PAGINATION_LENGTH:
+        return from_to(1, num_pages)
     else:
-        pages = []
-        i = 1
-        while i <= total:
-            pages.append(i)
-            i = i + 1
-        return pages
+        if index - 1 <= 5:
+            tail = [num_pages - 1, num_pages]
+            head = from_to(1, PAGINATION_LENGTH - 3)
+        else:
+            if index + 1 >= num_pages - 3:
+                tail = from_to(index - 1, num_pages)
+            else:
+                tail = [index - 1, index, index + 1,
+                        None, num_pages - 1, num_pages]
+            head = from_to(1, PAGINATION_LENGTH - len(tail) - 1)
+        return head + [None] + tail
 
 
 def get_field_display(obj, fieldname):
@@ -108,7 +106,7 @@ def build_crud(model, *layout):
             current_page = context_data['page_obj']
             # TODO set custom_page_range to something like
             #   [1, 2, None, 10, 11, 12, None, 29, 30]
-            context_data['custom_page_range'] = makePagination(
+            context_data['custom_page_range'] = make_pagination(
                 current_page.number, paginator.num_pages)
             return context_data
 

sapl/test_crud.py

@@ -3,23 +3,55 @@ from django.core.urlresolvers import reverse
 from model_mommy import mommy
 
 from comissoes.models import Comissao, TipoComissao
-from .crud import get_field_display, build_crud, makePagination
+from .crud import get_field_display, build_crud, make_pagination, from_to
 
 pytestmark = pytest.mark.django_db
 
 # XXX These tests are based on comissoes app
 #     but could be done with a stub one
 
-
-def test_pagination():
-    assert makePagination(1, 1) == [1]
-    assert makePagination(1, 10) == [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
-    assert makePagination(3, 5) == [1, 2, 3, 4, 5]
-    assert makePagination(9, 11) == [1, 2, None, 7, 8, 9, 10, 11]
-    assert makePagination(8, 22) == [1, 2, None, 7, 8, 9, None, 21, 22]
-    assert makePagination(2, 5) == [1, 2, 3, 4, 5]
-    assert makePagination(1, 17) == [1, 2, 3, 4, 5, None, 16, 17]
-    assert makePagination(22, 25) == [1, 2, None, 21, 22, 23, 24, 25]
+__ = None  # for test readability
+
+
+@pytest.mark.parametrize(
+    "index, num_pages, result",
+    [(i, k, from_to(1, k))
+     for i in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+     for k in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+     ] + [
+        (11, 11, [1, 2, 3, 4, 5, 6, 7, __, 10, (11)]),
+        (10, 11, [1, 2, 3, 4, 5, 6, __, 9, (10), 11]),
+        (9, 11, [1, 2, 3, 4, 5, __, 8, (9), 10, 11]),
+        (8, 11, [1, 2, 3, 4, __, 7, (8), 9, 10, 11]),
+        (7, 11, [1, 2, 3, __, 6, (7), 8, 9, 10, 11]),
+        (6, 11, [1, 2, 3, 4, 5, (6), 7, __, 10, 11]),
+        (5, 11, [1, 2, 3, 4, (5), 6, 7, __, 10, 11]),
+        (4, 11, [1, 2, 3, (4), 5, 6, 7, __, 10, 11]),
+        (3, 11, [1, 2, (3), 4, 5, 6, 7, __, 10, 11]),
+        (2, 11, [1, (2), 3, 4, 5, 6, 7, __, 10, 11]),
+        (1, 11, [(1), 2, 3, 4, 5, 6, 7, __, 10, 11]),
+
+        (12, 12, [1, 2, 3, 4, 5, 6, 7, __, 11, (12)]),
+        (11, 12, [1, 2, 3, 4, 5, 6, __, 10, (11), 12]),
+        (10, 12, [1, 2, 3, 4, 5, __, 9, (10), 11, 12]),
+        (9, 12, [1, 2, 3, 4, __, 8, (9), 10, 11, 12]),
+        (8, 12, [1, 2, 3, __, 7, (8), 9, 10, 11, 12]),
+        (7, 12, [1, 2, 3, __, 6, (7), 8, __, 11, 12]),
+        (6, 12, [1, 2, 3, 4, 5, (6), 7, __, 11, 12]),
+        (5, 12, [1, 2, 3, 4, (5), 6, 7, __, 11, 12]),
+        (4, 12, [1, 2, 3, (4), 5, 6, 7, __, 11, 12]),
+        (3, 12, [1, 2, (3), 4, 5, 6, 7, __, 11, 12]),
+        (2, 12, [1, (2), 3, 4, 5, 6, 7, __, 11, 12]),
+        (1, 12, [(1), 2, 3, 4, 5, 6, 7, __, 11, 12]),
+
+        # some random entries
+        (8, 22, [1, 2, 3, __, 7, (8), 9, __, 21, 22]),
+        (1, 17, [(1), 2, 3, 4, 5, 6, 7, __, 16, 17]),
+        (22, 25, [1, 2, 3, 4, __, 21, (22), 23, 24, 25]),
+    ])
+def test_pagination(index, num_pages, result):
+    assert num_pages < 10 or len(result) == 10
+    assert make_pagination(index, num_pages) == result
 
 
 def test_get_field_display():