Added the navigation links for pagination.

accounting/templates/accounting/cash.html

@@ -34,6 +34,8 @@ First written: 2020/7/1
   <p>{{ request.resolver_match.app_name }}</p>
 
 {% if records %}
+  {% include "mia_core/pagination.html" %}
+
   {# The table for large screens #}
   <table class="table table-striped table-hover d-none d-md-table general-journal-table">
     <thead>

accounting/views.py

@@ -201,5 +201,5 @@ ORDER BY
                  self.kwargs["subject_code"] + "%",
                  self.kwargs["subject_code"] + "%"])
         self.pagination = Pagination(
-            records, self.page_no, self.page_size, True)
+            self.request, records, self.page_no, self.page_size, True)
         return self.pagination.records

mia_core/templates/mia_core/pagination.html

@@ -0,0 +1,38 @@
+{% comment %}
+The Mia Website
+base.html: The side-wide layout template
+
+ Copyright (c) 2020 imacat.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+Author: imacat@mail.imacat.idv.tw (imacat)
+First written: 2020/7/1
+{% endcomment %}
+
+{# The pagination, if any #}
+{% if pagination.is_paged %}
+  <ul class="pagination">
+    {% for link in pagination.links %}
+      {% if link.url is not None %}
+        <li class="page-item {% if link.is_active %} active {% endif %}{% if not link.is_small_screen %} d-none d-md-inline {% endif %}">
+          <a class="page-link" href="{{ link.url }}">{{ link.title }}</a>
+        </li>
+      {% else %}
+        <li class="page-item disabled {% if link.is_active %} active {% endif %}{% if not link.is_small_screen %} d-none d-md-inline {% endif %}">
+          <span class="page-link">{{ link.title }}</span>
+        </li>
+      {% endif %}
+    {% endfor %}
+  </ul>
+{% endif %}

mia_core/utils.py

@@ -21,6 +21,8 @@
 
 import urllib.parse
 
+from django.utils.translation import pgettext
+
 
 class UrlBuilder:
     """The URL builder.
@@ -91,6 +93,17 @@ class UrlBuilder:
         """
         return self.del_param(name).add_param(name, value)
 
+    def clone(self):
+        """Returns a copy of this URL builder.
+
+        Returns:
+            UrlBuilder: A copy of this URL builder.
+        """
+        another = UrlBuilder(self.base_path)
+        another.params = [
+            self.Param(x.name, x.value) for x in self.params]
+        return another
+
     def __str__(self):
         if len(self.params) == 0:
             return self.base_path
@@ -134,42 +147,170 @@ class Pagination:
     """The pagination.
 
     Args:
+        request (HttpRequest): The request
         records (list[Model]): All the 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
+        is_reversed (bool): Whether we should display the last
-                           page first
+                            page first
 
     Raises:
         PageNoOutOfRangeError: if the specified page number is out
             of range or is redundant.
 
     Attributes:
-        page_no (int): The current page number
+        is_reversed (bool): Whether we should display the last
-        page_size (int): The page size
+                            page first
-        records (list[Model]): The records in the current page
+        page_size (int): The page size.
+        total_pages (int): The total number of pages available.
+        is_paged (bool): Whether there are more than one page.
+        page_no (int): The current page number.
+        records (list[Model]): The records in the current page.
+        links (list[Link]): The navigation links in the pagination
+                            bar.
     """
-    page_no = None
+    is_reversed = False
     page_size = None
+    total_pages = None
+    is_paged = None
+    page_no = None
     records = None
+    links = None
 
     DEFAULT_PAGE_SIZE = 10
 
-    def __init__(self, records, page_no, page_size, is_reverse=False):
+    def __init__(self, request, records, page_no,
+                 page_size, is_reversed=False):
+        self.is_reversed = is_reversed
         self.page_size = page_size \
             if page_size is not None \
             else self.DEFAULT_PAGE_SIZE
-        total_pages = int((len(records) - 1) / self.page_size) + 1
+        self.total_pages = int(
-        default_page = 1 if not is_reverse else total_pages
+            (len(records) - 1) / self.page_size) + 1
+        self.is_paged = self.total_pages > 1
+        if not self.is_paged:
+            self.page_no = 1
+            self.records = records
+            self.links = []
+            return
+        default_page = 1 if not is_reversed else self.total_pages
         if page_no == default_page:
             raise PageNoOutOfRangeException()
         self.page_no = page_no \
             if page_no is not None \
             else default_page
-        if self.page_no > total_pages:
+        if self.page_no > self.total_pages:
             raise PageNoOutOfRangeException()
         start_no = self.page_size * (self.page_no - 1)
         self.records = records[start_no:start_no + self.page_size]
+        self.create_pagination_bar(request)
+
+    def create_pagination_bar(self, request):
+        """Creates the pagination bar.
+
+        Args:
+            request (HttpRequest): The request
+        """
+        base_url = UrlBuilder(
+            request.get_full_path()).del_param("page")
+        self.links = []
+        # The previous page
+        link = self.Link()
+        link.title = pgettext("Pagination|", "Previous")
+        if self.page_no > 1:
+            if self.page_no - 1 == 1:
+                if not self.is_reversed:
+                    link.url = str(base_url)
+                else:
+                    link.url = str(base_url.clone().add_param(
+                        "page", "1"))
+            else:
+                link.url = str(base_url.clone().add_param(
+                    "page", str(self.page_no - 1)))
+        link.is_small_screen = True
+        self.links.append(link)
+        # The first page
+        link = self.Link()
+        link.title = "1"
+        if not self.is_reversed:
+            link.url = str(base_url)
+        else:
+            link.url = str(base_url.clone().add_param("page", "1"))
+        if self.page_no == 1:
+            link.is_active = True
+        self.links.append(link)
+        # The previous ellipsis
+        if self.page_no > 4:
+            link = self.Link()
+            if self.page_no > 5:
+                link.title = pgettext("Pagination|", "...")
+            else:
+                link.title = "2"
+                link.url = str(base_url.clone().add_param(
+                    "page", "2"))
+            self.links.append(link)
+        # The nearby pages
+        for no in range(self.page_no - 2, self.page_no + 3):
+            if no <= 1 or no >= self.total_pages:
+                continue
+            link = self.Link()
+            link.title = str(no)
+            link.url = str(base_url.clone().add_param(
+                "page", str(no)))
+            if no == self.page_no:
+                link.is_active = True
+            self.links.append(link)
+        # The next ellipsis
+        if self.page_no + 3 < self.total_pages:
+            link = self.Link()
+            if self.page_no + 4 < self.total_pages:
+                link.title = pgettext("Pagination|", "...")
+            else:
+                link.title = str(self.total_pages - 1)
+                link.url = str(base_url.clone().add_param(
+                    "page", str(self.total_pages - 1)))
+            self.links.append(link)
+        # The last page
+        link = self.Link()
+        link.title = str(self.total_pages)
+        if self.is_reversed:
+            link.url = str(base_url)
+        else:
+            link.url = str(base_url.clone().add_param(
+                "page", str(self.total_pages)))
+        if self.page_no == self.total_pages:
+            link.is_active = True
+        self.links.append(link)
+        # The next page
+        link = self.Link()
+        link.title = pgettext("Pagination|", "Next")
+        if self.page_no < self.total_pages:
+            if self.page_no + 1 == self.total_pages:
+                if self.is_reversed:
+                    link.url = str(base_url)
+                else:
+                    link.url = str(base_url.clone().add_param(
+                        "page", str(self.total_pages)))
+            else:
+                link.url = str(base_url.clone().add_param(
+                    "page", str(self.page_no + 1)))
+        link.is_small_screen = True
+        self.links.append(link)
+
+    class Link:
+        """A navigation link in the pagination bar.
+
+        Attributes:
+            url (str): The link URL, or for a non-link slot.
+            title (str): The title of the link.
+            is_active (bool): Whether this link is currently active.
+            is_small_screen (bool): Whether this link is for small
+                                    screens
+        """
+        url = None
+        title = None
+        is_active = False
+        is_small_screen = False
 
 
 class PageNoOutOfRangeException(Exception):