322 lines
12 KiB
Python
322 lines
12 KiB
Python
# The Mia! Accounting Project.
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# Author: imacat@mail.imacat.idv.tw (imacat), 2023/1/25
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# Copyright (c) 2023 imacat.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""The pagination utilities.
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This module should not import any other module from the application.
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"""
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from typing import TypeVar, Generic
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from urllib.parse import urlparse, parse_qsl, urlencode, urlunparse, \
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ParseResult
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from flask import request
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from werkzeug.routing import RequestRedirect
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from accounting.locale import pgettext
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class Link:
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"""A link."""
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def __init__(self, text: str, uri: str | None = None,
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is_current: bool = False, is_for_mobile: bool = False):
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"""Constructs the link.
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:param text: The link text.
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:param uri: The link URI, or None if there is no link.
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:param is_current: True if the page is the current page, or False
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otherwise.
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:param is_for_mobile: True if the page should be shown on small
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screens, or False otherwise.
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"""
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self.text: str = text
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"""The link text"""
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self.uri: str | None = uri
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"""The link URI, or None if there is no link."""
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self.is_current: bool = is_current
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"""Whether the link is the current page."""
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self.is_for_mobile: bool = is_for_mobile
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"""Whether the link should be shown on mobile screens."""
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class Redirection(RequestRedirect):
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"""The redirection."""
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code = 302
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"""The HTTP code."""
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DEFAULT_PAGE_SIZE: int = 10
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"""The default page size."""
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T = TypeVar("T")
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class Pagination(Generic[T]):
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"""The pagination utility."""
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def __init__(self, items: list[T], is_reversed: bool = False):
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"""Constructs the pagination.
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:param items: The items.
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:param is_reversed: True if the default page is the last page, or False
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otherwise.
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:raise Redirection: When the pagination parameters are malformed.
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"""
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pagination: AbstractPagination[T] = EmptyPagination[T]() \
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if len(items) == 0 \
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else NonEmptyPagination[T](items, is_reversed)
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self.is_paged: bool = pagination.is_paged
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"""Whether there should be pagination."""
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self.list: list[T] = pagination.list
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"""The items shown in the list"""
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self.pages: list[Link] = pagination.pages
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"""The pages."""
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self.page_size: int = pagination.page_size
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"""The number of items in a page."""
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self.page_size_options: list[Link] = pagination.page_size_options
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"""The options to the number of items in a page."""
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class AbstractPagination(Generic[T]):
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"""An abstract pagination."""
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def __init__(self):
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"""Constructs an empty pagination."""
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self.page_size: int = DEFAULT_PAGE_SIZE
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"""The number of items in a page."""
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self.is_paged: bool = False
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"""Whether there should be pagination."""
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self.list: list[T] = []
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"""The items shown in the list"""
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self.pages: list[Link] = []
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"""The pages."""
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self.page_size_options: list[Link] = []
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"""The options to the number of items in a page."""
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class EmptyPagination(AbstractPagination[T]):
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"""The pagination from empty data."""
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pass
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class NonEmptyPagination(AbstractPagination[T]):
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"""The pagination with real data."""
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PAGE_SIZE_OPTION_VALUES: list[int] = [10, 100, 200]
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"""The page size options."""
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def __init__(self, items: list[T], is_reversed: bool = False):
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"""Constructs the pagination.
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:param items: The items.
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:param is_reversed: True if the default page is the last page, or False
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otherwise.
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:raise Redirection: When the pagination parameters are malformed.
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"""
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super().__init__()
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self.__current_uri: str = request.full_path if request.query_string \
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else request.path
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"""The current URI."""
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self.__is_reversed: bool = is_reversed
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"""Whether the default page is the last page."""
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self.page_size = self.__get_page_size()
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self.__total_pages: int = int((len(items) - 1) / self.page_size) + 1
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"""The total number of pages."""
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self.is_paged = self.__total_pages > 1
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self.__default_page_no: int = self.__total_pages \
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if self.__is_reversed else 1
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"""The default page number."""
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self.__page_no: int = self.__get_page_no()
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"""The current page number."""
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lower_bound: int = (self.__page_no - 1) * self.page_size
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upper_bound: int = lower_bound + self.page_size
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if upper_bound > len(items):
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upper_bound = len(items)
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self.list = items[lower_bound:upper_bound]
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self.pages = self.__get_pages()
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self.page_size_options = self.__get_page_size_options()
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def __get_page_size(self) -> int:
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"""Returns the page size.
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:return: The page size.
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:raise Redirection: When the page size is malformed.
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"""
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if "page-size" not in request.args:
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return DEFAULT_PAGE_SIZE
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try:
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page_size: int = int(request.args["page-size"])
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except ValueError:
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raise Redirection(self.__uri_set("page-size", None))
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if page_size == DEFAULT_PAGE_SIZE or page_size < 1:
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raise Redirection(self.__uri_set("page-size", None))
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return page_size
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def __get_page_no(self) -> int:
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"""Returns the page number.
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:return: The page number.
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:raise Redirection: When the page number is malformed.
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"""
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if "page-no" not in request.args:
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return self.__default_page_no
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try:
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page_no: int = int(request.args["page-no"])
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except ValueError:
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raise Redirection(self.__uri_set("page-no", None))
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if page_no == self.__default_page_no:
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raise Redirection(self.__uri_set("page-no", None))
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if page_no < 1:
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if not self.__is_reversed:
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raise Redirection(self.__uri_set("page-no", None))
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raise Redirection(self.__uri_set("page-no", "1"))
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if page_no > self.__total_pages:
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if self.__is_reversed:
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raise Redirection(self.__uri_set("page-no", None))
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raise Redirection(self.__uri_set("page-no",
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str(self.__total_pages)))
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return page_no
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def __get_pages(self) -> list[Link]:
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"""Returns the page links in the pagination navigation.
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:return: The page links in the pagination navigation.
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"""
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if not self.is_paged:
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return []
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uri: str | None
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links: list[Link] = []
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# The previous page.
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uri = None if self.__page_no == 1 \
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else self.__uri_page(self.__page_no - 1)
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links.append(Link(pgettext("Pagination|", "Previous"), uri,
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is_for_mobile=True))
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# The first page.
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if self.__page_no > 1:
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links.append(Link("1", self.__uri_page(1)))
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# The eclipse of the previous pages.
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if self.__page_no - 3 == 2:
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links.append(Link(str(self.__page_no - 3),
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self.__uri_page(self.__page_no - 3)))
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elif self.__page_no - 3 > 2:
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links.append(Link("…"))
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# The previous two pages.
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if self.__page_no - 2 > 1:
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links.append(Link(str(self.__page_no - 2),
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self.__uri_page(self.__page_no - 2)))
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if self.__page_no - 1 > 1:
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links.append(Link(str(self.__page_no - 1),
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self.__uri_page(self.__page_no - 1)))
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# The current page.
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links.append(Link(str(self.__page_no), self.__uri_page(self.__page_no),
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is_current=True))
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# The next two pages.
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if self.__page_no + 1 < self.__total_pages:
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links.append(Link(str(self.__page_no + 1),
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self.__uri_page(self.__page_no + 1)))
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if self.__page_no + 2 < self.__total_pages:
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links.append(Link(str(self.__page_no + 2),
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self.__uri_page(self.__page_no + 2)))
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# The eclipse of the next pages.
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if self.__page_no + 3 == self.__total_pages - 1:
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links.append(Link(str(self.__page_no + 3),
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self.__uri_page(self.__page_no + 3)))
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elif self.__page_no + 3 < self.__total_pages - 1:
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links.append(Link("…"))
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# The last page.
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if self.__page_no < self.__total_pages:
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links.append(Link(str(self.__total_pages),
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self.__uri_page(self.__total_pages)))
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# The next page.
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uri = None if self.__page_no == self.__total_pages \
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else self.__uri_page(self.__page_no + 1)
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links.append(Link(pgettext("Pagination|", "Next"), uri,
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is_for_mobile=True))
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return links
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def __uri_page(self, page_no: int) -> str:
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"""Returns the URI of a page.
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:param page_no: The page number.
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:return: The URI of the page.
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"""
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if page_no == self.__page_no:
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return self.__current_uri
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if page_no == self.__default_page_no:
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return self.__uri_set("page-no", None)
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return self.__uri_set("page-no", str(page_no))
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def __get_page_size_options(self) -> list[Link]:
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"""Returns the page size options.
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:return: The page size options.
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"""
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if not self.is_paged:
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return []
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return [Link(str(x), self.__uri_size(x),
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is_current=x == self.page_size)
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for x in self.PAGE_SIZE_OPTION_VALUES]
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def __uri_size(self, page_size: int) -> str:
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"""Returns the URI of a page size.
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:param page_size: The page size.
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:return: The URI of the page size.
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"""
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if page_size == self.page_size:
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return self.__current_uri
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if page_size == DEFAULT_PAGE_SIZE:
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return self.__uri_set("page-size", None)
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return self.__uri_set("page-size", str(page_size))
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def __uri_set(self, name: str, value: str | None) -> str:
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"""Raises current URI with a parameter set.
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:param name: The name of the parameter.
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:param value: The value, or None to remove the parameter.
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:return: The URI with the parameter set.
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"""
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uri_p: ParseResult = urlparse(self.__current_uri)
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params: list[tuple[str, str]] = parse_qsl(uri_p.query)
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# Try to keep the position of the parameter.
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i: int = 0
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is_found: bool = False
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while i < len(params):
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if params[i][0] == name:
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if is_found or value is None:
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params = params[:i] + params[i + 1:]
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continue
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params[i] = (name, value)
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is_found = True
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i = i + 1
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if not is_found and value is not None:
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params.append((name, value))
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parts: list[str] = list(uri_p)
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parts[4] = urlencode(params)
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return urlunparse(parts)
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