from django.utils.safestring import mark_safe

from django.http.request import QueryDict

class Pagination:

    """

    page: 当前的页码数

    all_count： 总的数据量

    per_num ：  每页显示的数据量

    max_show：  最多显示的页码数

    """

    def __init__(self, page, all_count, params=None, per_num=, max_show=):

        try:

            self.page = int(page)

            if self.page <= :

                self.page =

        except Exception:

            self.page =

        # 查询条件

        self.params = params

        if not self.params:

            self.params = QueryDict(mutable=True)

        # 总的数据量

        all_count = all_count

        # 每页显示的数据量  

        # 总的页码数

        total_num, more = divmod(all_count, per_num)

        if more:

            total_num +=

        # 最大显示的页码数

        half_show = max_show //

        if total_num <= max_show:

            page_start =

            page_end = total_num

        else:

            if self.page - half_show <= :

                # 页码的起始值

                page_start =

                # 页码的终止值

                page_end = max_show

            elif self.page + half_show > total_num:

                page_end = total_num

                page_start = total_num - max_show + 

            else:

                # 页码的起始值

                page_start = self.page - half_show

                # 页码的终止值

                page_end = self.page + half_show

        self.page_start = page_start

        self.page_end = page_end

        self.total_num = total_num

        self.start = (self.page - ) * per_num

        self.end = self.page * per_num

    @property

    def page_html(self):

        li_list = []

        if self.page == :

            li_list.append(

                '<li class="disabled"><a aria-label="Previous"> <span aria-hidden="true">&laquo;</span></a></li>')

        else:

            self.params['page'] = self.page -   # { query: ,page :  }

            li_list.append(

                '<li><a href="?{}" aria-label="Previous"> <span aria-hidden="true">&laquo;</span></a></li>'.format(

                    self.params.urlencode()))   #  ?query=&page=

        for i in range(self.page_start, self.page_end + ):

            self.params['page'] = i  # { query: ,page : i}

            if i == self.page:

                li_list.append('<li class="active"><a href="?{}">{}</a></li>'.format(self.params.urlencode(), i))

            else:

                li_list.append('<li><a href="?{}">{}</a></li>'.format(self.params.urlencode(), i))

        if self.page == self.total_num:

            li_list.append(

                '<li ><a aria-label="Next"> <span aria-hidden="true">&raquo;</span></a></li>')

        else:

            self.params['page'] = self.page +

            li_list.append(

                '<li ><a href="?{}" aria-label="Next"> <span aria-hidden="true">&raquo;</span></a></li>'.format(

                    self.params.urlencode()))

        return mark_safe(''.join(li_list))

  <nav aria-label="Page navigation">

  <ul class="pagination">

    <li>

      <a href="#" aria-label="Previous">

        <span aria-hidden="true">&laquo;</span>

      </a>

    </li>

    {{ page_html }}  #使用分页代码

      <li>

      <a href="#" aria-label="Next">

        <span aria-hidden="true">&raquo;</span>

      </a>

    </li>

  </ul>

</nav>