class Pagination(object):

    # 第一步  初始化頁面
    def __init__(self,current_page_num,all_count,request,per_page_num=5,pager_count=11):
        """
        封裝分頁相關資料
        :param current_page_num: 當前訪問頁的數字
        :param all_count:    分頁資料中的資料總條數
        :param per_page_num: 每頁顯示的資料條數
        :param pager_count:  最多顯示的頁碼個數
        
 
"""
        try:
            current_page_num = int(current_page_num)
        except Exception as e:
            current_page_num = 1

        if current_page_num <1:
            current_page_num = 1

        self.current_page_num = current_page_num

        self.all_count = all_count
        self.per_page_num 
 
= per_page_num


        # 第二步  實際總頁碼
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager


        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)  # 5


        # 儲存搜尋條件

        import
 
 copy
        self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}

    @property  #屬性方法  在外部views裡 切片的時候不用加括號  直接呼叫 start就可以
    def start(self):
        return (self.current_page_num - 1) * self.per_page_num

    @property
    def end(self):
        return self.current_page_num * self.per_page_num

    def page_html(self):
        # 如果總頁碼 < 11個：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 總頁碼  > 11
        else:
            # 當前頁如果<=頁面上最多顯示11/2個頁碼
            if self.current_page_num <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1
            # 當前頁大於5
            else:
                # 頁碼翻到最後
                if (self.current_page_num + self.pager_count_half) > self.all_pager:

                    pager_start = self.all_pager - self.pager_count + 1
                    pager_end = self.all_pager + 1

                else:
                    pager_start = self.current_page_num - self.pager_count_half
                    pager_end = self.current_page_num + self.pager_count_half + 1

        page_html_list = []

        first_page = '<li><a href="?page=%s">首頁</a></li>' % (1,)
        page_html_list.append(first_page)

        if self.current_page_num <= 1:
            prev_page = '<li class="disabled"><a href="#">上一頁</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一頁</a></li>' % (self.current_page_num - 1,)

        page_html_list.append(prev_page)


        #self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}
        # 主要的for迴圈
        for i in range(pager_start, pager_end):

            self.params["page"]=i

            if i == self.current_page_num:
                temp = '<li class="active"><a href="?%s">%s</a></li>' %(self.params.urlencode(),i)
            else:
                temp = '<li><a href="?%s">%s</a></li>' % (self.params.urlencode(),i,)
            page_html_list.append(temp)


        if self.current_page_num >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一頁</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一頁</a></li>' % (self.current_page_num + 1,)
        page_html_list.append(next_page)
        last_page = '<li><a href="?page=%s">尾頁</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)

        return ''.join(page_html_list)