from config import settings
from common.module import Module


class Search(Module):
    """
    Search base class
    """
    def __init__(self):
        Module.__init__(self)
        self.page_num = 0  # 要显示搜索起始条数
        self.per_page_num = 50  # 每页显示搜索条数
        self.recursive_search = settings.enable_recursive_search
        self.recursive_times = settings.search_recursive_times
        self.full_search = settings.enable_full_search

    @staticmethod
    def filter(domain, subdomain):
        """
        生成搜索过滤语句
        使用搜索引擎支持的-site:语法过滤掉搜索页面较多的子域以发现新域

        :param str domain: 域名
        :param set subdomain: 子域名集合
        :return: 过滤语句
        :rtype: str
        """
        statements_list = []
        subdomains_temp = set(map(lambda x: x + '.' + domain, settings.common_subnames))
        subdomains_temp = list(subdomain.intersection(subdomains_temp))
        for i in range(0, len(subdomains_temp), 2):  # 同时排除2个子域
            statements_list.append(''.join(set(map(lambda s: ' -site:' + s,
                                                   subdomains_temp[i:i + 2]))))
        return statements_list

    def match_location(self, url):
        """
        匹配跳转之后的url
        针对部分搜索引擎(如百度搜索)搜索展示url时有显示不全的情况
        此函数会向每条结果的链接发送head请求获取响应头的location值并做子域匹配

        :param str url: 展示结果的url链接
        :return: 匹配的子域
        :rtype set
        """
        resp = self.head(url, check=False, allow_redirects=False)
        if not resp:
            return set()
        location = resp.headers.get('location')
        if not location:
            return set()
        return set(self.match_subdomains(location))

    def check_subdomains(self, subdomains):
        """
        检查搜索出的子域结果是否满足条件

        :param subdomains: 子域结果
        :return:
        """
        if not subdomains:
            # 搜索没有发现子域名则停止搜索
            return False
        if not self.full_search and subdomains.issubset(self.subdomains):
            # 在全搜索过程中发现搜索出的结果有完全重复的结果就停止搜索
            return False
        return True

    def recursive_subdomain(self):
        # 递归搜索下一层的子域
        # 从1开始是之前已经做过1层子域搜索了,当前实际递归层数是layer+1
        subdomains = self.subdomains.copy()
        for layer_num in range(1, self.recursive_times):
            for subdomain in subdomains:
                # 进行下一层子域搜索的限制条件
                count = subdomain.count('.') - self.domain.count('.')
                if count == layer_num:
                    yield subdomain