import os
import re
##
import requests
from lxml import etree


class Config(object):
    default_xsd = 'http://schema.xml.r00t2.io/projects/he_ipv6.xsd'

    def __init__(self, xml_path, *args, **kwargs):
        self.xml_path = os.path.abspath(os.path.expanduser(xml_path))
        if not os.path.isfile(self.xml_path):
            raise ValueError('xml_path does not exist')
        self.tree = None
        self.ns_tree = None
        self.xml = None
        self.ns_xml = None
        self.raw = None
        self.xsd = None
        self.defaults_parser = None
        self.obj = None
        self.tunnels = {}
        self.creds = {}
        self.parse_raw()
        self.get_xsd()
        self.populate_defaults()
        self.validate()

    def get_xsd(self):
        raw_xsd = None
        base_url = None
        xsi = self.xml.nsmap.get('xsi', 'http://www.w3.org/2001/XMLSchema-instance')
        schemaLocation = '{{{0}}}schemaLocation'.format(xsi)
        schemaURL = self.xml.attrib.get(schemaLocation, self.default_xsd)
        split_url = schemaURL.split()
        if len(split_url) == 2:  # a properly defined schemaLocation
            schemaURL = split_url[1]
        else:
            schemaURL = split_url[0]  # a LAZY schemaLocation
        if schemaURL.startswith('file://'):
            schemaURL = re.sub(r'^file://', r'', schemaURL)
            with open(schemaURL, 'rb') as fh:
                raw_xsd = fh.read()
            base_url = os.path.dirname(schemaURL) + '/'
        else:
            req = requests.get(schemaURL)
            if not req.ok:
                raise RuntimeError('Could not download XSD')
            raw_xsd = req.content
            base_url = os.path.split(req.url)[0] + '/'  # This makes me feel dirty.
        self.xsd = etree.XMLSchema(etree.XML(raw_xsd, base_url = base_url))
        return(None)

    def parse_raw(self, parser = None):
        if not self.raw:
            with open(self.xml_path, 'rb') as fh:
                self.raw = fh.read()
        self.xml = etree.fromstring(self.raw, parser = parser)
        self.ns_xml = etree.fromstring(self.raw, parser = parser)
        self.tree = self.xml.getroottree()
        self.ns_tree = self.ns_xml.getroottree()
        self.tree.xinclude()
        self.ns_tree.xinclude()
        self.strip_ns()
        return(None)

    def populate_defaults(self):
        if not self.xsd:
            self.get_xsd()
        if not self.defaults_parser:
            self.defaults_parser = etree.XMLParser(schema = self.xsd, attribute_defaults = True)
        self.parse_raw(parser = self.defaults_parser)
        return(None)

    def remove_defaults(self):
        self.parse_raw()
        return(None)

    def strip_ns(self, obj = None):
        # https://stackoverflow.com/questions/30232031/how-can-i-strip-namespaces-out-of-an-lxml-tree/30233635#30233635
        xpathq = "descendant-or-self::*[namespace-uri()!='']"
        if not obj:
            for x in (self.tree, self.xml):
                for e in x.xpath(xpathq):
                    e.tag = etree.QName(e).localname
        elif isinstance(obj, (etree._Element, etree._ElementTree)):
            obj = copy.deepcopy(obj)
            for e in obj.xpath(xpathq):
                e.tag = etree.QName(e).localname
            return(obj)
        else:
            raise ValueError('Did not know how to parse obj parameter')
        return(None)

    def validate(self):
        if not self.xsd:
            self.get_xsd()
        self.xsd.assertValid(self.ns_tree)
        return(None)