"""defines a validating HTML parser used in web application tests"""

import re

from lxml import etree

ERR_COUNT = 0

class Validator(object):

    def parse_string(self, data, sysid=None):

        try:

            data = self.preprocess_data(data)

            return PageInfo(data, etree.fromstring(data, self.parser))

        except etree.XMLSyntaxError, exc:

            def save_in(fname=''):

                file(fname, 'w').write(data)

            new_exc = AssertionError(u'invalid xml %s' % exc)

            new_exc.position = exc.position

            raise new_exc

    def preprocess_data(self, data):

        return data

class DTDValidator(Validator):

    def __init__(self):

        Validator.__init__(self)

        self.parser = etree.XMLParser(dtd_validation=True)

    def preprocess_data(self, data):

        """used to fix potential blockquote mess generated by docutils"""

        if STRICT_DOCTYPE not in data:

            return data

        # parse using transitional DTD

        data = data.replace(STRICT_DOCTYPE, TRANSITIONAL_DOCTYPE)

        tree = etree.fromstring(data, self.parser)

        namespace = tree.nsmap.get(None)

        # this is the list of authorized child tags for <blockquote> nodes

        expected = 'p h1 h2 h3 h4 h5 h6 div ul ol dl pre hr blockquote address ' \

                   'fieldset table form noscript ins del script'.split()

        if namespace:

            blockquotes = tree.findall('.//{%s}blockquote' % namespace)

            expected = ['{%s}%s' % (namespace, tag) for tag in expected]

        else:

            blockquotes = tree.findall('.//blockquote')

        # quick and dirty approach: remove all blockquotes

        for blockquote in blockquotes:

            parent = blockquote.getparent()

            parent.remove(blockquote)

        data = etree.tostring(tree)

        return '<?xml version="1.0" encoding="UTF-8"?>%s\n%s' % (STRICT_DOCTYPE, data)

class SaxOnlyValidator(Validator):

    def __init__(self):

        Validator.__init__(self)

        self.parser = etree.XMLParser()

class HTMLValidator(Validator):

    def __init__(self):

        Validator.__init__(self)

        self.parser = etree.HTMLParser()

class PageInfo(object):

    """holds various informations on the view's output"""

    def __init__(self, source, root):

        self.source = source

        self.etree = root

        self.source = source

        self.raw_text = u''.join(root.xpath('//text()'))

        self.namespace = self.etree.nsmap

        self.default_ns = self.namespace.get(None)

        self.a_tags = self.find_tag('a')

        self.h1_tags = self.find_tag('h1')

        self.h2_tags = self.find_tag('h2')

        self.h3_tags = self.find_tag('h3')

        self.h4_tags = self.find_tag('h4')

        self.input_tags = self.find_tag('input')

        self.title_tags = [self.h1_tags, self.h2_tags, self.h3_tags, self.h4_tags]

    def find_tag(self, tag):

        """return a list which contains text of all "tag" elements """

        if self.default_ns is None:

            iterstr = ".//%s" % tag

        else:

            iterstr = ".//{%s}%s" % (self.default_ns, tag)

        if tag in ('a', 'input'):

            return [(elt.text, elt.attrib) for elt in self.etree.iterfind(iterstr)]

        return [u''.join(elt.xpath('.//text()')) for elt in self.etree.iterfind(iterstr)]

    def appears(self, text):

        """returns True if <text> appears in the page"""

        return text in self.raw_text

    def __contains__(self, text):

        return text in self.source

    def has_title(self, text, level=None):

        """returns True if <h?>text</h?>

        :param level: the title's level (1 for h1, 2 for h2, etc.)

        """

        if level is None:

            for hlist in self.title_tags:

                if text in hlist:

                    return True

            return False

        else:

            hlist = self.title_tags[level - 1]

            return text in hlist

    def has_title_regexp(self, pattern, level=None):

        """returns True if <h?>pattern</h?>"""

        sre = re.compile(pattern)

        if level is None:

            for hlist in self.title_tags:

                for title in hlist:

                    if sre.match(title):

                        return True

            return False

        else:

            hlist = self.title_tags[level - 1]

            for title in hlist:

                if sre.match(title):

                    return True

            return False

    def has_link(self, text, url=None):

        """returns True if <a href=url>text</a> was found in the page"""

        for link_text, attrs in self.a_tags:

            if text == link_text:

                if url is None:

                    return True

                try:

                    href = attrs['href']

                    if href == url:

                        return True

                except KeyError:

                    continue

        return False

    def has_link_regexp(self, pattern, url=None):

        """returns True if <a href=url>pattern</a> was found in the page"""

        sre = re.compile(pattern)

        for link_text, attrs in self.a_tags:

            if sre.match(link_text):

                if url is None:

                    return True

                try:

                    href = attrs['href']

                    if href == url:

                        return True

                except KeyError:

                    continue

        return False