# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

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

import re

import sys

from lxml import etree

from logilab.common.deprecation import class_deprecated, class_renamed

from cubicweb.view import STRICT_DOCTYPE, TRANSITIONAL_DOCTYPE

STRICT_DOCTYPE = str(STRICT_DOCTYPE)

TRANSITIONAL_DOCTYPE = str(TRANSITIONAL_DOCTYPE)

ERR_COUNT = 0

class Validator(object):

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

        try:

            return PageInfo(self, data)

        except etree.XMLSyntaxError as exc:

            def save_in(fname=''):

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

            new_exc = AssertionError(u'invalid document: %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)

        # XXX understand what's happening under windows

        self.parser = etree.XMLParser(dtd_validation=sys.platform != 'win32')

    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 XMLValidator(Validator):

    """ A fully compliant XML parser """

    def __init__(self):

        Validator.__init__(self)

        self.parser = etree.XMLParser()

SaxOnlyValidator = class_renamed('SaxOnlyValidator',

                                 XMLValidator,

                                 '[3.17] you should use the '

                                 'XMLValidator class instead')

class XMLDemotingValidator(XMLValidator):

    """ some views produce html instead of xhtml, using demote_to_html

    this is typically related to the use of external dependencies

    which do not produce valid xhtml (google maps, ...)

    """

    __metaclass__ = class_deprecated

    __deprecation_warning__ = '[3.10] this is now handled in testlib.py'

    def preprocess_data(self, data):

        if data.startswith('<?xml'):

            self.parser = etree.XMLParser()

        else:

            self.parser = etree.HTMLParser()

        return data

REM_SCRIPT_RGX = re.compile(r"<script[^>]*>.*?</script>", re.U|re.M|re.I|re.S)

class HTMLValidator(Validator):

    def __init__(self):

        Validator.__init__(self)

        self.parser = etree.HTMLParser(recover=False)

    def preprocess_data(self, data):

        """ Here we essentially wipe the javascript tags to help the HTMLParser

        do its job. Without that, it chokes on tags embedded in JS strings.

        """

        # Notice we may want to use lxml cleaner, but it's far too intrusive:

        #

        # cleaner = Cleaner(scripts=True,

        #                   javascript=False,

        #                   comments=False,

        #                   style=False,

        #                   links=False,

        #                   meta=False,

        #                   page_structure=False,

        #                   processing_instructions=False,

        #                   embedded=False,

        #                   frames=False,

        #                   forms=False,

        #                   annoying_tags=False,

        #                   remove_tags=(),

        #                   remove_unknown_tags=False,

        #                   safe_attrs_only=False,

        #                   add_nofollow=False)

        # >>> cleaner.clean_html('<body></body>')

        # '<span></span>'

        # >>> cleaner.clean_html('<!DOCTYPE html><body></body>')

        # '<html><body></body></html>'

        # >>> cleaner.clean_html('<body><div/></body>')

        # '<div></div>'

        # >>> cleaner.clean_html('<html><body><div/><br></body><html>')

        # '<html><body><div></div><br></body></html>'

        # >>> cleaner.clean_html('<html><body><div/><br><span></body><html>')

        # '<html><body><div></div><br><span></span></body></html>'

        #

        # using that, we'll miss most actual validation error we want to

        # catch. For now, use dumb regexp

        return REM_SCRIPT_RGX.sub('', data)

class PageInfo(object):

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

    def __init__(self, validator, source):

        self.source = source

        root = etree.fromstring(validator.preprocess_data(source), validator.parser)

        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 _iterstr(self, tag):

        if self.default_ns is None:

            return ".//%s" % tag

        else:

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

    def matching_nodes(self, tag, **attrs):

        for elt in self.etree.iterfind(self._iterstr(tag)):

            eltattrs  = elt.attrib

            for attr, value in attrs.iteritems():

                try:

                    if eltattrs[attr] != value:

                        break

                except KeyError:

                    break

            else: # all attributes match

                yield elt

    def has_tag(self, tag, nboccurs=1, **attrs):

        """returns True if tag with given attributes appears in the page

        `nbtimes` (any if None)

        """

        for elt in self.matching_nodes(tag, **attrs):

            if nboccurs is None: # no need to check number of occurences

                return True

            if not nboccurs: # too much occurences

                return False

            nboccurs -= 1

        if nboccurs == 0: # correct number of occurences

            return True

        return False # no matching tag/attrs

    def find_tag(self, tag, gettext=True):

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

        iterstr = self._iterstr(tag)

        if not gettext or 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