"""Use the HTMLParser library to parse HTML files that aren't too bad."""

from __future__ import absolute_import
from six import unichr
import six
__all__ = [
    'HTMLParserTreeBuilder',
    ]

from six.moves.html_parser import HTMLParser
if six.PY2:
  from six.moves.html_parser import HTMLParseError
else:
  class HTMLParseError(Exception):
    pass
import sys
import warnings

# Starting in Python 3.2, the HTMLParser constructor takes a 'strict'
# argument, which we'd like to set to False. Unfortunately,
# http://bugs.python.org/issue13273 makes strict=True a better bet
# before Python 3.2.3.
#
# At the end of this file, we monkeypatch HTMLParser so that
# strict=True works well on Python 3.2.2.
major, minor, release = sys.version_info[:3]
CONSTRUCTOR_TAKES_STRICT = (
    major > 3
    or (major == 3 and minor > 2)
    or (major == 3 and minor == 2 and release >= 3))

from bs4.element import (
    CData,
    Comment,
    Declaration,
    Doctype,
    ProcessingInstruction,
    )
from bs4.dammit import EntitySubstitution, UnicodeDammit

from bs4.builder import (
    HTML,
    HTMLTreeBuilder,
    STRICT,
    )


HTMLPARSER = 'html.parser'

class BeautifulSoupHTMLParser(HTMLParser):
    def handle_starttag(self, name, attrs):
        # XXX namespace
        attr_dict = {}
        for key, value in attrs:
            # Change None attribute values to the empty string
            # for consistency with the other tree builders.
            if value is None:
                value = ''
            attr_dict[key] = value
            attrvalue = '""'
        self.soup.handle_starttag(name, None, None, attr_dict)

    def handle_endtag(self, name):
        self.soup.handle_endtag(name)

    def handle_data(self, data):
        self.soup.handle_data(data)

    def handle_charref(self, name):
        # XXX workaround for a bug in HTMLParser. Remove this once
        # it's fixed.
        if name.startswith('x'):
            real_name = int(name.lstrip('x'), 16)
        elif name.startswith('X'):
            real_name = int(name.lstrip('X'), 16)
        else:
            real_name = int(name)

        try:
            data = unichr(real_name)
        except (ValueError, OverflowError) as e:
            data = u"\N{REPLACEMENT CHARACTER}"

        self.handle_data(data)

    def handle_entityref(self, name):
        character = EntitySubstitution.HTML_ENTITY_TO_CHARACTER.get(name)
        if character is not None:
            data = character
        else:
            data = "&%s;" % name
        self.handle_data(data)

    def handle_comment(self, data):
        self.soup.endData()
        self.soup.handle_data(data)
        self.soup.endData(Comment)

    def handle_decl(self, data):
        self.soup.endData()
        if data.startswith("DOCTYPE "):
            data = data[len("DOCTYPE "):]
        elif data == 'DOCTYPE':
            # i.e. "<!DOCTYPE>"
            data = ''
        self.soup.handle_data(data)
        self.soup.endData(Doctype)

    def unknown_decl(self, data):
        if data.upper().startswith('CDATA['):
            cls = CData
            data = data[len('CDATA['):]
        else:
            cls = Declaration
        self.soup.endData()
        self.soup.handle_data(data)
        self.soup.endData(cls)

    def handle_pi(self, data):