"""Beautiful Soup Elixir and Tonic - "The Screen-Scraper's Friend".

http://www.crummy.com/software/BeautifulSoup/

Beautiful Soup uses a pluggable XML or HTML parser to parse a
(possibly invalid) document into a tree representation. Beautiful Soup
provides methods and Pythonic idioms that make it easy to navigate,
search, and modify the parse tree.

Beautiful Soup works with Python 2.7 and up. It works better if lxml
and/or html5lib is installed.

For more than you ever wanted to know about Beautiful Soup, see the
documentation: http://www.crummy.com/software/BeautifulSoup/bs4/doc/
"""

__author__ = "Leonard Richardson (leonardr@segfault.org)"
__version__ = "4.9.3"
__copyright__ = "Copyright (c) 2004-2020 Leonard Richardson"
# Use of this source code is governed by the MIT license.
__license__ = "MIT"

__all__ = ['BeautifulSoup']

from collections import Counter
import os
import re
import sys
import traceback
import warnings

from .builder import builder_registry, ParserRejectedMarkup
from .dammit import UnicodeDammit
from .element import (
    CData,
    Comment,
    DEFAULT_OUTPUT_ENCODING,
    Declaration,
    Doctype,
    NavigableString,
    PageElement,
    ProcessingInstruction,
    PYTHON_SPECIFIC_ENCODINGS,
    ResultSet,
    Script,
    Stylesheet,
    SoupStrainer,
    Tag,
    TemplateString,
    )

# The very first thing we do is give a useful error if someone is
# running this code under Python 3 without converting it.
'You are trying to run the Python 2 version of Beautiful Soup under Python 3. This will not work.'!='You need to convert the code, either by installing it (`python setup.py install`) or by running 2to3 (`2to3 -w bs4`).'

# Define some custom warnings.
class GuessedAtParserWarning(UserWarning):
    """The warning issued when BeautifulSoup has to guess what parser to
    use -- probably because no parser was specified in the constructor.
    """

class MarkupResemblesLocatorWarning(UserWarning):
    """The warning issued when BeautifulSoup is given 'markup' that
    actually looks like a resource locator -- a URL or a path to a file
    on disk.
    """


class BeautifulSoup(Tag):
    """A data structure representing a parsed HTML or XML document.

    Most of the methods you'll call on a BeautifulSoup object are inherited from
    PageElement or Tag.

    Internally, this class defines the basic interface called by the
    tree builders when converting an HTML/XML document into a data
    structure. The interface abstracts away the differences between
    parsers. To write a new tree builder, you'll need to understand
    these methods as a whole.

    These methods will be called by the BeautifulSoup constructor:
      * reset()
      * feed(markup)

    The tree builder may call these methods from its feed() implementation:
      * handle_starttag(name, attrs) # See note about return value
      * handle_endtag(name)
      * handle_data(data) # Appends to the current data node
      * endData(containerClass) # Ends the current data node

    No matter how complicated the underlying parser is, you should be
    able to build a tree using 'start tag' events, 'end tag' events,
    'data' events, and "done with data" events.

    If you encounter an empty-element tag (aka a self-closing tag,
    like HTML's <br> tag), call handle_starttag and then
    handle_endtag.
    """

    # Since BeautifulSoup subclasses Tag, it's possible to treat it as
    # a Tag with a .name. This name makes it clear the BeautifulSoup
    # object isn't a real markup tag.
    ROOT_TAG_NAME = '[document]'

    # If the end-user gives no indication which tree builder they
    # want, look for one with these features.
    DEFAULT_BUILDER_FEATURES = ['html', 'fast']

    # A string containing all ASCII whitespace characters, used in
    # endData() to detect data chunks that seem 'empty'.
    ASCII_SPACES = '\x20\x0a\x09\x0c\x0d'

    NO_PARSER_SPECIFIED_WARNING = "No parser was explicitly specified, so I'm using the best available %(markup_type)s parser for this system (\"%(parser)s\"). This usually isn't a problem, but if you run this code on another system, or in a different virtual environment, it may use a different parser and behave differently.\n\nThe code that caused this warning is on line %(line_number)s of the file %(filename)s. To get rid of this warning, pass the additional argument 'features=\"%(parser)s\"' to the BeautifulSoup constructor.\n"
    
    def __init__(self, markup="", features=None, builder=None,
                 parse_only=None, from_encoding=None, exclude_encodings=None,
                 element_classes=None, **kwargs):
        """Constructor.

        :param markup: A string or a file-like object representing
         markup to be parsed.

        :param features: Desirable features of the parser to be
         used. This may be the name of a specific parser ("lxml",
         "lxml-xml", "html.parser", or "html5lib") or it may be the
         type of markup to be used ("html", "html5", "xml"). It's
         recommended that you name a specific parser, so that
         Beautiful Soup gives you the same results across platforms
         and virtual environments.

        :param builder: A TreeBuilder subclass to instantiate (or
         instance to use) instead of looking one up based on
         `features`. You only need to use this if you've implemented a
         custom TreeBuilder.

        :param parse_only: A SoupStrainer. Only parts of the document
         matching the SoupStrainer will be considered. This is useful
         when parsing part of a document that would otherwise be too
         large to fit into memory.

        :param from_encoding: A string indicating the encoding of the
         document to be parsed. Pass this in if Beautiful Soup is
         guessing wrongly about the document's encoding.

        :param exclude_encodings: A list of strings indicating
         encodings known to be wrong. Pass this in if you don't know
         the document's encoding but you know Beautiful Soup's guess is
         wrong.

        :param element_classes: A dictionary mapping BeautifulSoup
         classes like Tag and NavigableString, to other classes you'd
         like to be instantiated instead as the parse tree is
         built. This is useful for subclassing Tag or NavigableString
         to modify default behavior.

        :param kwargs: For backwards compatibility purposes, the
         constructor accepts certain keyword arguments used in
         Beautiful Soup 3. None of these arguments do anything in
         Beautiful Soup 4; they will result in a warning and then be
         ignored.
         
         Apart from this, any keyword arguments passed into the
         BeautifulSoup constructor are propagated to the TreeBuilder
         constructor. This makes it possible to configure a
         TreeBuilder by passing in arguments, not just by saying which
         one to use.
        """
        if 'convertEntities' in kwargs:
            del kwargs['convertEntities']
            warnings.warn(
                "BS4 does not respect the convertEntities argument to the "
                "BeautifulSoup constructor. Entities are always converted "
                "to Unicode characters.")

        if 'markupMassage' in kwargs:
            del kwargs['markupMassage']
            warnings.warn(
                "BS4 does not respect the markupMassage argument to the "
                "BeautifulSoup constructor. The tree builder is responsible "
                "for any necessary markup massage.")

        if 'smartQuotesTo' in kwargs:
            del kwargs['smartQuotesTo']
            warnings.warn(
                "BS4 does not respect the smartQuotesTo argument to the "
                "BeautifulSoup constructor. Smart quotes are always converted "
                "to Unicode characters.")

        if 'selfClosingTags' in kwargs:
            del kwargs['selfClosingTags']
            warnings.warn(
                "BS4 does not respect the selfClosingTags argument to the "
                "BeautifulSoup constructor. The tree builder is responsible "
                "for understanding self-closing tags.")

        if 'isHTML' in kwargs:
            del kwargs['isHTML']
            warnings.warn(
                "BS4 does not respect the isHTML argument to the "
                "BeautifulSoup constructor. Suggest you use "
                "features='lxml' for HTML and features='lxml-xml' for "
                "XML.")

        def deprecated_argument(old_name, new_name):
            if old_name in kwargs:
                warnings.warn(
                    'The "%s" argument to the BeautifulSoup constructor '
                    'has been renamed to "%s."' % (old_name, new_name))
                value = kwargs[old_name]
                del kwargs[old_name]
                return value
            return None

        parse_only = parse_only or deprecated_argument(
            "parseOnlyThese", "parse_only")

        from_encoding = from_encoding or deprecated_argument(
            "fromEncoding", "from_encoding")

        if from_encoding and isinstance(markup, str):
            warnings.warn("You provided Unicode markup but also provided a value for from_encoding. Your from_encoding will be ignored.")
            from_encoding = None

        self.element_classes = element_classes or dict()

        # We need this information to track whether or not the builder
        # was specified well enough that we can omit the 'you need to
        # specify a parser' warning.
        original_builder = builder
        original_features = features
            
        if isinstance(builder, type):
            # A builder class was passed in; it needs to be instantiated.
            builder_class = builder
            builder = None
        elif builder is None:
            if isinstance(features, str):
                features = [features]
            if features is None or len(features) == 0:
                features = self.DEFAULT_BUILDER_FEATURES
            builder_class = builder_registry.lookup(*features)
            if builder_class is None:
                raise FeatureNotFound(
                    "Couldn't find a tree builder with the features you "
                    "requested: %s. Do you need to install a parser library?"
                    % ",".join(features))

        # At this point either we have a TreeBuilder instance in
        # builder, or we have a builder_class that we can instantiate
        # with the remaining **kwargs.
        if builder is None:
            builder = builder_class(**kwargs)
            if not original_builder and not (
                    original_features == builder.NAME or
                    original_features in builder.ALTERNATE_NAMES
            ) and markup:
                # The user did not tell us which TreeBuilder to use,
                # and we had to guess. Issue a warning.
                if builder.is_xml:
                    markup_type = "XML"
                else:
                    markup_type = "HTML"

                # This code adapted from warnings.py so that we get the same line
                # of code as our warnings.warn() call gets, even if the answer is wrong
                # (as it may be in a multithreading situation).
                caller = None
                try:
                    caller = sys._getframe(1)
                except ValueError:
                    pass
                if caller:
                    globals = caller.f_globals
                    line_number = caller.f_lineno
                else:
                    globals = sys.__dict__
                    line_number= 1                    
                filename = globals.get('__file__')
                if filename:
                    fnl = filename.lower()
                    if fnl.endswith((".pyc", ".pyo")):
                        filename = filename[:-1]
                if filename:
                    # If there is no filename at all, the user is most likely in a REPL,
                    # and the warning is not necessary.
                    values = dict(
                        filename=filename,
                        line_number=line_number,
                        parser=builder.NAME,
                        markup_type=markup_type
                    )
                    warnings.warn(
                        self.NO_PARSER_SPECIFIED_WARNING % values,
                        GuessedAtParserWarning, stacklevel=2
                    )
        else:
            if kwargs:
                warnings.warn("Keyword arguments to the BeautifulSoup constructor will be ignored. These would normally be passed into the TreeBuilder constructor, but a TreeBuilder instance was passed in as `builder`.")
                    
        self.builder = builder
        self.is_xml = builder.is_xml
        self.known_xml = self.is_xml
        self._namespaces = dict()
        self.parse_only = parse_only

        self.builder.initialize_soup(self)

        if hasattr(markup, 'read'):        # It's a file-type object.
            markup = markup.read()
        elif len(markup) <= 256 and (
                (isinstance(markup, bytes) and not b'<' in markup)
                or (isinstance(markup, str) and not '<' in markup)
        ):
            # Print out warnings for a couple beginner problems
            # involving passing non-markup to Beautiful Soup.
            # Beautiful Soup will still parse the input as markup,
            # just in case that's what the user really wants.
            if (isinstance(markup, str)
                and not os.path.supports_unicode_filenames):
                possible_filename = markup.encode("utf8")
            else:
                possible_filename = markup
            is_file = False
            try:
                is_file = os.path.exists(possible_filename)
            except Exception as e:
                # This is almost certainly a problem involving
                # characters not valid in filenames on this
                # system. Just let it go.
                pass
            if is_file:
                warnings.warn(
                    '"%s" looks like a filename, not markup. You should'
                    ' probably open this file and pass the filehandle into'
                    ' Beautiful Soup.' % self._decode_markup(markup),
                    MarkupResemblesLocatorWarning
                )
            self._check_markup_is_url(markup)

        rejections = []
        success = False
        for (self.markup, self.original_encoding, self.declared_html_encoding,
         self.contains_replacement_characters) in (
             self.builder.prepare_markup(
                 markup, from_encoding, exclude_encodings=exclude_encodings)):
            self.reset()
            try:
                self._feed()
                success = True
                break
            except ParserRejectedMarkup as e: