"""
Python Markdown
===============

Python Markdown converts Markdown to HTML and can be used as a library or
called from the command line.

## Basic usage as a module:

    import markdown
    md = Markdown()
    html = md.convert(your_text_string)

## Basic use from the command line:

    python markdown.py source.txt > destination.html

Run "python markdown.py --help" to see more options.

## Extensions

See <http://www.freewisdom.org/projects/python-markdown/> for more
information and instructions on how to extend the functionality of
Python Markdown.  Read that before you try modifying this file.

## Authors and License

Started by [Manfred Stienstra](http://www.dwerg.net/).  Continued and
maintained  by [Yuri Takhteyev](http://www.freewisdom.org), [Waylan
Limberg](http://achinghead.com/) and [Artem Yunusov](http://blog.splyer.com).

Contact: markdown@freewisdom.org

Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
Copyright 200? Django Software Foundation (OrderedDict implementation)
Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
Copyright 2004 Manfred Stienstra (the original version)

License: BSD (see docs/LICENSE for details).
"""

version = "2.0-beta-2"
version_info = (2,0,0, "beta-2")

import re
import codecs
import logging
from logging import DEBUG, INFO, WARN, ERROR, CRITICAL

"""
CONSTANTS
=============================================================================
"""

"""
Constants you might want to modify
-----------------------------------------------------------------------------
"""

# default logging level for command-line use
COMMAND_LINE_LOGGING_LEVEL = CRITICAL
TAB_LENGTH = 4               # expand tabs to this many spaces
ENABLE_ATTRIBUTES = True     # @id = xyz -> <... id="xyz">
SMART_EMPHASIS = True        # this_or_that does not become this<i>or</i>that
HTML_REMOVED_TEXT = "[HTML_REMOVED]" # text used instead of HTML in safe mode
BLOCK_LEVEL_ELEMENTS = re.compile("p|div|h[1-6]|blockquote|pre|table|dl|ol|ul"
                                  "|script|noscript|form|fieldset|iframe|math"
                                  "|ins|del|hr|hr/|style|li|dt|dd|tr")

# Placeholders
STX = u'\u0002'  # Use STX ("Start of text") for start-of-placeholder
ETX = u'\u0003'  # Use ETX ("End of text") for end-of-placeholder
INLINE_PLACEHOLDER_PREFIX = STX+"klzzwxh:"
INLINE_PLACEHOLDER = INLINE_PLACEHOLDER_PREFIX + "%s" + ETX
AMP_SUBSTITUTE = STX+"amp"+ETX

import preprocessors, blockprocessors, treeprocessors, inlinepatterns
import postprocessors
import blockparser
import etree_loader
import odict

# Extensions should use "markdown.etree" instead of "etree" (or do `from
# markdown import etree`).  Do not import it by yourself.

etree = etree_loader.importETree()


"""
Constants you probably do not need to change
-----------------------------------------------------------------------------
"""

RTL_BIDI_RANGES = ( (u'\u0590', u'\u07FF'),
                     # Hebrew (0590-05FF), Arabic (0600-06FF),
                     # Syriac (0700-074F), Arabic supplement (0750-077F),
                     # Thaana (0780-07BF), Nko (07C0-07FF).
                    (u'\u2D30', u'\u2D7F'), # Tifinagh
                    )



"""
AUXILIARY GLOBAL FUNCTIONS
=============================================================================
"""

def message(level, text):
    """ A wrapper method for logging debug messages. """
    logging.getLogger('MARKDOWN').log(level, text)


def isBlockLevel(tag):
    """Check if the tag is a block level HTML tag."""
    return BLOCK_LEVEL_ELEMENTS.match(tag)

"""
MISC AUXILIARY CLASSES
=============================================================================
"""

class AtomicString(unicode):
    """A string which should not be further processed."""
    pass


"""
OVERALL DESIGN
=============================================================================

Markdown processing takes place in four steps:

1. A bunch of "preprocessors" munge the input text.
2. BlockParser() parses the high-level structural elements of the
   pre-processed text into an ElementTree.
3. A bunch of "treeprocessors" are run against the ElementTree. One such
   treeprocessor runs InlinePatterns against the ElementTree, detecting inline
   markup.
4. Some post-processors are run against the text after the ElementTree has
   been serialized into text.
5. The output is written to a string.

Those steps are put together by the Markdown() class.

"""


class Markdown:
    """Convert Markdown to HTML."""

    def __init__(self,
                 extensions=[],
                 extension_configs={},
                 safe_mode = False):
        """
        Creates a new Markdown instance.

        Keyword arguments:

        * extensions: A list of extensions.
           If they are of type string, the module mdx_name.py will be loaded.
           If they are a subclass of markdown.Extension, they will be used
           as-is.
        * extension-configs: Configuration setting for extensions.
        * safe_mode: Disallow raw html. One of "remove", "replace" or "escape".

        """
        
        self.safeMode = safe_mode
        self.registeredExtensions = []
        self.docType = ""
        self.stripTopLevelTags = True

        # Preprocessors
        self.preprocessors = odict.OrderedDict()
        self.preprocessors["html_block"] = \
                preprocessors.HtmlBlockPreprocessor(self)
        self.preprocessors["reference"] = \
                preprocessors.ReferencePreprocessor(self)
        # footnote preprocessor will be inserted with "<reference"

        # Block processors - ran by the parser
        self.parser = blockparser.BlockParser()
        self.parser.blockprocessors['empty'] = \
                blockprocessors.EmptyBlockProcessor(self.parser)
        self.parser.blockprocessors['indent'] = \
                blockprocessors.ListIndentProcessor(self.parser)
        self.parser.blockprocessors['code'] = \
                blockprocessors.CodeBlockProcessor(self.parser)
        self.parser.blockprocessors['hashheader'] = \
                blockprocessors.HashHeaderProcessor(self.parser)
        self.parser.blockprocessors['setextheader'] = \
                blockprocessors.SetextHeaderProcessor(self.parser)
        self.parser.blockprocessors['hr'] = \
                blockprocessors.HRProcessor(self.parser)
        self.parser.blockprocessors['olist'] = \
                blockprocessors.OListProcessor(self.parser)
        self.parser.blockprocessors['ulist'] = \
                blockprocessors.UListProcessor(self.parser)
        self.parser.blockprocessors['quote'] = \
                blockprocessors.BlockQuoteProcessor(self.parser)
        self.parser.blockprocessors['paragraph'] = \
                blockprocessors.ParagraphProcessor(self.parser)


        #self.prePatterns = []

        # Inline patterns - Run on the tree
        self.inlinePatterns = odict.OrderedDict()
        self.inlinePatterns["backtick"] = \
                inlinepatterns.BacktickPattern(inlinepatterns.BACKTICK_RE)
        self.inlinePatterns["escape"] = \
                inlinepatterns.SimpleTextPattern(inlinepatterns.ESCAPE_RE)
        self.inlinePatterns["reference"] = \
            inlinepatterns.ReferencePattern(inlinepatterns.REFERENCE_RE, self)
        self.inlinePatterns["link"] = \
                inlinepatterns.LinkPattern(inlinepatterns.LINK_RE, self)
        self.inlinePatterns["image_link"] = \
                inlinepatterns.ImagePattern(inlinepatterns.IMAGE_LINK_RE, self)
        self.inlinePatterns["image_reference"] = \
            inlinepatterns.ImageReferencePattern(inlinepatterns.IMAGE_REFERENCE_RE, self)
        self.inlinePatterns["autolink"] = \
            inlinepatterns.AutolinkPattern(inlinepatterns.AUTOLINK_RE, self)
        self.inlinePatterns["automail"] = \
            inlinepatterns.AutomailPattern(inlinepatterns.AUTOMAIL_RE, self)
        self.inlinePatterns["linebreak2"] = \
            inlinepatterns.SubstituteTagPattern(inlinepatterns.LINE_BREAK_2_RE, 'br')
        self.inlinePatterns["linebreak"] = \
            inlinepatterns.SubstituteTagPattern(inlinepatterns.LINE_BREAK_RE, 'br')
        self.inlinePatterns["html"] = \
                inlinepatterns.HtmlPattern(inlinepatterns.HTML_RE, self)
        self.inlinePatterns["entity"] = \
                inlinepatterns.HtmlPattern(inlinepatterns.ENTITY_RE, self)
        self.inlinePatterns["not_strong"] = \
                inlinepatterns.SimpleTextPattern(inlinepatterns.NOT_STRONG_RE)
        self.inlinePatterns["strong_em"] = \
            inlinepatterns.DoubleTagPattern(inlinepatterns.STRONG_EM_RE, 'strong,em')
        self.inlinePatterns["strong"] = \
            inlinepatterns.SimpleTagPattern(inlinepatterns.STRONG_RE, 'strong')
        self.inlinePatterns["emphasis"] = \
            inlinepatterns.SimpleTagPattern(inlinepatterns.EMPHASIS_RE, 'em')
        self.inlinePatterns["emphasis2"] = \
            inlinepatterns.SimpleTagPattern(inlinepatterns.EMPHASIS_2_RE, 'em')
        # The order of the handlers matters!!!


        # Tree processors - run once we have a basic parse.
        self.treeprocessors = odict.OrderedDict()
        self.treeprocessors["inline"] = treeprocessors.InlineProcessor(self)
        self.treeprocessors["prettify"] = \
                treeprocessors.PrettifyTreeprocessor(self)

        # Postprocessors - finishing touches.
        self.postprocessors = odict.OrderedDict()
        self.postprocessors["raw_html"] = \
                postprocessors.RawHtmlPostprocessor(self)
        self.postprocessors["amp_substitute"] = \
                postprocessors.AndSubstitutePostprocessor()
        # footnote postprocessor will be inserted with ">amp_substitute"

        self.references = {}
        self.htmlStash = preprocessors.HtmlStash()
        self.registerExtensions(extensions = extensions,
                                configs = extension_configs)
        self.reset()

    def registerExtensions(self, extensions, configs):
        """
        Register extensions with this instance of Markdown.

        Keyword aurguments:

        * extensions: A list of extensions, which can either
           be strings or objects.  See the docstring on Markdown.
        * configs: A dictionary mapping module names to config options.

        """
        for ext in extensions:
            if isinstance(ext, basestring):
                ext = load_extension(ext, configs.get(ext, []))
            elif hasattr(ext, 'extendMarkdown'):
                # Looks like an Extension.
                # Nothing to do here.
                pass
            else:
                message(ERROR, "Incorrect type! Extension '%s' is "
                               "neither a string or an Extension." %(repr(ext)))
                continue
            ext.extendMarkdown(self, globals())

    def registerExtension(self, extension):
        """ This gets called by the extension """
        self.registeredExtensions.append(extension)

    def reset(self):
        """
        Resets all state variables so that we can start with a new text.
        """
        self.htmlStash.reset()
        self.references.clear()

        for extension in self.registeredExtensions:
            extension.reset()

    def convert (self, source):
        """Convert markdown to serialized XHTML."""

        # Fixup the source text
        if not source:
            return u""  # a blank unicode string
        try:
            source = unicode(source)
        except UnicodeDecodeError:
            message(CRITICAL, 'UnicodeDecodeError: Markdown only accepts unicode or ascii input.')
            return u""

        source = source.replace(STX, "").replace(ETX, "")
        source = source.replace("\r\n", "\n").replace("\r", "\n") + "\n\n"
        source = re.sub(r'\n\s+\n', '\n\n', source)
        source = source.expandtabs(TAB_LENGTH)

        # Split into lines and run the line preprocessors.
        self.lines = source.split("\n")
        for prep in self.preprocessors.values():
            self.lines = prep.run(self.lines)

        # Parse the high-level elements.
        root = self.parser.parseDocument(self.lines).getroot()

        # Run the tree-processors
        for treeprocessor in self.treeprocessors.values():
            newRoot = treeprocessor.run(root)
            if newRoot:
                root = newRoot

        # Serialize _properly_.  Strip top-level tags.
        xml, length = codecs.utf_8_decode(etree.tostring(root, encoding="utf8"))
        if self.stripTopLevelTags:
            xml = xml.strip()[44:-7] + "\n"

        # Run the text post-processors
        for pp in self.postprocessors.values():
            xml = pp.run(xml)

        return xml.strip()

    def convertFile(self, input = None, output = None, encoding = None):
        """Converts a markdown file and returns the HTML as a unicode string.

        Decodes the file using the provided encoding (defaults to utf-8),
        passes the file content to markdown, and outputs the html to either
        the provided stream or the file with provided name, using the same
        encoding as the source file.

        **Note:** This is the only place that decoding and encoding of unicode
        takes place in Python-Markdown.  (All other code is unicode-in /
        unicode-out.)

        Keyword arguments:

        * input: Name of source text file.
        * output: Name of output file. Writes to stdout if `None`.
        * extensions: A list of extension names (may contain config args).
        * encoding: Encoding of input and output files. Defaults to utf-8.
        * safe_mode: Disallow raw html. One of "remove", "replace" or "escape".

        """

        encoding = encoding or "utf-8"

        # Read the source
        input_file = codecs.open(input, mode="r", encoding=encoding)
        text = input_file.read()
        input_file.close()
        text = text.lstrip(u'\ufeff') # remove the byte-order mark

        # Convert
        html = self.convert(text)

        # Write to file or stdout
        if type(output) == type("string"):
            output_file = codecs.open(output, "w", encoding=encoding)
            output_file.write(html)
            output_file.close()
        else:
            output.write(html.encode(encoding))


"""
Extensions
-----------------------------------------------------------------------------
"""

class Extension:
    """ Base class for extensions to subclass. """
    def __init__(self, configs = {}):
        """Create an instance of an Extention.

        Keyword arguments:

        * configs: A dict of configuration setting used by an Extension.
        """
        self.config = configs

    def getConfig(self, key):
        """ Return a setting for the given key or an empty string. """
        if self.config.has_key(key):
            return self.config[key][0]
        else:
            return ""

    def getConfigInfo(self):
        """ Return all config settings as a list of tuples. """
        return [(key, self.config[key][1]) for key in self.config.keys()]

    def setConfig(self, key, value):
        """ Set a config setting for `key` with the given `value`. """
        self.config[key][0] = value

    def extendMarkdown(self, md, md_globals):
        """
        Add the various proccesors and patterns to the Markdown Instance.

        This method must be overriden by every extension.

        Keyword arguments:

        * md: The Markdown instance.

        * md_globals: Global variables in the markdown module namespace.

        """
        pass


def load_extension(ext_name, configs = []):
    """Load extension by name, then return the module.

    The extension name may contain arguments as part of the string in the
    following format: "extname(key1=value1,key2=value2)"

    """

    # Parse extensions config params (ignore the order)
    configs = dict(configs)
    pos = ext_name.find("(") # find the first "("
    if pos > 0:
        ext_args = ext_name[pos+1:-1]
        ext_name = ext_name[:pos]
        pairs = [x.split("=") for x in ext_args.split(",")]
        configs.update([(x.strip(), y.strip()) for (x, y) in pairs])

    # Setup the module names
    ext_module = 'markdown.extensions'
    module_name_new_style = '.'.join([ext_module, ext_name])
    module_name_old_style = '_'.join(['mdx', ext_name])

    # Try loading the extention first from one place, then another
    try: # New style (markdown_extensons.<extension>)
        module = __import__(module_name_new_style, {}, {}, [ext_module])
    except ImportError:
        try: # Old style (mdx.<extension>)
            module = __import__(module_name_old_style)
        except ImportError:
           message(CRITICAL, "Failed loading extension '%s' from '%s' or '%s'"
               % (ext_name, module_name_new_style, module_name_old_style))

    # If the module is loaded successfully, we expect it to define a
    # function called makeExtension()
    try:
        return module.makeExtension(configs.items())
    except:
        message(CRITICAL, "Failed to instantiate extension '%s'" % ext_name)


def load_extensions(ext_names):
    """Loads multiple extensions"""
    extensions = []
    for ext_name in ext_names:
        extension = load_extension(ext_name)
        if extension:
            extensions.append(extension)
    return extensions


"""
EXPORTED FUNCTIONS
=============================================================================

Those are the two functions we really mean to export: markdown() and
markdownFromFile().
"""

def markdown(text,
             extensions = [],
             safe_mode = False):
    """Convert a markdown string to HTML and return HTML as a unicode string.

    This is a shortcut function for `Markdown` class to cover the most
    basic use case.  It initializes an instance of Markdown, loads the
    necessary extensions and runs the parser on the given text.

    Keyword arguments:

    * text: Markdown formatted text as Unicode or ASCII string.
    * extensions: A list of extensions or extension names (may contain config args).
    * safe_mode: Disallow raw html.  One of "remove", "replace" or "escape".

    Returns: An HTML document as a string.

    """
    md = Markdown(extensions=load_extensions(extensions),
                  safe_mode = safe_mode)
    return md.convert(text)


def markdownFromFile(input = None,
                     output = None,
                     extensions = [],
                     encoding = None,
                     safe = False):
    """Read markdown code from a file and write it to a file or a stream."""
    md = Markdown(extensions=load_extensions(extensions), safe_mode = safe)
    md.convertFile(input, output, encoding)