# mako/filters.py
# Copyright 2006-2022 the Mako authors and contributors <see AUTHORS file>
#
# This module is part of Mako and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php


import codecs
from html.entities import codepoint2name
from html.entities import name2codepoint
import re
from urllib.parse import quote_plus

import markupsafe

html_escape = markupsafe.escape

xml_escapes = {
    "&": "&amp;",
    ">": "&gt;",
    "<": "&lt;",
    '"': "&#34;",  # also &quot; in html-only
    "'": "&#39;",  # also &apos; in html-only
}


def xml_escape(string):
    return re.sub(r'([&<"\'>])', lambda m: xml_escapes[m.group()], string)


def url_escape(string):
    # convert into a list of octets
    string = string.encode("utf8")
    return quote_plus(string)


def trim(string):
    return string.strip()


class Decode:
    def __getattr__(self, key):
        def decode(x):
            if isinstance(x, str):
                return x
            elif not isinstance(x, bytes):
                return decode(str(x))
            else:
                return str(x, encoding=key)

        return decode


decode = Decode()


class XMLEntityEscaper:
    def __init__(self, codepoint2name, name2codepoint):
        self.codepoint2entity = {
            c: str("&%s;" % n) for c, n in codepoint2name.items()
        }
        self.name2codepoint = name2codepoint

    def escape_entities(self, text):
        """Replace characters with their character entity references.

        Only characters corresponding to a named entity are replaced.
        """
        return str(text).translate(self.codepoint2entity)

    def __escape(self, m):
        codepoint = ord(m.group())
        try:
            return self.codepoint2entity[codepoint]
        except (KeyError, IndexError):
            return "&#x%X;" % codepoint

    __escapable = re.compile(r'["&<>]|[^\x00-\x7f]')

    def escape(self, text):
        """Replace characters with their character references.

        Replace characters by their named entity references.
        Non-ASCII characters, if they do not have a named entity reference,
        are replaced by numerical character references.

        The return value is guaranteed to be ASCII.
        """
        return self.__escapable.sub(self.__escape, str(text)).encode("ascii")

    # XXX: This regexp will not match all valid XML entity names__.
    # (It punts on details involving involving CombiningChars and Extenders.)
    #
    # .. __: http://www.w3.org/TR/2000/REC-xml-20001006#NT-EntityRef
    __characterrefs = re.compile(
        r"""& (?:
                                          \#(\d+)
                                          | \#x([\da-f]+)
                                          | ( (?!\d) [:\w] [-.:\w]+ )
                                          ) ;""",
        re.X | re.UNICODE,
    )

    def __unescape(self, m):
        dval, hval, name = m.groups()
        if dval:
            codepoint = int(dval)
        elif hval:
            codepoint = int(hval, 16)
        else:
            codepoint = self.name2codepoint.get(name, 0xFFFD)
            # U+FFFD = "REPLACEMENT CHARACTER"
        if codepoint < 128:
            return chr(codepoint)
        return chr(codepoint)

    def unescape(self, text):
        """Unescape character references.

        All character references (both entity references and numerical
        character references) are unescaped.
        """
        return self.__characterrefs.sub(self.__unescape, text)


_html_entities_escaper = XMLEntityEscaper(codepoint2name, name2codepoint)

html_entities_escape = _html_entities_escaper.escape_entities
html_entities_unescape = _html_entities_escaper.unescape


def htmlentityreplace_errors(ex):
    """An encoding error handler.

    This python codecs error handler replaces unencodable
    characters with HTML entities, or, if no HTML entity exists for
    the character, XML character references::

        >>> 'The cost was \u20ac12.'.encode('latin1', 'htmlentityreplace')
        'The cost was &euro;12.'
    """
    if isinstance(ex, UnicodeEncodeError):
        # Handle encoding errors
        bad_text = ex.object[ex.start : ex.end]
        text = _html_entities_escaper.escape(bad_text)
        return (str(text), ex.end)
    raise ex


codecs.register_error("htmlentityreplace", htmlentityreplace_errors)


DEFAULT_ESCAPES = {
    "x": "filters.xml_escape",
    "h": "filters.html_escape",
    "u": "filters.url_escape",
    "trim": "filters.trim",
    "entity": "filters.html_entities_escape",
    "unicode": "str",
    "decode": "decode",
    "str": "str",
    "n": "n",
}
