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.venv2/Lib/site-packages/telethon/extensions/html.py

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+"""
+Simple HTML -> Telegram entity parser.
+"""
+import struct
+from collections import deque
+from html import escape
+from html.parser import HTMLParser
+from typing import Iterable, Optional, Tuple, List
+
+from ..helpers import add_surrogate, del_surrogate, within_surrogate, strip_text
+from ..tl import TLObject
+from ..tl.types import (
+    MessageEntityBold, MessageEntityItalic, MessageEntityCode,
+    MessageEntityPre, MessageEntityEmail, MessageEntityUrl,
+    MessageEntityTextUrl, MessageEntityMentionName,
+    MessageEntityUnderline, MessageEntityStrike, MessageEntityBlockquote,
+    TypeMessageEntity
+)
+
+
+class HTMLToTelegramParser(HTMLParser):
+    def __init__(self):
+        super().__init__()
+        self.text = ''
+        self.entities = []
+        self._building_entities = {}
+        self._open_tags = deque()
+        self._open_tags_meta = deque()
+
+    def handle_starttag(self, tag, attrs):
+        self._open_tags.appendleft(tag)
+        self._open_tags_meta.appendleft(None)
+
+        attrs = dict(attrs)
+        EntityType = None
+        args = {}
+        if tag == 'strong' or tag == 'b':
+            EntityType = MessageEntityBold
+        elif tag == 'em' or tag == 'i':
+            EntityType = MessageEntityItalic
+        elif tag == 'u':
+            EntityType = MessageEntityUnderline
+        elif tag == 'del' or tag == 's':
+            EntityType = MessageEntityStrike
+        elif tag == 'blockquote':
+            EntityType = MessageEntityBlockquote
+        elif tag == 'code':
+            try:
+                # If we're in the middle of a <pre> tag, this <code> tag is
+                # probably intended for syntax highlighting.
+                #
+                # Syntax highlighting is set with
+                #     <code class='language-...'>codeblock</code>
+                # inside <pre> tags
+                pre = self._building_entities['pre']
+                try:
+                    pre.language = attrs['class'][len('language-'):]
+                except KeyError:
+                    pass
+            except KeyError:
+                EntityType = MessageEntityCode
+        elif tag == 'pre':
+            EntityType = MessageEntityPre
+            args['language'] = ''
+        elif tag == 'a':
+            try:
+                url = attrs['href']
+            except KeyError:
+                return
+            if url.startswith('mailto:'):
+                url = url[len('mailto:'):]
+                EntityType = MessageEntityEmail
+            else:
+                if self.get_starttag_text() == url:
+                    EntityType = MessageEntityUrl
+                else:
+                    EntityType = MessageEntityTextUrl
+                    args['url'] = del_surrogate(url)
+                    url = None
+            self._open_tags_meta.popleft()
+            self._open_tags_meta.appendleft(url)
+
+        if EntityType and tag not in self._building_entities:
+            self._building_entities[tag] = EntityType(
+                offset=len(self.text),
+                # The length will be determined when closing the tag.
+                length=0,
+                **args)
+
+    def handle_data(self, text):
+        previous_tag = self._open_tags[0] if len(self._open_tags) > 0 else ''
+        if previous_tag == 'a':
+            url = self._open_tags_meta[0]
+            if url:
+                text = url
+
+        for tag, entity in self._building_entities.items():
+            entity.length += len(text)
+
+        self.text += text
+
+    def handle_endtag(self, tag):
+        try:
+            self._open_tags.popleft()
+            self._open_tags_meta.popleft()
+        except IndexError:
+            pass
+        entity = self._building_entities.pop(tag, None)
+        if entity:
+            self.entities.append(entity)
+
+
+def parse(html: str) -> Tuple[str, List[TypeMessageEntity]]:
+    """
+    Parses the given HTML message and returns its stripped representation
+    plus a list of the MessageEntity's that were found.
+
+    :param html: the message with HTML to be parsed.
+    :return: a tuple consisting of (clean message, [message entities]).
+    """
+    if not html:
+        return html, []
+
+    parser = HTMLToTelegramParser()
+    parser.feed(add_surrogate(html))
+    text = strip_text(parser.text, parser.entities)
+    parser.entities.reverse()
+    parser.entities.sort(key=lambda entity: entity.offset)
+    return del_surrogate(text), parser.entities
+
+
+ENTITY_TO_FORMATTER = {
+    MessageEntityBold: ('<strong>', '</strong>'),
+    MessageEntityItalic: ('<em>', '</em>'),
+    MessageEntityCode: ('<code>', '</code>'),
+    MessageEntityUnderline: ('<u>', '</u>'),
+    MessageEntityStrike: ('<del>', '</del>'),
+    MessageEntityBlockquote: ('<blockquote>', '</blockquote>'),
+    MessageEntityPre: lambda e, _: (
+        "<pre>\n"
+        "    <code class='language-{}'>\n"
+        "        ".format(e.language), "{}\n"
+        "    </code>\n"
+        "</pre>"
+    ),
+    MessageEntityEmail: lambda _, t: ('<a href="mailto:{}">'.format(t), '</a>'),
+    MessageEntityUrl: lambda _, t: ('<a href="{}">'.format(t), '</a>'),
+    MessageEntityTextUrl: lambda e, _: ('<a href="{}">'.format(escape(e.url)), '</a>'),
+    MessageEntityMentionName: lambda e, _: ('<a href="tg://user?id={}">'.format(e.user_id), '</a>'),
+}
+
+
+def unparse(text: str, entities: Iterable[TypeMessageEntity]) -> str:
+    """
+    Performs the reverse operation to .parse(), effectively returning HTML
+    given a normal text and its MessageEntity's.
+
+    :param text: the text to be reconverted into HTML.
+    :param entities: the MessageEntity's applied to the text.
+    :return: a HTML representation of the combination of both inputs.
+    """
+    if not text:
+        return text
+    elif not entities:
+        return escape(text)
+
+    if isinstance(entities, TLObject):
+        entities = (entities,)
+
+    text = add_surrogate(text)
+    insert_at = []
+    for i, entity in enumerate(entities):
+        s = entity.offset
+        e = entity.offset + entity.length
+        delimiter = ENTITY_TO_FORMATTER.get(type(entity), None)
+        if delimiter:
+            if callable(delimiter):
+                delimiter = delimiter(entity, text[s:e])
+            insert_at.append((s, i, delimiter[0]))
+            insert_at.append((e, -i, delimiter[1]))
+
+    insert_at.sort(key=lambda t: (t[0], t[1]))
+    next_escape_bound = len(text)
+    while insert_at:
+        # Same logic as markdown.py
+        at, _, what = insert_at.pop()
+        while within_surrogate(text, at):
+            at += 1
+
+        text = text[:at] + what + escape(text[at:next_escape_bound]) + text[next_escape_bound:]
+        next_escape_bound = at
+
+    text = escape(text[:next_escape_bound]) + text[next_escape_bound:]
+
+    return del_surrogate(text)