Teknium
97 lines
4.4 KiB
Python
97 lines
4.4 KiB
Python
"""Shared Signal formatting helpers: Markdown → Signal native formatting lives here so both the live
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adapter and the standalone send paths emit the same bodyRanges."""
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from __future__ import annotations
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import re
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_CODE_BLOCK_RE = re.compile(r"```[a-zA-Z0-9_+-]*\n?(.*?)```", re.DOTALL)
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_HEADING_RE = re.compile(r"^#{1,6}\s+", re.MULTILINE)
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_INLINE_PATTERNS = [
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(re.compile(r"\*\*(.+?)\*\*", re.DOTALL), "BOLD"),
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(re.compile(r"__(.+?)__", re.DOTALL), "BOLD"),
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(re.compile(r"~~(.+?)~~", re.DOTALL), "STRIKETHROUGH"),
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(re.compile(r"`(.+?)`"), "MONOSPACE"),
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(re.compile(r"(?<!\*)\*(?!\*| )(.+?)(?<!\*)\*(?!\*)"), "ITALIC"),
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(re.compile(r"(?<!\w)_(?!_)(.+?)(?<!_)_(?!\w)"), "ITALIC")]
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def _utf16_len(s: str) -> int:
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"""Length of *s* in UTF-16 code units."""
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return len(s.encode("utf-16-le")) // 2
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def _normalize_bullet_markers(source: str) -> str:
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"""Replace Markdown bullet markers with plain Unicode bullets (Signal renders ``- item`` literally).
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Fenced code blocks are kept byte-for-byte: list-looking lines inside code are code, not bullets."""
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parts = re.split(r"(```.*?```)", source, flags=re.DOTALL)
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return "".join(re.sub(r"(?m)^([ \t]{0,3})[-*+]\s+", r"\1• ", part) if idx % 2 == 0 else part
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for idx, part in enumerate(parts))
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def markdown_to_signal(text: str) -> tuple[str, list[str]]:
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"""Convert markdown to plain text + Signal textStyles list. Signal uses ``bodyRanges`` (signal-cli
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``textStyle`` / ``textStyles`` params) as ``start:length:STYLE`` with positions in UTF-16 code units.
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Supported styles: BOLD, ITALIC, STRIKETHROUGH, MONOSPACE."""
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text = _normalize_bullet_markers(re.sub(r"\n{3,}", "\n\n", text).strip())
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styles: list[tuple[int, int, str]] = []
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while match := _CODE_BLOCK_RE.search(text):
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inner = match.group(1).rstrip("\n")
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styles.append((match.start(), len(inner), "MONOSPACE"))
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text = text[: match.start()] + inner + text[match.end() :]
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new_text, last_end = "", 0
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for match in _HEADING_RE.finditer(text):
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new_text += text[last_end : match.start()]
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eol = text.find("\n", match.end())
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if eol == -1:
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eol = len(text)
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heading_text = text[match.end() : eol]
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styles.append((len(new_text), len(heading_text), "BOLD"))
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new_text += heading_text
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last_end = eol
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text = new_text + text[last_end:]
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# Inline markers: first pattern to claim a span wins; later overlapping matches are dropped.
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all_matches: list[tuple[int, int, int, int, str]] = []
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occupied: list[tuple[int, int]] = []
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for pattern, style in _INLINE_PATTERNS:
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for match in pattern.finditer(text):
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ms, me = match.start(), match.end()
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if not any(ms < oe and me > os for os, oe in occupied):
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all_matches.append((ms, me, match.start(1), match.end(1), style))
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occupied.append((ms, me))
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all_matches.sort()
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# Strip the markers, recording (pos, len) removals so earlier block/heading ranges can be
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# shifted, and capturing inline ranges in the stripped text.
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result, last_end = "", 0
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removals: list[tuple[int, int]] = []
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inline_styles: list[tuple[int, int, str]] = []
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for ms, me, g1s, g1e, style in all_matches:
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if g1s > ms:
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removals.append((ms, g1s - ms))
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if me > g1e:
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removals.append((g1e, me - g1e))
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result += text[last_end:ms]
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inner = text[g1s:g1e]
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inline_styles.append((len(result), len(inner), style))
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result += inner
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last_end = me
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removals.sort()
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def _adjust(pos: int) -> int:
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shift = 0
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for remove_pos, remove_len in removals:
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if remove_pos >= pos:
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break
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shift += min(remove_len, pos - remove_pos)
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return pos - shift
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adjusted_prior = [(_adjust(start), _adjust(start + length) - _adjust(start), style)
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for start, length, style in styles if _adjust(start + length) > _adjust(start)]
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text = result + text[last_end:]
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style_strings: list[str] = []
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for cp_start, cp_len, style_type in sorted(adjusted_prior + inline_styles):
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if 0 <= cp_start and cp_start + cp_len <= len(text):
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u16_start, u16_len = _utf16_len(text[:cp_start]), _utf16_len(text[cp_start : cp_start + cp_len])
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style_strings.append(f"{u16_start}:{u16_len}:{style_type}")
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return text, style_strings
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