from __future__ import annotations

import re

_CONTROL_CHAR_PATTERN = re.compile(r"[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]")
_MULTI_NEWLINE_PATTERN = re.compile(r"\n{3,}")


def sanitize_text(text: str) -> str:
    cleaned = _CONTROL_CHAR_PATTERN.sub("", text)
    cleaned = _MULTI_NEWLINE_PATTERN.sub("\n\n", cleaned)
    return cleaned.strip()


def chunk_markdown_text(text: str, limit: int = 4000) -> list[str]:
    if len(text) <= limit:
        return [text]

    chunks = []
    lines = text.split("\n")
    current = ""

    for line in lines:
        if len(current) + len(line) + 1 > limit:
            if current:
                chunks.append(current.strip())
                current = ""
            if len(line) > limit:
                while len(line) > limit:
                    split_at = _find_code_block_split(line, limit)
                    chunks.append(line[:split_at].strip())
                    line = line[split_at:].strip()
                if line:
                    current = line
            else:
                current = line
        else:
            if current:
                current += "\n" + line
            else:
                current = line

    if current.strip():
        chunks.append(current.strip())

    return chunks


def _find_code_block_split(line: str, limit: int) -> int:
    in_block = False
    chars = 0
    for i, ch in enumerate(line):
        if ch == "`":
            if line[i:i+3] == "```":
                in_block = not in_block
        if not in_block and chars >= limit:
            return i
        chars += 1
    return limit


def format_conversation_label(user_name: str, space_name: str) -> str:
    if space_name:
        return f"googlechat::{space_name}"
    return f"googlechat::{user_name}"


def build_typing_indicator_text(bot_name: str) -> str:
    return f"_{bot_name} is typing..._"


def resolve_bot_display_name(account: dict) -> str:
    resolved = account.get("resolved")
    if resolved and resolved.name:
        return resolved.name
    return account.get("name", "Bot")


def format_thread_context(recent_messages: list[dict]) -> str:
    if not recent_messages:
        return ""

    lines = [
        "[Thread conversation - previous replies. You are participating in this thread.]",
        "",
        "[Previous messages]",
    ]
    for msg in recent_messages[-10:]:
        author = msg.get("author", "Unknown")
        content = msg.get("content", "")
        if content:
            lines.append(f"{author}: {content}")

    lines.append("")
    lines.append("[Current message]")
    return "\n".join(lines)