"""
Shared utilities for FunguyBot plugins.
"""
import html
import ipaddress
import socket
import logging

logger = logging.getLogger(__name__)

# Networks considered unsafe for outbound connections
_PRIVATE_RANGES = [
    ipaddress.ip_network('10.0.0.0/8'),
    ipaddress.ip_network('172.16.0.0/12'),
    ipaddress.ip_network('192.168.0.0/16'),
    ipaddress.ip_network('127.0.0.0/8'),
    ipaddress.ip_network('169.254.0.0/16'),
    ipaddress.ip_network('0.0.0.0/8'),
    ipaddress.ip_network('::1/128'),
    ipaddress.ip_network('fc00::/7'),
    ipaddress.ip_network('fe80::/10'),
    ipaddress.ip_network('::/128'),
]

def html_escape(text: str) -> str:
    """Escape HTML special characters for safe embedding in messages."""
    return html.escape(str(text), quote=False)

def collapsible_summary(title: str, body: str, expanded: bool = False) -> str:
    """Wrap content in a collapsible HTML details block."""
    open_attr = ' open' if expanded else ''
    return f"<details{open_attr}>\n<summary><strong>{title}</strong></summary>\n{body}\n</details>"

def is_public_destination(target: str) -> bool:
    """
    Returns True if `target` (hostname or IP) does NOT resolve to any
    private, loopback, or link‑local address.
    """
    try:
        addr = ipaddress.ip_address(target)
        if any(addr in net for net in _PRIVATE_RANGES):
            return False
        return True
    except ValueError:
        pass

    try:
        addrinfo = socket.getaddrinfo(target, None)
        for _, _, _, _, sockaddr in addrinfo:
            ip = sockaddr[0]
            addr = ipaddress.ip_address(ip)
            if any(addr in net for net in _PRIVATE_RANGES):
                return False
        return True
    except Exception as e:
        logger.warning(f"Cannot resolve {target}: {e}")
        return False

async def handle_command(room, message, bot, prefix, config):
    """No-op handler so the bot doesn't crash when loading this module as a plugin."""
    pass

async def send_html_message(bot, room_id, html_body, markdown_fallback):
    """Send an HTML-formatted message with a Markdown fallback.

    Args:
        bot: simplematrixbotlib.Bot instance
        room_id: Matrix room ID
        html_body: HTML string (table, etc.)
        markdown_fallback: Markdown/plain text for clients that don't render HTML
    """
    content = {
        "msgtype": "m.text",
        "body": markdown_fallback,
        "format": "org.matrix.custom.html",
        "formatted_body": html_body
    }
    await bot.async_client.room_send(
        room_id=room_id,
        message_type="m.room.message",
        content=content
    )