from __future__ import annotations

import re
from typing import Any

_IRC_LINE_PATTERN = re.compile(
    r"^(?:@(?P<tags>[^ ]+) )?(?::(?P<prefix>[^ ]+) )?(?P<command>[a-zA-Z]+|\d{3})"
    r"(?: (?P<params>.+?))?(?: :(?P<trailing>.*))?$"
)

_IRC_PREFIX_PATTERN = re.compile(r"^([^!@]+)(?:!([^@]+))?(?:@(.+))?$")


def parse_irc_line(line: str) -> tuple[str | None, str, list[str]]:
    match = _IRC_LINE_PATTERN.match(line)
    if match is None:
        return None, line, []

    command = match.group("command").upper()
    prefix = match.group("prefix") or None

    args: list[str] = []
    params = match.group("params") or ""
    if params:
        args.extend(params.split())

    trailing = match.group("trailing")
    if trailing is not None:
        args.append(trailing)

    return prefix, command, args


def parse_irc_prefix(prefix: str | None) -> dict[str, str | None]:
    if not prefix:
        return {"nick": None, "user": None, "host": None}

    m = _IRC_PREFIX_PATTERN.match(prefix)
    if m is None:
        return {"nick": prefix, "user": None, "host": None}

    return {
        "nick": m.group(1) or None,
        "user": m.group(2) or None,
        "host": m.group(3) or None,
    }


def extract_nick(prefix: str | None) -> str:
    if not prefix:
        return "unknown"
    return prefix.split("!")[0]


def parse_irc_tags(line: str) -> dict[str, Any] | None:
    if not line.startswith("@"):
        return None

    space_idx = line.find(" ")
    if space_idx == -1:
        return None

    tag_str = line[1:space_idx]
    tags: dict[str, Any] = {}

    for tag in tag_str.split(";"):
        if "=" in tag:
            key, value = tag.split("=", 1)
            tags[key] = value
        else:
            tags[tag] = True

    return tags


def parse_irc_tags_dict(line: str) -> dict[str, Any]:
    return parse_irc_tags(line) or {}


def is_ctcp_message(text: str) -> bool:
    return text.startswith("\x01") and text.endswith("\x01")


def parse_ctcp(text: str) -> tuple[str, str]:
    inner = text[1:-1]
    parts = inner.split(" ", 1)
    command = parts[0].upper()
    args = parts[1] if len(parts) > 1 else ""
    return command, args


def format_ctcp(command: str, args: str = "") -> str:
    if args:
        return f"\x01{command} {args}\x01"
    return f"\x01{command}\x01"


def extract_account_from_tags(tags: dict[str, Any]) -> str | None:
    return tags.get("account") or None


def is_identified(tags: dict[str, Any]) -> bool:
    account = extract_account_from_tags(tags)
    return account is not None and account != "*"