from __future__ import annotations

from dataclasses import dataclass
from typing import Optional, Union


@dataclass
class HelloServer:
    description: str


@dataclass
class NewGame:
    player1: str
    player2: str


@dataclass
class MoveBroadcast:
    square: Optional[int]
    value: int  # piece index or 16/17


@dataclass
class GameOver:
    reason: str  # "VICTORY" | "DRAW" | "DISCONNECT"
    winner: Optional[str]


@dataclass
class UnknownCommand:
    raw: str


ServerMessage = Union[HelloServer, NewGame, MoveBroadcast, GameOver, UnknownCommand]


def parse_server_line(line: str) -> ServerMessage:
    parts = line.strip().split("~")
    if not parts:
        return UnknownCommand(raw=line)
    cmd = parts[0]
    if cmd == "HELLO" and len(parts) == 2:
        return HelloServer(description=parts[1])
    if cmd == "NEWGAME" and len(parts) == 3:
        return NewGame(player1=parts[1], player2=parts[2])
    if cmd == "MOVE":
        if len(parts) == 2:
            try:
                value = int(parts[1])
            except ValueError:
                return UnknownCommand(raw=line)
            return MoveBroadcast(square=None, value=value)
        if len(parts) == 3:
            try:
                square = int(parts[1])
                value = int(parts[2])
            except ValueError:
                return UnknownCommand(raw=line)
            return MoveBroadcast(square=square, value=value)
    if cmd == "GAMEOVER":
        if len(parts) == 2:
            return GameOver(reason=parts[1], winner=None)
        if len(parts) == 3:
            return GameOver(reason=parts[1], winner=parts[2])
    return UnknownCommand(raw=line)


def format_hello(description: str) -> str:
    return f"HELLO~{description}"


def format_queue() -> str:
    return "QUEUE"


def format_move_initial(piece: int) -> str:
    return f"MOVE~{piece}"


def format_move_normal(square: int, m_value: int) -> str:
    return f"MOVE~{square}~{m_value}"