import os
import sys
from pathlib import Path

APP_NAME = "browser-cli"
RUNTIME_DIRNAME = ".browser_cli"
DEFAULT_ALIAS = "default"

def is_windows() -> bool:
    return sys.platform.startswith("win")

def runtime_dir() -> Path:
    if is_windows():
        base = Path(os.environ.get("LOCALAPPDATA", Path.home() / "AppData" / "Local"))
        return base / APP_NAME
    return Path("/tmp") / RUNTIME_DIRNAME

def registry_path() -> Path:
    return runtime_dir() / "registry.json"

def install_base_dir() -> Path:
    if is_windows():
        return runtime_dir()
    if sys.platform == "darwin":
        return Path.home() / "Library" / "Application Support" / APP_NAME
    return Path(os.environ.get("XDG_DATA_HOME", Path.home() / ".local" / "share")) / APP_NAME

def sanitize_alias(alias:str) -> str:
    cleaned = "".join(ch if ch.isalnum() or ch in "._-" else "_" for ch in alias.strip())
    return cleaned or DEFAULT_ALIAS

def endpoint_for_alias(alias:str) -> str:
    safe = sanitize_alias(alias)
    if is_windows():
        return rf"\\.\pipe\browser-cli-{safe}"
    return str(runtime_dir() / f"{safe}.sock")