from __future__ import annotations

import os
import sys
from pathlib import Path
from typing import Optional


def is_frozen() -> bool:
    return getattr(sys, "frozen", False)


def _find_app_bundle_root(exe_path: Path) -> Optional[Path]:
    for parent in exe_path.parents:
        if parent.suffix.lower() == ".app":
            return parent
    return None


def _pick_runtime_root(exe_path: Path) -> Path:
    candidates: list[Path] = []
    app_root = _find_app_bundle_root(exe_path)
    if app_root is not None:
        candidates.append(app_root.parent)
    candidates.append(exe_path.parent)
    for candidate in candidates:
        if (candidate / "conf" / "factory_private.json.enc").exists():
            return candidate
        if (candidate / "conf").exists() or (candidate / "bin").exists() or (candidate / "keys").exists():
            return candidate
    return exe_path.parent


def venv_python(base_dir: Path) -> Path:
    scripts = "Scripts" if os.name == "nt" else "bin"
    exe = "python.exe" if os.name == "nt" else "python3"
    return base_dir / ".venv" / scripts / exe


def resolve_python(base_dir: Path) -> Path:
    venv_py = venv_python(base_dir)
    if venv_py.exists():
        return venv_py
    raise FileNotFoundError(
        "未找到当前目录的虚拟环境：\n"
        f"{venv_py}\n"
        "请先创建并安装依赖：\n"
        f"  python3 -m venv {base_dir / '.venv'}\n"
        f"  {venv_py} -m pip install -r {base_dir / 'requirements.txt'}"
    )


def get_base_dir() -> Path:
    if is_frozen():
        return _pick_runtime_root(Path(sys.executable).resolve())
    return Path(__file__).resolve().parent.parent


def resolve_bin_dir(base_dir: Path, configured: Path) -> Path:
    if configured.is_absolute():
        return configured
    return base_dir / configured


def select_bin_dir(base_dir: Path, configured: Path) -> Path:
    return resolve_bin_dir(base_dir, configured)


def _display_path(base_dir: Path, path: Path) -> str:
    try:
        rel = path.relative_to(base_dir)
        return str(rel)
    except ValueError:
        return path.name