#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright (c) 2025-2026 Renato Xavier da Silveira Rosa
# See [LICENSE](./LICENSE) or [BSD-3-Clause-Clear](https://spdx.org/licenses/BSD-3-Clause-Clear.html)
"""Utilities for running vendored EPUB->TTS repositories in isolated venvs."""

import subprocess
import sys
import venv
from pathlib import Path
from typing import Optional


def get_vendor_root() -> Path:
    return Path(__file__).resolve().parents[1] / "vendor"


def get_repo_path(repo_name: str) -> Path:
    repo_path = get_vendor_root() / repo_name
    if not repo_path.exists():
        raise FileNotFoundError(
            f"Vendored repository '{repo_name}' not found under {get_vendor_root()}"
        )
    return repo_path


def get_venv_path(repo_name: str) -> Path:
    return get_repo_path(repo_name) / ".venv"


def get_venv_python(repo_name: str) -> Path:
    venv_path = get_venv_path(repo_name)
    python_executable = (
        venv_path / "Scripts" / "python.exe"
        if sys.platform == "win32"
        else venv_path / "bin" / "python"
    )
    if not python_executable.exists():
        raise FileNotFoundError(
            f"Python executable not found in virtualenv at {python_executable}"
        )
    return python_executable


def ensure_venv(repo_name: str) -> Path:
    repo_path = get_repo_path(repo_name)
    venv_path = get_venv_path(repo_name)
    if not venv_path.exists():
        venv.EnvBuilder(with_pip=True).create(venv_path)
        python_executable = get_venv_python(repo_name)
        subprocess.run(
            [str(python_executable), "-m", "pip", "install", "-e", str(repo_path)],
            check=True,
        )
    return get_venv_python(repo_name)


def build_run_command(
    repo_name: str,
    module_name: str,
    backend_cmd: Optional[str] = None,
) -> list[str]:
    if backend_cmd is None or backend_cmd == repo_name:
        python_executable = ensure_venv(repo_name)
        return [str(python_executable), "-m", module_name]
    return [backend_cmd]