#!/usr/bin/env python3
"""Create the private runtime used by the platform wrappers."""

from __future__ import annotations

import os
from pathlib import Path
import shutil
import subprocess
import sys
import venv


def default_venv() -> Path:
    override = os.environ.get("CODEX_IMAGEGEN_VENV", "").strip()
    if override:
        return Path(override).expanduser()
    if os.name == "nt":
        documents = os.environ.get("CODEX_DOCUMENTS") or (Path.home() / "Documents")
        return Path(documents) / "Codex" / ".shared" / "image-gen-custom" / "venv"
    if sys.platform == "darwin":
        return Path.home() / "Library" / "Caches" / "Codex" / "image-gen-custom" / "venv"
    root = os.environ.get("XDG_CACHE_HOME") or (Path.home() / ".cache")
    return Path(root) / "codex" / "image-gen-custom" / "venv"


def bootstrap_python() -> list[str]:
    override = os.environ.get("CODEX_IMAGEGEN_PYTHON", "").strip()
    if override:
        return [override]
    candidates: list[list[str]] = []
    if os.name == "nt":
        cache_root = Path.home() / ".cache" / "codex-runtimes"
        for path in sorted(cache_root.glob("**/dependencies/python/python.exe")):
            if path.is_file():
                candidates.append([str(path)])
        for candidate in ("py", "python", "python3"):
            found = shutil.which(candidate)
            if found:
                candidates.append([found, "-3"] if candidate == "py" else [found])
    else:
        for candidate in ("python3", "python"):
            found = shutil.which(candidate)
            if found:
                candidates.append([found])
    probe = "import sys"
    for candidate in candidates:
        try:
            result = subprocess.run([*candidate, "-c", probe], check=False, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        except OSError:
            continue
        if result.returncode == 0:
            return candidate
    raise RuntimeError("Python 3 was not found; install Python or set CODEX_IMAGEGEN_PYTHON")


def ensure_runtime(require_keyring: bool = False) -> Path:
    target = default_venv()
    python_path = target / ("Scripts/python.exe" if os.name == "nt" else "bin/python")
    if not python_path.exists():
        target.parent.mkdir(parents=True, exist_ok=True)
        command = bootstrap_python() + ["-m", "venv", str(target)]
        subprocess.run(command, check=True)
    if require_keyring:
        check = subprocess.run([str(python_path), "-c", "import keyring"], check=False)
    else:
        check = None
    if check is not None and check.returncode:
        packages = ["keyring"]
        subprocess.run(
            [str(python_path), "-m", "pip", "install", "--disable-pip-version-check", *packages],
            check=True,
            stdout=subprocess.DEVNULL,
        )
    return python_path


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--keyring", action="store_true")
    options = parser.parse_args()
    try:
        print(ensure_runtime(options.keyring))
    except Exception as exc:
        print(f"Error: {exc}", file=sys.stderr)
        raise SystemExit(1)