"""Java/JVM presence check with actionable error messages."""

from __future__ import annotations

import shutil
import subprocess
import sys


def ensure_java() -> None:
    """Raise a clear RuntimeError if Java is not installed."""
    if shutil.which("java") is not None:
        return

    # Try jpype's own detection as a fallback
    try:
        import jpype  # noqa: PLC0415
        jpype.getDefaultJVMPath()
        return
    except Exception:  # noqa: BLE001
        pass

    _install_cmd = _get_install_cmd()
    raise RuntimeError(
        "\n"
        "╔══════════════════════════════════════════════════════════════╗\n"
        "║  TurkTokenizer requires Java (JVM) — not found on this system  ║\n"
        "╠══════════════════════════════════════════════════════════════╣\n"
        f"║  Install Java with:                                          ║\n"
        f"║    {_install_cmd:<58}║\n"
        "║                                                              ║\n"
        "║  Then re-run your script.                                    ║\n"
        "╚══════════════════════════════════════════════════════════════╝\n"
    )


def _get_install_cmd() -> str:
    if sys.platform == "linux":
        # Try to detect distro
        try:
            out = subprocess.check_output(
                ["cat", "/etc/os-release"], text=True, stderr=subprocess.DEVNULL
            )
            if "ubuntu" in out.lower() or "debian" in out.lower():
                return "sudo apt install default-jre"
            if "fedora" in out.lower() or "rhel" in out.lower() or "centos" in out.lower():
                return "sudo dnf install java-latest-openjdk"
            if "arch" in out.lower():
                return "sudo pacman -S jre-openjdk"
        except Exception:  # noqa: BLE001
            pass
        return "sudo apt install default-jre"
    if sys.platform == "darwin":
        return "brew install openjdk"
    if sys.platform == "win32":
        return "winget install Microsoft.OpenJDK.21"
    return "Install Java from https://adoptium.net"