"""
HWID Generator
==============
Generates a stable hardware fingerprint for this machine using:
  - Windows MachineGuid (most stable, survives most software changes)
  - CPU Processor ID (hardware-level, very stable)

Returns a SHA-256 hex digest. Never changes unless hardware changes.
"""

import functools
import hashlib
import subprocess
import winreg


@functools.lru_cache(maxsize=None)
def get_hwid() -> str:
    """Return a stable SHA-256 HWID string for the current machine."""
    components = []

    # Windows MachineGuid — set once at OS install, very stable
    try:
        key = winreg.OpenKey(
            winreg.HKEY_LOCAL_MACHINE,
            r"SOFTWARE\Microsoft\Cryptography"
        )
        guid, _ = winreg.QueryValueEx(key, "MachineGuid")
        winreg.CloseKey(key)
        components.append(f"guid:{guid}")
    except Exception:
        pass

    # CPU Processor ID — hardware-level identifier
    try:
        result = subprocess.run(
            ["wmic", "cpu", "get", "ProcessorId", "/value"],
            capture_output=True, text=True, timeout=5
        )
        for line in result.stdout.splitlines():
            line = line.strip()
            if line.startswith("ProcessorId=") and "=" in line:
                cpu_id = line.split("=", 1)[1].strip()
                if cpu_id:
                    components.append(f"cpu:{cpu_id}")
                break
    except Exception:
        pass

    if not components:
        raise RuntimeError(
            "Could not generate HWID. "
            "This application requires Windows and access to system information."
        )

    raw = "|".join(components)
    return hashlib.sha256(raw.encode("utf-8")).hexdigest()