import os

def read_file(path):
    """Reads the content of a file, returning None if the file doesn't exist or can't be read."""
    try:
        with open(path, 'r') as f:
            return f.read().strip()
    except (FileNotFoundError, PermissionError):
        return None

def detect_hypervisor():
    """Detects the hypervisor (Hyper-V or KVM) based on system files."""

    # 1. Check for Hyper-V
    # The presence of this directory is a strong indicator of Hyper-V
    if os.path.isdir("/sys/hypervisor/microsoft"):
        return "Hyper-V"

    # 2. Check DMI information (often reliable for VMs)
    product_name = read_file("/sys/class/dmi/id/product_name")
    sys_vendor = read_file("/sys/class/dmi/id/sys_vendor")

    if product_name:
        product_name_lower = product_name.lower()
        if "virtualbox" in product_name_lower:
            return "VirtualBox"
        elif "vmware" in product_name_lower:
            return "VMware"
        elif "kvm" in product_name_lower or "qemu" in product_name_lower:
            return "KVM/QEMU"
        elif "microsoft corporation" in sys_vendor.lower() and "virtual machine" in product_name_lower:
            # Fallback for Hyper-V if /sys/hypervisor/microsoft is not present
            return "Hyper-V (via DMI)"

    # 3. Check for KVM device (requires /dev access, but worth a try)
    if os.path.exists("/dev/kvm"):
        return "KVM (via /dev/kvm)"

    # 4. Check for Xen (common alternative)
    if os.path.isdir("/sys/hypervisor/xen"):
        return "Xen"

    # 5. Check for common cloud/container environments (e.g., AWS, GCP, Docker)
    if sys_vendor and "amazon ec2" in sys_vendor.lower():
        return "AWS EC2"
    if sys_vendor and "google" in sys_vendor.lower():
        return "Google Compute Engine"
    if os.path.exists("/.dockerenv"):
        return "Docker Container"

    return "Unknown or Bare Metal"

if __name__ == "__main__":
    hypervisor = detect_hypervisor()
    print(f"Hypervisor: {hypervisor}")