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"""
Utilities for common functionality used by several examples in this directory.
"""

import ctypes
from getpass import getpass

from fido2.client import DefaultClientDataCollector, Fido2Client, UserInteraction
from fido2.hid import CtapHidDevice

# Support NFC devices if we can
try:
    from fido2.pcsc import CtapPcscDevice
except ImportError:
    CtapPcscDevice = None

# Use the Windows WebAuthn API if available, and we're not running as admin
try:
    from fido2.client.windows import WindowsClient

    use_winclient = (
        WindowsClient.is_available() and not ctypes.windll.shell32.IsUserAnAdmin()
    )
except Exception:
    use_winclient = False


# Handle user interaction via CLI prompts
class CliInteraction(UserInteraction):
    def __init__(self):
        self._pin = None

    def prompt_up(self):
        print("\nTouch your authenticator device now...\n")

    def request_pin(self, permissions, rd_id):
        if not self._pin:
            self._pin = getpass("Enter PIN: ")
        return self._pin

    def request_uv(self, permissions, rd_id):
        print("User Verification required.")
        return True


def enumerate_devices():
    for dev in CtapHidDevice.list_devices():
        yield dev
    if CtapPcscDevice:
        for dev in CtapPcscDevice.list_devices():
            yield dev


def get_client(predicate=None, **kwargs):
    """Locate a CTAP device suitable for use.

    If running on Windows as non-admin, the predicate check will be skipped and
    a webauthn.dll based client will be returned.

    Extra kwargs will be passed to the constructor of Fido2Client.

    The client will be returned, with the CTAP2 Info, if available.
    """

    client_data_collector = DefaultClientDataCollector("https://example.com")

    if use_winclient:
        return WindowsClient(client_data_collector), None

    user_interaction = kwargs.pop("user_interaction", None) or CliInteraction()

    # Locate a device
    for dev in enumerate_devices():
        # Set up a FIDO 2 client using the origin https://example.com
        client = Fido2Client(
            dev,
            client_data_collector=client_data_collector,
            user_interaction=user_interaction,
            **kwargs,
        )
        # Check if it is suitable for use
        if predicate is None or predicate(client.info):
            return client, client.info
    else:
        raise ValueError("No suitable Authenticator found!")