import os
from typing import Any, Dict
from urllib.error import HTTPError

from uaclient import util
from uaclient.clouds import AutoAttachCloudInstance

IMDS_BASE_URL = "http://169.254.169.254/metadata/"

API_VERSION = "2020-09-01"  # Needed to get subscription ID in attested data
IMDS_URLS = {
    "pkcs7": IMDS_BASE_URL + "attested/document?api-version=" + API_VERSION,
    "compute": IMDS_BASE_URL + "instance/compute?api-version=" + API_VERSION,
}

DMI_CHASSIS_ASSET_TAG = "/sys/class/dmi/id/chassis_asset_tag"
AZURE_OVF_ENV_FILE = "/var/lib/cloud/seed/azure/ovf-env.xml"
AZURE_CHASSIS_ASSET_TAG = "7783-7084-3265-9085-8269-3286-77"


class UAAutoAttachAzureInstance(AutoAttachCloudInstance):

    # mypy does not handle @property around inner decorators
    # https://github.com/python/mypy/issues/1362
    @property  # type: ignore
    @util.retry(HTTPError, retry_sleeps=[1, 2, 5])
    def identity_doc(self) -> Dict[str, Any]:
        responses = {}
        for key, url in sorted(IMDS_URLS.items()):
            url_response, _headers = util.readurl(
                url, headers={"Metadata": "true"}
            )
            if key == "pkcs7":
                responses[key] = url_response["signature"]
            else:
                responses[key] = url_response
        return responses

    @property
    def cloud_type(self) -> str:
        return "azure"

    @property
    def is_viable(self) -> bool:
        """This machine is a viable AzureInstance"""
        if os.path.exists(DMI_CHASSIS_ASSET_TAG):
            chassis_asset_tag = util.load_file(DMI_CHASSIS_ASSET_TAG)
            if AZURE_CHASSIS_ASSET_TAG == chassis_asset_tag.strip():
                return True
        return os.path.exists(AZURE_OVF_ENV_FILE)
