"""

    AUTHOR:

        Khushal P Soonderji

    DATE:

        Friday, 22nd Nov., 2024

    OBJECTIVE:

        To handle OAuth2.0 activities for Google's services.

    REFERENCES:

        1. https://developers.google.com/calendar/api/quickstart/python
        2. https://developers.google.com/identity/protocols/oauth2/web-server#python
        3. https://www.youtube.com/watch?v=vQQEaSnQ_bs&t=940s&pp=ygUVb2F1dGgyIHB5dGhvbiB5b3V0dWJl

    DOWNLOADS:

        N/A

"""


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                   IMPORT                                                      ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# To make sibling directories accessible for imports:
import sys
sys.path.append(".")
sys.path.append("..")

# System-level activities:
import io

# My utils:
from utils_v2.string import json
from utils_v2.date_time import date_time

# The base model:
from utils_v2.oauth.base import OAuthBase

# Related to Google:
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow

# For asynchronous activities:
import asyncio

# To make deep-copies:
import copy

# To work with date and time:
import datetime


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                           MACROS / ONE-TIME INIT                                              ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# Google Scopes:
SCOPES_GMAIL_MAIL_MANAGEMENT = [
    r"https://www.googleapis.com/auth/gmail.modify",
    r"https://www.googleapis.com/auth/gmail.labels"
]
SCOPES_GMAIL_FULL = [r"https://mail.google.com/"]


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                VARIABLES                                                      ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# --- Nothing Yet


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                  FUNCTIONS                                                    ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# --- Nothing Yet


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                   CLASSES                                                     ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


class GoogleOAuth(OAuthBase):

    # Class variables:
    __flow = None

    # ┏┓┓           ┳┳┓   ┓    ┓
    # ┣┫┣┓┏╋┏┓┏┓┏╋  ┃┃┃┏┓╋┣┓┏┓┏┫┏
    # ┛┗┗┛┛┗┛ ┗┻┗┗  ┛ ┗┗ ┗┛┗┗┛┗┻┛

    async def initialize(
            self,
            scopes,
            raise_exception = False
    ) -> bool:

        """
        Initialize the Google OAuth mechanism by creating an app-flow. This defines the app that you are trying to
        deploy. You must create this app in Google's Cloud Platform's console.
        :param scopes: The scopes (permissions) needed by this app.
        :param raise_exception: If set to True, any exception that occurs will be propagated. If set to false, any
            exception that occurs will be suppressed.
        :return: True if the initialization succeeded, False if it failed.
        """

        # Start by assuming success:
        success = True

        try:

            # Initialize your Google App:
            self._printer("Initializing flow.")
            self.__flow = InstalledAppFlow.from_client_config(
                self._config,
                scopes = scopes,
                redirect_uri = self._redirect_url
            )

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            if raise_exception: raise
            success = False

        # Done here:
        return success

    async def get_authorization_url(
            self,
            raise_exception = False,
            **kwargs,
    ) -> str | None:

        """
        To generate an authorization URL that can be sent to the front end. When the
        :param raise_exception: If set to True, any exception that occurs will be propagated. If set to false, any
            exception that occurs will be suppressed.
        :param kwargs: Any no. of keyword args that you might want to give to this specific service.
        :return:
        """

        # Start by assuming failure:
        authorization_url = None

        try:

            # Request a URL that will be sent to the user to request
            # permissions to access their account:
            authorization_url, _ = self.__flow.authorization_url(
                access_type = kwargs.get("access_type", "offline"),
                approval_prompt = kwargs.get("approval_prompt", "force"),
                include_granted_scopes = kwargs.get("include_granted_scopes", "true"),
                login_hint = kwargs.get("email"),
                state = kwargs.get("user_id")
            )

            # Done here:
            return authorization_url

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            if raise_exception: raise
            authorization_url = None

        # Done here:
        return authorization_url

    async def get_tokens(
            self,
            raise_exception = False,
            **kwargs
    ) -> Credentials | dict | None:

        # Start by assuming failure:
        tokens = None

        try:

            # Fetch the tokens:
            credentials = self.__flow.fetch_token(authorization_response = kwargs["redirect_url"])
            tokens = {
                "access_token": credentials.get("access_token"),
                "refresh_token": credentials.get("refresh_token"),
                "expires_in": (ttl := credentials["expires_in"] - 60),
                "expires_at": date_time.get_current_utc_date_time() + datetime.timedelta(seconds = ttl),
                "scopes": credentials.get("scope"),
            }

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            if raise_exception: raise
            tokens = None

        # Done here:
        return tokens

    async def refresh_tokens(
            self,
            old_tokens: dict,
            raise_exception = False
    ) -> dict | None:

        # Start by assuming failure:
        tokens = None

        try:

            # If the tokens haven't expired, just return the existing tokens back:
            tokens_expired = True if date_time.get_current_utc_date_time() >= old_tokens["expires_at"] else False
            if not tokens_expired: return old_tokens

            # Construct the credentials and request a refresh:
            credentials = await self.credentials_from_tokens(old_tokens)
            if tokens_expired and credentials.refresh_token:
                credentials.refresh(Request())
                tokens = {
                    "access_token": credentials.token,
                    "refresh_token": credentials.refresh_token,
                    "expires_at": (exp_at := date_time.as_if_timezone(
                        credentials.expiry,
                        timezone = date_time.TIMEZONE_UTC
                    )),
                    "expires_in": (exp_at - date_time.get_current_utc_date_time()).total_seconds(),
                    "scopes": credentials.scopes,
                }

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            if raise_exception: raise
            tokens = None

        # Done here:
        return tokens

    # ┏┓      •     ┏┓     •┏•
    # ┗┓┏┓┏┓┓┏┓┏┏┓  ┗┓┏┓┏┓┏┓╋┓┏
    # ┗┛┗ ┛ ┗┛┗┗┗   ┗┛┣┛┗ ┗┗┛┗┗
    #                 ┛

    async def credentials_from_tokens(
            self,
            tokens: dict,
            raise_exception = False
    ) -> Credentials | None:

        # Start by assuming failure:
        credentials = None

        try:

            # Make a deep-copy and add some fields from the config:
            tokens_copy = copy.deepcopy(tokens)
            first_key = list(self._config.keys())[0]
            tokens_copy["client_id"] = self._config.get(first_key, {}).get("client_id")
            tokens_copy["client_secret"] = self._config.get(first_key, {}).get("client_secret")

            # Create the credentials:
            credentials = Credentials.from_authorized_user_info(info = tokens_copy)

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            if raise_exception: raise
            credentials = None

        # Done here:
        return credentials


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                               MAIN PROGRAM                                                    ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


if __name__ == "__main__":

    import dateparser

    secrets_file = r"../../../creds/google_tcaoff_test_oauth_20241125.json"
    secrets_dict = json.from_file(secrets_file)

    my_goog = GoogleOAuth(
        config = secrets_dict,
        redirect_url = r"https://thecaoffice.com/nexcom/converse/mail/callback/gmail",
        debug = True,
        debug_prefix = "OAuth (Goog) | "
    )

    async def main():

        await my_goog.initialize(scopes = SCOPES_GMAIL_MAIL_MANAGEMENT)
        await asyncio.sleep(1.0)
        print("AUTH URL 0:", await my_goog.get_authorization_url(
            user_id = "BHOPLI",
            # email = "pskhushal@gmail.com"
        ))

        redirect_url = input("Paste the redirect URL here: ")
        print("TOKENS:", json.to_string(await my_goog.get_tokens(redirect_url = redirect_url), default = str))

        # old_tok = {
        #     "access_token": "ya29.a0AeDClZAjmLUZ1hh0aTbddz4ThjRzwQNMwdi_H4AYO-C4ETvWpK8aHYz5eV9PTUlFDJKQoHYtFgu4u2XfoiOdIEMVNwAKFbb8sakIWef7Yk5HdiDYC0A-MUp5XZnoNGLuP_GW_O3IxfCLH7cC0fb3AfHx4OsBpa_Qu1X-IpvfaCgYKAaoSARMSFQHGX2MiX81qoRex393eWE229OMCUg0175",
        #     "refresh_token": "1//0g4mVQrydnc1ECgYIARAAGBASNgF-L9Irk_UxcRjgkz_YyK5Ujs1qCaj8nKL7bqQ0jHnHYlpVRh_Pwm77X4Angp8R-o-fgmKfzg",
        #     "expires_in": 3539,
        #     "expires_at": dateparser.parse("2024-11-25 09:24:56.690876+00:00"),
        #     "token_type": "Bearer",
        #     "scopes": [
        #         "https://www.googleapis.com/auth/gmail.labels",
        #         "https://www.googleapis.com/auth/gmail.modify"
        #     ]
        # }
        #
        # new_tok = await my_goog.refresh_tokens(old_tokens = old_tok)
        # print("NEW TOKENS:", json.to_string(new_tok, default = str))


    asyncio.run(main())