# -*- coding: utf-8 -*-
#
# This file is part of Invenio.
# Copyright (C) 2015-2019 CERN.
#
# Invenio is free software; you can redistribute it and/or modify it
# under the terms of the MIT License; see LICENSE file for more details.

"""Handlers for customizing oauthclient endpoints."""

from functools import partial, wraps

from flask import (
    current_app,
    flash,
    redirect,
    render_template,
    request,
    session,
    url_for,
)
from flask_security.utils import do_flash, get_message
from invenio_db import db
from invenio_i18n import gettext as _

from ..errors import (
    AlreadyLinkedError,
    OAuthClientAlreadyAuthorized,
    OAuthClientError,
    OAuthClientMustRedirectLogin,
    OAuthClientMustRedirectSignup,
    OAuthClientTokenNotFound,
    OAuthClientTokenNotSet,
    OAuthClientUnAuthorized,
    OAuthClientUserNotRegistered,
    OAuthClientUserRequiresConfirmation,
    OAuthError,
    OAuthRejectedRequestError,
)
from ..utils import create_registrationform, fill_form
from .authorized import authorized_handler, extra_signup_handler
from .base import base_disconnect_handler
from .decorators import can_extra_signup
from .token import response_token_setter, token_session_key


def _oauth_error_handler(remote, f, *args, **kwargs):
    """Function to handle exceptions."""
    try:
        return f(remote, *args, **kwargs)
    except OAuthClientError as e:
        current_app.logger.warning(e.message, exc_info=True)
        return oauth2_handle_error(e.remote, e.response, e.code, e.uri, e.description)
    except OAuthClientUnAuthorized:
        return current_app.login_manager.unauthorized()
    except AlreadyLinkedError:
        flash(
            _("External service is already linked to another account."),
            category="danger",
        )
        return redirect(url_for("invenio_oauthclient_settings.index"))
    except OAuthRejectedRequestError:
        flash(_("You rejected the authentication request."), category="info")
        return redirect("/")
    except OAuthClientAlreadyAuthorized:
        return redirect("/")
    except OAuthClientTokenNotFound:
        return redirect("/")
    except OAuthClientUserNotRegistered:
        raise OAuthError("Could not create user.", remote)
    except OAuthClientTokenNotSet:
        raise OAuthError("Could not create token for user.", remote)
    except OAuthClientMustRedirectSignup as e:
        return redirect(
            url_for(
                ".signup",
                remote_app=remote.name,
            )
        )
    except OAuthClientMustRedirectLogin as e:
        return redirect(
            url_for(
                ".login",
                remote_app=remote.name,
            )
        )


#
# Error handling decorators
#
def oauth_resp_remote_error_handler(f):
    """Decorator to handle exceptions."""

    @wraps(f)
    def inner(resp, remote, *args, **kwargs):
        # OAuthErrors should not happen, so they are not caught here. Hence
        # they will result in a 500 Internal Server Error which is what we
        # are interested in.
        _f = partial(f, resp)
        return _oauth_error_handler(remote, _f, *args, **kwargs)

    return inner


def oauth_remote_error_handler(f):
    """Decorator to handle exceptions."""

    @wraps(f)
    def inner(remote, *args, **kwargs):
        # OAuthErrors should not happen, so they are not caught here. Hence
        # they will result in a 500 Internal Server Error which is what we
        # are interested in.
        return _oauth_error_handler(remote, f, *args, **kwargs)

    return inner


#
# Handlers
#
@oauth_resp_remote_error_handler
def authorized_default_handler(resp, remote, *args, **kwargs):
    """Store access token in session.

    Default authorized handler.

    :param remote: The remote application.
    :param resp: The response.
    :returns: Redirect response.
    """
    response_token_setter(remote, resp)
    db.session.commit()
    return redirect(url_for("invenio_oauthclient_settings.index"))


@oauth_resp_remote_error_handler
def authorized_signup_handler(resp, remote, *args, **kwargs):
    """Handle sign-in/up functionality.

    :param remote: The remote application.
    :param resp: The response.
    :returns: Redirect response.
    """
    try:
        next_url = authorized_handler(resp, remote, *args, **kwargs)
        # Redirect to next
        if next_url:
            return redirect(next_url)
        return redirect(url_for("invenio_oauthclient_settings.index"))
    except OAuthClientUserRequiresConfirmation as exc:
        do_flash(
            _(
                f"A confirmation email has already been sent to {exc.user.email}. Please confirm your email to be able to log in."
            ),
            category="success",
        )
        return redirect("/")


@oauth_remote_error_handler
def disconnect_handler(remote, *args, **kwargs):
    """Handle unlinking of remote account.

    This default handler will just delete the remote account link. You may
    wish to extend this module to perform clean-up in the remote service
    before removing the link (e.g. removing install webhooks).

    :param remote: The remote application.
    :returns: Redirect response.
    """
    base_disconnect_handler(remote, *args, **kwargs)
    return redirect(url_for("invenio_oauthclient_settings.index"))


@oauth_remote_error_handler
@can_extra_signup
def signup_handler(remote, *args, **kwargs):
    """Handle extra signup information.

    This should be called when the account info from the remote `info` endpoint is
    not enough to register the user (e.g. e-mail missing): it will show the
    registration form, validate it on submission and register the user.

    :param remote: The remote application.
    :returns: Redirect response or the template rendered.
    """
    form = create_registrationform(request.form, oauth_remote_app=remote)
    if not form.is_submitted():
        # Show the form when the user is redirected here after `authorized`
        # (GET request), to fill in the missing information (e.g. e-mail)
        session_prefix = token_session_key(remote.name)
        account_info = session.get(session_prefix + "_account_info")
        # Pre-fill form
        fill_form(form, account_info["user"])
        return render_template(
            current_app.config["OAUTHCLIENT_SIGNUP_TEMPLATE"],
            form=form,
            remote=remote,
            app_title=current_app.config["OAUTHCLIENT_REMOTE_APPS"][remote.name].get(
                "title", ""
            ),
            app_description=current_app.config["OAUTHCLIENT_REMOTE_APPS"][
                remote.name
            ].get("description", ""),
            app_icon=current_app.config["OAUTHCLIENT_REMOTE_APPS"][remote.name].get(
                "icon", None
            ),
        )
    elif form.is_submitted() and not form.errors:
        # Form is submitted (POST request): validate the user input and register
        # the user
        try:
            next_url = extra_signup_handler(remote, form, *args, **kwargs)
        except OAuthClientUnAuthorized:
            # Redirect the user to login page
            return redirect(url_for("security.login"))
        except OAuthClientUserRequiresConfirmation as exc:
            # Redirect the user after registration (which doesn't include the
            # activation), waiting for user to confirm his email.
            do_flash(*get_message("CONFIRM_REGISTRATION", email=exc.user.email))
            return redirect("/")

        if next_url:
            return redirect(next_url)
        else:
            return redirect("/")


def oauth2_handle_error(remote, resp, error_code, error_uri, error_description):
    """Handle errors during exchange of one-time code for an access tokens."""
    flash(_("Authorization with remote service failed."))
    return redirect("/")
