# -*- coding: utf-8 -*-
"""
Backend base module
"""
import logging
import os
from functools import wraps
from io import StringIO
from logging.config import dictConfig
from logging.handlers import MemoryHandler
from typing import Union

import coloredlogs as coloredlogs
import jwt
import requests
from flask import Flask, jsonify, abort
from flask_httpauth import HTTPTokenAuth, HTTPBasicAuth, MultiAuth
from flask_jwt_extended import JWTManager, decode_token, get_jwt_identity
from flask_login import LoginManager
from flask_sqlalchemy import SQLAlchemy
from flask_cors import CORS
from backend.config import Config

__author__ = "Tobias Kurze"
__copyright__ = "Copyright 2019, Tobias Kurze, KIT"
__credits__ = ["Tobias Kurze"]
__license__ = ""
__version__ = "0.9.0"
__maintainer__ = "Tobias Kurze"
__email__ = "it@t-kurze.de"
# __status__ = "Production"
__status__ = "Development"

from .tools.send_mail import get_smtp_default_handler

dictConfig({
    'version': 1,
    'formatters': {
        'default': {
            'format': '[%(asctime)s] {%(threadName)s} %(levelname)s in %(module)s, line %(lineno)d: %(message)s',
        }
    },
    'handlers': {
        'wsgi': {
            'class': 'logging.StreamHandler',
            'stream': 'ext://flask.logging.wsgi_errors_stream',
            'formatter': 'default'
        },
        'root_file': {
            'class': 'logging.handlers.TimedRotatingFileHandler',
            'filename': Config.ROOT_LOG_FILE,
            'when': 'd',
            'interval': 1,
            'backupCount': 3,
            'formatter': 'default',
        },
        'file': {
            'class': 'logging.handlers.TimedRotatingFileHandler',
            'filename': Config.LOG_FILE,
            'when': 'd',
            'interval': 1,
            'backupCount': 5,
            'formatter': 'default',
        },
        'errors_file': {
            'class': 'logging.handlers.TimedRotatingFileHandler',
            'filename': Config.ERROR_LOG_FILE,
            'when': 'd',
            'interval': 1,
            'backupCount': 5,
            'level': 'ERROR',
            'formatter': 'default',
        },
    },
    'loggers': {
        'lrc': {
            'level': Config.LOG_LEVEL,
            'handlers': ['wsgi', 'file', 'errors_file']
        }
    },
    'root': {
        'level': 'ERROR',
        'handlers': ['root_file', 'errors_file']
    }
})

main_logger = logging.getLogger("lrc")

# following might be dangerous, as buffer might be filled without a mechanism to empty it
smtp_error_handler = get_smtp_default_handler(subject="Warnings, errors and worse...!")
mem_handler = MemoryHandler(capacity=10, flushLevel=logging.ERROR, target=smtp_error_handler)
mem_handler.setLevel(logging.WARNING)
# error_log_stream = StringIO()
# error_log_stream_handler = logging.StreamHandler(stream=error_log_stream)
# error_log_stream_handler.setLevel(logging.ERROR)
# main_logger.addHandler(error_log_stream_handler)

coloredlogs.install(level='DEBUG', logger=main_logger)


class LrcException(Exception):
    def __init__(self, message_or_exception: Union[str, Exception], html_code: int = None):
        if isinstance(message_or_exception, str):
            super().__init__(message_or_exception)
            self.type = None
        else:
            super().__init__(str(message_or_exception))
            self.type = type(message_or_exception)
        self.html_code = html_code

    def __repr__(self):
        if self.type is None:
            msg = "LRC Exception: \"{}\"".format(', '.join(super().args))
        else:
            msg = "LRC Exception: (original Exception: {}) \"{}\"".format(self.type, ', '.join(super().args))
        if self.html_code is not None:
            msg += " (HTML Code: {})".format(self.html_code)
        return msg

    def __str__(self):
        return self.__repr__()


app = Flask(__name__)
if os.environ.get('FLASK_ENV', None) == "development":
    app.config.from_object('backend.config.DevelopmentConfig')
else:
    app.config.from_object('backend.config.Config')
db = SQLAlchemy(app)

login_manager = LoginManager()
login_manager.init_app(app)

# flask_jwt_extended: to be used usually by API
jwt_extended = JWTManager(app)
# this is another library.... this is (probaby ->verify) used to check JWTs provided by external sources (KIT, etc.)
jwt_auth = HTTPTokenAuth('Bearer')


@jwt_auth.verify_token
def verify_token(token):
    """This function (and HTTPTokenAuth('Bearer')) has been defined to be used together with MultiAuth. For API calls
    solely using JWT authentication, jwt_required of flask_jwt_extended should be used directly."""
    app.logger.info(token)
    try:
        decoded = decode_token(token)
    except jwt.exceptions.DecodeError as e:
        app.logger.warn("Could not verify token: {}".format(str(e)))
        return False
    except jwt.exceptions.ExpiredSignatureError as e:
        app.logger.warn("Could not verify token: {}".format(str(e)))
        return False
    app.logger.info(decoded)
    return True


basic_auth = HTTPBasicAuth()
multi_auth = MultiAuth(basic_auth, jwt_auth)

from backend.auth import oidc_auth, auth_bp

try:
    oidc_auth.init_app(app)
except requests.exceptions.ConnectionError as err:
    app.logger.error("Could not connect to OIDC!!", err)

# oidc_multi_auth = MultiAuth(oidc_auth, jwt_auth) <- can't work as OIDCAuthentication not implementing HTTPAuth

from .serve_frontend import fe_bp
from .api import auth_api_bp, api_v1, api_bp

app.register_blueprint(auth_bp)
app.register_blueprint(auth_api_bp)
app.register_blueprint(api_bp)
app.register_blueprint(fe_bp)

CORS(app)
CORS(api_bp)
CORS(auth_api_bp)

logging.getLogger('flask_cors').level = logging.DEBUG


# Fix jwt_extended by 'duck typing' error handlers
# jwt_extended._set_error_handler_callbacks(api_v1)  # removed for the moment, might raise new (old) problems


@jwt_extended.invalid_token_loader
def unauthorized_jwt(token):
    main_logger.info("Unauthorized access; invalid token provided: {}".format(token))
    abort(401)


@jwt_extended.expired_token_loader
def unauthorized_jwt(token):
    main_logger.info("Unauthorized access; expired token provided: {}".format(token))
    abort(401)