#!/usr/bin/env python3
# -*-coding:UTF-8 -*

import os
import time
import uuid
import redis

from flask import escape

host_redis_metadata = os.getenv('D4_REDIS_METADATA_HOST', "localhost")
port_redis_metadata = int(os.getenv('D4_REDIS_METADATA_PORT', 6380))

r_serv_db = redis.StrictRedis(
    host=host_redis_metadata,
    port=port_redis_metadata,
    db=0,
    decode_responses=True)

def is_valid_uuid_v4(UUID):
    UUID = UUID.replace('-', '')
    try:
        uuid_test = uuid.UUID(hex=UUID, version=4)
        return uuid_test.hex == UUID
    except:
        return False

def _get_sensor_metadata(sensor_uuid, first_seen=True, last_seen=True, mail=True, description=True):

    meta_sensor = {}
    meta_sensor['uuid'] = sensor_uuid
    if first_seen:
        meta_sensor['first_seen'] = r_serv_db.hget('metadata_uuid:{}'.format(sensor_uuid), 'first_seen')
    if last_seen:
        meta_sensor['last_seen'] = r_serv_db.hget('metadata_uuid:{}'.format(sensor_uuid), 'last_seen')
    if description:
        meta_sensor['description'] = r_serv_db.hget('metadata_uuid:{}'.format(sensor_uuid), 'description')
    if mail:
        meta_sensor['mail'] = r_serv_db.hget('metadata_uuid:{}'.format(sensor_uuid), 'user_mail')
    return meta_sensor

## TODO: add description
def register_sensor(req_dict):
    sensor_uuid = req_dict.get('uuid', None)
    hmac_key = req_dict.get('hmac_key', None)
    user_id = req_dict.get('mail', None)
    # verify uuid
    if not is_valid_uuid_v4(sensor_uuid):
        return ({"status": "error", "reason": "Invalid uuid"}, 400)
    sensor_uuid = sensor_uuid.replace('-', '')
    # sensor already exist
    if r_serv_db.exists('metadata_uuid:{}'.format(sensor_uuid)):
        return ({"status": "error", "reason": "Sensor already registred"}, 409)

    # hmac key
    if not hmac_key:
        return ({"status": "error", "reason": "Mandatory parameter(s) not provided"}, 400)
    else:
        hmac_key = escape(hmac_key)
        if len(hmac_key)>100:
            hmac_key=hmac_key[:100]


    res = _register_sensor(sensor_uuid, hmac_key, user_id=user_id, description=None)
    return res


def _register_sensor(sensor_uuid, secret_key, user_id=None, description=None):
    r_serv_db.hset('metadata_uuid:{}'.format(sensor_uuid), 'hmac_key', secret_key)
    if user_id:
        r_serv_db.hset('metadata_uuid:{}'.format(sensor_uuid), 'user_mail', user_id)
    if description:
        r_serv_db.hset('metadata_uuid:{}'.format(sensor_uuid), 'description', description)
    r_serv_db.sadd('sensor_pending_registration', sensor_uuid)
    return ({'uuid': sensor_uuid}, 200)

def get_pending_sensor():
    return list(r_serv_db.smembers('sensor_pending_registration'))

def approve_sensor(req_dict):
    sensor_uuid = req_dict.get('uuid', None)
    if not is_valid_uuid_v4(sensor_uuid):
        return ({"status": "error", "reason": "Invalid uuid"}, 400)
    sensor_uuid = sensor_uuid.replace('-', '')
    # sensor not registred
    #if r_serv_db.sismember('sensor_pending_registration', sensor_uuid):
    #    return ({"status": "error", "reason": "Sensor not registred"}, 404)
    # sensor already approved
    if r_serv_db.sismember('registered_uuid', sensor_uuid):
        return ({"status": "error", "reason": "Sensor already approved"}, 409)
    return _approve_sensor(sensor_uuid)

def _approve_sensor(sensor_uuid):
    r_serv_db.sadd('registered_uuid', sensor_uuid)
    r_serv_db.srem('sensor_pending_registration', sensor_uuid)
    return ({'uuid': sensor_uuid}, 200)

def delete_pending_sensor(req_dict):
    sensor_uuid = req_dict.get('uuid', None)
    if not is_valid_uuid_v4(sensor_uuid):
        return ({"status": "error", "reason": "Invalid uuid"}, 400)
    sensor_uuid = sensor_uuid.replace('-', '')
    # sensor not registred
    #if r_serv_db.sismember('sensor_pending_registration', sensor_uuid):
    #    return ({"status": "error", "reason": "Sensor not registred"}, 404)
    # sensor already approved
    if not r_serv_db.sismember('sensor_pending_registration', sensor_uuid):
        return ({"status": "error", "reason": "Not Pending Sensor"}, 409)
    return _delete_pending_sensor(sensor_uuid)

def _delete_pending_sensor(sensor_uuid):
    r_serv_db.srem('sensor_pending_registration', sensor_uuid)
    return ({'uuid': sensor_uuid}, 200)