#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# MISP modules helper - cache
#
# Copyright (C) 2016 Alexandre Dulaunoy
# Copyright (C) 2016 CIRCL - Computer Incident Response Center Luxembourg
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os

import redis
import hashlib

port = int(os.getenv("REDIS_PORT")) if os.getenv("REDIS_PORT") else 6379
hostname = os.getenv("REDIS_BACKEND") or '127.0.0.1'
db = int(os.getenv("REDIS_DATABASE")) if os.getenv("REDIS_DATABASE") else 0
password = os.getenv("REDIS_PW") or None


def selftest(enable=True):
    if not enable:
        return False
    r = redis.Redis(host=hostname, password=password, port=port, db=db)
    try:
        r.ping()
    except Exception:
        return 'Redis not running or not installed. Helper will be disabled.'


def get(modulename=None, query=None, value=None, debug=False):
    if (modulename is None or query is None):
        return False
    r = redis.Redis(host=hostname, password=password, port=port, db=db, decode_responses=True)
    h = hashlib.sha1()
    h.update(query.encode('UTF-8'))
    hv = h.hexdigest()
    key = "m:{}:{}".format(modulename, hv)

    if not r.exists(key):
        if debug:
            print("Key {} added in cache".format(key))
        r.setex(key, 86400, value)
    else:
        if debug:
            print("Cache hit with Key {}".format(key))

    return r.get(key)


def flush():
    r = redis.StrictRedis(host=hostname, password=password, port=port, db=db, decode_responses=True)
    returncode = r.flushdb()
    return returncode


if __name__ == "__main__":
    import sys
    if selftest() is not None:
        sys.exit()
    else:
        print("Selftest ok")
    v = get(modulename="testmodule", query="abcdef", value="barfoo", debug=True)
    if v == 'barfoo':
        print("Cache ok")
    v = get(modulename="testmodule", query="abcdef")
    print(v)
    v = get(modulename="testmodule")
    if (not v):
        print("Failed ok")
    if flush():
        print("Cache flushed ok")