# -*- coding: utf-8 -*-
# Copyright 2016 Camptocamp SA
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)

import logging
import os

from distutils.util import strtobool

import openerp
from openerp.addons.web import http
from werkzeug.contrib.sessions import Session

from .session import RedisSessionStore

_logger = logging.getLogger(__name__)

try:
    import redis
    from redis.sentinel import Sentinel
except ImportError:
    redis = None  # noqa
    _logger.debug("Cannot 'import redis'.")


def is_true(strval):
    return bool(strtobool(strval or "0".lower()))


sentinel_host = os.environ.get("ODOO_SESSION_REDIS_SENTINEL_HOST")
sentinel_master_name = os.environ.get("ODOO_SESSION_REDIS_SENTINEL_MASTER_NAME")
if sentinel_host and not sentinel_master_name:
    raise Exception(
        "ODOO_SESSION_REDIS_SENTINEL_MASTER_NAME must be defined "
        "when using session_redis"
    )
sentinel_port = int(os.environ.get("ODOO_SESSION_REDIS_SENTINEL_PORT", 26379))
host = os.environ.get("ODOO_SESSION_REDIS_URL", "localhost")
port = int(os.environ.get("ODOO_SESSION_REDIS_PORT", 6379))
prefix = os.environ.get("ODOO_SESSION_REDIS_PREFIX")
url = os.environ.get("ODOO_SESSION_REDIS_URL")
password = os.environ.get("ODOO_SESSION_REDIS_PASSWORD")
expiration = os.environ.get("ODOO_SESSION_REDIS_EXPIRATION")
anon_expiration = os.environ.get("ODOO_SESSION_REDIS_EXPIRATION_ANONYMOUS")


def session_store():
    if sentinel_host:
        sentinel = Sentinel([(sentinel_host, sentinel_port)], password=password)
        redis_client = sentinel.master_for(sentinel_master_name)
    elif url:
        redis_client = redis.from_url(url)
    else:
        redis_client = redis.Redis(host=host, port=port, password=password)
    return RedisSessionStore(
        redis=redis_client,
        prefix=prefix,
        expiration=expiration,
        anon_expiration=anon_expiration,
        session_class=Session,
    )


def session_gc(session_store):
    """Do not garbage collect the sessions

    Redis keys are automatically cleaned at the end of their
    expiration.
    """
    return


def purge_fs_sessions(path):
    for fname in os.listdir(path):
        path = os.path.join(path, fname)
        try:
            os.unlink(path)
        except OSError:
            pass


if is_true(os.environ.get("ODOO_SESSION_REDIS")):
    if sentinel_host:
        _logger.debug(
            "HTTP sessions stored in Redis with prefix '%s'. "
            "Using Sentinel on %s:%s",
            sentinel_host,
            sentinel_port,
            prefix or "",
        )
    else:
        _logger.debug(
            "HTTP sessions stored in Redis with prefix '%s' on " "%s:%s",
            host,
            port,
            prefix or "",
        )

    store = session_store()
    for handler in openerp.service.wsgi_server.module_handlers:
        if hasattr(handler, "session_store"):
            handler.session_store = store
    http.session_gc = session_gc
    # clean the existing sessions on the file system
    purge_fs_sessions(http.session_path())