# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from os.path import join as joinpath
from os.path import basename
from os import makedirs

from dateutil import parser as dateparser

from tfw.event_handler_base import EventHandlerBase
from tfw.components.snapshot_provider import SnapshotProvider
from tfw.config import TFWENV
from tfw.config.logs import logging

LOG = logging.getLogger(__name__)


class DirectorySnapshottingEventHandler(EventHandlerBase):
    def __init__(self, key, directories):
        super().__init__(key)
        self.snapshot_providers = {}
        self.init_snapshot_providers(directories)

        self.command_handlers = {
            'take_snapshot': self.handle_take_snapshot,
            'restore_snapshot': self.handle_restore_snapshot
        }

    def init_snapshot_providers(self, directories):
        for index, directory in enumerate(directories):
            git_dir = self.init_git_dir(index, directory)
            self.snapshot_providers[directory] = SnapshotProvider(directory, git_dir)

    @staticmethod
    def init_git_dir(index, directory):
        git_dir = joinpath(
            TFWENV.SNAPSHOTS_DIR,
            f'{basename(directory)}-{index}'
        )
        makedirs(git_dir, exist_ok=True)
        return git_dir

    def handle_event(self, message):
        try:
            data = message['data']
            message['data'] = self.command_handlers[data['command']](data)
            return message
        except KeyError:
            LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)

    def handle_take_snapshot(self, data):
        LOG.debug('Taking snapshots of directories %s', self.snapshot_providers.keys())
        for provider in self.snapshot_providers.values():
            provider.take_snapshot()
        return data

    def handle_restore_snapshot(self, data):
        date = dateparser.parse(data['value'])
        LOG.debug(
            'Restoring snapshots (@ %s) of directories %s',
            date,
            self.snapshot_providers.keys()
        )
        for provider in self.snapshot_providers.values():
            provider.restore_snapshot(date)
        return data