# 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 datetime import datetime

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.get(
                'value',
                datetime.now().isoformat()
            )
        )
        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