# Copyright 2015 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import hashlib
import io
import json
import logging
import yaml

from slugify import slugify

from grafana_dashboards.schema import Schema

LOG = logging.getLogger(__name__)


class YamlParser(object):

    def __init__(self):
        self.data = {}

    def get_dashboard(self, slug):
        data = self.data.get('dashboard', {}).get(slug, None)
        md5 = self._generate_md5(data)
        LOG.debug('Dashboard %s: %s' % (slug, md5))

        return data, md5

    def get_datasource(self, slug):
        data = self.data.get('datasource', {}).get(slug, None)
        md5 = self._generate_md5(data)
        LOG.debug('Datasource %s: %s' % (slug, md5))

        return data, md5

    def parse(self, fn):
        with io.open(fn, 'r', encoding='utf-8') as fp:
            self.parse_fp(fp)

    def parse_fp(self, fp):
        data = yaml.safe_load(fp)
        # Since a json file is valid YAML, we just pass through
        # any JSON files
        if fp.name.endswith('.json'):
            slug = slugify(data['title'])
            if not self.data.get('dashboard'):
                self.data['dashboard'] = {}
            # The idea is that people work interactively locally using
            # the GUI editor, then export the .json using the sharing
            # panel.  That mostly works, but it can leave a id & uid
            # that isn't valid when importing to another grafana
            # instance.  Remove them.
            data.pop('id', None)
            data.pop('uid', None)
            self.data['dashboard'][slug] = data
        else:
            result = self.validate(data)
            for item in result.items():
                group = self.data.get(item[0], {})
                # Create slug to make it easier to find dashboards.
                if item[0] == 'dashboard':
                    name = item[1]['title']
                else:
                    name = item[1]['name']
                slug = slugify(name)
                if slug in group:
                    raise Exception(
                        "Duplicate {0} found in '{1}: '{2}' "
                        "already defined".format(item[0], fp.name, name))
                group[slug] = item[1]
                self.data[item[0]] = group

    def validate(self, data):
        schema = Schema()
        return schema.validate(data)

    def _generate_md5(self, data):
        md5 = None
        if data:
            # Sort json keys to help our md5 hash are constant.
            content = json.dumps(data, sort_keys=True)
            md5 = hashlib.md5(content.encode('utf-8')).hexdigest()
        return md5