# -*- coding: utf-8 -*-

#    Copyright 2015 Mirantis, 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.

from __future__ import print_function

import argparse
from fnmatch import fnmatch
import jsonschema
import logging
import os
import sys
import yaml

from tasklib import graph
from tasklib.schemas import VERSIONS_SCHEMAS_MAP

logging.basicConfig(level=logging.ERROR)
LOG = logging.getLogger(__name__)


class TasksValidator(object):

    def __init__(self, tasks, version):
        self.version = version
        self.tasks = tasks
        self.graph = graph.DeploymentGraph(tasks)

    def validate_schema(self):
        '''Validate tasks schema

        :raise: jsonschema.ValidationError
        '''
        checker = jsonschema.FormatChecker()
        schema = VERSIONS_SCHEMAS_MAP.get(self.version)().tasks_schema
        jsonschema.validate(self.tasks, schema, format_checker=checker)

    def validate_unique_tasks(self):
        '''Check if all tasks have unique ids

        :raise: ValueError when ids are duplicated
        '''
        if not len(self.tasks) == len(set(task['id'] for task in self.tasks)):
            raise ValueError("All tasks should have unique id")

    def validate_graph(self):
        '''Validate graph if is executable completely by fuel nailgun

        :raise: ValueEror when one of requirements is not satisfied
        '''
        msgs = []

        # deployment graph should be without cycles
        cycles = self.graph.find_cycles()
        if len(cycles):
            msgs.append('Graph is not acyclic. Cycles: {0}'.format(cycles))

        # graph should be connected to execute all tasks
        if not self.graph.is_connected():
            msgs.append('Graph is not connected.')

        # deployment graph should have filled all nodes
        empty_nodes = self.graph.find_empty_nodes()
        if len(empty_nodes):
            msgs.append('Graph have empty nodes: {0}'.format(empty_nodes))

        if msgs:
            raise ValueError('Graph validation fail: {0}'.format(msgs))


def get_files(base_dir, file_pattern='*tasks.yaml'):
    for root, _dirs, files in os.walk(base_dir):
        for file_name in files:
            if fnmatch(file_name, file_pattern):
                yield os.path.join(root, file_name)


def get_tasks(base_dir):
    tasks = []
    for file_path in get_files(base_dir):
        with open(file_path) as f:
            LOG.debug('Reading tasks from file %s', file_path)
            tasks.extend(yaml.load(f.read()))
    return tasks


def main(args=sys.argv):
    parser = argparse.ArgumentParser(
        description='''Validator of tasks, gather all yaml files with name
        contains tasks and read and validate tasks from them''')
    parser.add_argument('-d', '--dir', dest='dir', required=True,
                        help='directory where tasks are localised')
    parser.add_argument('-v', '--version', dest='ver', default='last',
                        metavar='VERSION', help='version of fuel for which '
                        'tasks should be validated')
    parser.add_argument("--debug", dest="debug", action="store_true",
                        default=False, help="Enable debug mode")
    args, _ = parser.parse_known_args(args)

    tasks = get_tasks(args.dir)
    if args.debug:
        LOG.setLevel(logging.DEBUG)

    if tasks:
        t_validator = TasksValidator(tasks, args.ver)
        t_validator.validate_schema()
        t_validator.validate_unique_tasks()
        t_validator.validate_graph()
    else:
        print("No tasks in the provided directory %s" % args.dir)
        sys.exit(1)