#!/usr/bin/env python
#
# 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 json
import logging
import os
import subprocess
import sys

import yaml


CONF_FILE = os.environ.get('HEAT_SHELL_CONFIG',
                           '/var/run/heat-config/heat-config')

WORKING_DIR = os.environ.get(
    'HEAT_DOCKER_CMD_WORKING',
    '/var/lib/heat-config/heat-config-docker-cmd')

DOCKER_CMD = os.environ.get('HEAT_DOCKER_CMD', 'docker')


log = None


def main(argv=sys.argv):
    global log
    log = logging.getLogger('heat-config')
    handler = logging.StreamHandler(sys.stderr)
    handler.setFormatter(
        logging.Formatter(
            '[%(asctime)s] (%(name)s) [%(levelname)s] %(message)s'))
    log.addHandler(handler)
    log.setLevel('DEBUG')

    if not os.path.exists(CONF_FILE):
        log.warning('No config file %s' % CONF_FILE)
        return 1

    if not os.path.isdir(WORKING_DIR):
        os.makedirs(WORKING_DIR, 0o700)

    try:
        configs = json.load(open(CONF_FILE))
    except ValueError as e:
        log.warning('Could not load config json: %s' % e)
        return 1

    cmd_configs = list(build_configs(configs))
    try:
        delete_missing_projects(cmd_configs)
        for c in cmd_configs:
            delete_changed_project(c)
            write_project(c)
    except Exception as e:
        log.exception(e)


def build_configs(configs):
    for c in configs:
        if c['group'] != 'docker-cmd':
            continue
        if not isinstance(c['config'], dict):
            # convert config to dict
            c['config'] = yaml.safe_load(c['config'])
        yield c


def current_projects():
    for proj_file in os.listdir(WORKING_DIR):
        if proj_file.endswith('.json'):
            proj = proj_file[:-5]
            yield proj


def remove_project(proj):
    proj_file = os.path.join(WORKING_DIR, '%s.json' % proj)
    with open(proj_file, 'r') as f:
        proj_data = json.load(f)
        for name in extract_container_names(proj, proj_data):
            remove_container(name)
    os.remove(proj_file)


def remove_container(name):
    cmd = [DOCKER_CMD, 'rm', '-f', name]
    log.debug(' '.join(cmd))
    subproc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)
    stdout, stderr = subproc.communicate()
    log.info(stdout)
    log.debug(stderr)


def delete_missing_projects(configs):
    config_names = [c['name'] for c in configs]
    for proj in current_projects():
        if proj not in config_names:
            log.debug('%s no longer exists, deleting containers' % proj)
            remove_project(proj)


def extract_container_names(proj, proj_data):
        # For now, assume a docker-compose v1 format where the
        # root keys are service names
        for name in sorted(proj_data):
            yield '%s__%s' % (proj, name)


def delete_changed_project(c):
    proj = c['name']
    proj_file = os.path.join(WORKING_DIR, '%s.json' % proj)
    proj_data = c.get('config', {})
    if os.path.isfile(proj_file):
        with open(proj_file, 'r') as f:
            prev_proj_data = json.load(f)
            if proj_data != prev_proj_data:
                log.debug('%s has changed, deleting containers' % proj)
                remove_project(proj)


def write_project(c):
    proj = c['name']
    proj_file = os.path.join(WORKING_DIR, '%s.json' % proj)
    proj_data = c.get('config', {})

    with os.fdopen(os.open(
            proj_file, os.O_CREAT | os.O_WRONLY | os.O_TRUNC, 0o600),
            'w') as f:
        json.dump(proj_data, f, indent=2)


if __name__ == '__main__':
    sys.exit(main(sys.argv))