# This file is part of CloudControl.
#
# CloudControl is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# CloudControl is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with CloudControl.  If not, see <http://www.gnu.org/licenses/>.


"""Interface implementation for JobsManager from cc-common."""

from datetime import datetime
import subprocess

from cloudcontrol.common.jobs import JobsManagerInterface, Job, JobCancelError
from cloudcontrol.common.tql.db.helpers import taggify
from cloudcontrol.common.client.tags import TagDB, Tag


class NodeJobsManagerInterface(JobsManagerInterface):

    TAG_ATTRIBUTES = ('title', 'status', 'state', 'owner', 'created', 'ended',
                      'attachments', 'batch')

    def __init__(self, host_handler):
        self.handler = host_handler
        self.tag_db = TagDB(self.handler.tag_db)

    def on_job_created(self, job):
        def get_tag_value(tag):
            return lambda job: taggify(getattr(job, tag))

        self.tag_db.add_sub_object(
            job.id,
            (Tag(tag, get_tag_value(tag), parent=job)
             for tag in self.TAG_ATTRIBUTES),
            'job',
        )

        def tag_duration(job):
            if job.ended is None:
                ended = datetime.fromtimestamp(self.handler.main.evloop.now())
            else:
                ended = job.ended

            return taggify(ended - job.created)

        self.tag_db.add_sub_tag(job.id, Tag('duration', tag_duration, 2, 1, job))

    def on_job_updated(self, job):
        for tag in self.TAG_ATTRIBUTES:
            self.tag_db[job.id][tag].update_value()

    def on_job_purged(self, job_id):
        self.tag_db.remove_sub_object(job_id)


class ScriptJob(Job):
    """Job that runs a script."""

    def job(self, script, filename, args):
        self.title = 'Script: %s %s' % (script, ' '.join(args))
        self.process = None
        to_exec = (filename,) + args
        output = self.attachment('output')
        self.logger.debug('To exec: %s', to_exec)
        try:
            self.process = subprocess.Popen(to_exec, stdout=output,
                                            stderr=output, close_fds=True)
            self.logger.info('Script running with pid: %d', self.process.pid)
            ex = self.process.wait()
            if ex != 0:
                raise JobCancelError('Script returned exit code %d' % ex)
        except subprocess.CalledProcessError:
            self.logger.error('Error while executing script: %s', script)
            raise

    def cancel(self):
        super(ScriptJob, self).cancel()
        if self.process is not None:
            self.logger.info('Terminating job %s', self.title)
            self.process.terminate()