#!/usr/bin/python3
# Copyright 2017-2018  Lars Wirzenius
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


import logging
import time

import apifw
import cliapp
import Crypto.PublicKey.RSA
import urllib3
import ick2


urllib3.disable_warnings()
logging.captureWarnings(False)


class WorkerManager(cliapp.Application):

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self._token = None
        self._token_until = None

    def add_settings(self):
        self.settings.string(
            ['controller'],
            'base URL for the controller',
            metavar='URL',
        )

        self.settings.string(
            ['name'],
            'name of this worker',
            metavar='URL',
        )

        self.settings.string(
            ['token-key'],
            'get token signing private key from FILE',
            metavar='FILE',
        )

        self.settings.string(
            ['token-key-pub'],
            'this is not used',
            metavar='NOPE',
        )

        self.settings.integer(
            ['sleep'],
            'sleep for SECS seconds if there is no work currently',
            metavar='SECS',
            default=5,
        )

        self.settings.string(
            ['workspace'],
            'use DIR as the workspace where commands are run',
            metavar='DIR',
            default='/var/lib/ick/workspace',
        )

        self.settings.string(
            ['systree'],
            'use DIR as the system tree for containers',
            metavar='DIR',
            default='/var/lib/ick/systree',
        )

    def process_args(self, args):
        try:
            self.main_program(args)
        except BaseException as e:
            logging.error(str(e), exc_info=True)
            raise

    def main_program(self, args):
        self.settings.require('name')
        self.settings.require('controller')

        name = self.settings['name']
        url = self.settings['controller']
        workspace = self.settings['workspace']
        systree = self.settings['systree']

        tg = TokenGenerator()
        tg.set_key(self.settings['token-key'])
        api = ControllerAPI(name, url, tg)
        worker = Worker(name, api, workspace, systree)

        logging.info('Worker manager %s starts, controller is %s', name, url)

        api.register()
        while True:
            work = api.get_work()
            if work:
                worker.do_work(work)
            else:
                self.sleep_a_little()

    def sleep_a_little(self):
        secs = self.settings['sleep']
        time.sleep(secs)


class ControllerAPI:

    def __init__(self, name, url, token_generator):
        self._token_generator = token_generator
        self._cc = ick2.ControllerClient()
        self._cc.set_client_name(name)
        self._cc.set_controller_url(url)
        self._blobs = None

    def get_token(self):
        return self._token_generator.get_token()

    def register(self):
        self._cc.set_token(self.get_token())
        self._cc.register()

    def get_work(self):
        self._cc.set_token(self.get_token())
        return self._cc.get_work()

    def report_work(self, work):
        self._cc.set_token(self.get_token())
        self._cc.report_work(work)

    def get_blob_upload_url(self, name):
        blobs = self.get_blob_client()
        return blobs.url(name)

    def upload_blob(self, blob_id, blob):
        blobs = self.get_blob_client()
        blobs.upload(blob_id, blob)

    def download_blob(self, blob_id):
        blobs = self.get_blob_client()
        return blobs.download(blob_id)

    def get_blob_client(self):
        if self._blobs is None:
            self._blobs = self._cc.get_blob_client()
        return self._blobs


class TokenGenerator:

    max_age = 3600  # 1 hour
    sub = 'subject-uuid'
    iss = 'localhost'
    aud = 'localhost'
    scopes = ' '.join([
        'uapi_version_get',
        'uapi_work_id_get',
        'uapi_work_post',
        'uapi_workers_post',
        'uapi_blobs_id_get',
        'uapi_blobs_id_put',
    ])

    def __init__(self):
        self._token = None
        self._token_key = None
        self._token_until = None

    def is_valid(self, now):
        return (
            self._token is not None and
            (self._token_until is None or now <= self._token_until)
        )

    def set_token(self, token):
        self._token = token
        self._token_until = None
        assert self.is_valid(time.time())

    def set_key(self, filename):
        key_text = self.cat(filename)
        self._token_key = Crypto.PublicKey.RSA.importKey(key_text)

    def cat(self, filename):
        with open(filename) as f:
            return f.read()

    def get_token(self):
        now = time.time()
        if not self.is_valid(now):
            self._token = self.create_token()
            self._token_until = now + self.max_age
        assert self.is_valid(now)
        return self._token

    def create_token(self):
        now = time.time()
        claims = {
            'iss': self.iss,
            'sub': self.sub,
            'aud': self.aud,
            'exp': now + self.max_age,
            'scope': self.scopes,
        }

        token = apifw.create_token(claims, self._token_key)
        return token.decode('ascii')


class Worker:

    def __init__(self, name, api, workspace, systree):
        self._name = name
        self._api = api
        self._workspace = workspace
        self._systree = systree

    def do_work(self, work):
        project_name = work['project']
        step = work.get('step', {})
        params = work.get('parameters', {})
        reporter = ick2.Reporter(self._api, work)
        af = ick2.ActionFactory(self._systree, self._workspace, reporter)
        af.set_token(self._api.get_token())
        af.set_blob_url_func(self._api.get_blob_upload_url)
        action = af.create_action(step, project_name)
        exit_code = action.execute(params, step)


if __name__ == '__main__':
    WorkerManager(version=ick2.__version__).run()