# Copyright 2015 gRPC authors.
#
# 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.
"""Helpers to run docker instances as jobs."""

from __future__ import print_function

import tempfile
import time
import uuid
import os
import subprocess

import jobset

_DEVNULL = open(os.devnull, 'w')


def random_name(base_name):
    """Randomizes given base name."""
    return '%s_%s' % (base_name, uuid.uuid4())


def docker_kill(cid):
    """Kills a docker container. Returns True if successful."""
    return subprocess.call(
        ['docker', 'kill', str(cid)],
        stdin=subprocess.PIPE,
        stdout=_DEVNULL,
        stderr=subprocess.STDOUT) == 0


def docker_mapped_port(cid, port, timeout_seconds=15):
    """Get port mapped to internal given internal port for given container."""
    started = time.time()
    while time.time() - started < timeout_seconds:
        try:
            output = subprocess.check_output(
                'docker port %s %s' % (cid, port), stderr=_DEVNULL, shell=True)
            return int(output.split(':', 2)[1])
        except subprocess.CalledProcessError as e:
            pass
    raise Exception('Failed to get exposed port %s for container %s.' % (port,
                                                                         cid))


def wait_for_healthy(cid, shortname, timeout_seconds):
    """Wait timeout_seconds for the container to become healthy"""
    started = time.time()
    while time.time() - started < timeout_seconds:
        try:
            output = subprocess.check_output(
                [
                    'docker', 'inspect', '--format="{{.State.Health.Status}}"',
                    cid
                ],
                stderr=_DEVNULL)
            if output.strip('\n') == 'healthy':
                return
        except subprocess.CalledProcessError as e:
            pass
        time.sleep(1)
    raise Exception('Timed out waiting for %s (%s) to pass health check' %
                    (shortname, cid))


def finish_jobs(jobs):
    """Kills given docker containers and waits for corresponding jobs to finish"""
    for job in jobs:
        job.kill(suppress_failure=True)

    while any(job.is_running() for job in jobs):
        time.sleep(1)


def image_exists(image):
    """Returns True if given docker image exists."""
    return subprocess.call(
        ['docker', 'inspect', image],
        stdin=subprocess.PIPE,
        stdout=_DEVNULL,
        stderr=subprocess.STDOUT) == 0


def remove_image(image, skip_nonexistent=False, max_retries=10):
    """Attempts to remove docker image with retries."""
    if skip_nonexistent and not image_exists(image):
        return True
    for attempt in range(0, max_retries):
        if subprocess.call(
            ['docker', 'rmi', '-f', image],
                stdin=subprocess.PIPE,
                stdout=_DEVNULL,
                stderr=subprocess.STDOUT) == 0:
            return True
        time.sleep(2)
    print('Failed to remove docker image %s' % image)
    return False


class DockerJob:
    """Encapsulates a job"""

    def __init__(self, spec):
        self._spec = spec
        self._job = jobset.Job(
            spec, newline_on_success=True, travis=True, add_env={})
        self._container_name = spec.container_name

    def mapped_port(self, port):
        return docker_mapped_port(self._container_name, port)

    def wait_for_healthy(self, timeout_seconds):
        wait_for_healthy(self._container_name, self._spec.shortname,
                         timeout_seconds)

    def kill(self, suppress_failure=False):
        """Sends kill signal to the container."""
        if suppress_failure:
            self._job.suppress_failure_message()
        return docker_kill(self._container_name)

    def is_running(self):
        """Polls a job and returns True if given job is still running."""
        return self._job.state() == jobset._RUNNING