import logging
import daemon
import argparse
import os
import requests
import re
import json
import shutil

from docker import Client, APIError
from tempfile import TemporaryFile, mkdtemp
from zipfile import ZipFile

from data.queue import dockerfile_build_queue
from data import model
from workers.worker import Worker
from app import app


root_logger = logging.getLogger('')
root_logger.setLevel(logging.DEBUG)

FORMAT = '%(asctime)-15s - %(levelname)s - %(pathname)s - %(funcName)s - %(message)s'
formatter = logging.Formatter(FORMAT)

logger = logging.getLogger(__name__)


class DockerfileBuildWorker(Worker):
  def __init__(self, *vargs, **kwargs):
    super(DockerfileBuildWorker, self).__init__(*vargs, **kwargs)

    self._mime_processors = {
      'application/zip': DockerfileBuildWorker.__prepare_zip,
      'text/plain': DockerfileBuildWorker.__prepare_dockerfile,
      'application/octet-stream': DockerfileBuildWorker.__prepare_dockerfile,
    }

  @staticmethod
  def __count_steps(dockerfile_path):
    with open(dockerfile_path, 'r') as dockerfileobj:
      steps = 0
      for line in dockerfileobj.readlines():
        stripped = line.strip()
        if stripped and stripped[0] is not '#':
          steps += 1
      return steps

  @staticmethod
  def __prepare_zip(request_file):
    build_dir = mkdtemp(prefix='docker-build-')

    # Save the zip file to temp somewhere
    with TemporaryFile() as zip_file:
      zip_file.write(request_file.content)
      to_extract = ZipFile(zip_file)
      to_extract.extractall(build_dir)

    return build_dir

  @staticmethod
  def __prepare_dockerfile(request_file):
    build_dir = mkdtemp(prefix='docker-build-')
    dockerfile_path = os.path.join(build_dir, "Dockerfile")
    with open(dockerfile_path, 'w') as dockerfile:
      dockerfile.write(request_file.content)

    return build_dir

  @staticmethod
  def __total_completion(statuses, total_images):
    percentage_with_sizes = float(len(statuses.values()))/total_images
    sent_bytes = sum([status[u'current'] for status in statuses.values()])
    total_bytes = sum([status[u'total'] for status in statuses.values()])
    return float(sent_bytes)/total_bytes*percentage_with_sizes

  @staticmethod
  def __build_image(build_dir, tag_name, num_steps, result_object):
    try:
      logger.debug('Starting build.')
      docker_cl = Client(timeout=1200)

      result_object['status'] = 'building'
      build_status = docker_cl.build(path=build_dir, tag=tag_name, stream=True)

      current_step = 0
      built_image = None
      for status in build_status:
        # logger.debug('Status: %s', str(status))
        step_increment = re.search(r'Step ([0-9]+) :', status)
        if step_increment:
          current_step = int(step_increment.group(1))
          logger.debug('Step now: %s/%s' % (current_step, num_steps))
          result_object['current_command'] = current_step
          continue

        complete = re.match(r'Successfully built ([a-z0-9]+)$', status)
        if complete:
          built_image = complete.group(1)
          logger.debug('Final image ID is: %s' % built_image)
          continue

      shutil.rmtree(build_dir)

      # Get the image count
      if not built_image:
        result_object['status'] = 'error'
        result_object['message'] = 'Unable to build dockerfile.'
        return

      return built_image
    except Exception as exc:
      logger.exception('Exception when processing request.')
      result_object['status'] = 'error'
      result_object['message'] = str(exc.message)

  @staticmethod
  def __push_image(built_image, token, tag_name, result_object):
    try:
      # Login to the registry
      host = re.match(r'([a-z0-9.:]+)/.+/.+$', tag_name)
      if not host:
        raise Exception('Invalid tag name: %s' % tag_name)

      docker_cl = Client(timeout=1200)

      for protocol in ['https', 'http']:
        registry_endpoint = '%s://%s/v1/' % (protocol, host.group(1))
        logger.debug('Attempting login to registry: %s' % registry_endpoint)

        try:
          docker_cl.login('$token', token, registry=registry_endpoint)
          break
        except APIError:
          pass  # Probably the wrong protocol

      history = json.loads(docker_cl.history(built_image))
      num_images = len(history)
      result_object['total_images'] = num_images

      result_object['status'] = 'pushing'
      logger.debug('Pushing to tag name: %s' % tag_name)
      resp = docker_cl.push(tag_name, stream=True)

      for status_str in resp:
        status = json.loads(status_str)
        logger.debug('Status: %s', status_str)
        if u'status' in status:
          status_msg = status[u'status']

          if status_msg == 'Pushing':
            if u'progressDetail' in status and u'id' in status:
              image_id = status[u'id']
              detail = status[u'progressDetail']

              if u'current' in detail and 'total' in detail:
                images = result_object['image_completion']

                images[image_id] = detail
                result_object['push_completion'] = \
                  DockerfileBuildWorker.__total_completion(images, num_images)

        elif u'errorDetail' in status:
          result_object['status'] = 'error'
          if u'message' in status[u'errorDetail']:
            result_object['message'] = str(status[u'errorDetail'][u'message'])
          return

      result_object['status'] = 'complete'
    except Exception as exc:
      logger.exception('Exception when processing request.')
      result_object['status'] = 'error'
      result_object['message'] = str(exc.message)

  @staticmethod
  def __cleanup():
    docker_cl = Client(timeout=1200)

    # First clean up any containers that might be holding the images
    for running in docker_cl.containers(quiet=True):
      docker_cl.kill(running['Id'])

    # Next, remove all of the containers (which should all now be killed)
    for container in docker_cl.containers(all=True, quiet=True):
      docker_cl.remove_container(container['Id'])

    # Iterate all of the images and remove the ones that the public registry
    # doesn't know about, this should preserve base images.
    images_to_remove = set()
    repos = set()
    for image in docker_cl.images():
      images_to_remove.add(image['Id'])
      repos.add(image['Repository'])

    for repo in repos:
      repo_url = 'https://index.docker.io/v1/repositories/%s/images' % repo
      repo_info = requests.get(repo_url)
      if repo_info.status_code / 100 == 2:      
        for repo_image in repo_info.json():
          if repo_image['id'] in images_to_remove:
            logger.debug('Image was deemed public: %s' % repo_image['id'])
            images_to_remove.remove(repo_image['id'])

    for to_remove in images_to_remove:
      logger.debug('Removing private image: %s' % to_remove)
      try:
        docker_cl.remove_image(to_remove)
      except APIError:
        # Sometimes an upstream image removed this one
        pass

    # Verify that our images were actually removed
    for image in docker_cl.images():
      if image['Id'] in images_to_remove:
        raise RuntimeError('Image was not removed: %s' % image['Id'])

  def process_queue_item(self, job_details):
    repository_build = model.get_repository_build(job_details['build_id'])

    user_files = app.config['USERFILES']
    resource_url = user_files.get_file_url(repository_build.resource_key)
    tag_name = repository_build.tag
    access_token = repository_build.access_token.code

    feedback = {
      'total_commands': None,
      'current_command': None,
      'push_completion': 0.0,
      'status': 'waiting',
      'message': None,
      'image_completion': {},
    }

    logger.debug('Starting job with resource url: %s tag: %s and token: %s' %
                 (resource_url, tag_name, access_token))

    docker_resource = requests.get(resource_url)
    c_type = docker_resource.headers['content-type']

    logger.info('Request to build file of type: %s with tag: %s' %
                (c_type, tag_name))

    if c_type not in self._mime_processors:
      raise Exception('Invalid dockerfile content type: %s' % c_type)

    build_dir = self._mime_processors[c_type](docker_resource)

    dockerfile_path = os.path.join(build_dir, "Dockerfile")
    num_steps = DockerfileBuildWorker.__count_steps(dockerfile_path)
    logger.debug('Dockerfile had %s steps' % num_steps)

    built_image = DockerfileBuildWorker.__build_image(build_dir, tag_name,
                                                      num_steps, feedback)

    DockerfileBuildWorker.__push_image(built_image, access_token, tag_name,
                                       feedback)

    DockerfileBuildWorker.__cleanup()


desc = 'Worker daemon to monitor dockerfile build'
parser = argparse.ArgumentParser(description=desc)
parser.add_argument('-D', action='store_true', default=False,
                    help='Run the worker in daemon mode.')
parser.add_argument('--log', default='dockerfilebuild.log',
                    help='Specify the log file for the worker as a daemon.')
args = parser.parse_args()


worker = DockerfileBuildWorker(dockerfile_build_queue)

if args.D:
  handler = logging.FileHandler(args.log)
  handler.setFormatter(formatter)
  root_logger.addHandler(handler)
  with daemon.DaemonContext(files_preserve=[handler.stream]):
    worker.start()

else:
  handler = logging.StreamHandler()
  handler.setFormatter(formatter)
  root_logger.addHandler(handler)
  worker.start()