import json
import logging
import urlparse

from functools import wraps

from flask import request, make_response, jsonify, session

from app import userevents, metric_queue, storage
from auth.auth_context import get_authenticated_context, get_authenticated_user
from auth.credentials import validate_credentials, CredentialKind
from auth.decorators import process_auth
from auth.permissions import (
  ModifyRepositoryPermission, UserAdminPermission, ReadRepositoryPermission,
  CreateRepositoryPermission, repository_read_grant, repository_write_grant)
from auth.signedgrant import generate_signed_token
from data import model
from data.registry_model import registry_model
from data.registry_model.manifestbuilder import create_manifest_builder, lookup_manifest_builder
from endpoints.decorators import anon_protect, anon_allowed, parse_repository_name
from endpoints.v1 import v1_bp
from notifications import spawn_notification
from util.audit import track_and_log
from util.http import abort
from util.names import REPOSITORY_NAME_REGEX

logger = logging.getLogger(__name__)


class GrantType(object):
  READ_REPOSITORY = 'read'
  WRITE_REPOSITORY = 'write'


def ensure_namespace_enabled(f):
  @wraps(f)
  def wrapper(namespace_name, repo_name, *args, **kwargs):
    namespace = model.user.get_namespace_user(namespace_name)
    is_namespace_enabled = namespace is not None and namespace.enabled
    if not is_namespace_enabled:
      abort(400, message='Namespace is disabled. Please contact your system administrator.')

    return f(namespace_name, repo_name, *args, **kwargs)
  return wrapper


def generate_headers(scope=GrantType.READ_REPOSITORY, add_grant_for_status=None):
  def decorator_method(f):
    @wraps(f)
    def wrapper(namespace_name, repo_name, *args, **kwargs):
      response = f(namespace_name, repo_name, *args, **kwargs)

      # Setting session namespace and repository
      session['namespace'] = namespace_name
      session['repository'] = repo_name

      # We run our index and registry on the same hosts for now
      registry_server = urlparse.urlparse(request.url).netloc
      response.headers['X-Docker-Endpoints'] = registry_server

      has_token_request = request.headers.get('X-Docker-Token', '')
      force_grant = (add_grant_for_status == response.status_code)

      if has_token_request or force_grant:
        grants = []

        if scope == GrantType.READ_REPOSITORY:
          if force_grant or ReadRepositoryPermission(namespace_name, repo_name).can():
            grants.append(repository_read_grant(namespace_name, repo_name))
        elif scope == GrantType.WRITE_REPOSITORY:
          if force_grant or ModifyRepositoryPermission(namespace_name, repo_name).can():
            grants.append(repository_write_grant(namespace_name, repo_name))

        # Generate a signed token for the user (if any) and the grants (if any)
        if grants or get_authenticated_user():
          user_context = get_authenticated_user() and get_authenticated_user().username
          signature = generate_signed_token(grants, user_context)
          response.headers['WWW-Authenticate'] = signature
          response.headers['X-Docker-Token'] = signature

      return response

    return wrapper

  return decorator_method


@v1_bp.route('/users', methods=['POST'])
@v1_bp.route('/users/', methods=['POST'])
@anon_allowed
def create_user():
  user_data = request.get_json()
  if not user_data or not 'username' in user_data:
    abort(400, 'Missing username')

  username = user_data['username']
  password = user_data.get('password', '')

  # UGH! we have to use this response when the login actually worked, in order
  # to get the CLI to try again with a get, and then tell us login succeeded.
  success = make_response('"Username or email already exists"', 400)
  result, kind = validate_credentials(username, password)
  if not result.auth_valid:
    if kind == CredentialKind.token:
      abort(400, 'Invalid access token.', issue='invalid-access-token')

    if kind == CredentialKind.robot:
      abort(400, 'Invalid robot account or password.', issue='robot-login-failure')

    if kind == CredentialKind.oauth_token:
      abort(400, 'Invalid oauth access token.', issue='invalid-oauth-access-token')

    if kind == CredentialKind.user:
      # Mark that the login failed.
      event = userevents.get_event(username)
      event.publish_event_data('docker-cli', {'action': 'loginfailure'})
      abort(400, result.error_message, issue='login-failure')

    # Default case: Just fail.
    abort(400, result.error_message, issue='login-failure')

  if result.has_nonrobot_user:
    # Mark that the user was logged in.
    event = userevents.get_event(username)
    event.publish_event_data('docker-cli', {'action': 'login'})

  return success


@v1_bp.route('/users', methods=['GET'])
@v1_bp.route('/users/', methods=['GET'])
@process_auth
@anon_allowed
def get_user():
  context = get_authenticated_context()
  if not context or context.is_anonymous:
    abort(404)

  return jsonify({
    'username': context.credential_username,
    'email': None,
  })


@v1_bp.route('/users/<username>/', methods=['PUT'])
@process_auth
@anon_allowed
def update_user(username):
  permission = UserAdminPermission(username)
  if permission.can():
    update_request = request.get_json()

    if 'password' in update_request:
      logger.debug('Updating user password')
      model.user.change_password(get_authenticated_user(), update_request['password'])

    return jsonify({
      'username': get_authenticated_user().username,
      'email': get_authenticated_user().email,
    })

  abort(403)


@v1_bp.route('/repositories/<repopath:repository>/', methods=['PUT'])
@process_auth
@parse_repository_name()
@ensure_namespace_enabled
@generate_headers(scope=GrantType.WRITE_REPOSITORY, add_grant_for_status=201)
@anon_allowed
def create_repository(namespace_name, repo_name):
  # Verify that the repository name is valid.
  if not REPOSITORY_NAME_REGEX.match(repo_name):
    abort(400, message='Invalid repository name. Repository names cannot contain slashes.')

  logger.debug('Looking up repository %s/%s', namespace_name, repo_name)
  repository_ref = registry_model.lookup_repository(namespace_name, repo_name)
  if repository_ref is None and get_authenticated_user() is None:
    logger.debug('Attempt to create repository %s/%s without user auth', namespace_name, repo_name)
    abort(401,
          message='Cannot create a repository as a guest. Please login via "docker login" first.',
          issue='no-login')
  elif repository_ref:
    modify_perm = ModifyRepositoryPermission(namespace_name, repo_name)
    if not modify_perm.can():
      abort(403,
            message='You do not have permission to modify repository %(namespace)s/%(repository)s',
            issue='no-repo-write-permission', namespace=namespace_name, repository=repo_name)
    elif repository_ref.kind != 'image':
      msg = ('This repository is for managing %s resources and not container images.' %
             repository_ref.kind)
      abort(405, message=msg, namespace=namespace_name)
  else:
    create_perm = CreateRepositoryPermission(namespace_name)
    if not create_perm.can():
      logger.warning('Attempt to create a new repo %s/%s with insufficient perms', namespace_name,
                     repo_name)
      msg = 'You do not have permission to create repositories in namespace "%(namespace)s"'
      abort(403, message=msg, issue='no-create-permission', namespace=namespace_name)

    # Attempt to create the new repository.
    logger.debug('Creating repository %s/%s with owner: %s', namespace_name, repo_name,
                 get_authenticated_user().username)

    repository_ref = model.repository.create_repository(namespace_name, repo_name,
                                                        get_authenticated_user())

  if get_authenticated_user():
    user_event_data = {
      'action': 'push_start',
      'repository': repo_name,
      'namespace': namespace_name,
    }

    event = userevents.get_event(get_authenticated_user().username)
    event.publish_event_data('docker-cli', user_event_data)

  # Start a new builder for the repository and save its ID in the session.
  assert repository_ref
  builder = create_manifest_builder(repository_ref, storage)
  logger.debug('Started repo push with manifest builder %s', builder)
  if builder is None:
    abort(404, message='Unknown repository', issue='unknown-repo')

  session['manifest_builder'] = builder.builder_id
  return make_response('Created', 201)


@v1_bp.route('/repositories/<repopath:repository>/images', methods=['PUT'])
@process_auth
@parse_repository_name()
@ensure_namespace_enabled
@generate_headers(scope=GrantType.WRITE_REPOSITORY)
@anon_allowed
def update_images(namespace_name, repo_name):
  permission = ModifyRepositoryPermission(namespace_name, repo_name)

  if permission.can():
    logger.debug('Looking up repository')
    repository_ref = registry_model.lookup_repository(namespace_name, repo_name,
                                                      kind_filter='image')
    if repository_ref is None:
      # Make sure the repo actually exists.
      abort(404, message='Unknown repository', issue='unknown-repo')

    builder = lookup_manifest_builder(repository_ref, session.get('manifest_builder'), storage)
    if builder is None:
      abort(400)

    # Generate a job for each notification that has been added to this repo
    logger.debug('Adding notifications for repository')
    event_data = {
      'updated_tags': [tag.name for tag in builder.committed_tags],
    }

    builder.done()

    track_and_log('push_repo', repository_ref)
    spawn_notification(repository_ref, 'repo_push', event_data)
    metric_queue.repository_push.Inc(labelvalues=[namespace_name, repo_name, 'v1', True])
    return make_response('Updated', 204)

  abort(403)


@v1_bp.route('/repositories/<repopath:repository>/images', methods=['GET'])
@process_auth
@parse_repository_name()
@ensure_namespace_enabled
@generate_headers(scope=GrantType.READ_REPOSITORY)
@anon_protect
def get_repository_images(namespace_name, repo_name):
  repository_ref = registry_model.lookup_repository(namespace_name, repo_name,
                                                    kind_filter='image')

  permission = ReadRepositoryPermission(namespace_name, repo_name)
  if permission.can() or (repository_ref and repository_ref.is_public):
    # We can't rely on permissions to tell us if a repo exists anymore
    if repository_ref is None:
      abort(404, message='Unknown repository', issue='unknown-repo')

    logger.debug('Building repository image response')
    resp = make_response(json.dumps([]), 200)
    resp.mimetype = 'application/json'

    track_and_log('pull_repo', repository_ref,
                  analytics_name='pull_repo_100x',
                  analytics_sample=0.01)
    metric_queue.repository_pull.Inc(labelvalues=[namespace_name, repo_name, 'v1', True])
    return resp

  abort(403)


@v1_bp.route('/repositories/<repopath:repository>/images', methods=['DELETE'])
@process_auth
@parse_repository_name()
@ensure_namespace_enabled
@generate_headers(scope=GrantType.WRITE_REPOSITORY)
@anon_allowed
def delete_repository_images(namespace_name, repo_name):
  abort(501, 'Not Implemented', issue='not-implemented')


@v1_bp.route('/repositories/<repopath:repository>/auth', methods=['PUT'])
@parse_repository_name()
@ensure_namespace_enabled
@anon_allowed
def put_repository_auth(namespace_name, repo_name):
  abort(501, 'Not Implemented', issue='not-implemented')


@v1_bp.route('/search', methods=['GET'])
@process_auth
@anon_protect
def get_search():
  query = request.args.get('q') or ''

  try:
    limit = min(100, max(1, int(request.args.get('n', 25))))
  except ValueError:
    limit = 25

  try:
    page = max(0, int(request.args.get('page', 1)))
  except ValueError:
    page = 1

  username = None
  user = get_authenticated_user()
  if user is not None:
    username = user.username

  data = _conduct_repo_search(username, query, limit, page)
  resp = make_response(json.dumps(data), 200)
  resp.mimetype = 'application/json'
  return resp


def _conduct_repo_search(username, query, limit=25, page=1):
  """ Finds matching repositories. """
  # Note that we put a maximum limit of five pages here, because this API should only really ever
  # be used by the Docker CLI, and it doesn't even paginate.
  page = min(page, 5)
  offset = (page - 1) * limit

  if query:
    matching_repos = model.repository.get_filtered_matching_repositories(query,
                                                                         filter_username=username,
                                                                         offset=offset,
                                                                         limit=limit + 1)
  else:
    matching_repos = []

  results = []
  for repo in matching_repos[0:limit]:
    results.append({
      'name': repo.namespace_user.username + '/' + repo.name,
      'description': repo.description,
      'is_public': model.repository.is_repository_public(repo),
      'href': '/repository/' + repo.namespace_user.username + '/' + repo.name
    })

  # Defined: https://docs.docker.com/v1.6/reference/api/registry_api/
  return {
    'query': query,
    'num_results': len(results),
    'num_pages': page + 1 if len(matching_repos) > limit else page,
    'page': page,
    'page_size': limit,
    'results': results,
  }