import cStringIO as StringIO
import os
import logging

import boto.s3.connection
import boto.gs.connection
import boto.s3.key
import boto.gs.key

from io import BufferedIOBase

import app
from storage.basestorage import BaseStorage


logger = logging.getLogger(__name__)


class StreamReadKeyAsFile(BufferedIOBase):
  def __init__(self, key):
    self._key = key

  def read(self, amt=None):
    if self.closed:
      return None

    resp = self._key.read(amt)
    return resp

  def readable(self):
    return True

  @property
  def closed(self):
    return self._key.closed

  def close(self):
    self._key.close(fast=True)


class _CloudStorage(BaseStorage):
  def __init__(self, connection_class, key_class, connect_kwargs, upload_params, storage_path,
               access_key, secret_key, bucket_name):
    self._initialized = False
    self._bucket_name = bucket_name
    self._access_key = access_key
    self._secret_key = secret_key
    self._root_path = storage_path
    self._connection_class = connection_class
    self._key_class = key_class
    self._upload_params = upload_params
    self._connect_kwargs = connect_kwargs
    self._cloud_conn = None
    self._cloud_bucket = None

  def _initialize_cloud_conn(self):
    if not self._initialized:
      self._cloud_conn = self._connection_class(self._access_key, self._secret_key,
                                                **self._connect_kwargs)
      self._cloud_bucket = self._cloud_conn.get_bucket(self._bucket_name)
      self._initialized = True

  def _debug_key(self, key):
    """Used for debugging only."""
    orig_meth = key.bucket.connection.make_request

    def new_meth(*args, **kwargs):
      print '#' * 16
      print args
      print kwargs
      print '#' * 16
      return orig_meth(*args, **kwargs)
    key.bucket.connection.make_request = new_meth

  def _init_path(self, path=None):
    path = os.path.join(self._root_path, path) if path else self._root_path
    if path and path[0] == '/':
      return path[1:]
    return path

  def get_cloud_conn(self):
    self._initialize_cloud_conn()
    return self._cloud_conn

  def get_cloud_bucket(self):
    return self._cloud_bucket

  def get_content(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    if not key.exists():
      raise IOError('No such key: \'{0}\''.format(path))
    return key.get_contents_as_string()

  def put_content(self, path, content):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    key.set_contents_from_string(content, **self._upload_params)
    return path

  def get_supports_resumable_downloads(self):
    return True

  def get_direct_download_url(self, path, expires_in=60, requires_cors=False):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    k = self._key_class(self._cloud_bucket, path)
    return k.generate_url(expires_in)

  def get_direct_upload_url(self, path, mime_type, requires_cors=True):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    url = key.generate_url(300, 'PUT', headers={'Content-Type': mime_type}, encrypt_key=True)
    return url

  def stream_read(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    if not key.exists():
      raise IOError('No such key: \'{0}\''.format(path))
    while True:
      buf = key.read(self.buffer_size)
      if not buf:
        break
      yield buf

  def stream_read_file(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    if not key.exists():
      raise IOError('No such key: \'{0}\''.format(path))
    return StreamReadKeyAsFile(key)

  def stream_write(self, path, fp, content_type=None, content_encoding=None):
    # Minimum size of upload part size on S3 is 5MB
    self._initialize_cloud_conn()
    buffer_size = 5 * 1024 * 1024
    if self.buffer_size > buffer_size:
      buffer_size = self.buffer_size
    path = self._init_path(path)

    metadata = {}
    if content_type is not None:
      metadata['Content-Type'] = content_type

    if content_encoding is not None:
      metadata['Content-Encoding'] = content_encoding

    mp = self._cloud_bucket.initiate_multipart_upload(path, metadata=metadata,
                                                      **self._upload_params)
    app.metric_queue.put('MultipartUploadStart', 1)
    num_part = 1
    while True:
      try:
        buf = fp.read(buffer_size)
        if not buf:
          break
        io = StringIO.StringIO(buf)
        mp.upload_part_from_file(io, num_part)
        num_part += 1
        io.close()
      except IOError:
        app.metric_queue.put('MultipartUploadFailure', 1)
        mp.cancel_upload()
        raise

    app.metric_queue.put('MultipartUploadSuccess', 1)
    mp.complete_upload()

  def list_directory(self, path=None):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    if not path.endswith('/'):
      path += '/'
    ln = 0
    if self._root_path != '/':
      ln = len(self._root_path)
    exists = False
    for key in self._cloud_bucket.list(prefix=path, delimiter='/'):
      exists = True
      name = key.name
      if name.endswith('/'):
        yield name[ln:-1]
      else:
        yield name[ln:]
    if exists is False:
      # In order to be compliant with the LocalStorage API. Even though
      # S3 does not have a concept of folders.
      raise OSError('No such directory: \'{0}\''.format(path))

  def exists(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    return key.exists()

  def remove(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    if key.exists():
      # It's a file
      key.delete()
      return
    # We assume it's a directory
    if not path.endswith('/'):
      path += '/'
    for key in self._cloud_bucket.list(prefix=path):
      key.delete()

  def get_checksum(self, path):
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)
    k = self._cloud_bucket.lookup(key)
    if k is None:
      raise IOError('No such key: \'{0}\''.format(path))

    return k.etag[1:-1][:7]

  def copy_to(self, destination, path):
    self._initialize_cloud_conn()

    # First try to copy directly via boto, but only if the storages are the
    # same type, with the same access information.
    if (self.__class__ == destination.__class__ and
        self._access_key == destination._access_key and
        self._secret_key == destination._secret_key):
      logger.debug('Copying file from %s to %s via a direct boto copy', self._cloud_bucket,
                   destination._cloud_bucket)

      source_path = self._init_path(path)
      source_key = self._key_class(self._cloud_bucket, source_path)

      destination._initialize_cloud_conn()
      dest_path = destination._init_path(path)
      source_key.copy(destination._cloud_bucket, dest_path)
      return

    # Fallback to a slower, default copy.
    logger.debug('Copying file from %s to %s via a streamed copy', self._cloud_bucket,
                 destination)
    with self.stream_read_file(path) as fp:
      destination.stream_write(path, fp)


class S3Storage(_CloudStorage):
  def __init__(self, storage_path, s3_access_key, s3_secret_key, s3_bucket):
    upload_params = {
      'encrypt_key': True,
    }
    connect_kwargs = {}
    super(S3Storage, self).__init__(boto.s3.connection.S3Connection, boto.s3.key.Key,
                                    connect_kwargs, upload_params, storage_path, s3_access_key,
                                    s3_secret_key, s3_bucket)

  def setup(self):
    self.get_cloud_bucket().set_cors_xml("""<?xml version="1.0" encoding="UTF-8"?>
      <CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
          <CORSRule>
              <AllowedOrigin>*</AllowedOrigin>
              <AllowedMethod>GET</AllowedMethod>
              <MaxAgeSeconds>3000</MaxAgeSeconds>
              <AllowedHeader>Authorization</AllowedHeader>
          </CORSRule>
          <CORSRule>
              <AllowedOrigin>*</AllowedOrigin>
              <AllowedMethod>PUT</AllowedMethod>
              <MaxAgeSeconds>3000</MaxAgeSeconds>
              <AllowedHeader>Content-Type</AllowedHeader>
              <AllowedHeader>x-amz-acl</AllowedHeader>
              <AllowedHeader>origin</AllowedHeader>
          </CORSRule>
      </CORSConfiguration>""")

class GoogleCloudStorage(_CloudStorage):
  def __init__(self, storage_path, access_key, secret_key, bucket_name):
    upload_params = {}
    connect_kwargs = {}
    super(GoogleCloudStorage, self).__init__(boto.gs.connection.GSConnection, boto.gs.key.Key,
                                             connect_kwargs, upload_params, storage_path,
                                             access_key, secret_key, bucket_name)

  def setup(self):
    self.get_cloud_bucket().set_cors_xml("""<?xml version="1.0" encoding="UTF-8"?>
      <CorsConfig>
        <Cors>
          <Origins>
            <Origin>*</Origin>
          </Origins>
          <Methods>
            <Method>GET</Method>
            <Method>PUT</Method>
          </Methods>
          <ResponseHeaders>
            <ResponseHeader>Content-Type</ResponseHeader>
          </ResponseHeaders>
          <MaxAgeSec>3000</MaxAgeSec>
        </Cors>
      </CorsConfig>""")

  def stream_write(self, path, fp, content_type=None, content_encoding=None):
    # Minimum size of upload part size on S3 is 5MB
    self._initialize_cloud_conn()
    path = self._init_path(path)
    key = self._key_class(self._cloud_bucket, path)

    if content_type is not None:
      key.set_metadata('Content-Type', content_type)

    if content_encoding is not None:
      key.set_metadata('Content-Encoding', content_encoding)

    key.set_contents_from_stream(fp)


class RadosGWStorage(_CloudStorage):
  def __init__(self, hostname, is_secure, storage_path, access_key, secret_key, bucket_name):
    upload_params = {}
    connect_kwargs = {
      'host': hostname,
      'is_secure': is_secure,
      'calling_format': boto.s3.connection.OrdinaryCallingFormat(),
    }
    super(RadosGWStorage, self).__init__(boto.s3.connection.S3Connection, boto.s3.key.Key,
                                         connect_kwargs, upload_params, storage_path, access_key,
                                         secret_key, bucket_name)

  # TODO remove when radosgw supports cors: http://tracker.ceph.com/issues/8718#change-38624
  def get_direct_download_url(self, path, expires_in=60, requires_cors=False):
    if requires_cors:
      return None

    return super(RadosGWStorage, self).get_direct_download_url(path, expires_in, requires_cors)

  # TODO remove when radosgw supports cors: http://tracker.ceph.com/issues/8718#change-38624
  def get_direct_upload_url(self, path, mime_type, requires_cors=True):
    if requires_cors:
      return None

    return super(RadosGWStorage, self).get_direct_upload_url(path, mime_type, requires_cors)