import cStringIO as StringIO
import hashlib

from collections import defaultdict
from uuid import uuid4

from storage.basestorage import BaseStorageV2

_FAKE_STORAGE_MAP = defaultdict(StringIO.StringIO)

class FakeStorage(BaseStorageV2):
  def _init_path(self, path=None, create=False):
    return path

  def get_content(self, path):
    if not path in _FAKE_STORAGE_MAP:
      raise IOError('Fake file %s not found' % path)

    _FAKE_STORAGE_MAP.get(path).seek(0)
    return _FAKE_STORAGE_MAP.get(path).read()

  def put_content(self, path, content):
    _FAKE_STORAGE_MAP.pop(path, None)
    _FAKE_STORAGE_MAP[path].write(content)

  def stream_read(self, path):
    io_obj = _FAKE_STORAGE_MAP[path]
    io_obj.seek(0)
    while True:
      buf = io_obj.read(self.buffer_size)
      if not buf:
        break
      yield buf

  def stream_write(self, path, fp, content_type=None, content_encoding=None):
    out_fp = _FAKE_STORAGE_MAP[path]
    out_fp.seek(0)
    self.stream_write_to_fp(fp, out_fp)

  def remove(self, path):
    _FAKE_STORAGE_MAP.pop(path, None)

  def exists(self, path):
    return path in _FAKE_STORAGE_MAP

  def get_checksum(self, path):
    return hashlib.sha256(_FAKE_STORAGE_MAP[path].read()).hexdigest()[:7]

  def initiate_chunked_upload(self):
    new_uuid = str(uuid4())
    _FAKE_STORAGE_MAP[new_uuid].seek(0)
    return new_uuid, {}

  def stream_upload_chunk(self, uuid, offset, length, in_fp, _):
    upload_storage = _FAKE_STORAGE_MAP[uuid]
    upload_storage.seek(offset)
    return self.stream_write_to_fp(in_fp, upload_storage, length)

  def complete_chunked_upload(self, uuid, final_path, _):
    _FAKE_STORAGE_MAP[final_path] = _FAKE_STORAGE_MAP[uuid]
    _FAKE_STORAGE_MAP.pop(uuid, None)

  def cancel_chunked_upload(self, uuid, _):
    _FAKE_STORAGE_MAP.pop(uuid, None)