import os
import shutil

from . import Storage


class LocalStorage(Storage):

    def __init__(self, storage_path):
        self._root_path = storage_path

    def _init_path(self, path=None, create=False):
        path = os.path.join(self._root_path, path) if path else self._root_path
        if create is True:
            dirname = os.path.dirname(path)
            if not os.path.exists(dirname):
                os.makedirs(dirname)
        return path

    def get_content(self, path):
        path = self._init_path(path)
        with open(path, mode='r') as f:
            return f.read()

    def put_content(self, path, content):
        path = self._init_path(path, create=True)
        with open(path, mode='w') as f:
            f.write(content)
        return path

    def stream_read(self, path):
        path = self._init_path(path)
        with open(path, mode='rb') as f:
            while True:
                buf = f.read(self.buffer_size)
                if not buf:
                    break
                yield buf

    def stream_write(self, path, fp):
        # Size is mandatory
        path = self._init_path(path, create=True)
        with open(path, mode='wb') as f:
            while True:
                try:
                    buf = fp.read(self.buffer_size)
                    if not buf:
                        break
                    f.write(buf)
                except IOError:
                    break

    def list_directory(self, path=None):
        path = self._init_path(path)
        prefix = path[len(self._root_path) + 1:] + '/'
        exists = False
        for d in os.listdir(path):
            exists = True
            yield prefix + d
        if exists is False:
            # Raises OSError even when the directory is empty
            # (to be consistent with S3)
            raise OSError('No such directory: \'{0}\''.format(path))

    def exists(self, path):
        path = self._init_path(path)
        return os.path.exists(path)

    def remove(self, path):
        path = self._init_path(path)
        if os.path.isdir(path):
            shutil.rmtree(path)
            return
        try:
            os.remove(path)
        except OSError:
            pass

    def get_size(self, path):
        path = self._init_path(path)
        return os.path.getsize(path)