'''
metadatadb.py
'''
import contextlib
import collections
import hashlib
import uuid

import sqlalchemy
import sqlalchemy.ext.declarative
import sqlalchemy.orm

# TODO: l o g g i n g
HASH_CHUNK_SIZE = 10485760 # 10mb
_db_session_maker = sqlalchemy.orm.sessionmaker()
_engine = None

ImageData = collections.namedtuple('ImageData', 'UUID, sha1sum, filename, release_group')
ReleaseGroupData = collections.namedtuple('ReleaseGroupData', 'UUID, name, platform')
DatData = collections.namedtuple('DatData', 'UUID, name, website, version, image_list')


def _uuidgen():
    return str(uuid.uuid4())

_SQLBase = sqlalchemy.ext.declarative.declarative_base()

class Platform(_SQLBase):
    __tablename__ = 'platforms'
    id = sqlalchemy.Column(sqlalchemy.Integer, sqlalchemy.Sequence('platform_id_sequence'),
                           primary_key=True)
    uuid = sqlalchemy.Column(sqlalchemy.String, nullable=False, default=_uuidgen)
    fullname = sqlalchemy.Column(sqlalchemy.String, nullable=False)
    shortcode = sqlalchemy.Column(sqlalchemy.String, unique=True, nullable=False)

    def __repr__(self):
        return 'Platform: id: %s, uuid: %s, fullname: %s, shortcode: %s' % (self.id, self.uuid,
                self.fullname, self.shortcode)

# TODO: This should go in the eventual romdb class.
def get_file_sha1sum(filename):
    sha1sum = hashlib.sha1()
    with open(filename, 'rb') as file_contents:
        while True:
            chunk = file_contents.read(HASH_CHUNK_SIZE)
            if not chunk:
                break
            sha1sum.update(chunk)

    return sha1sum.hexdigest()

def configure(db_path):
    _engine = sqlalchemy.create_engine('sqlite:///%s' % db_path)

    _SQLBase.metadata.create_all(_engine)
    _db_session_maker.configure(bind=_engine)

def search(session, table_object, inclusive=True, **constraints):
    query = session.query(table_object)

    for key, value in constraints.items():
        query = query.filter(getattr(table_object, key).ilike('%%%s%%' % value))

    item_list = []
    for item in query:
        item_list.append(item)

    return item_list

@contextlib.contextmanager
def get_db_session():
    session = _db_session_maker()
    try:
        yield session

    except:
        session.rollback()
        raise
    else:
        session.commit()
    finally:
        session.close()