Refactoring, adding db context manager

groove/db/__init__.py

@@ -0,0 +1 @@
+from groove.db.schema import metadata, track, playlist, entry

groove/db/manager.py

@@ -0,0 +1,43 @@
+import os
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from . import metadata
+
+
+class DatabaseManager:
+    """
+    A context manager for working with sqllite database.
+    """
+
+    def __init__(self):
+        self._engine = None
+        self._session = None
+
+    @property
+    def engine(self):
+        if not self._engine:
+            self._engine = create_engine(f"sqlite:///{os.environ.get('DATABASE_PATH')}", future=True)
+        return self._engine
+
+    @property
+    def session(self):
+        if not self._session:
+            Session = sessionmaker(bind=self.engine, future=True)
+            self._session = Session()
+        return self._session
+
+    def import_from_filesystem(self):
+        pass
+
+    def __enter__(self):
+        metadata.create_all(bind=self.engine)
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        if self.session:
+            self.session.close()
+
+
+database_manager = DatabaseManager()

groove/db/schema.py

@@ -0,0 +1,29 @@
+from sqlalchemy import MetaData
+from sqlalchemy import Table, Column, Integer, String, UnicodeText, ForeignKey, PrimaryKeyConstraint
+
+metadata = MetaData()
+
+track = Table(
+    "track",
+    metadata,
+    Column("id", Integer, primary_key=True, autoincrement=True),
+    Column("relpath", UnicodeText, index=True, unique=True),
+)
+
+playlist = Table(
+    "playlist",
+    metadata,
+    Column("id", Integer, primary_key=True, autoincrement=True),
+    Column("name", String),
+    Column("description", UnicodeText),
+    Column("slug", String, index=True, unique=True),
+)
+
+entry = Table(
+    "entry",
+    metadata,
+    Column("track", Integer),
+    Column("playlist_id", Integer, ForeignKey("playlist.id")),
+    Column("track_id", Integer, ForeignKey("track.id")),
+    PrimaryKeyConstraint("playlist_id", "track"),
+)