modularize src

+ merge main.py and manage.py
+ move start logic to swingmusic/__main__.py
+ add a run.py on the project root

swingmusic/db/__init__.py

@@ -0,0 +1,66 @@
+from typing import Any
+
+from sqlalchemy import (
+    delete,
+    func,
+    insert,
+    select,
+)
+
+from sqlalchemy.orm import DeclarativeBase, MappedAsDataclass
+from swingmusic.db.engine import DbEngine
+
+
+class Base(MappedAsDataclass, DeclarativeBase):
+    """
+    Base class for all database models.
+
+    It has methods common to all tables. eg. `insert_one`, `insert_many`, `remove_all`, `remove_one`, `all`, `count`.
+    """
+
+    @classmethod
+    def execute(cls, stmt: Any, commit: bool = False):
+        with DbEngine.manager(commit=commit) as session:
+            result = session.execute(stmt.execution_options(yield_per=100))
+
+            if commit:
+                session.commit()
+
+            yield result
+
+    @classmethod
+    def insert_many(cls, items: list[dict[str, Any]]):
+        """
+        Inserts multiple items into the database.
+        """
+        return next(cls.execute(insert(cls).values(items), commit=True))
+
+    @classmethod
+    def insert_one(cls, item: dict[str, Any]):
+        """
+        Inserts a single item into the database.
+        """
+        return cls.insert_many([item])
+
+    @classmethod
+    def remove_all(cls):
+        return next(cls.execute(delete(cls), commit=True))
+
+    @classmethod
+    def remove_one(cls, id: int):
+        return next(cls.execute(delete(cls).where(cls.id == id), commit=True))
+
+    @classmethod
+    def all(cls):
+        return next(cls.execute(select(cls).execution_options(yield_per=100)))
+
+    @classmethod
+    def count(cls):
+        return next(cls.execute(select(func.count()).select_from(cls))).scalar()
+
+
+def create_all_tables():
+    """
+    Creates all the tables that build on the Base class.
+    """
+    Base().metadata.create_all(DbEngine.engine)