core/sqlite: experiment at typing SELECT query (to some extent)

ideally would be cool to use TypedDict here somehow, but perhaps it'd only be possible after variadic generics https://peps.python.org/pep-0646

my/bumble/android.py

@@ -56,7 +56,7 @@ import json
 from typing import Union
 from ..core import Res, assert_never
 import sqlite3
-from ..core.sqlite import sqlite_connect_immutable
+from ..core.sqlite import sqlite_connect_immutable, select
 
 EntitiesRes = Res[Union[Person, _Message]]
 
@@ -72,20 +72,22 @@ def _handle_db(db: sqlite3.Connection) -> Iterator[EntitiesRes]:
     # on the other, it's somewhat of a complication, and
     # would be nice to have something type-directed for sql queries though
     # e.g. with typeddict or something, so the number of parameter to the sql query matches?
-    for row in db.execute(f'SELECT user_id, user_name FROM conversation_info'):
-        (user_id, user_name) = row
+    for     (user_id,   user_name) in select(
+            ('user_id', 'user_name'),
+            'FROM conversation_info',
+            db=db,
+    ):
         yield Person(
             user_id=user_id,
             user_name=user_name,
         )
 
-    # has sender_name, but it's always None
-    for row in db.execute(f'''
-    SELECT id, conversation_id, created_timestamp, is_incoming, payload_type, payload, reply_to_id
-    FROM message
-    ORDER BY created_timestamp
-    '''):
-        (id, conversation_id, created, is_incoming, payload_type, payload, reply_to_id) = row
+    # note: has sender_name, but it's always None
+    for     ( id,   conversation_id ,  created           ,  is_incoming ,  payload_type ,  payload ,  reply_to_id) in select(
+            ('id', 'conversation_id', 'created_timestamp', 'is_incoming', 'payload_type', 'payload', 'reply_to_id'),
+            'FROM message ORDER BY created_timestamp',
+            db=db
+    ):
         try:
             key = {'TEXT': 'text', 'QUESTION_GAME': 'text', 'IMAGE': 'url', 'GIF': 'url'}[payload_type]
             text = json.loads(payload)[key]

my/core/sqlite.py

@@ -50,3 +50,43 @@ def sqlite_copy_and_open(db: PathIsh) -> sqlite3.Connection:
             sqlite_backup(source=conn, dest=dest)
         conn.close()
     return dest
+
+
+from typing import Tuple, Any, Iterator
+
+# NOTE hmm, so this kinda works
+# V = TypeVar('V', bound=Tuple[Any, ...])
+# def select(cols: V, rest: str, *, db: sqlite3.Connetion) -> Iterator[V]:
+# but sadly when we pass columns (Tuple[str, ...]), it seems to bind this type to V?
+# and then the return type ends up as Iterator[Tuple[str, ...]], which isn't desirable :(
+# a bit annoying to have this copy-pasting, but hopefully not a big issue
+
+from typing import overload
+@overload
+def select(cols: Tuple[str                                   ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any                                   ]]: ...
+@overload
+def select(cols: Tuple[str, str                              ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any                              ]]: ...
+@overload
+def select(cols: Tuple[str, str, str                         ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any                         ]]: ...
+@overload
+def select(cols: Tuple[str, str, str, str                    ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any, Any                    ]]: ...
+@overload
+def select(cols: Tuple[str, str, str, str, str               ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any, Any, Any               ]]: ...
+@overload
+def select(cols: Tuple[str, str, str, str, str, str          ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any, Any, Any, Any          ]]: ...
+@overload
+def select(cols: Tuple[str, str, str, str, str, str, str     ], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any, Any, Any, Any, Any     ]]: ...
+@overload
+def select(cols: Tuple[str, str, str, str, str, str, str, str], rest: str, *, db: sqlite3.Connection) -> \
+        Iterator[Tuple[Any, Any, Any, Any, Any, Any, Any, Any]]: ...
+
+def select(cols, rest, *, db):
+    # db arg is last cause that results in nicer code formatting..
+    return db.execute('SELECT ' + ','.join(cols) + ' ' + rest)

my/instagram/android.py

@@ -90,7 +90,7 @@ import json
 from typing import Union
 from ..core import Res, assert_never
 import sqlite3
-from ..core.sqlite import sqlite_connect_immutable
+from ..core.sqlite import sqlite_connect_immutable, select
 def _entities() -> Iterator[Res[Union[User, _Message]]]:
     # NOTE: definitely need to merge multiple, app seems to recycle old messages
     # TODO: hmm hard to guarantee timestamp ordering when we use synthetic input data...
@@ -98,15 +98,14 @@ def _entities() -> Iterator[Res[Union[User, _Message]]]:
     for f in inputs():
         with sqlite_connect_immutable(f) as db:
 
-            for row in db.execute(f'SELECT user_id, thread_info FROM threads'):
-                (self_uid, js,) = row
+            for (self_uid, thread_json) in select(('user_id', 'thread_info'), 'FROM threads', db=db):
                 # ugh wtf?? no easier way to extract your own user id/name??
                 yield User(
                     id=str(self_uid),
                     full_name='You',
                     username='you',
                 )
-                j = json.loads(js)
+                j = json.loads(thread_json)
                 for r in j['recipients']:
                     yield User(
                         id=str(r['id']), # for some reason it's int in the db
@@ -114,10 +113,9 @@ def _entities() -> Iterator[Res[Union[User, _Message]]]:
                         username=r['username'],
                     )
 
-            for row in db.execute(f'SELECT message FROM messages ORDER BY timestamp'):
+            for (msg_json,) in select(('message',), 'FROM messages ORDER BY timestamp', db=db):
                 # eh, seems to contain everything in json?
-                (js,) = row
-                j = json.loads(js)
+                j = json.loads(msg_json)
                 try:
                     m = _parse_message(j)
                     if m is not None: