add proper support for "around" parameter

litecord/blueprints/channel/messages.py

@@ -18,7 +18,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 
 from pathlib import Path
-from typing import Optional
+from typing import Optional, List
 
 from quart import Blueprint, request, current_app as app, jsonify
 from logbook import Logger
@@ -49,6 +49,49 @@ log = Logger(__name__)
 bp = Blueprint("channel_messages", __name__)
 
 
+async def message_search(
+    channel_id: int,
+    before: Optional[int],
+    after: Optional[int],
+    limit: int,
+) -> List[int]:
+    where_clause = ""
+    if before:
+        where_clause += f"AND id < {before}"
+
+    if after:
+        where_clause += f"AND id > {after}"
+
+    return await app.db.fetch(
+        f"""
+        SELECT id
+        FROM messages
+        WHERE channel_id = $1 {where_clause}
+        ORDER BY id DESC
+        LIMIT {limit}
+        """,
+        channel_id,
+    )
+
+
+async def around_message_search(
+    channel_id: int,
+    around_id: int,
+    limit: int,
+) -> List[int]:
+    # search limit/2 messages BEFORE around_id
+    # search limit/2 messages AFTER around_id
+    # merge it all together: before + [around_id] + after
+    halved_limit = limit // 2
+    before_messages = await message_search(
+        channel_id, before=around_id, after=None, limit=halved_limit
+    )
+    after_messages = await message_search(
+        channel_id, before=None, after=around_id, limit=halved_limit
+    )
+    return before_messages + [around_id] + after_messages
+
+
 @bp.route("/<int:channel_id>/messages", methods=["GET"])
 async def get_messages(channel_id):
     user_id = await token_check()
@@ -64,24 +107,14 @@ async def get_messages(channel_id):
 
     limit = extract_limit(request, 50)
 
-    where_clause = ""
+    if "around" in request.args:
+        message_ids = await around_message_search(
+            channel_id, int(request.args["around"]), limit
+        )
+    else:
         before, after = query_tuple_from_args(request.args, limit)
-
+        message_ids = await message_search(
-    if before:
+            channel_id, before=before, after=after, limit=limit
-        where_clause += f"AND id < {before}"
-
-    if after:
-        where_clause += f"AND id > {after}"
-
-    message_ids = await app.db.fetch(
-        f"""
-    SELECT id
-    FROM messages
-    WHERE channel_id = $1 {where_clause}
-    ORDER BY id DESC
-    LIMIT {limit}
-    """,
-        channel_id,
         )
 
     result = []

litecord/utils.py

@@ -26,7 +26,7 @@ from typing import Any, Iterable, Optional, Sequence, List, Dict, Union
 
 from logbook import Logger
 from quart.json import JSONEncoder
-from quart import current_app as app, request
+from quart import current_app as app
 
 from .errors import BadRequest
 
@@ -274,14 +274,7 @@ def query_tuple_from_args(args: dict, limit: int) -> tuple:
     """Extract a 2-tuple out of request arguments."""
     before, after = None, None
 
-    if "around" in request.args:
+    if "before" in args:
-        average = int(limit / 2)
-        around = int(args["around"])
-
-        after = around - average
-        before = around + average
-
-    elif "before" in args:
         before = int(args["before"])
     elif "after" in args:
         before = int(args["after"])