refactor: split database.py into package (ref.md 3.2)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

devplacepy/database/pagination.py

@@ -0,0 +1,95 @@
+# retoor <retoor@molodetz.nl>
+
+from .core import db, get_table
+from .relations import get_blocked_uids
+
+
+PAGE_SIZE = 25
+
+
+def paginate(
+    table,
+    *clauses,
+    before=None,
+    order=None,
+    cursor_field="created_at",
+    viewer_uid=None,
+    **filters,
+):
+    order = order or ["-" + cursor_field]
+    clauses = list(clauses)
+    if table.has_column("deleted_at") and "deleted_at" not in filters:
+        clauses.append(table.table.columns.deleted_at.is_(None))
+    if viewer_uid and table.has_column("user_uid"):
+        blocked = get_blocked_uids(viewer_uid)
+        if blocked:
+            clauses.append(table.table.columns.user_uid.notin_(blocked))
+    if before:
+        clauses.append(table.table.columns[cursor_field] < before)
+    rows = list(table.find(*clauses, **filters, order_by=order, _limit=PAGE_SIZE + 1))
+    has_more = len(rows) > PAGE_SIZE
+    rows = rows[:PAGE_SIZE]
+    next_cursor = rows[-1][cursor_field] if has_more and rows else None
+    return rows, next_cursor
+
+
+def interleave_by_author(rows, uid_key="user_uid"):
+    remaining = list(rows)
+    spread = []
+    last_owner = object()
+    while remaining:
+        pick = next(
+            (
+                index
+                for index, row in enumerate(remaining)
+                if row.get(uid_key) != last_owner
+            ),
+            0,
+        )
+        row = remaining.pop(pick)
+        spread.append(row)
+        last_owner = row.get(uid_key)
+    return spread
+
+
+def paginate_diverse(
+    table,
+    *clauses,
+    before=None,
+    order=None,
+    cursor_field="created_at",
+    uid_key="user_uid",
+    viewer_uid=None,
+    **filters,
+):
+    rows, next_cursor = paginate(
+        table,
+        *clauses,
+        before=before,
+        order=order,
+        cursor_field=cursor_field,
+        viewer_uid=viewer_uid,
+        **filters,
+    )
+    return interleave_by_author(rows, uid_key=uid_key), next_cursor
+
+
+def get_user_post_count(user_uid: str) -> int:
+    if "posts" not in db.tables:
+        return 0
+    return get_table("posts").count(user_uid=user_uid, deleted_at=None)
+
+
+def build_pagination(page, total, per_page=25):
+    total_pages = max(1, __import__("math").ceil(total / per_page))
+    page = max(1, min(page, total_pages))
+    return {
+        "page": page,
+        "per_page": per_page,
+        "total": total,
+        "total_pages": total_pages,
+        "has_prev": page > 1,
+        "has_next": page < total_pages,
+        "prev_page": page - 1,
+        "next_page": page + 1,
+    }