Refactor campaign delivery decision paths

src/govoplan_campaign/backend/router.py

@@ -2712,8 +2712,7 @@ def _campaign_jobs_page_response(
     cursor: str | None = None,
     changed_job_ids: set[str] | None = None,
 ) -> CampaignJobsResponse:
-    total_unfiltered = int(session.query(func.count(CampaignJob.id)).filter(*base_filters).scalar() or 0)
-    total = int(session.query(func.count(CampaignJob.id)).filter(*filtered).scalar() or 0)
+    total_unfiltered, total = _campaign_jobs_page_counts(session, base_filters=base_filters, filtered=filtered)
     pages = (total + page_size - 1) // page_size if total else 0
     fingerprint = _campaign_jobs_cursor_fingerprint(
         campaign_id=campaign_id,
@@ -2728,47 +2727,26 @@ def _campaign_jobs_page_response(
         sort_direction=sort_direction,
     )
     ordering = _campaign_jobs_ordering(sort_by, sort_direction)
-    ordered_query = session.query(CampaignJob).filter(*filtered).order_by(*ordering)
-    start_cursor: str | None = None
-    effective_offset = 0
-    if cursor:
-        if sort_by != "number" or sort_direction != "asc":
-            raise HTTPException(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail="Campaign job cursors require number ascending order",
-            )
-        try:
-            cursor_values = decode_keyset_cursor(CAMPAIGN_JOBS_CURSOR_SCOPE, cursor, fingerprint=fingerprint)
-            if cursor_values is None:
-                raise KeysetCursorError("Invalid pagination cursor")
-            page_query = session.query(CampaignJob).filter(*filtered).filter(_campaign_jobs_cursor_condition(cursor_values))
-        except KeysetCursorError as exc:
-            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
-        start_cursor = cursor
-    else:
-        effective_offset = (page - 1) * page_size
-        page_query = session.query(CampaignJob).filter(*filtered)
-        if effective_offset > 0 and sort_by == "number" and sort_direction == "asc":
-            previous_row = ordered_query.offset(effective_offset - 1).limit(1).first()
-            if previous_row is not None:
-                start_cursor = _campaign_jobs_cursor_for_row(previous_row, fingerprint=fingerprint)
-
-    rows_plus_one = (
-        page_query
-        .order_by(*ordering)
-        .offset(effective_offset)
-        .limit(page_size + 1)
-        .all()
+    rows_plus_one, start_cursor = _campaign_jobs_page_rows(
+        session,
+        filtered=filtered,
+        ordering=ordering,
+        page=page,
+        page_size=page_size,
+        sort_by=sort_by,
+        sort_direction=sort_direction,
+        cursor=cursor,
+        fingerprint=fingerprint,
     )
     jobs = rows_plus_one[:page_size]
-    next_cursor = (
-        _campaign_jobs_cursor_for_row(jobs[-1], fingerprint=fingerprint)
-        if changed_job_ids is None
-        and sort_by == "number"
-        and sort_direction == "asc"
-        and len(rows_plus_one) > page_size
-        and jobs
-        else None
+    next_cursor = _campaign_jobs_next_cursor(
+        jobs,
+        rows_plus_one=rows_plus_one,
+        page_size=page_size,
+        sort_by=sort_by,
+        sort_direction=sort_direction,
+        changed_job_ids=changed_job_ids,
+        fingerprint=fingerprint,
     )
     if changed_job_ids is not None:
         jobs = [job for job in jobs if job.id in changed_job_ids]
@@ -2787,6 +2765,110 @@ def _campaign_jobs_page_response(
     )
 
 
+def _campaign_jobs_page_counts(
+    session: Session,
+    *,
+    base_filters: list[object],
+    filtered: list[object],
+) -> tuple[int, int]:
+    total_unfiltered = int(session.query(func.count(CampaignJob.id)).filter(*base_filters).scalar() or 0)
+    total = int(session.query(func.count(CampaignJob.id)).filter(*filtered).scalar() or 0)
+    return total_unfiltered, total
+
+
+def _campaign_jobs_page_rows(
+    session: Session,
+    *,
+    filtered: list[object],
+    ordering: list[object],
+    page: int,
+    page_size: int,
+    sort_by: str,
+    sort_direction: str,
+    cursor: str | None,
+    fingerprint: str,
+) -> tuple[list[CampaignJob], str | None]:
+    if cursor:
+        page_query = _campaign_jobs_query_after_cursor(
+            session,
+            filtered=filtered,
+            cursor=cursor,
+            fingerprint=fingerprint,
+            sort_by=sort_by,
+            sort_direction=sort_direction,
+        )
+        return page_query.order_by(*ordering).limit(page_size + 1).all(), cursor
+
+    effective_offset = (page - 1) * page_size
+    page_query = session.query(CampaignJob).filter(*filtered)
+    start_cursor = _campaign_jobs_offset_cursor(
+        page_query,
+        ordering=ordering,
+        effective_offset=effective_offset,
+        sort_by=sort_by,
+        sort_direction=sort_direction,
+        fingerprint=fingerprint,
+    )
+    rows = page_query.order_by(*ordering).offset(effective_offset).limit(page_size + 1).all()
+    return rows, start_cursor
+
+
+def _campaign_jobs_query_after_cursor(
+    session: Session,
+    *,
+    filtered: list[object],
+    cursor: str,
+    fingerprint: str,
+    sort_by: str,
+    sort_direction: str,
+):
+    if sort_by != "number" or sort_direction != "asc":
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Campaign job cursors require number ascending order",
+        )
+    try:
+        cursor_values = decode_keyset_cursor(CAMPAIGN_JOBS_CURSOR_SCOPE, cursor, fingerprint=fingerprint)
+        if cursor_values is None:
+            raise KeysetCursorError("Invalid pagination cursor")
+    except KeysetCursorError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
+    return session.query(CampaignJob).filter(*filtered).filter(_campaign_jobs_cursor_condition(cursor_values))
+
+
+def _campaign_jobs_offset_cursor(
+    query,
+    *,
+    ordering: list[object],
+    effective_offset: int,
+    sort_by: str,
+    sort_direction: str,
+    fingerprint: str,
+) -> str | None:
+    if effective_offset <= 0 or sort_by != "number" or sort_direction != "asc":
+        return None
+    previous_row = query.order_by(*ordering).offset(effective_offset - 1).limit(1).first()
+    if previous_row is None:
+        return None
+    return _campaign_jobs_cursor_for_row(previous_row, fingerprint=fingerprint)
+
+
+def _campaign_jobs_next_cursor(
+    jobs: list[CampaignJob],
+    *,
+    rows_plus_one: list[CampaignJob],
+    page_size: int,
+    sort_by: str,
+    sort_direction: str,
+    changed_job_ids: set[str] | None,
+    fingerprint: str,
+) -> str | None:
+    cursor_supported = sort_by == "number" and sort_direction == "asc"
+    if changed_job_ids is not None or not cursor_supported or len(rows_plus_one) <= page_size or not jobs:
+        return None
+    return _campaign_jobs_cursor_for_row(jobs[-1], fingerprint=fingerprint)
+
+
 def _campaign_jobs_cursor_fingerprint(
     *,
     campaign_id: str,