fix: mealplan pagination (#1464)

* added pagination to get_slice route

* updated mealplan tests

* renamed vars to match pagination query

mealie/repos/repository_meals.py

@@ -1,8 +1,13 @@
 from datetime import date
+from math import ceil
 from uuid import UUID
 
+from sqlalchemy import func
+from sqlalchemy.sql import sqltypes
+
 from mealie.db.models.group import GroupMealPlan
-from mealie.schema.meal_plan.new_meal import ReadPlanEntry
+from mealie.schema.meal_plan.new_meal import PlanEntryPagination, ReadPlanEntry
+from mealie.schema.response.pagination import OrderDirection, PaginationQuery
 
 from .repository_generic import RepositoryGeneric
 
@@ -11,15 +16,67 @@ class RepositoryMeals(RepositoryGeneric[ReadPlanEntry, GroupMealPlan]):
     def by_group(self, group_id: UUID) -> "RepositoryMeals":
         return super().by_group(group_id)  # type: ignore
 
-    def get_slice(self, start: date, end: date, group_id: UUID) -> list[ReadPlanEntry]:
-        start_str = start.strftime("%Y-%m-%d")
-        end_str = end.strftime("%Y-%m-%d")
-        qry = self.session.query(GroupMealPlan).filter(
+    def get_slice(
+        self, pagination: PaginationQuery, start_date: date, end_date: date, group_id: UUID
+    ) -> PlanEntryPagination:
+        start_str = start_date.strftime("%Y-%m-%d")
+        end_str = end_date.strftime("%Y-%m-%d")
+
+        # get the total number of documents
+        q = self.session.query(GroupMealPlan).filter(
             GroupMealPlan.date.between(start_str, end_str),
             GroupMealPlan.group_id == group_id,
         )
 
-        return [self.schema.from_orm(x) for x in qry.all()]
+        count = q.count()
+
+        # interpret -1 as "get_all"
+        if pagination.per_page == -1:
+            pagination.per_page = count
+
+        try:
+            total_pages = ceil(count / pagination.per_page)
+
+        except ZeroDivisionError:
+            total_pages = 0
+
+        # interpret -1 as "last page"
+        if pagination.page == -1:
+            pagination.page = total_pages
+
+        # failsafe for user input error
+        if pagination.page < 1:
+            pagination.page = 1
+
+        if pagination.order_by:
+            if order_attr := getattr(self.model, pagination.order_by, None):
+                # queries handle uppercase and lowercase differently, which is undesirable
+                if isinstance(order_attr.type, sqltypes.String):
+                    order_attr = func.lower(order_attr)
+
+                if pagination.order_direction == OrderDirection.asc:
+                    order_attr = order_attr.asc()
+                elif pagination.order_direction == OrderDirection.desc:
+                    order_attr = order_attr.desc()
+
+                q = q.order_by(order_attr)
+
+        q = q.limit(pagination.per_page).offset((pagination.page - 1) * pagination.per_page)
+
+        try:
+            data = [self.schema.from_orm(x) for x in q.all()]
+        except Exception as e:
+            self._log_exception(e)
+            self.session.rollback()
+            raise e
+
+        return PlanEntryPagination(
+            page=pagination.page,
+            per_page=pagination.per_page,
+            total=count,
+            total_pages=total_pages,
+            items=data,
+        )
 
     def get_today(self, group_id: UUID) -> list[ReadPlanEntry]:
         today = date.today()