fix: address code review issues and improve code quality

- Add owner_id check in repository delete operation
- Fix time range validation for partial updates
- Wrap pre-query in try/except for consistent error handling
- Use default_factory instead of mutable defaults
- Add max_length constraint for timezone field
- Remove unused dependencies and empty validators
- Extract magic numbers to constants
- Simplify update logic with model_dump

backend/src/v1/schedule_items/dependencies.py

@@ -12,12 +12,6 @@ from v1.schedule_items.service import ScheduleItemService
 from v1.users.dependencies import get_current_user
 
 
-async def get_schedule_item_repository(
-    session: Annotated[AsyncSession, Depends(get_db)],
-) -> SQLAlchemyScheduleItemRepository:
-    return SQLAlchemyScheduleItemRepository(session)
-
-
 def get_schedule_item_service(
     session: Annotated[AsyncSession, Depends(get_db)],
     user: Annotated[CurrentUser, Depends(get_current_user)],

backend/src/v1/schedule_items/repository.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Protocol
 from uuid import UUID
 
@@ -95,7 +95,17 @@ class SQLAlchemyScheduleItemRepository(BaseRepository[ScheduleItem]):
         self, item_id: UUID, owner_id: UUID
     ) -> ScheduleItem | None:
         try:
-            return await self.soft_delete_by_id(item_id)
+            stmt = (
+                update(ScheduleItem)
+                .where(ScheduleItem.id == item_id)
+                .where(ScheduleItem.owner_id == owner_id)
+                .where(ScheduleItem.deleted_at.is_(None))
+                .values(deleted_at=datetime.now(timezone.utc))
+                .returning(ScheduleItem)
+            )
+            result = await self._session.execute(stmt)
+            await self._session.flush()
+            return result.scalar_one_or_none()
         except SQLAlchemyError:
             logger.exception("Schedule item delete failed", item_id=str(item_id))
             raise

backend/src/v1/schedule_items/schemas.py

@@ -5,7 +5,7 @@ from enum import Enum
 from typing import ClassVar
 from uuid import UUID
 
-from pydantic import BaseModel, ConfigDict, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field
 
 
 class AttachmentType(str, Enum):
@@ -16,7 +16,7 @@ class AttachmentType(str, Enum):
 class ScheduleItemMetadataAttachment(BaseModel):
     name: str
     type: AttachmentType
-    visible_to: list[UUID] = []
+    visible_to: list[UUID] = Field(default_factory=list)
     url: str | None = None
     note: str | None = None
     content: str | None = None
@@ -26,7 +26,7 @@ class ScheduleItemMetadata(BaseModel):
     color: str | None = None
     location: str | None = None
     notes: str | None = None
-    attachments: list[ScheduleItemMetadataAttachment] = []
+    attachments: list[ScheduleItemMetadataAttachment] = Field(default_factory=list)
     version: int = 1
 
 
@@ -50,7 +50,7 @@ class ScheduleItemCreateRequest(BaseModel):
     description: str | None = Field(default=None, max_length=2000)
     start_at: datetime
     end_at: datetime | None = None
-    timezone: str = "UTC"
+    timezone: str = Field(default="UTC", max_length=50)
     metadata: ScheduleItemMetadata | None = None
 
 
@@ -61,15 +61,10 @@ class ScheduleItemUpdateRequest(BaseModel):
     description: str | None = Field(default=None, max_length=2000)
     start_at: datetime | None = None
     end_at: datetime | None = None
-    timezone: str | None = None
+    timezone: str | None = Field(default=None, max_length=50)
     metadata: ScheduleItemMetadata | None = None
     status: ScheduleItemStatus | None = None
 
-    @field_validator("end_at", mode="before")
-    @classmethod
-    def validate_end_at(cls, v: datetime | None, info) -> datetime | None:
-        return v
-
 
 class ScheduleItemResponse(BaseModel):
     model_config: ClassVar[ConfigDict] = ConfigDict(from_attributes=True)

backend/src/v1/schedule_items/service.py

@@ -93,33 +93,39 @@ class ScheduleItemService(BaseService):
     ) -> ScheduleItemResponse:
         user_id = self.require_user_id()
 
-        existing = await self._repository.get_by_item_id(item_id, user_id)
-        if existing is None:
-            raise HTTPException(status_code=404, detail="Schedule item not found")
-
-        update_data: dict = {}
-        if request.title is not None:
-            update_data["title"] = request.title
-        if request.description is not None:
-            update_data["description"] = request.description
-        if request.start_at is not None:
-            update_data["start_at"] = request.start_at
-        if request.end_at is not None:
-            update_data["end_at"] = request.end_at
-        if request.timezone is not None:
-            update_data["timezone"] = request.timezone
-        if request.status is not None:
-            update_data["status"] = request.status
-        if request.metadata is not None:
-            update_data["metadata"] = request.metadata.model_dump()
-
-        if request.end_at and request.start_at and request.end_at <= request.start_at:
-            raise HTTPException(status_code=400, detail="end_at must be after start_at")
-
-        if not update_data:
-            return self._to_response(existing)
-
         try:
+            existing = await self._repository.get_by_item_id(item_id, user_id)
+            if existing is None:
+                raise HTTPException(status_code=404, detail="Schedule item not found")
+
+            update_data: dict = {}
+            if request.title is not None:
+                update_data["title"] = request.title
+            if request.description is not None:
+                update_data["description"] = request.description
+            if request.start_at is not None:
+                update_data["start_at"] = request.start_at
+            if request.end_at is not None:
+                update_data["end_at"] = request.end_at
+            if request.timezone is not None:
+                update_data["timezone"] = request.timezone
+            if request.status is not None:
+                update_data["status"] = request.status
+            if request.metadata is not None:
+                update_data["metadata"] = request.metadata.model_dump()
+
+            next_start = (
+                request.start_at if request.start_at is not None else existing.start_at
+            )
+            next_end = request.end_at if request.end_at is not None else existing.end_at
+            if next_end is not None and next_end <= next_start:
+                raise HTTPException(
+                    status_code=400, detail="end_at must be after start_at"
+                )
+
+            if not update_data:
+                return self._to_response(existing)
+
             item = await self._repository.update_by_item_id(
                 item_id, user_id, update_data
             )
@@ -139,11 +145,11 @@ class ScheduleItemService(BaseService):
     async def delete(self, item_id: UUID) -> None:
         user_id = self.require_user_id()
 
-        existing = await self._repository.get_by_item_id(item_id, user_id)
-        if existing is None:
-            raise HTTPException(status_code=404, detail="Schedule item not found")
-
         try:
+            existing = await self._repository.get_by_item_id(item_id, user_id)
+            if existing is None:
+                raise HTTPException(status_code=404, detail="Schedule item not found")
+
             await self._repository.delete_by_item_id(item_id, user_id)
             await self._session.commit()
         except SQLAlchemyError: