"""MCP tool for updating tasks in the todo list. [Task]: T037 [From]: specs/004-ai-chatbot/tasks.md This tool allows the AI agent to update existing tasks on behalf of users through natural language conversations. """ from typing import Optional, Any from uuid import UUID from datetime import datetime from sqlalchemy import select from models.task import Task from core.database import engine from sqlmodel import Session # Tool metadata for MCP registration tool_metadata = { "name": "update_task", "description": """Update an existing task in the user's todo list. Use this tool when the user wants to modify, change, or edit an existing task. You must identify the task first (by ID or by matching title/description). Parameters: - user_id (required): User ID (UUID) who owns the task - task_id (required): Task ID (UUID) of the task to update - title (optional): New task title - description (optional): New task description - due_date (optional): New due date (ISO 8601 date string or relative like 'tomorrow', 'next week') - priority (optional): New priority level - 'low', 'medium', or 'high' - completed (optional): Mark task as completed or not completed Returns: Updated task details with confirmation. """, "inputSchema": { "type": "object", "properties": { "user_id": { "type": "string", "description": "User ID (UUID) who owns this task" }, "task_id": { "type": "string", "description": "Task ID (UUID) of the task to update" }, "title": { "type": "string", "description": "New task title (brief description)", "maxLength": 255 }, "description": { "type": "string", "description": "New task description", "maxLength": 2000 }, "due_date": { "type": "string", "description": "New due date in ISO 8601 format (e.g., '2025-01-15') or relative terms" }, "priority": { "type": "string", "enum": ["low", "medium", "high"], "description": "New task priority level" }, "completed": { "type": "boolean", "description": "Mark task as completed or not completed" } }, "required": ["user_id", "task_id"] } } async def update_task( user_id: str, task_id: str, title: Optional[str] = None, description: Optional[str] = None, due_date: Optional[str] = None, priority: Optional[str] = None, completed: Optional[bool] = None ) -> dict[str, Any]: """Update an existing task for the user. [From]: specs/004-ai-chatbot/spec.md - US3 Args: user_id: User ID (UUID string) who owns the task task_id: Task ID (UUID string) of the task to update title: Optional new task title description: Optional new task description due_date: Optional new due date (ISO 8601 or relative) priority: Optional new priority level (low/medium/high) completed: Optional new completion status Returns: Dictionary with updated task details Raises: ValueError: If validation fails or task not found """ from core.validators import validate_task_title, validate_task_description # Get database session (synchronous) with Session(engine) as db: try: # Fetch the task stmt = select(Task).where( Task.id == UUID(task_id), Task.user_id == UUID(user_id) ) task = db.scalars(stmt).first() if not task: return { "success": False, "error": "Task not found", "message": f"Could not find task with ID {task_id}" } # Track changes for confirmation message changes = [] # Update title if provided if title is not None: validated_title = validate_task_title(title) old_title = task.title task.title = validated_title changes.append(f"title from '{old_title}' to '{validated_title}'") # Update description if provided if description is not None: validated_description = validate_task_description(description) if description else None task.description = validated_description changes.append("description") # Update due date if provided if due_date is not None: parsed_due_date = _parse_due_date(due_date) task.due_date = parsed_due_date changes.append(f"due date to '{parsed_due_date.isoformat() if parsed_due_date else 'None'}'") # Update priority if provided if priority is not None: normalized_priority = _normalize_priority(priority) old_priority = task.priority task.priority = normalized_priority changes.append(f"priority from '{old_priority}' to '{normalized_priority}'") # Update completion status if provided if completed is not None: old_status = "completed" if task.completed else "pending" task.completed = completed new_status = "completed" if completed else "pending" changes.append(f"status from '{old_status}' to '{new_status}'") # Always update updated_at timestamp task.updated_at = datetime.utcnow() # Save to database db.add(task) db.commit() db.refresh(task) # Build success message if changes: changes_str = " and ".join(changes) message = f"✅ Task updated: {changes_str}" else: message = f"✅ Task '{task.title}' retrieved (no changes made)" return { "success": True, "task": { "id": str(task.id), "title": task.title, "description": task.description, "due_date": task.due_date.isoformat() if task.due_date else None, "priority": task.priority, "completed": task.completed, "created_at": task.created_at.isoformat(), "updated_at": task.updated_at.isoformat() }, "message": message } except ValueError as e: db.rollback() raise ValueError(f"Failed to update task: {str(e)}") def _parse_due_date(due_date_str: str) -> Optional[datetime]: """Parse due date from ISO 8601 or natural language. [From]: specs/004-ai-chatbot/plan.md - Natural Language Processing Supports: - ISO 8601: "2025-01-15", "2025-01-15T10:00:00Z" - Relative: "today", "tomorrow", "next week", "in 3 days" Args: due_date_str: Date string to parse Returns: Parsed datetime or None if parsing fails Raises: ValueError: If date format is invalid """ from datetime import datetime import re # Try ISO 8601 format first try: # Handle YYYY-MM-DD format if re.match(r"^\d{4}-\d{2}-\d{2}$", due_date_str): return datetime.fromisoformat(due_date_str) # Handle full ISO 8601 with time if "T" in due_date_str: return datetime.fromisoformat(due_date_str.replace("Z", "+00:00")) except ValueError: pass # Fall through to natural language parsing # Natural language parsing (simplified) due_date_str = due_date_str.lower().strip() today = datetime.utcnow().replace(hour=23, minute=59, second=59, microsecond=999999) if due_date_str == "today": return today elif due_date_str == "tomorrow": return today + __import__('datetime').timedelta(days=1) elif due_date_str == "next week": return today + __import__('datetime').timedelta(weeks=1) elif due_date_str.startswith("in "): # Parse "in X days/weeks" match = re.match(r"in (\d+) (day|days|week|weeks)", due_date_str) if match: amount = int(match.group(1)) unit = match.group(2) if unit.startswith("day"): return today + __import__('datetime').timedelta(days=amount) elif unit.startswith("week"): return today + __import__('datetime').timedelta(weeks=amount) # If parsing fails, return None and let AI agent ask for clarification return None def _normalize_priority(priority: Optional[str]) -> str: """Normalize priority string to valid values. [From]: models/task.py - Task model Args: priority: Priority string to normalize Returns: Normalized priority: "low", "medium", or "high" Raises: ValueError: If priority is invalid """ if not priority: return "medium" # Default priority priority_normalized = priority.lower().strip() if priority_normalized in ["low", "medium", "high"]: return priority_normalized # Map common alternatives priority_map = { "1": "low", "2": "medium", "3": "high", "urgent": "high", "important": "high", "normal": "medium", "routine": "low" } normalized = priority_map.get(priority_normalized, "medium") return normalized # Register tool with MCP server def register_tool(mcp_server: Any) -> None: """Register this tool with the MCP server. [From]: backend/mcp_server/server.py Args: mcp_server: MCP server instance """ mcp_server.tool( name=tool_metadata["name"], description=tool_metadata["description"] )(update_task)