src/mcp/tools/complete_task.py

"""
Complete Task MCP Tool.

This tool allows the AI to mark tasks as completed by ID or title matching.
"""

import logging
from typing import Dict, Any, Optional
from sqlmodel import Session, select
from src.mcp.tools.base import MCPToolBase
from src.models.task import Task
from src.validation.security_guard import security_guard

logger = logging.getLogger(__name__)


class CompleteTaskTool(MCPToolBase):
    """MCP tool for completing tasks."""

    @property
    def name(self) -> str:
        return "complete_task"

    @property
    def description(self) -> str:
        return "Mark a task as completed. Accepts either task_id or task_title for identification. Validates that the task belongs to the authenticated user."

    @property
    def parameters(self) -> Dict[str, Any]:
        return {
            "user_id": {
                "description": "ID of the authenticated user (automatically provided by system)",
                "type": "integer",
                "required": True
            },
            "task_id": {
                "description": "ID of the task to complete",
                "type": "integer",
                "required": False
            },
            "task_title": {
                "description": "Title or partial title of the task to complete (case-insensitive substring match)",
                "type": "string",
                "required": False
            }
        }

    async def execute(
        self,
        user_id: int,
        task_id: Optional[int] = None,
        task_title: Optional[str] = None,
        db: Session = None,
        **kwargs
    ) -> Dict[str, Any]:
        """
        Execute complete_task tool.

        Args:
            user_id: Authenticated user ID
            task_id: Task ID to complete
            task_title: Task title for matching
            db: Database session

        Returns:
            Dictionary with success status and task details
        """
        try:
            # Validate user_id
            security_guard.validate_user_id(user_id)

            # Must provide either task_id or task_title
            if not task_id and not task_title:
                return self.create_error_result(
                    "Please specify either a task ID or task title",
                    "MISSING_IDENTIFIER"
                )

            # Find task
            if task_id:
                task = await security_guard.validate_task_ownership(db, task_id, user_id)
            else:
                # Search by title (case-insensitive substring match)
                statement = select(Task).where(
                    Task.user_id == user_id,
                    Task.title.ilike(f"%{task_title}%")
                )
                matching_tasks = db.exec(statement).all()

                if not matching_tasks:
                    return self.create_error_result(
                        "Task not found. Use 'show tasks' to see your list",
                        "TASK_NOT_FOUND"
                    )

                if len(matching_tasks) > 1:
                    task_titles = [f"- {t.title} (ID: {t.id})" for t in matching_tasks]
                    return self.create_error_result(
                        f"Multiple tasks match that description:\n" + "\n".join(task_titles) + "\nPlease be more specific or use the task ID.",
                        "AMBIGUOUS_MATCH"
                    )

                task = matching_tasks[0]

            # Check if already completed
            if task.completed:
                return self.create_success_result(
                    message=f"Task '{task.title}' is already marked as complete",
                    data={
                        "task_id": task.id,
                        "title": task.title,
                        "completed": True
                    }
                )

            # Mark as completed
            task.completed = True
            db.add(task)
            db.commit()
            db.refresh(task)

            logger.info(f"Task completed: ID={task.id}, User={user_id}")

            return self.create_success_result(
                message=f"Task '{task.title}' marked as complete",
                data={
                    "task_id": task.id,
                    "title": task.title,
                    "completed": task.completed,
                    "updated_at": task.updated_at.isoformat()
                }
            )

        except ValueError as e:
            logger.error(f"Validation error in complete_task: {str(e)}")
            return self.create_error_result(str(e), "VALIDATION_ERROR")
        except Exception as e:
            logger.error(f"Error completing task: {str(e)}")
            db.rollback()
            return self.create_error_result(
                "Failed to complete task. Please try again.",
                "DATABASE_ERROR"
            )


# Tool instance
complete_task_tool = CompleteTaskTool()