"""
Task Manager Module for managing task states and transitions.
"""

import logging
from typing import Dict, Any, List, Optional
from datetime import datetime, UTC
import uuid
from modules.interfaces.serviceChatModel import Task, ChatLog, ChatMessage

logger = logging.getLogger(__name__)

class TaskManager:
    """Manager for task state management and transitions."""
    
    _instance = None
    
    @classmethod
    def getInstance(cls):
        """Return a singleton instance of the task manager."""
        if cls._instance is None:
            cls._instance = cls()
        return cls._instance
    
    def __init__(self):
        """Initialize the task manager."""
        if TaskManager._instance is not None:
            raise RuntimeError("Singleton instance already exists - use getInstance()")
        
        self.service = None
    
    def initialize(self, service=None):
        """Initialize or update the manager with service references."""
        if service:
            # Validate required interfaces
            required_interfaces = ['base', 'msft', 'google']
            missing_interfaces = []
            for interface in required_interfaces:
                if not hasattr(service, interface):
                    missing_interfaces.append(interface)
            
            if missing_interfaces:
                logger.warning(f"Service container missing required interfaces: {', '.join(missing_interfaces)}")
                return False
        
        self.service = service
        return True
    
    def createTask(self, workflowId: str, agentName: str, prompt: str, userLanguage: str, 
                  filesInput: List[str] = None, filesOutput: List[str] = None) -> Task:
        """
        Create a new task.
        
        Args:
            workflowId: ID of the workflow this task belongs to
            agentName: Name of the agent to execute the task
            prompt: Task prompt
            userLanguage: User's preferred language
            filesInput: List of input files
            filesOutput: List of output files
            
        Returns:
            New Task object
        """
        return Task(
            id=str(uuid.uuid4()),
            workflowId=workflowId,
            agentName=agentName,
            status="pending",
            progress=0.0,
            prompt=prompt,
            userLanguage=userLanguage,
            filesInput=filesInput or [],
            filesOutput=filesOutput or [],
            startedAt=datetime.now(UTC).isoformat()
        )
    
    def updateTaskStatus(self, task: Task, newStatus: str, progress: float = None, 
                        error: str = None, result: ChatMessage = None) -> Task:
        """
        Update task status and related fields.
        
        Args:
            task: Task to update
            newStatus: New status value
            progress: Optional progress value
            error: Optional error message
            result: Optional result message
            
        Returns:
            Updated Task object
        """
        # Validate status transition
        valid_transitions = {
            "pending": ["running", "failed"],
            "running": ["completed", "failed"],
            "completed": [],
            "failed": []
        }
        
        if newStatus not in valid_transitions.get(task.status, []):
            logger.warning(f"Invalid status transition from {task.status} to {newStatus}")
            return task
        
        # Update task fields
        task.status = newStatus
        if progress is not None:
            task.progress = progress
        if error is not None:
            task.error = error
        if result is not None:
            task.result = result
        
        # Update timestamps
        if newStatus in ["completed", "failed"]:
            task.finishedAt = datetime.now(UTC).isoformat()
        
        return task
    
    def createTaskLog(self, task: Task, message: str, logType: str = "info") -> ChatLog:
        """
        Create a log entry for a task.
        
        Args:
            task: Task to create log for
            message: Log message
            logType: Type of log entry
            
        Returns:
            New ChatLog object
        """
        return ChatLog(
            id=str(uuid.uuid4()),
            workflowId=task.workflowId,
            message=message,
            type=logType,
            timestamp=datetime.now(UTC).isoformat(),
            agentName=task.agentName,
            status=task.status,
            progress=task.progress
        )
    
    def updateTaskProgress(self, task: Task, progress: float, message: str = None) -> Task:
        """
        Update task progress and optionally create a log entry.
        
        Args:
            task: Task to update
            progress: New progress value (0-100)
            message: Optional progress message
            
        Returns:
            Updated Task object
        """
        # Validate progress value
        if not 0 <= progress <= 100:
            logger.warning(f"Invalid progress value: {progress}")
            return task
        
        # Update progress
        task.progress = progress
        
        # Create log entry if message provided
        if message:
            log = self.createTaskLog(task, message, "progress")
            if self.service and hasattr(self.service, 'logAdd'):
                self.service.logAdd(log)
        
        return task
    
    def handleTaskError(self, task: Task, error: str) -> Task:
        """
        Handle task error and update task state.
        
        Args:
            task: Task to update
            error: Error message
            
        Returns:
            Updated Task object
        """
        # Update task status
        task = self.updateTaskStatus(task, "failed", error=error)
        
        # Create error log
        log = self.createTaskLog(task, f"Task failed: {error}", "error")
        if self.service and hasattr(self.service, 'logAdd'):
            self.service.logAdd(log)
        
        return task
    
    def completeTask(self, task: Task, result: ChatMessage) -> Task:
        """
        Mark task as completed and set result.
        
        Args:
            task: Task to complete
            result: Result message
            
        Returns:
            Updated Task object
        """
        # Update task status
        task = self.updateTaskStatus(task, "completed", progress=100.0, result=result)
        
        # Create completion log
        log = self.createTaskLog(task, "Task completed successfully", "info")
        if self.service and hasattr(self.service, 'logAdd'):
            self.service.logAdd(log)
        
        return task

# Singleton factory for the task manager
def getTaskManager():
    return TaskManager.getInstance()