# dnsrecon/core/task_manager.py

import threading
import time
import uuid
from enum import Enum
from dataclasses import dataclass, field
from typing import Dict, List, Optional, Any, Set
from datetime import datetime, timezone, timedelta
from collections import deque

from utils.helpers import _is_valid_ip, _is_valid_domain


class TaskStatus(Enum):
    """Enumeration of task execution statuses."""
    PENDING = "pending"
    RUNNING = "running"
    SUCCEEDED = "succeeded"
    FAILED_RETRYING = "failed_retrying"
    FAILED_PERMANENT = "failed_permanent"
    CANCELLED = "cancelled"


class TaskType(Enum):
    """Enumeration of task types for provider queries."""
    DOMAIN_QUERY = "domain_query"
    IP_QUERY = "ip_query"
    GRAPH_UPDATE = "graph_update"


@dataclass
class TaskResult:
    """Result of a task execution."""
    success: bool
    data: Optional[Any] = None
    error: Optional[str] = None
    metadata: Dict[str, Any] = field(default_factory=dict)


@dataclass
class ReconTask:
    """Represents a single reconnaissance task with retry logic."""
    task_id: str
    task_type: TaskType
    target: str
    provider_name: str
    depth: int
    status: TaskStatus = TaskStatus.PENDING
    created_at: datetime = field(default_factory=lambda: datetime.now(timezone.utc))
    
    # Retry configuration
    max_retries: int = 3
    current_retry: int = 0
    base_backoff_seconds: float = 1.0
    max_backoff_seconds: float = 60.0
    
    # Execution tracking
    last_attempt_at: Optional[datetime] = None
    next_retry_at: Optional[datetime] = None
    execution_history: List[Dict[str, Any]] = field(default_factory=list)
    
    # Results
    result: Optional[TaskResult] = None
    
    def __post_init__(self):
        """Initialize additional fields after creation."""
        if not self.task_id:
            self.task_id = str(uuid.uuid4())[:8]
    
    def calculate_next_retry_time(self) -> datetime:
        """Calculate next retry time with exponential backoff and jitter."""
        if self.current_retry >= self.max_retries:
            return None
        
        # Exponential backoff with jitter
        backoff_time = min(
            self.max_backoff_seconds,
            self.base_backoff_seconds * (2 ** self.current_retry)
        )
        
        # Add jitter (±25%)
        jitter = backoff_time * 0.25 * (0.5 - hash(self.task_id) % 1000 / 1000.0)
        final_backoff = max(self.base_backoff_seconds, backoff_time + jitter)
        
        return datetime.now(timezone.utc) + timedelta(seconds=final_backoff)
    
    def should_retry(self) -> bool:
        """Determine if task should be retried based on status and retry count."""
        if self.status != TaskStatus.FAILED_RETRYING:
            return False
        if self.current_retry >= self.max_retries:
            return False
        if self.next_retry_at and datetime.now(timezone.utc) < self.next_retry_at:
            return False
        return True
    
    def mark_failed(self, error: str, metadata: Dict[str, Any] = None):
        """Mark task as failed and prepare for retry or permanent failure."""
        self.current_retry += 1
        self.last_attempt_at = datetime.now(timezone.utc)
        
        # Record execution history
        execution_record = {
            'attempt': self.current_retry,
            'timestamp': self.last_attempt_at.isoformat(),
            'error': error,
            'metadata': metadata or {}
        }
        self.execution_history.append(execution_record)
        
        if self.current_retry >= self.max_retries:
            self.status = TaskStatus.FAILED_PERMANENT
            self.result = TaskResult(success=False, error=f"Permanent failure after {self.max_retries} attempts: {error}")
        else:
            self.status = TaskStatus.FAILED_RETRYING
            self.next_retry_at = self.calculate_next_retry_time()
    
    def mark_succeeded(self, data: Any = None, metadata: Dict[str, Any] = None):
        """Mark task as successfully completed."""
        self.status = TaskStatus.SUCCEEDED
        self.last_attempt_at = datetime.now(timezone.utc)
        self.result = TaskResult(success=True, data=data, metadata=metadata or {})
        
        # Record successful execution
        execution_record = {
            'attempt': self.current_retry + 1,
            'timestamp': self.last_attempt_at.isoformat(),
            'success': True,
            'metadata': metadata or {}
        }
        self.execution_history.append(execution_record)
    
    def get_summary(self) -> Dict[str, Any]:
        """Get task summary for progress reporting."""
        return {
            'task_id': self.task_id,
            'task_type': self.task_type.value,
            'target': self.target,
            'provider': self.provider_name,
            'status': self.status.value,
            'current_retry': self.current_retry,
            'max_retries': self.max_retries,
            'created_at': self.created_at.isoformat(),
            'last_attempt_at': self.last_attempt_at.isoformat() if self.last_attempt_at else None,
            'next_retry_at': self.next_retry_at.isoformat() if self.next_retry_at else None,
            'total_attempts': len(self.execution_history),
            'has_result': self.result is not None
        }


class TaskQueue:
    """Thread-safe task queue with retry logic and priority handling."""
    
    def __init__(self, max_concurrent_tasks: int = 5):
        """Initialize task queue."""
        self.max_concurrent_tasks = max_concurrent_tasks
        self.tasks: Dict[str, ReconTask] = {}
        self.pending_queue = deque()
        self.retry_queue = deque()
        self.running_tasks: Set[str] = set()
        
        self._lock = threading.Lock()
        self._stop_event = threading.Event()
    
    def __getstate__(self):
        """Prepare TaskQueue for pickling by excluding unpicklable objects."""
        state = self.__dict__.copy()
        # Exclude the unpickleable '_lock' and '_stop_event' attributes
        if '_lock' in state:
            del state['_lock']
        if '_stop_event' in state:
            del state['_stop_event']
        return state

    def __setstate__(self, state):
        """Restore TaskQueue after unpickling by reconstructing threading objects."""
        self.__dict__.update(state)
        # Re-initialize the '_lock' and '_stop_event' attributes
        self._lock = threading.Lock()
        self._stop_event = threading.Event()
    
    def add_task(self, task: ReconTask) -> str:
        """Add task to queue."""
        with self._lock:
            self.tasks[task.task_id] = task
            self.pending_queue.append(task.task_id)
            print(f"Added task {task.task_id}: {task.provider_name} query for {task.target}")
            return task.task_id
    
    def get_next_ready_task(self) -> Optional[ReconTask]:
        """Get next task ready for execution."""
        with self._lock:
            # Check if we have room for more concurrent tasks
            if len(self.running_tasks) >= self.max_concurrent_tasks:
                return None
            
            # First priority: retry queue (tasks ready for retry)
            while self.retry_queue:
                task_id = self.retry_queue.popleft()
                if task_id in self.tasks:
                    task = self.tasks[task_id]
                    if task.should_retry():
                        task.status = TaskStatus.RUNNING
                        self.running_tasks.add(task_id)
                        print(f"Retrying task {task_id} (attempt {task.current_retry + 1})")
                        return task
            
            # Second priority: pending queue (new tasks)
            while self.pending_queue:
                task_id = self.pending_queue.popleft()
                if task_id in self.tasks:
                    task = self.tasks[task_id]
                    if task.status == TaskStatus.PENDING:
                        task.status = TaskStatus.RUNNING
                        self.running_tasks.add(task_id)
                        print(f"Starting task {task_id}")
                        return task
            
            return None
    
    def complete_task(self, task_id: str, success: bool, data: Any = None, 
                     error: str = None, metadata: Dict[str, Any] = None):
        """Mark task as completed (success or failure)."""
        with self._lock:
            if task_id not in self.tasks:
                return
            
            task = self.tasks[task_id]
            self.running_tasks.discard(task_id)
            
            if success:
                task.mark_succeeded(data=data, metadata=metadata)
                print(f"Task {task_id} succeeded")
            else:
                task.mark_failed(error or "Unknown error", metadata=metadata)
                if task.status == TaskStatus.FAILED_RETRYING:
                    self.retry_queue.append(task_id)
                    print(f"Task {task_id} failed, scheduled for retry at {task.next_retry_at}")
                else:
                    print(f"Task {task_id} permanently failed after {task.current_retry} attempts")
    
    def cancel_all_tasks(self):
        """Cancel all pending and running tasks."""
        with self._lock:
            self._stop_event.set()
            for task in self.tasks.values():
                if task.status in [TaskStatus.PENDING, TaskStatus.RUNNING, TaskStatus.FAILED_RETRYING]:
                    task.status = TaskStatus.CANCELLED
            self.pending_queue.clear()
            self.retry_queue.clear()
            self.running_tasks.clear()
            print("All tasks cancelled")
    
    def is_complete(self) -> bool:
        """Check if all tasks are complete (succeeded, permanently failed, or cancelled)."""
        with self._lock:
            for task in self.tasks.values():
                if task.status in [TaskStatus.PENDING, TaskStatus.RUNNING, TaskStatus.FAILED_RETRYING]:
                    return False
            return True
    
    def get_statistics(self) -> Dict[str, Any]:
        """Get queue statistics."""
        with self._lock:
            stats = {
                'total_tasks': len(self.tasks),
                'pending': len(self.pending_queue),
                'running': len(self.running_tasks),
                'retry_queue': len(self.retry_queue),
                'succeeded': 0,
                'failed_permanent': 0,
                'cancelled': 0,
                'failed_retrying': 0
            }
            
            for task in self.tasks.values():
                if task.status == TaskStatus.SUCCEEDED:
                    stats['succeeded'] += 1
                elif task.status == TaskStatus.FAILED_PERMANENT:
                    stats['failed_permanent'] += 1
                elif task.status == TaskStatus.CANCELLED:
                    stats['cancelled'] += 1
                elif task.status == TaskStatus.FAILED_RETRYING:
                    stats['failed_retrying'] += 1
            
            stats['completion_rate'] = (stats['succeeded'] / stats['total_tasks'] * 100) if stats['total_tasks'] > 0 else 0
            stats['is_complete'] = self.is_complete()
            
            return stats
    
    def get_task_summaries(self) -> List[Dict[str, Any]]:
        """Get summaries of all tasks for detailed progress reporting."""
        with self._lock:
            return [task.get_summary() for task in self.tasks.values()]
    
    def get_failed_tasks(self) -> List[ReconTask]:
        """Get all permanently failed tasks for analysis."""
        with self._lock:
            return [task for task in self.tasks.values() if task.status == TaskStatus.FAILED_PERMANENT]


class TaskExecutor:
    """Executes reconnaissance tasks using providers."""
    
    def __init__(self, providers: List, graph_manager, logger):
        """Initialize task executor."""
        self.providers = {provider.get_name(): provider for provider in providers}
        self.graph = graph_manager
        self.logger = logger
    
    def execute_task(self, task: ReconTask) -> TaskResult:
        """
        Execute a single reconnaissance task.
        
        Args:
            task: Task to execute
            
        Returns:
            TaskResult with success/failure information
        """
        try:
            print(f"Executing task {task.task_id}: {task.provider_name} query for {task.target}")
            
            provider = self.providers.get(task.provider_name)
            if not provider:
                return TaskResult(
                    success=False, 
                    error=f"Provider {task.provider_name} not available"
                )
            
            if not provider.is_available():
                return TaskResult(
                    success=False,
                    error=f"Provider {task.provider_name} is not available (missing API key or configuration)"
                )
            
            # Execute provider query based on task type
            if task.task_type == TaskType.DOMAIN_QUERY:
                if not _is_valid_domain(task.target):
                    return TaskResult(success=False, error=f"Invalid domain: {task.target}")
                    
                relationships = provider.query_domain(task.target)
                
            elif task.task_type == TaskType.IP_QUERY:
                if not _is_valid_ip(task.target):
                    return TaskResult(success=False, error=f"Invalid IP: {task.target}")
                    
                relationships = provider.query_ip(task.target)
                
            else:
                return TaskResult(success=False, error=f"Unsupported task type: {task.task_type}")
            
            # Process results and update graph
            new_targets = set()
            relationships_added = 0
            
            for source, target, rel_type, confidence, raw_data in relationships:
                # Add nodes to graph
                from core.graph_manager import NodeType
                
                if _is_valid_ip(target):
                    self.graph.add_node(target, NodeType.IP)
                    new_targets.add(target)
                elif target.startswith('AS') and target[2:].isdigit():
                    self.graph.add_node(target, NodeType.ASN)
                elif _is_valid_domain(target):
                    self.graph.add_node(target, NodeType.DOMAIN)
                    new_targets.add(target)
                
                # Add edge to graph
                if self.graph.add_edge(source, target, rel_type, confidence, task.provider_name, raw_data):
                    relationships_added += 1
            
            # Log forensic information
            self.logger.logger.info(
                f"Task {task.task_id} completed: {len(relationships)} relationships found, "
                f"{relationships_added} added to graph, {len(new_targets)} new targets"
            )
            
            return TaskResult(
                success=True,
                data={
                    'relationships': relationships,
                    'new_targets': list(new_targets),
                    'relationships_added': relationships_added
                },
                metadata={
                    'provider': task.provider_name,
                    'target': task.target,
                    'depth': task.depth,
                    'execution_time': datetime.now(timezone.utc).isoformat()
                }
            )
            
        except Exception as e:
            error_msg = f"Task execution failed: {str(e)}"
            print(f"ERROR: {error_msg} for task {task.task_id}")
            self.logger.logger.error(error_msg)
            
            return TaskResult(
                success=False,
                error=error_msg,
                metadata={
                    'provider': task.provider_name,
                    'target': task.target,
                    'exception_type': type(e).__name__
                }
            )


class TaskManager:
    """High-level task management for reconnaissance scans."""
    
    def __init__(self, providers: List, graph_manager, logger, max_concurrent_tasks: int = 5):
        """Initialize task manager."""
        self.task_queue = TaskQueue(max_concurrent_tasks)
        self.task_executor = TaskExecutor(providers, graph_manager, logger)
        self.logger = logger
        
        # Execution control
        self._stop_event = threading.Event()
        self._execution_threads: List[threading.Thread] = []
        self._is_running = False
    
    def create_provider_tasks(self, target: str, depth: int, providers: List) -> List[str]:
        """
        Create tasks for querying all eligible providers for a target.
        
        Args:
            target: Domain or IP to query
            depth: Current recursion depth
            providers: List of available providers
            
        Returns:
            List of created task IDs
        """
        task_ids = []
        is_ip = _is_valid_ip(target)
        target_key = 'ips' if is_ip else 'domains'
        task_type = TaskType.IP_QUERY if is_ip else TaskType.DOMAIN_QUERY
        
        for provider in providers:
            if provider.get_eligibility().get(target_key) and provider.is_available():
                task = ReconTask(
                    task_id=str(uuid.uuid4())[:8],
                    task_type=task_type,
                    target=target,
                    provider_name=provider.get_name(),
                    depth=depth,
                    max_retries=3  # Configure retries per task type/provider
                )
                
                task_id = self.task_queue.add_task(task)
                task_ids.append(task_id)
        
        return task_ids
    
    def start_execution(self, max_workers: int = 3):
        """Start task execution with specified number of worker threads."""
        if self._is_running:
            print("Task execution already running")
            return
        
        self._is_running = True
        self._stop_event.clear()
        
        print(f"Starting task execution with {max_workers} workers")
        
        for i in range(max_workers):
            worker_thread = threading.Thread(
                target=self._worker_loop,
                name=f"TaskWorker-{i+1}",
                daemon=True
            )
            worker_thread.start()
            self._execution_threads.append(worker_thread)
    
    def stop_execution(self):
        """Stop task execution and cancel all tasks."""
        print("Stopping task execution")
        self._stop_event.set()
        self.task_queue.cancel_all_tasks()
        self._is_running = False
        
        # Wait for worker threads to finish
        for thread in self._execution_threads:
            thread.join(timeout=5.0)
        
        self._execution_threads.clear()
        print("Task execution stopped")
    
    def _worker_loop(self):
        """Worker thread loop for executing tasks."""
        thread_name = threading.current_thread().name
        print(f"{thread_name} started")
        
        while not self._stop_event.is_set():
            try:
                # Get next task to execute
                task = self.task_queue.get_next_ready_task()
                
                if task is None:
                    # No tasks ready, check if we should exit
                    if self.task_queue.is_complete() or self._stop_event.is_set():
                        break
                    time.sleep(0.1)  # Brief sleep before checking again
                    continue
                
                # Execute the task
                result = self.task_executor.execute_task(task)
                
                # Complete the task in queue
                self.task_queue.complete_task(
                    task.task_id,
                    success=result.success,
                    data=result.data,
                    error=result.error,
                    metadata=result.metadata
                )
                
            except Exception as e:
                print(f"ERROR: Worker {thread_name} encountered error: {e}")
                # Continue running even if individual task fails
                continue
        
        print(f"{thread_name} finished")
    
    def wait_for_completion(self, timeout_seconds: int = 300) -> bool:
        """
        Wait for all tasks to complete.
        
        Args:
            timeout_seconds: Maximum time to wait
            
        Returns:
            True if all tasks completed, False if timeout
        """
        start_time = time.time()
        
        while time.time() - start_time < timeout_seconds:
            if self.task_queue.is_complete():
                return True
            
            if self._stop_event.is_set():
                return False
            
            time.sleep(1.0)  # Check every second
        
        print(f"Timeout waiting for task completion after {timeout_seconds} seconds")
        return False
    
    def get_progress_report(self) -> Dict[str, Any]:
        """Get detailed progress report for UI updates."""
        stats = self.task_queue.get_statistics()
        failed_tasks = self.task_queue.get_failed_tasks()
        
        return {
            'statistics': stats,
            'failed_tasks': [task.get_summary() for task in failed_tasks],
            'is_running': self._is_running,
            'worker_count': len(self._execution_threads),
            'detailed_tasks': self.task_queue.get_task_summaries() if stats['total_tasks'] < 50 else []  # Limit detail for performance
        }