import os
import json
from datetime import datetime, timedelta
import shutil
import logging
from functools import wraps
from .exceptions import TransactionAlreadyProcessedError


class TransactionTracker:
    """Track processed transactions with automatic 3-day TTL."""

    def __init__(self, storage_dir="transaction_records", ttl_days=3):
        """Initialize with storage directory path and TTL in days."""
        self.storage_dir = storage_dir
        self.ttl_days = ttl_days
        self._ensure_storage_exists()
        self.logger = logging.getLogger(__name__)
        # Run cleanup at initialization
        self.cleanup_expired()

    def _ensure_storage_exists(self):
        """Create storage directory if it doesn't exist."""
        if not os.path.exists(self.storage_dir):
            os.makedirs(self.storage_dir)

    def mark_processed(self, transaction_id):
        """Mark a transaction as processed."""
        # Create record file with timestamp
        record_path = os.path.join(self.storage_dir, f"{transaction_id}.json")
        record_data = {
            "transaction_id": str(transaction_id),  # Convert to string for non-string IDs
            "processed_at": datetime.now().isoformat(),
            "expires_at": (datetime.now() + timedelta(days=self.ttl_days)).isoformat()
        }

        with open(record_path, "w") as f:
            json.dump(record_data, f)

        self.logger.debug(f"Transaction {transaction_id} marked as processed")

    def is_processed(self, transaction_id):
        """Check if transaction was already processed."""
        record_path = os.path.join(self.storage_dir, f"{transaction_id}.json")
        return os.path.exists(record_path)

    def require_unique_transaction(self, id_arg='transaction_id'):
        """
        Decorator factory to ensure a function is only run once per transaction ID.

        Args:
            id_arg: The argument name containing the transaction ID

        Usage:
            @tracker.require_unique_transaction()
            def process_payment(transaction_id, amount):
                # Process payment logic
                return "Success"
        """

        def decorator(func):
            @wraps(func)
            def wrapper(*args, **kwargs):
                # Extract transaction_id from args or kwargs
                if id_arg in kwargs:
                    transaction_id = kwargs[id_arg]
                else:
                    # Find the position of transaction_id in the function signature
                    import inspect
                    sig = inspect.signature(func)
                    param_names = list(sig.parameters.keys())
                    try:
                        idx = param_names.index(id_arg)
                        if idx < len(args):
                            transaction_id = args[idx]
                        else:
                            raise ValueError(f"Could not find {id_arg} in arguments")
                    except ValueError:
                        raise ValueError(f"Could not find {id_arg} in arguments")

                # Always convert to string for consistent handling
                str_transaction_id = str(transaction_id)

                # Check if transaction was already processed
                if self.is_processed(str_transaction_id):
                    raise TransactionAlreadyProcessedError(
                        f"Transaction {transaction_id} was already processed"
                    )

                # Process the transaction
                result = func(*args, **kwargs)

                # Mark as processed
                self.mark_processed(str_transaction_id)

                return result

            return wrapper

        return decorator

    def cleanup_expired(self):
        """Remove records older than the TTL period."""
        now = datetime.now()
        count = 0
        for filename in os.listdir(self.storage_dir):
            if not filename.endswith('.json'):
                continue

            file_path = os.path.join(self.storage_dir, filename)
            try:
                with open(file_path, 'r') as f:
                    record = json.load(f)

                expires_at = datetime.fromisoformat(record.get('expires_at'))
                if now >= expires_at:
                    os.remove(file_path)
                    count += 1
            except (json.JSONDecodeError, KeyError, ValueError):
                # If file is corrupted, remove it
                os.remove(file_path)
                count += 1

        if count > 0:
            self.logger.info(f"Cleaned up {count} expired transaction records")

    def clear_all(self):
        """Remove all transaction records."""
        if os.path.exists(self.storage_dir):
            shutil.rmtree(self.storage_dir)
            self._ensure_storage_exists()
            self.logger.info("Cleared all transaction records")


class TransactionProcessor:
    """Process transactions with duplicate detection."""

    def __init__(self, storage_dir="transaction_records", ttl_days=3):
        """Initialize with a TransactionTracker."""
        self.tracker = TransactionTracker(storage_dir, ttl_days)

    def unique_transaction(self, id_arg='transaction_id'):
        """
        Decorator to ensure a transaction is processed only once.

        Usage:
            @processor.unique_transaction()
            def process_payment(transaction_id, amount):
                # Your processing logic
                return "Success"
        """
        return self.tracker.require_unique_transaction(id_arg)

    def cleanup(self):
        """Clean up expired transactions."""
        self.tracker.cleanup_expired()

    def reset(self):
        """Clear all transaction records."""
        self.tracker.clear_all()