"""
Transaction Model

Tracks all gold transactions for audit and analytics purposes.
Includes shop purchases, sales, quest rewards, trades, etc.
"""

from dataclasses import dataclass, field
from datetime import datetime
from typing import Dict, Any, Optional
from enum import Enum


class TransactionType(Enum):
    """Types of gold transactions."""
    SHOP_PURCHASE = "shop_purchase"
    SHOP_SALE = "shop_sale"
    QUEST_REWARD = "quest_reward"
    ENEMY_LOOT = "enemy_loot"
    PLAYER_TRADE = "player_trade"
    NPC_GIFT = "npc_gift"
    SYSTEM_ADJUSTMENT = "system_adjustment"


@dataclass
class Transaction:
    """
    Represents a gold transaction for audit logging.

    Attributes:
        transaction_id: Unique identifier for this transaction
        transaction_type: Type of transaction (purchase, sale, reward, etc.)
        character_id: Character involved in the transaction
        session_id: Game session where transaction occurred (for cleanup on session delete)
        amount: Gold amount (negative for expenses, positive for income)
        description: Human-readable description of the transaction
        timestamp: When the transaction occurred
        metadata: Additional context-specific data
    """

    transaction_id: str
    transaction_type: TransactionType
    character_id: str
    session_id: Optional[str] = None  # Session context for cleanup
    amount: int = 0  # Negative for expenses, positive for income
    description: str = ""
    timestamp: datetime = field(default_factory=datetime.utcnow)
    metadata: Dict[str, Any] = field(default_factory=dict)

    def to_dict(self) -> Dict[str, Any]:
        """
        Serialize transaction to dictionary for storage.

        Returns:
            Dictionary containing all transaction data
        """
        return {
            "transaction_id": self.transaction_id,
            "transaction_type": self.transaction_type.value,
            "character_id": self.character_id,
            "session_id": self.session_id,
            "amount": self.amount,
            "description": self.description,
            "timestamp": self.timestamp.isoformat(),
            "metadata": self.metadata,
        }

    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> 'Transaction':
        """
        Deserialize transaction from dictionary.

        Args:
            data: Dictionary containing transaction data

        Returns:
            Transaction instance
        """
        return cls(
            transaction_id=data["transaction_id"],
            transaction_type=TransactionType(data["transaction_type"]),
            character_id=data["character_id"],
            session_id=data.get("session_id"),
            amount=data["amount"],
            description=data["description"],
            timestamp=datetime.fromisoformat(data["timestamp"]),
            metadata=data.get("metadata", {}),
        )

    @classmethod
    def create_purchase(
        cls,
        transaction_id: str,
        character_id: str,
        shop_id: str,
        item_id: str,
        quantity: int,
        total_cost: int,
        session_id: Optional[str] = None
    ) -> 'Transaction':
        """
        Factory method for creating a shop purchase transaction.

        Args:
            transaction_id: Unique transaction ID
            character_id: Character making the purchase
            shop_id: Shop where purchase was made
            item_id: Item purchased
            quantity: Number of items purchased
            total_cost: Total gold spent
            session_id: Optional session ID for cleanup tracking

        Returns:
            Transaction instance for the purchase
        """
        return cls(
            transaction_id=transaction_id,
            transaction_type=TransactionType.SHOP_PURCHASE,
            character_id=character_id,
            session_id=session_id,
            amount=-total_cost,  # Negative because spending gold
            description=f"Purchased {quantity}x {item_id} from {shop_id}",
            metadata={
                "shop_id": shop_id,
                "item_id": item_id,
                "quantity": quantity,
                "unit_price": total_cost // quantity if quantity > 0 else 0,
            }
        )

    @classmethod
    def create_sale(
        cls,
        transaction_id: str,
        character_id: str,
        shop_id: str,
        item_id: str,
        item_name: str,
        quantity: int,
        total_earned: int,
        session_id: Optional[str] = None
    ) -> 'Transaction':
        """
        Factory method for creating a shop sale transaction.

        Args:
            transaction_id: Unique transaction ID
            character_id: Character making the sale
            shop_id: Shop where sale was made
            item_id: Item sold
            item_name: Display name of the item
            quantity: Number of items sold
            total_earned: Total gold earned
            session_id: Optional session ID for cleanup tracking

        Returns:
            Transaction instance for the sale
        """
        return cls(
            transaction_id=transaction_id,
            transaction_type=TransactionType.SHOP_SALE,
            character_id=character_id,
            session_id=session_id,
            amount=total_earned,  # Positive because receiving gold
            description=f"Sold {quantity}x {item_name} to {shop_id}",
            metadata={
                "shop_id": shop_id,
                "item_id": item_id,
                "item_name": item_name,
                "quantity": quantity,
                "unit_price": total_earned // quantity if quantity > 0 else 0,
            }
        )

    def __repr__(self) -> str:
        """String representation of the transaction."""
        sign = "+" if self.amount >= 0 else ""
        return (
            f"Transaction({self.transaction_type.value}, "
            f"{sign}{self.amount}g, {self.description})"
        )