"""Transaction deduplication utilities."""
import hashlib
from datetime import date
from decimal import Decimal
from typing import Optional


def generate_transaction_hash(
    account_id: int,
    run_date: date,
    symbol: Optional[str],
    action: str,
    amount: Optional[Decimal],
    quantity: Optional[Decimal],
    price: Optional[Decimal],
) -> str:
    """
    Generate a unique SHA-256 hash for a transaction to prevent duplicates.

    The hash is generated from key transaction attributes that uniquely identify
    a transaction: account, date, symbol, action, amount, quantity, and price.

    Args:
        account_id: Account identifier
        run_date: Transaction date
        symbol: Trading symbol
        action: Transaction action description
        amount: Transaction amount
        quantity: Number of shares/contracts
        price: Price per unit

    Returns:
        str: 64-character hexadecimal SHA-256 hash

    Example:
        >>> generate_transaction_hash(
        ...     account_id=1,
        ...     run_date=date(2025, 12, 26),
        ...     symbol="AAPL",
        ...     action="YOU BOUGHT",
        ...     amount=Decimal("-1500.00"),
        ...     quantity=Decimal("10"),
        ...     price=Decimal("150.00")
        ... )
        'a1b2c3d4...'
    """
    # Convert values to strings, handling None values
    symbol_str = symbol or ""
    amount_str = str(amount) if amount is not None else ""
    quantity_str = str(quantity) if quantity is not None else ""
    price_str = str(price) if price is not None else ""

    # Create hash string with pipe delimiter
    hash_string = (
        f"{account_id}|"
        f"{run_date.isoformat()}|"
        f"{symbol_str}|"
        f"{action}|"
        f"{amount_str}|"
        f"{quantity_str}|"
        f"{price_str}"
    )

    # Generate SHA-256 hash
    return hashlib.sha256(hash_string.encode("utf-8")).hexdigest()