Token Transfer Gas Estimator

from web3 import Web3
from typing import Dict

class TokenGasEstimator:
    """
    Estimates gas costs for ERC-20 token transfers.
    """

    def __init__(self, provider_url: str):
        """
        Initialize the estimator with an Ethereum provider.

        Args:
            provider_url: URL of the Ethereum node (e.g., HTTP RPC endpoint)
        """
        pass

    def is_connected(self) -> bool:
        """
        Check if the connection to the Ethereum node is active.

        Returns:
            True if connected, False otherwise
        """
        pass

    def estimate_transfer_gas(
        self,
        token_address: str,
        from_address: str,
        to_address: str,
        amount: int
    ) -> int:
        """
        Estimate gas required for an ERC-20 token transfer.

        Args:
            token_address: Address of the ERC-20 token contract
            from_address: Address sending the tokens
            to_address: Address receiving the tokens
            amount: Amount of tokens to transfer (in smallest unit)

        Returns:
            Estimated gas units required for the transfer

        Raises:
            Exception: If estimation fails (e.g., insufficient balance, invalid contract)
        """
        pass

    def compare_transfer_costs(
        self,
        token_address: str,
        from_address: str,
        to_address: str,
        amounts: list[int]
    ) -> Dict[int, int]:
        """
        Compare gas costs for transferring different amounts.

        Args:
            token_address: Address of the ERC-20 token contract
            from_address: Address sending the tokens
            to_address: Address receiving the tokens
            amounts: List of different amounts to estimate

        Returns:
            Dictionary mapping each amount to its estimated gas cost

        Raises:
            Exception: If any estimation fails
        """
        pass