Script to select a raffle winner using ethereum's block hash as a source of randomnness.

tcap_raffle_winner.py

import hashlib
import random

def choose_weighted_winner(participants, points, block_hash):
    """
    Selects a winner using a weighted random selection based on points and a block hash.

    Args:
        participants (list): List of participant names or IDs.
        points (list): List of points corresponding to each participant.
        block_hash (str): Ethereum block hash used as the random seed.

    Returns:
        str: The winner of the raffle.
    """
    if not participants or not points:
        raise ValueError("Participants and points lists cannot be empty.")
    if len(participants) != len(points):
        raise ValueError("Participants and points lists must have the same length.")
    if not isinstance(block_hash, str) or len(block_hash) != 66 or not block_hash.startswith("0x"):
        raise ValueError("Invalid block hash format.")

    # Create a weighted pool based on points
    weighted_pool = []
    for participant, point in zip(participants, points):
        weighted_pool.extend([participant] * point)

    if not weighted_pool:
        raise ValueError("Weighted pool is empty. Ensure points are greater than zero.")

    # Convert the block hash to a random seed
    seed = int(hashlib.sha256(block_hash.encode()).hexdigest(), 16)

    # Use the seed to select a winner
    random.seed(seed)
    winner = random.choice(weighted_pool)
    return winner

# Example Usage
if __name__ == "__main__":
    # List of participants and their points
    participants = ["Alice", "Bob", "Charlie", "Diana"]
    points = [5, 3, 1, 10]  # Corresponding points for each participant

    # Example Ethereum block hash (replace with the real block hash)
    block_hash = "0xabc123abc123abc123abc123abc123abc123abc123abc123abc123abc123abc1"

    try:
        winner = choose_weighted_winner(participants, points, block_hash)
        print(f"The winner is: {winner}")
    except ValueError as e:
        print(f"Error: {e}")