src/blockchain.py

import os
import logging
from web3 import Web3
from typing import Callable, Optional
import asyncio

logger = logging.getLogger(__name__)

class BlockchainTracker:
    def __init__(self):
        """
        Track whale movements on Polygon (Polymarket's native chain).
        """
        # Alchemy or Infura RPC URL for Polygon Mainnet
        self.rpc_url = os.environ.get("POLYGON_RPC_URL", "https://polygon-rpc.com")
        self.w3 = Web3(Web3.HTTPProvider(self.rpc_url))
        
        if self.w3.is_connected():
             logger.info(f"Connected to Polygon Network via {self.rpc_url}")
        else:
             logger.error("Failed to connect to Polygon Network")

        # USDC Token Contract on Polygon
        self.usdc_address = self.w3.to_checksum_address("0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174")
        
        # Polymarket CTF Exchange Contract
        self.poly_exchange = self.w3.to_checksum_address("0x4bFb41d5B3570DeFd03C39a9A4D8dE6Bd8B8982E")

        # Standard ERC20 Transfer ABI (reduced form)
        self.erc20_abi = [
            {
                "anonymous": False,
                "inputs": [
                    {"indexed": True, "name": "from", "type": "address"},
                    {"indexed": True, "name": "to", "type": "address"},
                    {"indexed": False, "name": "value", "type": "uint256"}
                ],
                "name": "Transfer",
                "type": "event"
            }
        ]
        
        self.usdc_contract = self.w3.eth.contract(address=self.usdc_address, abi=self.erc20_abi)

    async def watch_whale_deposits(self, threshold_usdc: float = 100000.0, callback: Optional[Callable] = None):
        """
        Poll for large USDC transfers (whales) flowing into Polymarket.
        Threshold defaults to 100k USDC (USDC has 6 decimals on Polygon).
        """
        threshold_wei = int(threshold_usdc * (10 ** 6))
        
        # Create a filter for Transfer events to the Polymarket exchange
        # Note: In production, relying on direct get_logs polling can be rate limited. 
        # WebSockets (WSS) and async Web3 is preferred.
        
        filter_params = {
            'address': self.usdc_address,
            'topics': [
                self.w3.keccak(text="Transfer(address,address,uint256)").hex(),
                None, # from any
                "0x000000000000000000000000" + self.poly_exchange[2:] # to polymarket
            ]
        }
        
        latest_block = self.w3.eth.block_number
        
        while True:
            try:
                # Fetch logs from latest block
                logs = self.w3.eth.get_logs({**filter_params, 'fromBlock': latest_block, 'toBlock': 'latest'})
                
                for log in logs:
                    # value is not indexed, so it's in the data field
                    value = int(log['data'].hex(), 16)
                    
                    if value >= threshold_wei:
                         usdc_amount = value / (10 ** 6)
                         sender = "0x" + log['topics'][1].hex()[-40:]
                         logger.info(f"🐋 WHALE ALERT: {usdc_amount} USDC deposited to Polymarket by {sender}")
                         
                         if callback:
                             callback(f"🐋 WHALE ALERT", f"${usdc_amount:,.2f} deposited to Polymarket by `{sender}`")
                
                latest_block = self.w3.eth.block_number + 1
                
            except Exception as e:
                 logger.error(f"Blockchain poll error: {e}")
                 
            await asyncio.sleep(15) # Poll every 15 seconds (Polygon block time is ~2s)