"""
Bitcoin Mining Pipeline Implementation
Uses SHA-256 for block header hashing and handles full Bitcoin protocol
"""
import hashlib
import struct
import time
from typing import Optional, Dict

class BitcoinBlock:
    def __init__(self):
        self.version: int = 2
        self.prev_block_hash: str = ""
        self.merkle_root: str = ""
        self.timestamp: int = 0
        self.bits: int = 0
        self.nonce: int = 0

    def get_header(self) -> bytes:
        """Get block header for mining"""
        header = struct.pack("<L", self.version)
        header += bytes.fromhex(self.prev_block_hash)[::-1]
        header += bytes.fromhex(self.merkle_root)[::-1]
        header += struct.pack("<LLL", self.timestamp, self.bits, self.nonce)
        return header

class BitcoinMiner:
    def __init__(self):
        # Target difficulty (example: mainnet)
        self.target = int("00000000FFFF0000000000000000000000000000000000000000000000000000", 16)
        self.block = BitcoinBlock()
        
    def prepare_block(self, prev_hash: str, merkle_root: str, bits: int) -> None:
        """Prepare block for mining"""
        self.block.prev_block_hash = prev_hash
        self.block.merkle_root = merkle_root
        self.block.timestamp = int(time.time())
        self.block.bits = bits

    def verify_hash(self, block_hash: int) -> bool:
        """Verify if hash meets difficulty target"""
        return block_hash < self.target

    def get_mining_params(self) -> Dict:
        """Get parameters needed for mining"""
        return {
            'version': self.block.version,
            'prev_block': self.block.prev_block_hash,
            'merkle_root': self.block.merkle_root,
            'timestamp': self.block.timestamp,
            'bits': self.block.bits,
            'target': hex(self.target)[2:].zfill(64)
        }

class BTCWallet:
    def __init__(self, private_key: Optional[str] = None):
        """Initialize Bitcoin wallet with optional private key import"""
        self.private_key = private_key
        self.address = None
        self._generate_or_import_keys()

    def _generate_or_import_keys(self):
        """Generate new keys or import existing ones"""
        if not self.private_key:
            # Generate new private key
            import secrets
            self.private_key = secrets.token_hex(32)
        
        # Derive public key and address
        self._derive_public_key()
        self._generate_address()

    def _derive_public_key(self):
        """Derive public key from private key using secp256k1"""
        # Implementation using secp256k1 curve
        pass

    def _generate_address(self):
        """Generate Bitcoin address from public key"""
        # Implementation for P2PKH address generation
        pass

    def get_address(self) -> str:
        """Get wallet's Bitcoin address"""
        return self.address

    def sign_message(self, message: bytes) -> bytes:
        """Sign a message with wallet's private key"""
        # Implementation for message signing
        pass

    def verify_message(self, message: bytes, signature: bytes) -> bool:
        """Verify a message signature"""
        # Implementation for signature verification
        pass
