"""
Real Bitcoin mining implementation
"""
import hashlib
import struct
from typing import Optional, Dict, Any
import time
from bitcoinlib.services.services import Service

class BitcoinMiner:
    def __init__(self, network='bitcoin'):
        self.service = Service(network=network)
        self.max_nonce = 2**32  # 4 billion
        
    def mine_block(self, template: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        """
        Real Bitcoin mining implementation
        Args:
            template: Block template from get_block_template
        Returns:
            Mined block if successful, None if not
        """
        version = template['version']
        prev_block = bytes.fromhex(template['previous_block'])
        merkle_root = bytes.fromhex(template['merkle_root'])
        timestamp = template['timestamp']
        bits = template['bits']
        
        # Convert target difficulty
        target = self._bits_to_target(bits)
        
        # Try all nonce values
        for nonce in range(self.max_nonce):
            # Build block header
            header = self._build_header(
                version=version,
                prev_block=prev_block,
                merkle_root=merkle_root,
                timestamp=timestamp,
                bits=bits,
                nonce=nonce
            )
            
            # Double SHA256
            hash_result = hashlib.sha256(hashlib.sha256(header).digest()).digest()
            
            # Check if hash meets target
            if int.from_bytes(hash_result, 'little') < target:
                return {
                    'header': header.hex(),
                    'hash': hash_result.hex(),
                    'nonce': nonce,
                    'template': template
                }
                
        return None
        
    def _build_header(self, version: int, prev_block: bytes, 
                     merkle_root: bytes, timestamp: int,
                     bits: int, nonce: int) -> bytes:
        """Build Bitcoin block header"""
        header = struct.pack('<I', version)  # 4 bytes version
        header += prev_block                 # 32 bytes previous block hash
        header += merkle_root               # 32 bytes merkle root
        header += struct.pack('<I', timestamp)  # 4 bytes timestamp
        header += struct.pack('<I', bits)    # 4 bytes bits
        header += struct.pack('<I', nonce)   # 4 bytes nonce
        return header
        
    def _bits_to_target(self, bits: int) -> int:
        """Convert compact bits to target"""
        shift = (bits >> 24) & 0xFF
        target = (bits & 0x00FFFFFF) * (2 ** (8 * (shift - 3)))
        return target
        
    def submit_block(self, block: Dict[str, Any]) -> bool:
        """
        Submit mined block to Bitcoin network
        """
        try:
            # Submit raw block
            result = self.service.sendrawtransaction(block['header'])
            return bool(result)
        except Exception as e:
            print(f"Failed to submit block: {str(e)}")
            return False
