import struct

def parse_blk_file(filepath):
    # Mainnet Magic Bytes (Little-Endian)
    MAGIC_BYTES = b'\xf9\xbe\xb4\xd9'

    blocks_found = 0

    with open(filepath, 'rb') as f:
        while True:
            # 1. Read 4 bytes to check for Magic Marker
            marker = f.read(4)
            if not marker:
                break # End of file

            if marker != MAGIC_BYTES:
                # If we don't see the marker, we might be out of sync
                # or at the end of the file (padding zeroes)
                continue

            # 2. Read 4 bytes for Block Size (uint32, little-endian)
            size_data = f.read(4)
            block_size = struct.unpack('<I', size_data)[0]

            # 3. Read the 80-byte Header
            header = f.read(80)

            # 4. Skip the rest of the block (Transactions)
            # The header is 80 bytes, so we skip (block_size - 80)
            f.seek(block_size - 80, 1) # '1' means relative to current position

            blocks_found += 1
            print(f"Block #{blocks_found}: Found {block_size} byte block")
            print(f"   Header Hex: {header[:10].hex()}...")

    print(f"\n--- Scan Complete ---")
    print(f"Total blocks extracted from file: {blocks_found}")

# --- Instructions ---
# To use this on your own node, replace 'blk00000.dat' with your file path
# parse_blk_file('blk00000.dat')