"""
Implementation of WhatsApp's custom App State Sync LT-Hash (Lattice-based Hash)
used for syncing archive, mute, and contact profile states across devices.
"""
import hashlib
from typing import List

# WhatsApp uses a customized Hash algorithm for syncing app collection states dynamically
# This is a stub placeholder for the core logic
# In the real Baileys, this involves parsing protobuf Mutation structures
# and aggregating a rolling 128-byte hash using additive/subtractive blending.

def decode_app_state_sync_key(key_data: bytes) -> bytes:
    """Decodes sync key from AppStateSyncKeyData protobuf."""
    return b"stub_key"

def generate_mutation_mac(action: str, index: bytes, value: bytes, key: bytes) -> bytes:
    """Generates a MAC for an AppState mutation."""
    # mac = hmac_sha256(key, action + index + value)
    return b"stub_mac"

def update_lt_hash(current_hash: bytes, mutations: List[dict]) -> bytes:
    """
    Updates the 128-byte lattice hash with a set of new mutations.
    WhatsApp uses this to ensure both client and server state index perfectly match.
    """
    if not current_hash:
        current_hash = bytes(128)
        
    mutable_hash = bytearray(current_hash)
    
    for _mut in mutations:
        # Stub: perform 16-bit wide additive/subtractive hashing based on mutation ID
        # ...
        pass
        
    return bytes(mutable_hash)
