"""
ZK-Rollup Implementation for AITBC
Provides scalability through zero-knowledge proof aggregation
"""

import asyncio
import json
import hashlib
import time
from datetime import datetime, timedelta
from typing import Dict, List, Optional, Tuple
from dataclasses import dataclass, asdict
from enum import Enum
import logging
import random

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


class RollupStatus(Enum):
    """Rollup status"""
    ACTIVE = "active"
    PROVING = "proving"
    COMMITTED = "committed"
    FINALIZED = "finalized"


@dataclass
class RollupTransaction:
    """Transaction within rollup"""
    tx_hash: str
    from_address: str
    to_address: str
    amount: int
    gas_limit: int
    gas_price: int
    nonce: int
    data: str = ""
    timestamp: datetime = None
    
    def __post_init__(self):
        if self.timestamp is None:
            self.timestamp = datetime.utcnow()


@dataclass
class RollupBatch:
    """Batch of transactions with ZK proof"""
    batch_id: int
    transactions: List[RollupTransaction]
    merkle_root: str
    zk_proof: str
    previous_state_root: str
    new_state_root: str
    timestamp: datetime
    status: RollupStatus = RollupStatus.ACTIVE


@dataclass
class AccountState:
    """Account state in rollup"""
    address: str
    balance: int
    nonce: int
    storage_root: str


class ZKRollup:
    """ZK-Rollup implementation"""
    
    def __init__(self, layer1_address: str):
        self.layer1_address = layer1_address
        self.current_batch_id = 0
        self.pending_transactions: List[RollupTransaction] = []
        self.batches: Dict[int, RollupBatch] = {}
        self.account_states: Dict[str, AccountState] = {}
        self.status = RollupStatus.ACTIVE
        
        # Rollup parameters
        self.max_batch_size = 1000
        self.batch_interval = 60  # seconds
        self.proving_time = 30  # seconds (simulated)
        
        logger.info(f"Initialized ZK-Rollup at {layer1_address}")
    
    def deposit(self, address: str, amount: int) -> str:
        """Deposit funds from Layer 1 to rollup"""
        # Create deposit transaction
        deposit_tx = RollupTransaction(
            tx_hash=self._generate_tx_hash("deposit", address, amount),
            from_address=self.layer1_address,
            to_address=address,
            amount=amount,
            gas_limit=21000,
            gas_price=0,
            nonce=len(self.pending_transactions),
            data="deposit"
        )
        
        # Update account state
        if address not in self.account_states:
            self.account_states[address] = AccountState(
                address=address,
                balance=0,
                nonce=0,
                storage_root=""
            )
        
        self.account_states[address].balance += amount
        
        logger.info(f"Deposited {amount} to {address}")
        
        return deposit_tx.tx_hash
    
    def submit_transaction(
        self,
        from_address: str,
        to_address: str,
        amount: int,
        gas_limit: int = 21000,
        gas_price: int = 20 * 10**9,
        data: str = ""
    ) -> str:
        """Submit transaction to rollup"""
        
        # Validate sender
        if from_address not in self.account_states:
            raise ValueError(f"Account {from_address} not found")
        
        sender_state = self.account_states[from_address]
        
        # Check balance
        total_cost = amount + (gas_limit * gas_price)
        if sender_state.balance < total_cost:
            raise ValueError("Insufficient balance")
        
        # Create transaction
        tx = RollupTransaction(
            tx_hash=self._generate_tx_hash("transfer", from_address, to_address, amount),
            from_address=from_address,
            to_address=to_address,
            amount=amount,
            gas_limit=gas_limit,
            gas_price=gas_price,
            nonce=sender_state.nonce,
            data=data
        )
        
        # Add to pending
        self.pending_transactions.append(tx)
        
        # Update nonce
        sender_state.nonce += 1
        
        logger.info(f"Submitted transaction {tx.tx_hash[:8]} from {from_address} to {to_address}")
        
        return tx.tx_hash
    
    async def create_batch(self) -> Optional[RollupBatch]:
        """Create a batch from pending transactions"""
        if len(self.pending_transactions) == 0:
            return None
        
        # Take transactions for batch
        batch_txs = self.pending_transactions[:self.max_batch_size]
        self.pending_transactions = self.pending_transactions[self.max_batch_size:]
        
        # Calculate previous state root
        previous_state_root = self._calculate_state_root()
        
        # Process transactions
        new_states = self.account_states.copy()
        
        for tx in batch_txs:
            # Skip if account doesn't exist (except for deposits)
            if tx.from_address not in new_states and tx.data != "deposit":
                continue
            
            # Process transaction
            if tx.data == "deposit":
                # Deposits already handled in deposit()
                continue
            else:
                # Regular transfer
                sender = new_states[tx.from_address]
                receiver = new_states.get(tx.to_address)
                
                if receiver is None:
                    receiver = AccountState(
                        address=tx.to_address,
                        balance=0,
                        nonce=0,
                        storage_root=""
                    )
                    new_states[tx.to_address] = receiver
                
                # Transfer amount
                gas_cost = tx.gas_limit * tx.gas_price
                sender.balance -= (tx.amount + gas_cost)
                receiver.balance += tx.amount
        
        # Update states
        self.account_states = new_states
        new_state_root = self._calculate_state_root()
        
        # Create merkle root
        merkle_root = self._calculate_merkle_root(batch_txs)
        
        # Create batch
        batch = RollupBatch(
            batch_id=self.current_batch_id,
            transactions=batch_txs,
            merkle_root=merkle_root,
            zk_proof="",  # Will be generated
            previous_state_root=previous_state_root,
            new_state_root=new_state_root,
            timestamp=datetime.utcnow(),
            status=RollupStatus.PROVING
        )
        
        self.batches[self.current_batch_id] = batch
        self.current_batch_id += 1
        
        logger.info(f"Created batch {batch.batch_id} with {len(batch_txs)} transactions")
        
        return batch
    
    async def generate_zk_proof(self, batch: RollupBatch) -> str:
        """Generate ZK proof for batch (simulated)"""
        logger.info(f"Generating ZK proof for batch {batch.batch_id}")
        
        # Simulate proof generation time
        await asyncio.sleep(self.proving_time)
        
        # Generate mock proof
        proof_data = {
            "batch_id": batch.batch_id,
            "state_transition": f"{batch.previous_state_root}->{batch.new_state_root}",
            "transaction_count": len(batch.transactions),
            "timestamp": datetime.utcnow().isoformat()
        }
        
        proof = hashlib.sha256(json.dumps(proof_data, sort_keys=True).encode()).hexdigest()
        
        # Update batch
        batch.zk_proof = proof
        batch.status = RollupStatus.COMMITTED
        
        logger.info(f"Generated ZK proof for batch {batch.batch_id}")
        
        return proof
    
    async def submit_to_layer1(self, batch: RollupBatch) -> bool:
        """Submit batch to Layer 1 (simulated)"""
        logger.info(f"Submitting batch {batch.batch_id} to Layer 1")
        
        # Simulate network delay
        await asyncio.sleep(5)
        
        # Simulate success
        batch.status = RollupStatus.FINALIZED
        
        logger.info(f"Batch {batch.batch_id} finalized on Layer 1")
        
        return True
    
    def withdraw(self, address: str, amount: int) -> str:
        """Withdraw funds from rollup to Layer 1"""
        if address not in self.account_states:
            raise ValueError(f"Account {address} not found")
        
        if self.account_states[address].balance < amount:
            raise ValueError("Insufficient balance")
        
        # Create withdrawal transaction
        withdraw_tx = RollupTransaction(
            tx_hash=self._generate_tx_hash("withdraw", address, amount),
            from_address=address,
            to_address=self.layer1_address,
            amount=amount,
            gas_limit=21000,
            gas_price=0,
            nonce=self.account_states[address].nonce,
            data="withdraw"
        )
        
        # Update balance
        self.account_states[address].balance -= amount
        self.account_states[address].nonce += 1
        
        # Add to pending transactions
        self.pending_transactions.append(withdraw_tx)
        
        logger.info(f"Withdrawal of {amount} initiated for {address}")
        
        return withdraw_tx.tx_hash
    
    def get_account_balance(self, address: str) -> int:
        """Get account balance in rollup"""
        if address not in self.account_states:
            return 0
        return self.account_states[address].balance
    
    def get_pending_count(self) -> int:
        """Get number of pending transactions"""
        return len(self.pending_transactions)
    
    def get_batch_status(self, batch_id: int) -> Optional[RollupStatus]:
        """Get status of a batch"""
        if batch_id not in self.batches:
            return None
        return self.batches[batch_id].status
    
    def get_rollup_stats(self) -> Dict:
        """Get rollup statistics"""
        total_txs = sum(len(batch.transactions) for batch in self.batches.values())
        total_accounts = len(self.account_states)
        total_balance = sum(state.balance for state in self.account_states.values())
        
        return {
            "current_batch_id": self.current_batch_id,
            "total_batches": len(self.batches),
            "total_transactions": total_txs,
            "pending_transactions": len(self.pending_transactions),
            "total_accounts": total_accounts,
            "total_balance": total_balance,
            "status": self.status.value
        }
    
    def _generate_tx_hash(self, *args) -> str:
        """Generate transaction hash"""
        data = "|".join(str(arg) for arg in args)
        return hashlib.sha256(data.encode()).hexdigest()
    
    def _calculate_merkle_root(self, transactions: List[RollupTransaction]) -> str:
        """Calculate merkle root of transactions"""
        if not transactions:
            return hashlib.sha256(b"").hexdigest()
        
        tx_hashes = []
        for tx in transactions:
            tx_data = {
                "from": tx.from_address,
                "to": tx.to_address,
                "amount": tx.amount,
                "nonce": tx.nonce
            }
            tx_hash = hashlib.sha256(json.dumps(tx_data, sort_keys=True).encode()).hexdigest()
            tx_hashes.append(tx_hash)
        
        # Build merkle tree
        while len(tx_hashes) > 1:
            next_level = []
            for i in range(0, len(tx_hashes), 2):
                left = tx_hashes[i]
                right = tx_hashes[i + 1] if i + 1 < len(tx_hashes) else left
                combined = hashlib.sha256((left + right).encode()).hexdigest()
                next_level.append(combined)
            tx_hashes = next_level
        
        return tx_hashes[0]
    
    def _calculate_state_root(self) -> str:
        """Calculate state root"""
        if not self.account_states:
            return hashlib.sha256(b"").hexdigest()
        
        # Create sorted list of account states
        states = []
        for address, state in sorted(self.account_states.items()):
            state_data = {
                "address": address,
                "balance": state.balance,
                "nonce": state.nonce
            }
            state_hash = hashlib.sha256(json.dumps(state_data, sort_keys=True).encode()).hexdigest()
            states.append(state_hash)
        
        # Reduce to single root
        while len(states) > 1:
            next_level = []
            for i in range(0, len(states), 2):
                left = states[i]
                right = states[i + 1] if i + 1 < len(states) else left
                combined = hashlib.sha256((left + right).encode()).hexdigest()
                next_level.append(combined)
            states = next_level
        
        return states[0]
    
    async def run_rollup(self, duration_seconds: int = 300):
        """Run rollup for specified duration"""
        logger.info(f"Running ZK-Rollup for {duration_seconds} seconds")
        
        start_time = time.time()
        batch_count = 0
        
        while time.time() - start_time < duration_seconds:
            # Create batch if enough transactions
            if len(self.pending_transactions) >= 10 or \
               (len(self.pending_transactions) > 0 and time.time() - start_time > 30):
                
                # Create and process batch
                batch = await self.create_batch()
                if batch:
                    # Generate proof
                    await self.generate_zk_proof(batch)
                    
                    # Submit to Layer 1
                    await self.submit_to_layer1(batch)
                    
                    batch_count += 1
            
            # Small delay
            await asyncio.sleep(1)
        
        # Print stats
        stats = self.get_rollup_stats()
        logger.info(f"\n=== Rollup Statistics ===")
        logger.info(f"Batches processed: {batch_count}")
        logger.info(f"Total transactions: {stats['total_transactions']}")
        logger.info(f"Average TPS: {stats['total_transactions'] / duration_seconds:.2f}")
        logger.info(f"Total accounts: {stats['total_accounts']}")
        
        return stats


async def main():
    """Main function to run ZK-Rollup simulation"""
    logger.info("Starting ZK-Rollup Simulation")
    
    # Create rollup
    rollup = ZKRollup("0x1234...5678")
    
    # Create test accounts
    accounts = [f"user_{i:04d}" for i in range(100)]
    
    # Deposit initial funds
    for account in accounts[:50]:
        amount = random.randint(100, 1000) * 10**18
        rollup.deposit(account, amount)
    
    # Generate transactions
    logger.info("Generating test transactions...")
    
    for i in range(500):
        from_account = random.choice(accounts[:50])
        to_account = random.choice(accounts)
        amount = random.randint(1, 100) * 10**18
        
        try:
            rollup.submit_transaction(
                from_address=from_account,
                to_address=to_account,
                amount=amount,
                gas_limit=21000,
                gas_price=20 * 10**9
            )
        except ValueError as e:
            # Skip invalid transactions
            pass
    
    # Run rollup
    stats = await rollup.run_rollup(duration_seconds=60)
    
    # Print final stats
    logger.info("\n=== Final Statistics ===")
    for key, value in stats.items():
        logger.info(f"{key}: {value}")


if __name__ == "__main__":
    asyncio.run(main())
