"""
Security tests for state transition validation.

Tests that balance changes only occur through validated transactions.
"""

import pytest
from sqlmodel import Session, select

from aitbc_chain.state.state_transition import StateTransition, get_state_transition
from aitbc_chain.models import Account


class TestStateTransition:
    """Test state transition validation."""
    
    def test_transaction_validation_insufficient_balance(self):
        """Test that transactions with insufficient balance are rejected."""
        state_transition = StateTransition()
        
        # Mock session and transaction data
        # This would require a full database setup
        # For now, we test the validation logic
        
        tx_data = {
            "from": "test_sender",
            "to": "test_recipient",
            "value": 1000,
            "fee": 10,
            "nonce": 0
        }
        
        # This test would require database setup
        # For now, we document the test structure
        pass
    
    def test_transaction_validation_invalid_nonce(self):
        """Test that transactions with invalid nonce are rejected."""
        state_transition = StateTransition()
        
        tx_data = {
            "from": "test_sender",
            "to": "test_recipient",
            "value": 100,
            "fee": 10,
            "nonce": 999  # Invalid nonce
        }
        
        # This test would require database setup
        pass
    
    def test_replay_protection(self):
        """Test that replay attacks are prevented."""
        state_transition = StateTransition()
        
        tx_hash = "test_tx_hash"
        
        # Mark transaction as processed
        state_transition._processed_tx_hashes.add(tx_hash)
        
        # Try to process again - should fail
        assert tx_hash in state_transition._processed_tx_hashes
    
    def test_nonce_tracking(self):
        """Test that nonces are tracked correctly."""
        state_transition = StateTransition()
        
        address = "test_address"
        nonce = 5
        
        state_transition._processed_nonces[address] = nonce
        
        assert state_transition.get_processed_nonces()[address] == nonce
    
    def test_state_transition_reset(self):
        """Test that state transition can be reset."""
        state_transition = StateTransition()
        
        # Add some data
        state_transition._processed_tx_hashes.add("test_hash")
        state_transition._processed_nonces["test_addr"] = 5
        
        # Reset
        state_transition.reset()
        
        # Verify reset
        assert len(state_transition._processed_tx_hashes) == 0
        assert len(state_transition._processed_nonces) == 0