/*
 * Copyright (c) 2023 Proton AG
 *
 * This file is part of ProtonVPN.
 *
 * ProtonVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ProtonVPN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ProtonVPN.  If not, see <https://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.CompilerServices;
using ProtonVPN.Client.Logic.Auth.Contracts;
using ProtonVPN.Crypto.Contracts;

namespace ProtonVPN.Client.Logic.Auth.Tests;

public class MockOfConnectionKeyManager : IConnectionKeyManager
{
    private SecretKey _secretKey;
    private PublicKey _publicKey;

    public IDictionary<string, int> MethodCalls;

    public MockOfConnectionKeyManager()
    {
        _secretKey = null;
        _publicKey = null;

        MethodCalls = new Dictionary<string, int>();

        Type type = typeof(MockOfConnectionKeyManager);
        MethodInfo[] methods = type.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);
        foreach (MethodInfo method in methods)
        {
            MethodCalls.Add(method.Name, 0);
        }
    }

    public void InitializeTestKeyPair()
    {
        _secretKey = new SecretKey(CreateOrIncrementKeyBytes(_secretKey), KeyAlgorithm.Ed25519);
        _publicKey = new PublicKey(CreateOrIncrementKeyBytes(_publicKey), KeyAlgorithm.Ed25519);
    }

    public void RegenerateKeyPair()
    {
        IncrementMethodCalls();
        InitializeTestKeyPair();
    }

    private byte[] CreateOrIncrementKeyBytes(Key key)
    {
        return key == null ? new byte[32] : BitConverter.GetBytes(BitConverter.ToInt64(key.Bytes, 0) + 1);
    }

    private void IncrementMethodCalls([CallerMemberName] string caller = null)
    {
        MethodCalls[caller]++;
    }

    public void DeleteKeyPair()
    {
        IncrementMethodCalls();
        _secretKey = null;
        _publicKey = null;
    }

    public AsymmetricKeyPair GetKeyPairOrNull()
    {
        IncrementMethodCalls();
        return _secretKey == null || _publicKey == null ? null : new AsymmetricKeyPair(_secretKey, _publicKey);
    }

    public AsymmetricKeyPair GenerateTemporaryKeyPair()
    {
        return new AsymmetricKeyPair(_secretKey, _publicKey);
    }

    public SecretKey GetSecretKey()
    {
        IncrementMethodCalls();
        return _secretKey;
    }

    public PublicKey GetPublicKey()
    {
        IncrementMethodCalls();
        return _publicKey;
    }
}