using System;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Moq;
using TeleBot.Http;
using Xunit;

namespace TeleBot.Tests.Security
{
    /// <summary>
    /// Integration tests that verify actual TOR connectivity.
    /// These tests require a running TOR service on localhost:9050
    /// Skip these tests if TOR is not available (CI/CD environments).
    /// </summary>
    public class TorConnectivityTests : IDisposable
    {
        private readonly Mock<ILogger> _mockLogger;
        private bool _torAvailable;

        public TorConnectivityTests()
        {
            _mockLogger = new Mock<ILogger>();
            _torAvailable = CheckTorAvailability();
        }

        /// <summary>
        /// Checks if TOR is available on localhost:9050
        /// </summary>
        private bool CheckTorAvailability()
        {
            try
            {
                using var client = new TcpClient();
                var result = client.BeginConnect("127.0.0.1", 9050, null, null);
                var success = result.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(1));
                if (success)
                {
                    client.EndConnect(result);
                    return true;
                }
                return false;
            }
            catch
            {
                return false;
            }
        }

        [Fact]
        public async Task TorConnection_WhenAvailable_CanConnect()
        {
            // Skip if TOR not available
            if (!_torAvailable)
            {
                // Log skip reason
                return;
            }

            // Arrange
            var config = CreateTorConfiguration();
            var handler = Socks5HttpHandler.Create(config, _mockLogger.Object);
            using var client = new HttpClient(handler);
            client.Timeout = TimeSpan.FromSeconds(30);

            // Act & Assert
            try
            {
                // Try to connect to TOR check service
                var response = await client.GetAsync("https://check.torproject.org/api/ip");

                Assert.True(response.IsSuccessStatusCode,
                    "Should successfully connect through TOR proxy");

                var content = await response.Content.ReadAsStringAsync();

                // The TOR check API returns JSON with "IsTor" field
                Assert.Contains("IsTor", content,
                    "Response should indicate TOR connection status");
            }
            catch (HttpRequestException ex) when (ex.InnerException is SocketException)
            {
                // TOR might not be running - skip test
                return;
            }
        }

        [Fact]
        public async Task TorConnection_ChecksRealIP_IsDifferent()
        {
            // Skip if TOR not available
            if (!_torAvailable)
            {
                return;
            }

            // Arrange
            var config = CreateTorConfiguration();
            var torHandler = Socks5HttpHandler.Create(config, _mockLogger.Object);
            var directHandler = Socks5HttpHandler.CreateDirect(_mockLogger.Object);

            string? torIp = null;
            string? directIp = null;

            try
            {
                // Get IP through TOR
                using (var torClient = new HttpClient(torHandler))
                {
                    torClient.Timeout = TimeSpan.FromSeconds(30);
                    var response = await torClient.GetAsync("https://api.ipify.org");
                    if (response.IsSuccessStatusCode)
                    {
                        torIp = await response.Content.ReadAsStringAsync();
                    }
                }

                // Get IP directly
                using (var directClient = new HttpClient(directHandler))
                {
                    directClient.Timeout = TimeSpan.FromSeconds(10);
                    var response = await directClient.GetAsync("https://api.ipify.org");
                    if (response.IsSuccessStatusCode)
                    {
                        directIp = await response.Content.ReadAsStringAsync();
                    }
                }

                // Assert - IPs should be different (TOR exit node vs real IP)
                if (!string.IsNullOrEmpty(torIp) && !string.IsNullOrEmpty(directIp))
                {
                    Assert.NotEqual(torIp, directIp,
                        $"TOR IP ({torIp}) should be different from direct IP ({directIp})");
                }
            }
            catch (HttpRequestException)
            {
                // Network issue - skip test
                return;
            }
        }

        [Fact]
        public async Task TorConnection_Timeout_IsReasonable()
        {
            // Skip if TOR not available
            if (!_torAvailable)
            {
                return;
            }

            // Arrange
            var config = CreateTorConfiguration();
            var handler = Socks5HttpHandler.Create(config, _mockLogger.Object);
            using var client = new HttpClient(handler);
            client.Timeout = TimeSpan.FromSeconds(30);

            // Act
            var startTime = DateTime.UtcNow;
            try
            {
                var response = await client.GetAsync("https://check.torproject.org");
                var elapsed = DateTime.UtcNow - startTime;

                // Assert - TOR adds latency but should still be reasonable
                Assert.True(elapsed < TimeSpan.FromSeconds(30),
                    $"TOR connection took {elapsed.TotalSeconds}s - should be under 30s");
            }
            catch (HttpRequestException)
            {
                // Connection failed - could be TOR issue, skip
                return;
            }
        }

        [Fact]
        public void TorProxy_Address_IsLocalhost()
        {
            // Arrange
            var config = CreateTorConfiguration();

            // Act
            var handler = Socks5HttpHandler.Create(config, _mockLogger.Object);

            // Assert - Security check
            var proxy = handler.Proxy as WebProxy;
            Assert.NotNull(proxy);
            Assert.Contains("127.0.0.1", proxy.Address?.ToString() ?? "");
            Assert.DoesNotContain("0.0.0.0", proxy.Address?.ToString() ?? "");
        }

        [Fact]
        public void TorProxy_Protocol_IsSocks5()
        {
            // Arrange
            var config = CreateTorConfiguration();

            // Act
            var handler = Socks5HttpHandler.Create(config, _mockLogger.Object);

            // Assert - Verify SOCKS5 protocol
            var proxy = handler.Proxy as WebProxy;
            Assert.NotNull(proxy);
            Assert.Contains("socks5://", proxy.Address?.ToString() ?? "");
        }

        // Helper to create TOR configuration
        private IConfiguration CreateTorConfiguration()
        {
            var configData = new Dictionary<string, string>
            {
                ["Privacy:EnableTor"] = "true",
                ["Privacy:TorSocksPort"] = "9050"
            };

            return new ConfigurationBuilder()
                .AddInMemoryCollection(configData!)
                .Build();
        }

        public void Dispose()
        {
            // Cleanup if needed
        }
    }

    // Helper class for TCP client check
    class TcpClient : IDisposable
    {
        private readonly System.Net.Sockets.TcpClient _client;

        public TcpClient()
        {
            _client = new System.Net.Sockets.TcpClient();
        }

        public IAsyncResult BeginConnect(string host, int port, AsyncCallback? callback, object? state)
        {
            return _client.BeginConnect(host, port, callback, state);
        }

        public void EndConnect(IAsyncResult asyncResult)
        {
            _client.EndConnect(asyncResult);
        }

        public void Dispose()
        {
            _client?.Dispose();
        }
    }
}