using Svrnty.MCP.Client.Core.Abstractions;
using Svrnty.MCP.Client.Core.Exceptions;
using Svrnty.MCP.Client.Core.Models;
using Svrnty.MCP.Client.Infrastructure;
using Xunit;

namespace Svrnty.MCP.Client.Core.Tests.Infrastructure;

/// <summary>
/// Unit tests for StdioServerConnection following TDD approach.
/// Tests connection lifecycle, tool discovery, and tool execution.
/// </summary>
public class StdioServerConnectionTests
{
    [Fact]
    public void Constructor_WithValidConfig_CreatesConnection()
    {
        // Arrange
        var config = new McpServerConfig
        {
            Name = "test-server",
            Transport = new StdioTransportConfig
            {
                Type = "Stdio",
                Command = "dotnet",
                Args = new[] { "run" }
            }
        };

        // Act
        var connection = new StdioServerConnection(config);

        // Assert
        Assert.Equal("test-server", connection.ServerName);
        Assert.False(connection.IsConnected);
    }

    [Fact]
    public void ServerName_ReturnsConfiguredName()
    {
        // Arrange
        var config = new McpServerConfig
        {
            Name = "my-server",
            Transport = new StdioTransportConfig
            {
                Type = "Stdio",
                Command = "node",
                Args = new[] { "server.js" }
            }
        };
        var connection = new StdioServerConnection(config);

        // Act
        var serverName = connection.ServerName;

        // Assert
        Assert.Equal("my-server", serverName);
    }

    [Fact]
    public void IsConnected_BeforeConnect_ReturnsFalse()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);

        // Act
        var isConnected = connection.IsConnected;

        // Assert
        Assert.False(isConnected);
    }

    [Fact]
    public async Task ConnectAsync_WithValidConfig_SetsIsConnectedTrue()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);

        // Act
        await connection.ConnectAsync();

        // Assert
        Assert.True(connection.IsConnected);
    }

    [Fact]
    public async Task DisconnectAsync_AfterConnect_SetsIsConnectedFalse()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);
        await connection.ConnectAsync();

        // Act
        await connection.DisconnectAsync();

        // Assert
        Assert.False(connection.IsConnected);
    }

    [Fact]
    public async Task ListToolsAsync_WithoutConnection_ThrowsException()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);

        // Act & Assert
        await Assert.ThrowsAsync<McpConnectionException>(
            async () => await connection.ListToolsAsync()
        );
    }

    [Fact]
    public async Task CallToolAsync_WithoutConnection_ThrowsException()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);

        // Act & Assert
        await Assert.ThrowsAsync<McpConnectionException>(
            async () => await connection.CallToolAsync("test_tool")
        );
    }

    [Fact]
    public async Task PingAsync_WhenConnected_DoesNotThrow()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);
        await connection.ConnectAsync();

        // Act & Assert - should not throw
        await connection.PingAsync();
    }

    [Fact]
    public async Task DisposeAsync_AfterConnect_DisconnectsCleanly()
    {
        // Arrange
        var config = CreateTestConfig();
        var connection = new StdioServerConnection(config);
        await connection.ConnectAsync();

        // Act
        await connection.DisposeAsync();

        // Assert
        Assert.False(connection.IsConnected);
    }

    private static McpServerConfig CreateTestConfig()
    {
        return new McpServerConfig
        {
            Name = "test-server",
            Transport = new StdioTransportConfig
            {
                Type = "Stdio",
                Command = "echo",
                Args = new[] { "test" }
            }
        };
    }
}