using Xunit;
using Moq;
using Moq.Protected;
using System.Net;
using System.Net.Http;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using OpenHarbor.MCP.Core;
using CodexMcpServer.Tools;

namespace CodexMcpServer.Tests;

/// <summary>
/// Unit tests for ListDocumentsTool following TDD approach.
/// Tests integration with CODEX API /api/documents endpoint with pagination.
/// </summary>
public class ListDocumentsToolTests
{
    [Fact]
    public void ListDocumentsTool_ShouldHaveCorrectName()
    {
        // Arrange
        var httpClient = new HttpClient();
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var name = tool.Name;

        // Assert
        Assert.Equal("list_documents", name);
    }

    [Fact]
    public void ListDocumentsTool_ShouldHaveDescription()
    {
        // Arrange
        var httpClient = new HttpClient();
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var description = tool.Description;

        // Assert
        Assert.NotNull(description);
        Assert.NotEmpty(description);
        Assert.Contains("list", description.ToLower());
    }

    [Fact]
    public void ListDocumentsTool_ShouldHaveValidSchema()
    {
        // Arrange
        var httpClient = new HttpClient();
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var schema = tool.Schema;

        // Assert
        Assert.NotNull(schema);
        var root = schema.RootElement;
        Assert.Equal(JsonValueKind.Object, root.ValueKind);

        // Schema should have optional pagination properties
        Assert.True(root.TryGetProperty("properties", out var properties));
        // All properties should be optional (no required array or empty required)
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithNoArguments_ShouldCallCodexApi()
    {
        // Arrange
        var mockResponse = new
        {
            documents = new[]
            {
                new { id = "doc1", title = "Document 1" },
                new { id = "doc2", title = "Document 2" }
            },
            total = 2,
            page = 1,
            pageSize = 20
        };
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.Is<HttpRequestMessage>(req =>
                    req.Method == HttpMethod.Get &&
                    req.RequestUri.ToString().Contains("/api/documents")
                ),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync(new HttpResponseMessage
            {
                StatusCode = HttpStatusCode.OK,
                Content = new StringContent(JsonSerializer.Serialize(mockResponse))
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var result = await tool.ExecuteAsync(null);

        // Assert
        Assert.NotNull(result);
        var root = result.RootElement;
        Assert.True(root.TryGetProperty("documents", out _));
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithPaginationParams_ShouldIncludeInRequest()
    {
        // Arrange
        string capturedUri = null;
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync((HttpRequestMessage req, CancellationToken ct) =>
            {
                capturedUri = req.RequestUri?.ToString();
                return new HttpResponseMessage
                {
                    StatusCode = HttpStatusCode.OK,
                    Content = new StringContent("""{"documents": [], "total": 0}""")
                };
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);
        var arguments = JsonDocument.Parse("""{"page": 2, "pageSize": 10}""");

        // Act
        await tool.ExecuteAsync(arguments);

        // Assert
        Assert.NotNull(capturedUri);
        Assert.Contains("/api/documents", capturedUri);
        Assert.Contains("page=2", capturedUri);
        Assert.Contains("pageSize=10", capturedUri);
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithHttpError_ShouldReturnErrorResponse()
    {
        // Arrange
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync(new HttpResponseMessage
            {
                StatusCode = HttpStatusCode.InternalServerError,
                Content = new StringContent("Internal server error")
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var result = await tool.ExecuteAsync(null);

        // Assert
        Assert.NotNull(result);
        var root = result.RootElement;
        Assert.True(root.TryGetProperty("error", out _));
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithInvalidJson_ShouldReturnError()
    {
        // Arrange
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync(new HttpResponseMessage
            {
                StatusCode = HttpStatusCode.OK,
                Content = new StringContent("invalid json{{{")
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);

        // Act
        var result = await tool.ExecuteAsync(null);

        // Assert
        Assert.NotNull(result);
        var root = result.RootElement;
        Assert.True(root.TryGetProperty("error", out _));
    }

    [Fact]
    public void ListDocumentsTool_ShouldImplementIMcpTool()
    {
        // Arrange
        var httpClient = new HttpClient();

        // Act
        var tool = new ListDocumentsTool(httpClient);

        // Assert
        Assert.IsAssignableFrom<IMcpTool>(tool);
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithLimit_ShouldIncludeInRequest()
    {
        // Arrange
        string capturedUri = null;
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync((HttpRequestMessage req, CancellationToken ct) =>
            {
                capturedUri = req.RequestUri?.ToString();
                return new HttpResponseMessage
                {
                    StatusCode = HttpStatusCode.OK,
                    Content = new StringContent("""{"documents": [], "total": 0}""")
                };
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);
        var arguments = JsonDocument.Parse("""{"limit": 5}""");

        // Act
        await tool.ExecuteAsync(arguments);

        // Assert
        Assert.NotNull(capturedUri);
        Assert.Contains("limit=5", capturedUri);
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithOffset_ShouldIncludeInRequest()
    {
        // Arrange
        string capturedUri = null;
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync((HttpRequestMessage req, CancellationToken ct) =>
            {
                capturedUri = req.RequestUri?.ToString();
                return new HttpResponseMessage
                {
                    StatusCode = HttpStatusCode.OK,
                    Content = new StringContent("""{"documents": [], "total": 0}""")
                };
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);
        var arguments = JsonDocument.Parse("""{"offset": 10}""");

        // Act
        await tool.ExecuteAsync(arguments);

        // Assert
        Assert.NotNull(capturedUri);
        Assert.Contains("offset=10", capturedUri);
    }

    [Fact]
    public async Task ListDocumentsTool_ExecuteAsync_WithMultipleParams_ShouldIncludeAllInRequest()
    {
        // Arrange
        string capturedUri = null;
        var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
        mockHttpMessageHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.IsAny<HttpRequestMessage>(),
                ItExpr.IsAny<CancellationToken>()
            )
            .ReturnsAsync((HttpRequestMessage req, CancellationToken ct) =>
            {
                capturedUri = req.RequestUri?.ToString();
                return new HttpResponseMessage
                {
                    StatusCode = HttpStatusCode.OK,
                    Content = new StringContent("""{"documents": [], "total": 0}""")
                };
            });

        var httpClient = new HttpClient(mockHttpMessageHandler.Object)
        {
            BaseAddress = new System.Uri("http://localhost:5050")
        };
        var tool = new ListDocumentsTool(httpClient);
        var arguments = JsonDocument.Parse("""{"page": 3, "pageSize": 15, "limit": 100, "offset": 30}""");

        // Act
        await tool.ExecuteAsync(arguments);

        // Assert
        Assert.NotNull(capturedUri);
        Assert.Contains("page=3", capturedUri);
        Assert.Contains("pageSize=15", capturedUri);
        Assert.Contains("limit=100", capturedUri);
        Assert.Contains("offset=30", capturedUri);
    }
}