ps.ipam/classlib.tests/Mocks/MockHttpMessageHandler.cs

namespace PS.IPAM.Tests.Mocks;

using System.Net;

/// <summary>
/// A mock HTTP message handler for testing HTTP requests without making actual network calls.
/// This handler does not dispose itself when the HttpClient is disposed, allowing reuse in tests.
/// </summary>
public class MockHttpMessageHandler : HttpMessageHandler
{
    private readonly Queue<MockResponse> _responses = new();
    private readonly List<HttpRequestMessage> _requests = new();
    private bool _disposed = false;

    /// <summary>
    /// Gets all requests that were sent through this handler.
    /// </summary>
    public IReadOnlyList<HttpRequestMessage> Requests => _requests.AsReadOnly();

    /// <summary>
    /// Gets the last request that was sent through this handler.
    /// </summary>
    public HttpRequestMessage? LastRequest => _requests.LastOrDefault();

    /// <summary>
    /// Queues a response to be returned for the next request.
    /// </summary>
    public MockHttpMessageHandler WithResponse(HttpStatusCode statusCode, string content, string contentType = "application/json")
    {
        _responses.Enqueue(new MockResponse(statusCode, content, contentType));
        return this;
    }

    /// <summary>
    /// Queues a successful JSON response.
    /// </summary>
    public MockHttpMessageHandler WithJsonResponse(string jsonContent)
    {
        return WithResponse(HttpStatusCode.OK, jsonContent, "application/json");
    }

    /// <summary>
    /// Queues a successful response with phpIPAM-style wrapper.
    /// </summary>
    public MockHttpMessageHandler WithSuccessResponse(string dataJson)
    {
        var response = $"{{\"code\":200,\"success\":true,\"data\":{dataJson}}}";
        return WithJsonResponse(response);
    }

    /// <summary>
    /// Queues a 404 Not Found response.
    /// </summary>
    public MockHttpMessageHandler WithNotFoundResponse()
    {
        return WithResponse(HttpStatusCode.NotFound, "{\"code\":404,\"success\":false,\"message\":\"Not found\"}", "application/json");
    }

    /// <summary>
    /// Queues an error response.
    /// </summary>
    public MockHttpMessageHandler WithErrorResponse(HttpStatusCode statusCode, string message)
    {
        var response = $"{{\"code\":{(int)statusCode},\"success\":false,\"message\":\"{message}\"}}";
        return WithResponse(statusCode, response, "application/json");
    }

    /// <summary>
    /// Queues an exception to be thrown on the next request.
    /// </summary>
    public MockHttpMessageHandler WithException(Exception exception)
    {
        _responses.Enqueue(new MockResponse(exception));
        return this;
    }

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        if (_disposed)
        {
            throw new ObjectDisposedException(nameof(MockHttpMessageHandler));
        }

        _requests.Add(request);

        if (_responses.Count == 0)
        {
            throw new InvalidOperationException("No mock response configured. Call WithResponse() before making requests.");
        }

        var mockResponse = _responses.Dequeue();

        if (mockResponse.Exception != null)
        {
            throw mockResponse.Exception;
        }

        var response = new HttpResponseMessage(mockResponse.StatusCode)
        {
            Content = new StringContent(mockResponse.Content, System.Text.Encoding.UTF8, mockResponse.ContentType),
            RequestMessage = request
        };

        return Task.FromResult(response);
    }

    protected override void Dispose(bool disposing)
    {
        // Don't actually dispose - allow reuse in tests
        // The test itself is responsible for cleanup
    }

    /// <summary>
    /// Actually disposes the handler. Call this in test cleanup.
    /// </summary>
    public void ForceDispose()
    {
        _disposed = true;
        base.Dispose(true);
    }

    /// <summary>
    /// Verifies that a request was made to the expected URL.
    /// </summary>
    public bool WasRequestMadeTo(string urlContains)
    {
        return _requests.Any(r => r.RequestUri?.ToString().Contains(urlContains) == true);
    }

    /// <summary>
    /// Verifies that a request with the expected method was made.
    /// </summary>
    public bool WasRequestMadeWithMethod(HttpMethod method)
    {
        return _requests.Any(r => r.Method == method);
    }

    /// <summary>
    /// Gets the value of a header from the last request.
    /// </summary>
    public string? GetLastRequestHeader(string headerName)
    {
        if (LastRequest?.Headers.TryGetValues(headerName, out var values) == true)
        {
            return values.FirstOrDefault();
        }
        return null;
    }

    private class MockResponse
    {
        public HttpStatusCode StatusCode { get; }
        public string Content { get; }
        public string ContentType { get; }
        public Exception? Exception { get; }

        public MockResponse(HttpStatusCode statusCode, string content, string contentType)
        {
            StatusCode = statusCode;
            Content = content;
            ContentType = contentType;
        }

        public MockResponse(Exception exception)
        {
            Exception = exception;
            StatusCode = HttpStatusCode.InternalServerError;
            Content = string.Empty;
            ContentType = string.Empty;
        }
    }
}