namespace Yh.SchClass.OpenApi.Tests;

/// <summary>
/// 伪造 <see cref="HttpMessageHandler"/>：捕获最近一次请求并回放预设响应。
/// 与 <c>Yh.Platform.OpenApi.Tests</c> 的 FakeHandler 同构，便于两个 SDK 的测试互相参照。
/// </summary>
public sealed class FakeHandler : HttpMessageHandler
{
    private readonly Func<HttpRequestMessage, string?, HttpResponseMessage> _responder;

    public FakeHandler(Func<HttpRequestMessage, string?, HttpResponseMessage> responder)
    {
        _responder = responder;
    }

    /// <summary>最近一次捕获到的请求。</summary>
    public HttpRequestMessage? LastRequest { get; private set; }

    /// <summary>最近一次请求体（无请求体时为 null）。</summary>
    public string? LastRequestBody { get; private set; }

    /// <summary>最近一次请求体的 Content-Type（无请求体时为 null）。</summary>
    public string? LastContentType { get; private set; }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        LastRequest = request;
        if (request.Content == null)
        {
            LastRequestBody = null;
            LastContentType = null;
        }
        else
        {
            LastRequestBody = await request.Content.ReadAsStringAsync(cancellationToken);
            LastContentType = request.Content.Headers.ContentType?.MediaType;
        }
        return _responder(request, LastRequestBody);
    }

    /// <summary>回放一段固定 JSON（application/json）。</summary>
    public static FakeHandler Json(HttpStatusCode statusCode, string json)
        => new((_, _) => new HttpResponseMessage(statusCode)
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json"),
        });

    /// <summary>回放指定状态码且无响应体（模拟 204 / 404 空响应）。</summary>
    public static FakeHandler Empty(HttpStatusCode statusCode)
        => new((_, _) => new HttpResponseMessage(statusCode));

    /// <summary>回放纯文本响应（模拟非 JSON 的错误页）。</summary>
    public static FakeHandler Text(HttpStatusCode statusCode, string text)
        => new((_, _) => new HttpResponseMessage(statusCode)
        {
            Content = new StringContent(text, Encoding.UTF8, "text/plain"),
        });
}