using System.Net;
using System.Text;
using w4c_workflows.Services.Audit;
using Xunit;

namespace w4c_workflows.Tests;

public class OpenSearchActionAuditSinkTests
{
    private sealed class Handler : HttpMessageHandler
    {
        private readonly Func<HttpRequestMessage, HttpResponseMessage> _responder;

        public Handler(Func<HttpRequestMessage, HttpResponseMessage> responder) => _responder = responder;

        public HttpRequestMessage? LastRequest { get; private set; }
        public string? LastBody { get; private set; }
        public int Calls { get; private set; }

        protected override async Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken ct)
        {
            LastRequest = request;
            LastBody = request.Content == null ? null : await request.Content.ReadAsStringAsync(ct);
            Calls++;
            return _responder(request);
        }
    }

    private sealed class Factory : IHttpClientFactory
    {
        private readonly HttpMessageHandler _handler;
        public Factory(HttpMessageHandler handler) => _handler = handler;
        public HttpClient CreateClient(string name) => new(_handler, disposeHandler: false);
    }

    private static ActionAuditEntry Entry(string tenant = "acme") => new()
    {
        Timestamp = new DateTime(2026, 9, 11, 12, 0, 0, DateTimeKind.Utc),
        TenantId = tenant,
        Action = "node.executed",
        Outcome = "succeeded",
        RunId = "run-1",
        NodeId = "step",
    };

    [Theory]
    [InlineData("w4c-actions", "ACME Corp", "w4c-actions-acme-corp-2026.09")]
    [InlineData("w4c-actions", "tenant/with*chars", "w4c-actions-tenant-with-chars-2026.09")]
    [InlineData("w4c-actions", "", "w4c-actions-unknown-2026.09")]
    [InlineData("", "acme", "w4c-actions-acme-2026.09")]
    public void Index_name_is_tenant_scoped_and_monthly(string prefix, string tenant, string expected)
    {
        Assert.Equal(
            expected,
            OpenSearchActionAuditSink.IndexName(prefix, tenant, new DateTime(2026, 9, 11)));
    }

    [Fact]
    public async Task Posts_one_document_to_the_tenant_index()
    {
        var handler = new Handler(_ => new HttpResponseMessage(HttpStatusCode.Created));
        var options = new ActionAuditOptions { Enabled = true, Url = "http://os:9200" };
        var sink = new OpenSearchActionAuditSink(new Factory(handler), options);

        await sink.RecordAsync(Entry(), default);

        Assert.Equal(
            "http://os:9200/w4c-actions-acme-2026.09/_doc",
            handler.LastRequest!.RequestUri!.ToString());
        Assert.Equal(HttpMethod.Post, handler.LastRequest.Method);
        Assert.Contains("\"action\":\"node.executed\"", handler.LastBody);
        Assert.Contains("\"tenantId\":\"acme\"", handler.LastBody);
    }

    [Fact]
    public async Task Sends_basic_auth_when_configured()
    {
        var handler = new Handler(_ => new HttpResponseMessage(HttpStatusCode.Created));
        var options = new ActionAuditOptions
        {
            Enabled = true,
            Url = "http://os:9200/",
            Username = "aud",
            Password = "pw",
        };
        var sink = new OpenSearchActionAuditSink(new Factory(handler), options);

        await sink.RecordAsync(Entry(), default);

        var expected = "Basic " + Convert.ToBase64String(Encoding.UTF8.GetBytes("aud:pw"));
        Assert.Equal(expected, handler.LastRequest!.Headers.Authorization!.ToString());
    }

    [Fact]
    public async Task Empty_url_is_a_no_op()
    {
        var handler = new Handler(_ => new HttpResponseMessage(HttpStatusCode.Created));
        var sink = new OpenSearchActionAuditSink(new Factory(handler), new ActionAuditOptions());

        await sink.RecordAsync(Entry(), default);

        Assert.Equal(0, handler.Calls);
    }

    [Fact]
    public async Task Transport_failure_is_swallowed()
    {
        var handler = new Handler(_ => throw new HttpRequestException("os down"));
        var options = new ActionAuditOptions { Enabled = true, Url = "http://os:9200" };
        var sink = new OpenSearchActionAuditSink(new Factory(handler), options);

        // Best-effort: must not throw.
        await sink.RecordAsync(Entry(), default);
    }

    [Fact]
    public async Task Error_status_is_not_thrown()
    {
        var handler = new Handler(_ => new HttpResponseMessage(HttpStatusCode.ServiceUnavailable));
        var options = new ActionAuditOptions { Enabled = true, Url = "http://os:9200" };
        var sink = new OpenSearchActionAuditSink(new Factory(handler), options);

        await sink.RecordAsync(Entry(), default);

        Assert.Equal(1, handler.Calls);
    }
}