using System.Net;
using System.Text;
using System.Text.Json.Nodes;
using w4c_workflows.Models.Credentials;
using w4c_workflows.Models.Nodes;
using w4c_workflows.Services.Credentials;
using w4c_workflows.Services.Nodes;
using w4c_workflows.Services.Nodes.Executors;
using w4c_workflows.Services.Security;
using Xunit;

namespace w4c_workflows.Tests;

/// <summary>
/// Unit tests for the HTTP Request node, driven through a stub
/// <see cref="HttpMessageHandler"/> so no real network is touched.
/// </summary>
public class HttpRequestNodeExecutorTests
{
    private static readonly NodeBlueprintCatalog Catalog = NodeTestData.CoreCatalog();

    private sealed class StubHandler : HttpMessageHandler
    {
        private readonly Func<HttpRequestMessage, HttpResponseMessage> _responder;

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

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

        protected override async Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken cancellationToken)
        {
            LastRequest = request;
            if (request.Content != null)
                LastBody = await request.Content.ReadAsStringAsync(cancellationToken);
            return _responder(request);
        }
    }

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

    private static HttpResponseMessage Json(string body, HttpStatusCode status = HttpStatusCode.OK)
        => new(status) { Content = new StringContent(body, Encoding.UTF8, "application/json") };

    private static FlowItem Item(string json) => FlowItem.FromJson(JsonNode.Parse(json)!.AsObject());

    private static NodeExecutionContext Context(
        JsonObject parameters,
        IReadOnlyList<FlowItem>? input = null,
        IReadOnlyDictionary<string, CredentialData>? credentials = null)
        => new()
        {
            Blueprint = Catalog.Get("core.httpRequest")!,
            Parameters = parameters,
            Inputs = new IReadOnlyList<FlowItem>[] { input ?? Array.Empty<FlowItem>() },
            Credentials = credentials ?? new Dictionary<string, CredentialData>(),
        };

    private static HttpRequestNodeExecutor Executor(StubHandler handler)
        => new(
            new StubFactory(handler),
            new CredentialTypeCatalog(),
            EgressTestData.Guard(),
            EgressTestData.Quota(),
            BinaryTestData.Store());

    [Fact]
    public async Task Get_json_object_returns_one_item()
    {
        var handler = new StubHandler(_ => Json("""{"a":1}"""));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject { ["url"] = "https://example.com/x" }), default);

        Assert.True(outcome.Succeeded, outcome.Failure?.Message);
        Assert.Equal(1, Assert.Single(outcome.Outputs[0]).Json["a"]!.GetValue<int>());
        Assert.Equal(HttpMethod.Get, handler.LastRequest!.Method);
    }

    [Fact]
    public async Task Get_json_array_returns_one_item_per_element()
    {
        var handler = new StubHandler(_ => Json("""[{"n":1},{"n":2}]"""));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject { ["url"] = "https://example.com/x" }), default);

        Assert.Equal(2, outcome.Outputs[0].Count);
        Assert.Equal(2, outcome.Outputs[0][1].Json["n"]!.GetValue<int>());
    }

    [Fact]
    public async Task Non_success_status_fails_with_the_http_status()
    {
        var handler = new StubHandler(_ => Json("""{"message":"nope"}""", HttpStatusCode.NotFound));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject { ["url"] = "https://example.com/x" }), default);

        Assert.False(outcome.Succeeded);
        Assert.Equal("http_error", outcome.Failure!.Code);
        Assert.Equal(404, outcome.Failure.HttpStatus);
    }

    [Fact]
    public async Task Never_error_returns_the_body_instead_of_failing()
    {
        var handler = new StubHandler(_ => Json("""{"message":"nope"}""", HttpStatusCode.BadRequest));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["url"] = "https://example.com/x",
                ["options"] = new JsonObject { ["neverError"] = true },
            }), default);

        Assert.True(outcome.Succeeded, outcome.Failure?.Message);
        Assert.Equal("nope", Assert.Single(outcome.Outputs[0]).Json["message"]!.GetValue<string>());
    }

    [Fact]
    public async Task Post_sends_headers_and_a_json_body()
    {
        var handler = new StubHandler(_ => Json("""{"ok":true}"""));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["method"] = "POST",
                ["url"] = "https://example.com/x",
                ["sendHeaders"] = true,
                ["headers"] = new JsonArray(
                    new JsonObject { ["name"] = "X-Trace", ["value"] = "abc" }),
                ["sendBody"] = true,
                ["bodyContentType"] = "json",
                ["body"] = new JsonObject { ["name"] = "Ada" },
            }), default);

        Assert.True(outcome.Succeeded, outcome.Failure?.Message);
        Assert.Equal(HttpMethod.Post, handler.LastRequest!.Method);
        Assert.Equal("abc", handler.LastRequest.Headers.GetValues("X-Trace").Single());
        Assert.Contains("\"name\":\"Ada\"", handler.LastBody);
    }

    [Fact]
    public async Task Invalid_url_fails_before_sending()
    {
        var handler = new StubHandler(_ => Json("{}"));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject { ["url"] = "not a url" }), default);

        Assert.False(outcome.Succeeded);
        Assert.Equal("invalid_url", outcome.Failure!.Code);
        Assert.Null(handler.LastRequest);
    }

    [Fact]
    public async Task Text_response_format_wraps_the_body_in_data()
    {
        var handler = new StubHandler(_ => new HttpResponseMessage(HttpStatusCode.OK)
        {
            Content = new StringContent("hello", Encoding.UTF8, "text/plain"),
        });

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["url"] = "https://example.com/x",
                ["options"] = new JsonObject { ["responseFormat"] = "text" },
            }), default);

        Assert.Equal("hello", Assert.Single(outcome.Outputs[0]).Json["data"]!.GetValue<string>());
    }

    [Fact]
    public async Task Put_output_in_field_wraps_the_response()
    {
        var handler = new StubHandler(_ => Json("""{"a":1}"""));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["url"] = "https://example.com/x",
                ["options"] = new JsonObject { ["putOutputInField"] = "response" },
            }), default);

        var item = Assert.Single(outcome.Outputs[0]);
        Assert.Equal(1, item.Json["response"]!["a"]!.GetValue<int>());
    }

    [Fact]
    public async Task Credential_auth_applies_basic_authorization()
    {
        var handler = new StubHandler(_ => Json("{}"));
        var credentials = new Dictionary<string, CredentialData>
        {
            [HttpRequestNodeExecutor.CredentialAlias] = new(
                "httpBasicAuth",
                new JsonObject { ["username"] = "ada", ["password"] = "secret" }),
        };

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["url"] = "https://example.com/x",
                ["authentication"] = "credential",
            }, credentials: credentials), default);

        Assert.True(outcome.Succeeded, outcome.Failure?.Message);
        var expected = "Basic " + Convert.ToBase64String(Encoding.UTF8.GetBytes("ada:secret"));
        Assert.Equal(expected, handler.LastRequest!.Headers.Authorization!.ToString());
    }

    [Fact]
    public async Task Missing_required_credential_fails()
    {
        var handler = new StubHandler(_ => Json("{}"));

        var outcome = await Executor(handler).RunAsync(
            Context(new JsonObject
            {
                ["url"] = "https://example.com/x",
                ["authentication"] = "credential",
            }), default);

        Assert.False(outcome.Succeeded);
        Assert.Equal("missing_credential", outcome.Failure!.Code);
    }
}