using System.Net.Http.Json;
using System.Net.WebSockets;
using System.Text;
using System.Text.Json;
using FluentAssertions;
using Xunit;

namespace backend.tests;

public class DeviceHubHandshakeTests(ApiFactory factory) : IClassFixture<ApiFactory>
{
    private readonly ApiFactory _factory = factory;

    private async Task<string> PairAndGetTokenAsync(string email)
    {
        var http = _factory.CreateClient();
        await http.PostAsJsonAsync("/api/auth/register",
            new { email, password = "Passw0rd!" });
        await http.PostAsJsonAsync("/api/auth/login",
            new { email, password = "Passw0rd!" });
        var codeRes = await http.PostAsJsonAsync("/api/pair-code", new { name = "ws-test" });
        var code = (await codeRes.Content.ReadFromJsonAsync<Dictionary<string, object>>())!["code"].ToString()!;

        var pairRes = await _factory.CreateClient().PostAsJsonAsync("/api/pair",
            new { code, hostname = "smoke", client_version = "0.1" });
        var pairBody = await pairRes.Content.ReadFromJsonAsync<Dictionary<string, object>>();
        return pairBody!["device_token"].ToString()!;
    }

    [Fact]
    public async Task Connect_without_token_fails_upgrade()
    {
        var client = _factory.Server.CreateWebSocketClient();
        var uri = new Uri(_factory.Server.BaseAddress, "device");
        var act = async () => await client.ConnectAsync(uri, CancellationToken.None);
        await act.Should().ThrowAsync<Exception>();
    }

    [Fact]
    public async Task Hello_ack_includes_config()
    {
        var token = await PairAndGetTokenAsync("ws1@example.com");
        var client = _factory.Server.CreateWebSocketClient();
        client.ConfigureRequest = req => req.Headers["Authorization"] = $"Bearer {token}";

        var uri = new Uri(_factory.Server.BaseAddress, "device");
        var ws = await client.ConnectAsync(uri, CancellationToken.None);

        await SendJson(ws, new { type = "hello", device_id = Guid.NewGuid(), client_version = "0.1" });
        var ack = await ReceiveJson(ws);
        ack.GetProperty("type").GetString().Should().Be("hello_ack");
        ack.GetProperty("config").GetProperty("voice").GetString().Should().NotBeNullOrEmpty();
        ack.GetProperty("config").GetProperty("model").GetString().Should().NotBeNullOrEmpty();
        ack.GetProperty("config").GetProperty("enabled_tools").GetArrayLength().Should().BeGreaterThan(0);
    }

    [Fact]
    public async Task Ping_replies_with_pong()
    {
        var token = await PairAndGetTokenAsync("ws2@example.com");
        var client = _factory.Server.CreateWebSocketClient();
        client.ConfigureRequest = req => req.Headers["Authorization"] = $"Bearer {token}";
        var uri = new Uri(_factory.Server.BaseAddress, "device");
        var ws = await client.ConnectAsync(uri, CancellationToken.None);

        await SendJson(ws, new { type = "hello", device_id = Guid.NewGuid(), client_version = "0.1" });
        await ReceiveJson(ws);
        await SendJson(ws, new { type = "ping" });
        var pong = await ReceiveJson(ws);
        pong.GetProperty("type").GetString().Should().Be("pong");
    }

    private static async Task SendJson(WebSocket ws, object payload)
    {
        var bytes = Encoding.UTF8.GetBytes(JsonSerializer.Serialize(payload));
        await ws.SendAsync(bytes, WebSocketMessageType.Text, true, CancellationToken.None);
    }

    private static async Task<JsonElement> ReceiveJson(WebSocket ws)
    {
        var buf = new byte[8192];
        using var stream = new MemoryStream();
        while (true)
        {
            var r = await ws.ReceiveAsync(buf, CancellationToken.None);
            stream.Write(buf, 0, r.Count);
            if (r.EndOfMessage) break;
        }
        return JsonDocument.Parse(stream.ToArray()).RootElement.Clone();
    }
}