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

namespace backend.tests;

[Collection("WakeFlow")] // tests touch FakeRealtimeSessionFactory.Upstream static — serialize
public class DeviceHubWakeFlowTests(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 = "wake-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 Wake_opens_session_started_then_assistant_done_then_session_ended_on_cancel()
    {
        FakeRealtimeSessionFactory.Upstream = new ScriptedRealtimeUpstream();
        var token = await PairAndGetTokenAsync("wake1@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); // ack

        await SendJson(ws, new { type = "wake", at = 0L });
        var started = await ReceiveJson(ws);
        started.GetProperty("type").GetString().Should().Be("session_started");

        FakeRealtimeSessionFactory.Upstream.Push(new JsonObject
        {
            ["type"] = "response.audio_transcript.done",
            ["transcript"] = "hello!",
        });
        FakeRealtimeSessionFactory.Upstream.Push(new JsonObject { ["type"] = "response.done" });

        var done = await ReceiveUntil(ws, "assistant_done");
        done.GetProperty("type").GetString().Should().Be("assistant_done");

        await SendJson(ws, new { type = "cancel" });
        var ended = await ReceiveUntil(ws, "session_ended");
        ended.GetProperty("type").GetString().Should().Be("session_ended");
    }

    [Fact]
    public async Task Binary_uplink_after_wake_reaches_upstream_as_input_audio_buffer_append()
    {
        FakeRealtimeSessionFactory.Upstream = new ScriptedRealtimeUpstream();
        var token = await PairAndGetTokenAsync("wake2@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 = "wake", at = 0L });
        await ReceiveJson(ws); // session_started

        var frame = new byte[3840];
        for (int i = 0; i < frame.Length; i++) frame[i] = 0x55;
        await ws.SendAsync(frame, WebSocketMessageType.Binary, true, CancellationToken.None);

        // Allow time for the pump's 250 ms poll + send.
        var deadline = DateTime.UtcNow + TimeSpan.FromSeconds(2);
        while (DateTime.UtcNow < deadline)
        {
            if (FakeRealtimeSessionFactory.Upstream.Sent.Any(e =>
                (string?)e["type"] == "input_audio_buffer.append")) break;
            await Task.Delay(50);
        }
        FakeRealtimeSessionFactory.Upstream.Sent
            .Any(e => (string?)e["type"] == "input_audio_buffer.append")
            .Should().BeTrue();

        await SendJson(ws, new { type = "cancel" });
        await ReceiveJson(ws);
    }

    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[16384];
        using var stream = new MemoryStream();
        while (true)
        {
            var r = await ws.ReceiveAsync(buf, CancellationToken.None);
            if (r.MessageType == WebSocketMessageType.Binary) { stream.Write(buf, 0, r.Count); continue; }
            stream.Write(buf, 0, r.Count);
            if (r.EndOfMessage) break;
        }
        return JsonDocument.Parse(stream.ToArray()).RootElement.Clone();
    }

    // The relay forwards an upstream-event "debug" envelope for every event
    // it sees, so envelopes the test cares about are interleaved with debugs.
    private static async Task<JsonElement> ReceiveUntil(WebSocket ws, string type)
    {
        for (int i = 0; i < 50; i++)
        {
            var env = await ReceiveJson(ws);
            if (env.GetProperty("type").GetString() == type) return env;
        }
        throw new TimeoutException($"never saw envelope type={type}");
    }
}