#if DEBUG
using System.Buffers.Binary;
using System.Runtime.InteropServices;
using Foundation;
using UIKit;
using VoiceCat.Core;

namespace VoiceCat.iOS;

// An opt-in simulator gate for the real UIKit model and audio graph. Local development only.
internal static class SimulatorSmoke
{
    internal static void RunIfRequested()
    {
        string? endpoint = Environment.GetEnvironmentVariable("VOICECAT_SIM_SMOKE");
        if (endpoint is null || !RuntimeInformation.RuntimeIdentifier.StartsWith("iossimulator", StringComparison.Ordinal)) return;
        UIApplication.SharedApplication.BeginInvokeOnMainThread(async () =>
        {
            try
            {
                string[] parts = endpoint.Split(':', 3);
                Guid id = Guid.Parse("959da92f-f088-452d-a870-4c15007a6fd3");
                ServerProfile guest = ServerProfile.Create(parts[0], ushort.Parse(parts[1]), ServerAuthentication.Guest, nickname: "smoke", id: id);
                ServerProfile profile = ServerProfile.Create(parts[0], ushort.Parse(parts[1]), ServerAuthentication.Account, "smoke", id: id);
                AppModel model = AppModel.Shared;
                bool share = Environment.GetEnvironmentVariable("VOICECAT_SIM_SMOKE_MODE") == "share";
                string? ring = share ? PrepareRing() : null;
                model.IdentityRequested += _ => model.ResolveIdentity(true);
                if (Environment.GetEnvironmentVariable("VOICECAT_SIM_SMOKE_MODE") != "resume")
                {
                    model.UpsertProfile(guest, null);
                    model.UpsertProfile(profile, parts[2]);
                }
                model.Load();
                if (Environment.GetEnvironmentVariable("VOICECAT_SIM_SMOKE_MODE") == "stereo")
                    IosAudioRouter.Shared.SelectPreset(IosAudioPreset.StereoMicrophone);
                profile = model.Profiles.Single(value => value.Id == id);
                Console.Error.WriteLine("VC_SIM phase=connect");
                await model.ConnectAsync(profile);
                Console.Error.WriteLine($"VC_SIM phase=connected audioRunning={IosAudioEngine.Shared.IsRunning}");
                Require(model.IsConnected, "Account login did not connect.");
                if (ring is not null)
                {
                    // Start a synthetic producer while the microphone is off. This exercises
                    // screen-only subscription and the real BroadcastChanged audio recovery.
                    await Task.Delay(300);
                    Require(!model.ScreenRingMapped && !model.ScreenSharing,
                        "An unchanged ring from a previous broadcast remained mapped.");
                    WriteRing(ring, active: true, write: 3840);
                    await WaitUntil(() => model.ScreenSharing, "Screen stream did not start.");
                    Require(IosAudioEngine.Shared.IsRunning, "Screen sharing stopped the audio graph.");
                    WriteRing(ring, active: false, write: 3840);
                    await WaitUntil(() => !model.ScreenSharing, "Screen stream did not stop.");
                    Require(!model.ScreenRingMapped, "The stopped screen ring remained mapped.");
                    Console.Error.WriteLine("VC_SIM phase=screenSharePassed");
                }
                await model.ToggleVoiceAsync();
                Console.Error.WriteLine($"VC_SIM phase=joined audioRunning={IosAudioEngine.Shared.IsRunning}");
                await Task.Delay(2500);
                Require(model.VoiceJoined && IosAudioEngine.Shared.IsRunning, "The first voice graph stopped.");
                long beforeShare = IosAudioEngine.Shared.RenderCallbacks;
                IosAudioRouter.Shared.Recover("simulated screen sharing start", force: false);
                await Task.Delay(1000);
                Require(IosAudioEngine.Shared.IsRunning && IosAudioEngine.Shared.RenderCallbacks > beforeShare,
                    "Screen sharing recovery stopped the live audio graph.");
                if (ring is not null)
                {
                    WriteRing(ring, active: true, write: 3840);
                    await Task.Delay(300);
                    WriteRing(ring, active: true, write: 5760);
                    await WaitUntil(() => model.ScreenSharing, "Screen stream did not start during a voice call.");
                    Require(IosAudioEngine.Shared.IsRunning, "Starting screen sharing stopped the voice graph.");
                }
                await model.ToggleVoiceAsync();
                if (ring is not null)
                {
                    Require(model.ScreenSharing, "Leaving the microphone call unsubscribed active screen audio.");
                    WriteRing(ring, active: false, write: 5760);
                    await WaitUntil(() => !model.ScreenSharing, "The second screen stream did not stop.");
                }
                await model.DisconnectAsync();
                await Task.Delay(3000);
                model.Load();
                profile = model.Profiles.Single(value => value.Id == id);
                Console.Error.WriteLine("VC_SIM phase=reconnect");
                await model.ConnectAsync(profile);
                Console.Error.WriteLine($"VC_SIM phase=reconnected audioRunning={IosAudioEngine.Shared.IsRunning}");
                Require(model.IsConnected, "Saved account login did not reconnect.");
                await Task.Delay(2500);
                Console.Error.WriteLine($"VC_SIM phase=reconnectedSettled audioRunning={IosAudioEngine.Shared.IsRunning}");
                Require(IosAudioEngine.Shared.IsRunning, "The reconnect audio graph stopped.");
                await model.ToggleVoiceAsync();
                Console.Error.WriteLine($"VC_SIM phase=rejoined audioRunning={IosAudioEngine.Shared.IsRunning}");
                await Task.Delay(2500);
                Console.Error.WriteLine($"VC_SIM phase=rejoinedSettled audioRunning={IosAudioEngine.Shared.IsRunning}");
                Require(model.VoiceJoined && IosAudioEngine.Shared.IsRunning, "The rejoined voice graph stopped.");
                await model.DisconnectAsync();
                Console.Error.WriteLine("VC_SIM phase=passed");
            }
            catch (Exception exception) { Console.Error.WriteLine($"VC_SIM phase=failed exception={exception}"); }
        });
    }

    private static void Require(bool condition, string message)
    {
        if (!condition) throw new InvalidOperationException(message);
    }

    private static string PrepareRing()
    {
        string root = NSFileManager.DefaultManager.GetContainerUrl(IosConstants.AppGroup)?.Path
            ?? throw new InvalidOperationException("Simulator App Group is unavailable.");
        string path = Path.Combine(root, "voicecat", "broadcast_audio.ring");
        Directory.CreateDirectory(Path.GetDirectoryName(path)!);
        using var file = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.ReadWrite);
        file.SetLength(64 + 96_000 * sizeof(short));
        byte[] header = new byte[20];
        BinaryPrimitives.WriteUInt32LittleEndian(header, 0x56434252);
        BinaryPrimitives.WriteUInt32LittleEndian(header.AsSpan(4), 1);
        file.Write(header);
        file.Dispose();
        WriteRing(path, active: true, write: 1920);
        return path;
    }

    private static void WriteRing(string path, bool active, ulong write)
    {
        using var file = new FileStream(path, FileMode.Open, FileAccess.Write, FileShare.ReadWrite);
        byte[] value = new byte[8];
        BinaryPrimitives.WriteUInt64LittleEndian(value, write);
        file.Position = 24; file.Write(value);
        BinaryPrimitives.WriteUInt32LittleEndian(value, active ? 1u : 0u);
        file.Position = 16; file.Write(value, 0, 4);
    }

    private static async Task WaitUntil(Func<bool> condition, string error)
    {
        for (int attempt = 0; attempt < 30; attempt++)
        {
            if (condition()) return;
            await Task.Delay(100);
        }
        throw new InvalidOperationException(error);
    }
}
#endif