#nullable enable

using System;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Cysharp.Threading.Tasks;
using Godot;
using ShrinkApp;
using ShrinkNetwork;
using ShrinkSDK.Runtime;

namespace ShrinkSDK.Godot;

public partial class ShrinkGodotHost : Node, IShrinkMainThreadDispatcher,
    IShrinkDeferredMainThreadDispatcher, IShrinkLogger, IShrinkClock, IShrinkPathProvider,
    IShrinkScreenshotProvider, IShrinkApplicationLifecycle
{
    private readonly ShrinkGodotRuntime _runtime = new();
    private SceneTree? _tree;
    private ulong _lastTickFrame = ulong.MaxValue;
    private bool _signalsConnected;

    public ShrinkGodotRuntime Runtime => _runtime;

    [Export]
    public int DispatchBudgetPerFrame
    {
        get => _runtime.DispatchBudgetPerFrame;
        set => _runtime.DispatchBudgetPerFrame = value;
    }

    [Export]
    public int NetworkDispatchBudgetPerFrame
    {
        get => _runtime.NetworkDispatchBudgetPerFrame;
        set => _runtime.NetworkDispatchBudgetPerFrame = value;
    }

    public event Action? Paused
    {
        add => _runtime.Paused += value;
        remove => _runtime.Paused -= value;
    }

    public event Action? Resumed
    {
        add => _runtime.Resumed += value;
        remove => _runtime.Resumed -= value;
    }

    public event Action? Exiting
    {
        add => _runtime.Exiting += value;
        remove => _runtime.Exiting -= value;
    }

    public bool IsMainThread => _runtime.IsMainThread;
    public bool IsInitialized => _runtime.IsInitialized;
    public bool IsShutdown => _runtime.IsShutdown;
    public DateTimeOffset UtcNow => _runtime.UtcNow;
    public double UnscaledTimeSeconds => _runtime.UnscaledTimeSeconds;
    public string PersistentDataPath => _runtime.PersistentDataPath;
    public string TemporaryDataPath => _runtime.TemporaryDataPath;

    public override void _Ready()
    {
        _runtime.Initialize(this);
        SetProcess(true);
        if (_signalsConnected || !IsInsideTree())
            return;
        _tree = GetTree();
        _tree.ProcessFrame += OnProcessFrame;
        TreeExiting += OnTreeExiting;
        TreeExited += OnTreeExited;
        _signalsConnected = true;
    }

    public override void _Process(double delta) => Tick(delta);

    public override void _Notification(int what) => _runtime.Notify(what);

    public override void _ExitTree()
    {
        if (_runtime.IsInitialized && !_runtime.IsShutdown)
            _runtime.ShutdownAsync().Forget();
    }

    private void OnProcessFrame() => Tick(GetProcessDeltaTime());

    private void Tick(double delta)
    {
        var frame = Engine.GetProcessFrames();
        if (frame == _lastTickFrame)
            return;
        _lastTickFrame = frame;
        _runtime.Tick(delta);
    }

    private void OnTreeExiting()
    {
        if (_runtime.IsInitialized && !_runtime.IsShutdown)
            _runtime.ShutdownAsync().Forget();
    }

    private void OnTreeExited()
    {
        if (_tree != null)
        {
            _tree.ProcessFrame -= OnProcessFrame;
            _tree = null;
        }
        TreeExiting -= OnTreeExiting;
        TreeExited -= OnTreeExited;
        _signalsConnected = false;
        if (_runtime.IsInitialized && !_runtime.IsShutdown)
            _runtime.ShutdownAsync().Forget();
    }

    public UniTask<ShrinkAppRuntime> StartAppAsync(ShrinkAppSettings? settings = null,
        ShrinkAppServices? services = null) => _runtime.StartAppAsync(settings, services);

    public UniTask ShutdownAsync() => _runtime.ShutdownAsync();

    public UniTask ShutdownAppAsync() => _runtime.StopAppAsync();

    public bool TryPost(Action action) => _runtime.TryPost(action);

    public bool TryPostDeferred(Action action) => _runtime.TryPostDeferred(action);

    public void AddNetworkService(ShrinkNetworkService service) => _runtime.AddNetworkService(service);

    public bool RemoveNetworkService(ShrinkNetworkService service) => _runtime.RemoveNetworkService(service);

    public static ShrinkCodeGenWovenAttribute RequireWoven(Assembly assembly) =>
        ShrinkGodotRuntime.RequireWoven(assembly);

    public void Log(ShrinkLogLevel level, string message, Exception? exception = null) =>
        _runtime.Log(level, message, exception);

    public ValueTask<byte[]> CapturePngAsync(CancellationToken cancellationToken = default) =>
        _runtime.CapturePngAsync(cancellationToken);
}