using S3.Core;
using UnityEngine;
using UnityEngine.Scripting;

namespace S3.Modules.BaseGamePerf;

public sealed class BaseGamePerfModule : IModule
{
    const string SettingsFile = "S3.basegame.json";

    static bool _hasOriginal;
    static ulong _originalSliceNanoseconds;

    public static BaseGamePerfSettings Settings { get; private set; } = new();

    public BaseGamePerfModule() =>
        Settings = SettingsStore.Load<BaseGamePerfSettings>(SettingsFile);

    public string Id => "basegame";
    public string DisplayName => "Base Game Performance";
    public string Description =>
        "Evidence-backed vanilla-game hitch controls. Smooths incremental GC and " +
        "Nature Renderer grass-cell streaming without reducing density, draw distance, " +
        "resolution, or simulation quality.";

    public bool Enabled
    {
        get => Settings.enabled;
        set => Settings.enabled = value;
    }

    public void OnEnable()
    {
        if (!_hasOriginal)
        {
            _originalSliceNanoseconds = GarbageCollector.incrementalTimeSliceNanoseconds;
            _hasOriginal = true;
        }
        try { NatureStreamingOptimizer.Enable(); }
        catch (System.Exception ex)
        {
            Log.Warn(
                "[basegame] Nature streaming smoothing unavailable: " +
                ex.GetBaseException().Message);
        }
        ApplyRuntimeSettings();
    }

    public void OnDisable()
    {
        NatureStreamingOptimizer.Disable();
        if (_hasOriginal)
        {
            GarbageCollector.incrementalTimeSliceNanoseconds = _originalSliceNanoseconds;
            Log.Info(
                $"[basegame] Restored incremental GC slice to " +
                $"{_originalSliceNanoseconds / 1_000_000.0:0.###}ms.");
        }
    }

    public static void ApplyRuntimeSettings()
    {
        if (!GarbageCollector.isIncremental)
        {
            Log.Warn("[basegame] Unity incremental GC is disabled; smoothing was not applied.");
            return;
        }

        ulong desired = Settings.gcSmoothingEnabled
            ? (ulong)(Mathf.Clamp(Settings.incrementalSliceMs, 0.25f, 5f) * 1_000_000f)
            : _originalSliceNanoseconds;
        GarbageCollector.incrementalTimeSliceNanoseconds = desired;
        Log.Info(
            $"[basegame] Incremental GC slice={desired / 1_000_000.0:0.###}ms " +
            $"(smoothing={Settings.gcSmoothingEnabled}).");
        NatureStreamingOptimizer.ApplySettings();
    }

    public void SaveSettings() => Persist();
    public static void Persist() => SettingsStore.Save(SettingsFile, Settings);
    public void DrawSettings() => BaseGamePerfSettingsUI.Draw();
}