using System;
using System.Reflection;
using ADOFAIRenderer;
using ADOFAIRenderer.Component;
using ADOFAIRenderer.Util;
using MelonLoader;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.Rendering;
using Object = UnityEngine.Object;

[assembly: MelonInfo(typeof(RenderMod), "ADOFAI Renderer", "0.0.1-BETA", "ADOFAI Editor Forum")]
[assembly: MelonGame("7th Beat Games", "A Dance of Fire and Ice")]

namespace ADOFAIRenderer
{

    public class RenderMod : MelonMod
    {
        public static AssetBundle FontBundle = null!;
        // ReSharper disable once MemberCanBePrivate.Global
        public static AssetBundle SceneBundle = null!;
        public static bool WatchGameLoaded;
        public static string[] ModScenes = {};

        private static double _beforeTime;

        public static bool IsRendering = false;
        public static bool IsCapturing = false;

        public static double TimeBase;
        public static double UnscaledTimeBase;
        public static double DspTimeBase;
        public static int FrameCountBase;

        public static bool RenderCheck = true;
        public static int SkipCount = 0;

        public override void OnInitializeMelon()
        {
            var renderManagerObj = new GameObject("Render Manager");
            var updateHookerObj = new GameObject("Update Hooker");
            Object.DontDestroyOnLoad( renderManagerObj );
            Object.DontDestroyOnLoad( updateHookerObj );
            
            renderManagerObj.AddComponent<RenderManager>();
            updateHookerObj.AddComponent<FirstUpdateHook>();
            LoadBundles();
        }

        private static void LoadBundles()
        {
            FontBundle = BundleLoader.GetBundle("fonts");
            SceneBundle = BundleLoader.GetBundle("scenes");
            ModScenes = SceneBundle.GetAllScenePaths();
        }
        
        public static void FixEventSystem()
        {
            if (EventSystem.current == null) return;
            var currentModule = EventSystem.current.currentInputModule;

            if (currentModule != null) return;
            Melon<RenderMod>.Logger.Msg("Unity 6 인풋 모듈 이식.");
            
            var newModule = EventSystem.current.gameObject.AddComponent<StandaloneInputModule>();
            newModule.enabled = true;
        }

        public static void OnFirstUpdate()
        {
            if (_beforeTime == 0) _beforeTime = Time.realtimeSinceStartupAsDouble;
            
            var realDeltaTime = Time.realtimeSinceStartupAsDouble - _beforeTime;
            _beforeTime = Time.realtimeSinceStartupAsDouble;
            
            if (!IsRendering) return;

            // [렉으로 인한 프레임 렌더링 스킵 시 재시도 로직 (원본 모드 이식)]
            if (RenderCheck)
            {
                if (SkipCount < 60)
                {
                    Melon<RenderMod>.Logger.Warning($"[Render Skipped] Frame {RenderManager.FrameCount} rendering missed. Retrying... (Attempt {SkipCount + 1}/60)");
                    SkipCount++;
                    Time.timeScale = 0f; // 진행 시간 멈추기 (재시도)
                    return; // 업데이트 진행하지 않고 대기
                }

                // 60회 초과 시 최후의 블랙 프레임 삽입하여 전체 파이프라인 마비 방지
                Melon<RenderMod>.Logger.Error($"[Render Skipped] Frame {RenderManager.FrameCount} rendering failed after 60 retries. Supplying black frame.");
                
                int targetFps = (int)RenderManager.Configuration.TargetFPS;
                int videoFps = (int)RenderManager.Configuration.VideoFPS;
                int num = targetFps % videoFps != 0 ? 1 : targetFps / videoFps;

                if (FrameCountForVideo % num == 0)
                {
                    int byteSize = RenderManager.Configuration.RenderWidth * RenderManager.Configuration.RenderHeight * 4;
                    byte[] blackFrame = System.Buffers.ArrayPool<byte>.Shared.Rent(byteSize);
                    Array.Clear(blackFrame, 0, byteSize);
                    
                    lock (RenderManager.ImageQueue)
                    {
                        RenderManager.ImageQueue[FrameCountForVideo] = blackFrame;
                    }
                }
                
                FrameCountForVideo++;
                RenderCheck = false; // 진행 허용
            }

            SkipCount = 0;
            RenderCheck = true; // 다음 프레임 검사용으로 초기화
            RenderManager.FrameCount++;

            Time.timeScale = (float)(Time.deltaTime / realDeltaTime);
        }

        public static int FrameCountForVideo = 0;
        public static int ReadbackFailureCount = 0;
        public static int ThrottleCount = 0;
        public static bool IsThrottling = false;

        public static void OnPostRender(RenderTexture? texture)
        {
            if (!IsCapturing || !texture) return;

            RenderCheck = false; // 이번 프레임 정상 렌더링 완료

            // [Backpressure Throttling (2번 작업)]
            const int maxQueuedFrames = 60;
            IsThrottling = false;
            
            while (IsCapturing && IsRendering)
            {
                int count;
                lock (RenderManager.ImageQueue)
                {
                    count = RenderManager.ImageQueue.Count;
                }

                if (count <= maxQueuedFrames) break;

                if (!IsThrottling)
                {
                    IsThrottling = true;
                    ThrottleCount++;
                }
                System.Threading.Thread.Sleep(1);
            }
            IsThrottling = false;

            var currentFrame = FrameCountForVideo++;
            
            var targetFps = RenderManager.Configuration.TargetFPS;
            var videoFps = RenderManager.Configuration.VideoFPS;
            var num = targetFps % videoFps != 0.0 ? 1 : (int)(targetFps / videoFps);

            if (currentFrame % num != 0)
            {
                return;
            }

            AsyncGPUReadback.Request(texture, 0, delegate(AsyncGPUReadbackRequest req)
            {
                if (!IsCapturing) return;

                byte[] rawBytes;
                if (req.hasError)
                {
                    ReadbackFailureCount++;
                    Melon<RenderMod>.Logger.Warning($"[OOM Prevent] GPU Readback failed for frame {currentFrame}. Queue deadlock prevented by sending an empty frame.");
                    rawBytes = Array.Empty<byte>(); // 1번 작업: 빈 배열로 대체하여 정체 방지
                }
                else
                {
                    try
                    {
                        var data = req.GetData<byte>();
                        rawBytes = FFmpegProcess.RentRawBytes(data); // 3번 작업: ArrayPool에서 대여
                    }
                    catch (Exception ex)
                    {
                        ReadbackFailureCount++;
                        Melon<RenderMod>.Logger.Error($"[OOM Prevent] Native conversion failed for frame {currentFrame}: {ex}");
                        rawBytes = Array.Empty<byte>();
                    }
                }
                
                lock (RenderManager.ImageQueue)
                {
                    RenderManager.ImageQueue[currentFrame] = rawBytes;
                }
            });
        }

        public static void StartRender()
        {
            var targetMethod = typeof(scnEditor).GetMethod("TryApplicationQuit",
                BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public);

            if (targetMethod == null || scnEditor.instance == null) return;
            if (ADOBase.levelPath.IsNullOrEmpty())
            {
                scnEditor.instance.TryQuitToMenu();
                return;
            }
            
            RenderManager.LevelPath = ADOBase.levelPath;
            
            scnEditor.instance.CheckUnsavedChanges(() =>
            {
                var quitDelegate =
                    (Func<bool>)Delegate.CreateDelegate(typeof(Func<bool>), scnEditor.instance, targetMethod);
                
                Application.wantsToQuit -= quitDelegate;
                ADOBase.loader.LoadSceneWithTransition(WipeDirection.StartsFromRight, "Assets/Scenes/RenderSettingsScene.unity");
            });
        }
    }
}