using FFXIVClientStructs.FFXIV.Client.Game.Character;
using FFXIVClientStructs.FFXIV.Client.Graphics.Scene;
using LightlessSync.Services;
using LightlessSync.Services.Mediator;
using LightlessSync.Utils;
using Microsoft.Extensions.Logging;
using System.Runtime.CompilerServices;
using static FFXIVClientStructs.FFXIV.Client.Game.Character.DrawDataContainer;
using ObjectKind = LightlessSync.API.Data.Enum.ObjectKind;
using VisibilityFlags = FFXIVClientStructs.FFXIV.Client.Game.Object.VisibilityFlags;

namespace LightlessSync.PlayerData.Handlers;

public sealed class GameObjectHandler : DisposableMediatorSubscriberBase, IHighPriorityMediatorSubscriber
{
    private readonly DalamudUtilService _dalamudUtil;
    private readonly Func<IntPtr> _getAddress;
    private readonly bool _isOwnedObject;
    private readonly PerformanceCollectorService _performanceCollector;
    private readonly object _frameworkUpdateGate = new();
    private bool _frameworkUpdateSubscribed;
    private byte _classJob = 0;
    private Task? _delayedZoningTask;
    private bool _haltProcessing = false;
    private CancellationTokenSource _zoningCts = new();

    public GameObjectHandler(ILogger<GameObjectHandler> logger, PerformanceCollectorService performanceCollector,
        LightlessMediator mediator, DalamudUtilService dalamudUtil, ObjectKind objectKind, Func<IntPtr> getAddress, bool ownedObject = true) : base(logger, mediator)
    {
        _performanceCollector = performanceCollector;
        ObjectKind = objectKind;
        _dalamudUtil = dalamudUtil;
        _getAddress = () =>
        {
            _dalamudUtil.EnsureIsOnFramework();
            return getAddress.Invoke();
        };
        _isOwnedObject = ownedObject;
        Name = string.Empty;

        if (ownedObject)
        {
            Mediator.Subscribe<TransientResourceChangedMessage>(this, (msg) =>
            {
                if (_delayedZoningTask?.IsCompleted ?? true)
                {
                    if (msg.Address != Address) return;
                    Mediator.Publish(new CreateCacheForObjectMessage(this));
                }
            });
        }

        if (_isOwnedObject)
        {
            EnableFrameworkUpdates();
        }

        Mediator.Subscribe<ZoneSwitchEndMessage>(this, (_) => ZoneSwitchEnd());
        Mediator.Subscribe<ZoneSwitchStartMessage>(this, (_) => ZoneSwitchStart());

        Mediator.Subscribe<CutsceneStartMessage>(this, (_) =>
        {
            _haltProcessing = true;
        });
        Mediator.Subscribe<CutsceneEndMessage>(this, (_) =>
        {
            _haltProcessing = false;
            ZoneSwitchEnd();
        });
        Mediator.Subscribe<PenumbraStartRedrawMessage>(this, (msg) =>
        {
            if (msg.Address == Address)
            {
                _haltProcessing = true;
            }
        });
        Mediator.Subscribe<PenumbraEndRedrawMessage>(this, (msg) =>
        {
            if (msg.Address == Address)
            {
                _haltProcessing = false;
            }
        });

        Mediator.Publish(new GameObjectHandlerCreatedMessage(this, _isOwnedObject));

        _dalamudUtil.RunOnFrameworkThread(CheckAndUpdateObject).GetAwaiter().GetResult();
    }

    public enum DrawCondition
    {
        None,
        ObjectZero,
        DrawObjectZero,
        RenderFlags,
        ModelInSlotLoaded,
        ModelFilesInSlotLoaded
    }

    public IntPtr Address { get; private set; }
    public DrawCondition CurrentDrawCondition { get; set; } = DrawCondition.None;
    public byte Gender { get; private set; }
    public string Name { get; private set; }
    public uint EntityId { get; private set; } = uint.MaxValue;
    public ObjectKind ObjectKind { get; }
    public byte RaceId { get; private set; }
    public byte TribeId { get; private set; }
    private byte[] CustomizeData { get; set; } = new byte[26];
    private IntPtr DrawObjectAddress { get; set; }
    private byte[] EquipSlotData { get; set; } = new byte[40];
    private ushort[] MainHandData { get; set; } = new ushort[3];
    private ushort[] OffHandData { get; set; } = new ushort[3];

    public async Task ActOnFrameworkAfterEnsureNoDrawAsync(Action<Dalamud.Game.ClientState.Objects.Types.ICharacter> act, CancellationToken token)
    {
        while (await _dalamudUtil.RunOnFrameworkThread(() =>
        {
            EnsureLatestObjectState();
            if (CurrentDrawCondition != DrawCondition.None) return true;
            var gameObj = _dalamudUtil.CreateGameObject(Address);
            if (gameObj is Dalamud.Game.ClientState.Objects.Types.ICharacter chara)
            {
                act.Invoke(chara);
            }
            return false;
        }).ConfigureAwait(false))
        {
            await Task.Delay(250, token).ConfigureAwait(false);
        }
    }

    public void CompareNameAndThrow(string name)
    {
        if (!string.Equals(Name, name, StringComparison.OrdinalIgnoreCase))
        {
            throw new InvalidOperationException("Player name not equal to requested name, pointer invalid");
        }
        if (Address == IntPtr.Zero)
        {
            throw new InvalidOperationException("Player pointer is zero, pointer invalid");
        }
    }

    public Dalamud.Game.ClientState.Objects.Types.IGameObject? GetGameObject()
    {
        return _dalamudUtil.CreateGameObject(Address);
    }

    public void Invalidate()
    {
        Address = IntPtr.Zero;
        DrawObjectAddress = IntPtr.Zero;
        EntityId = uint.MaxValue;
        _haltProcessing = false;
    }

    public void Refresh()
    {
        _dalamudUtil.RunOnFrameworkThread(CheckAndUpdateObject).GetAwaiter().GetResult();
    }

    public async Task<bool> IsBeingDrawnRunOnFrameworkAsync()
    {
        return await _dalamudUtil.RunOnFrameworkThread(IsBeingDrawn).ConfigureAwait(false);
    }

    public override string ToString()
    {
        var owned = _isOwnedObject ? "Self" : "Other";
        return $"{owned}/{ObjectKind}:{Name} ({Address:X},{DrawObjectAddress:X})";
    }

    private void CheckAndUpdateObject() => CheckAndUpdateObject(allowPublish: true);

    private unsafe void CheckAndUpdateObject(bool allowPublish)
    {
        var prevAddr = Address;
        var prevDrawObj = DrawObjectAddress;
        string? nameString = null;

        var nextAddr = _getAddress();

        if (nextAddr != IntPtr.Zero && !PtrGuard.LooksLikePtr(nextAddr))
        {
            nextAddr = IntPtr.Zero;
        }

        if (nextAddr != IntPtr.Zero &&
            !PtrGuard.IsReadable(nextAddr, (nuint)sizeof(FFXIVClientStructs.FFXIV.Client.Game.Object.GameObject)))
        {
            nextAddr = IntPtr.Zero;
        }

        Address = nextAddr;

        if (Address != IntPtr.Zero)
        {
            var gameObject = (FFXIVClientStructs.FFXIV.Client.Game.Object.GameObject*)Address;

            var draw = (nint)gameObject->DrawObject;

            if (!PtrGuard.LooksLikePtr(draw) || !PtrGuard.IsReadable(draw, (nuint)sizeof(DrawObject)))
                draw = 0;

            DrawObjectAddress = draw;
            EntityId = gameObject->EntityId;

            if (PtrGuard.IsReadable(Address, (nuint)sizeof(Character)))
            {
                var chara = (Character*)Address;
                nameString = chara->GameObject.NameString;

                if (!string.IsNullOrEmpty(nameString) && !string.Equals(nameString, Name, StringComparison.Ordinal))
                    Name = nameString;
            }
        }
        else
        {
            DrawObjectAddress = IntPtr.Zero;
            EntityId = uint.MaxValue;
        }

        CurrentDrawCondition = (Address != IntPtr.Zero && DrawObjectAddress != IntPtr.Zero)
            ? IsBeingDrawnUnsafe()
            : DrawCondition.DrawObjectZero;

        if (_haltProcessing || !allowPublish) return;

        bool drawObjDiff = DrawObjectAddress != prevDrawObj;
        bool addrDiff = Address != prevAddr;

        if (Address != IntPtr.Zero && DrawObjectAddress != IntPtr.Zero
            && PtrGuard.IsReadable(Address, (nuint)sizeof(Character))
            && PtrGuard.IsReadable(DrawObjectAddress, (nuint)sizeof(DrawObject)))
        {
            var chara = (Character*)Address;
            var drawObj = (DrawObject*)DrawObjectAddress;

            var objType = drawObj->Object.GetObjectType();
            var isHuman = objType == ObjectType.CharacterBase
                          && ((CharacterBase*)drawObj)->GetModelType() == CharacterBase.ModelType.Human;

            nameString ??= chara->GameObject.NameString;
            var nameChange = !string.Equals(nameString, Name, StringComparison.Ordinal);
            if (nameChange) Name = nameString;

            bool equipDiff = false;

            if (isHuman)
            {
                if (PtrGuard.IsReadable(DrawObjectAddress, (nuint)sizeof(Human)))
                {
                    var classJob = chara->CharacterData.ClassJob;
                    if (classJob != _classJob)
                    {
                        Logger.LogTrace("[{this}] classjob changed from {old} to {new}", this, _classJob, classJob);
                        _classJob = classJob;
                        Mediator.Publish(new ClassJobChangedMessage(this));
                    }

                    equipDiff = CompareAndUpdateEquipByteData((byte*)&((Human*)drawObj)->Head);

                    ref var mh = ref chara->DrawData.Weapon(WeaponSlot.MainHand);
                    ref var oh = ref chara->DrawData.Weapon(WeaponSlot.OffHand);

                    equipDiff |= CompareAndUpdateMainHand((Weapon*)mh.DrawObject);
                    equipDiff |= CompareAndUpdateOffHand((Weapon*)oh.DrawObject);
                }
                else
                {
                    isHuman = false;
                }
            }

            if (!isHuman)
            {
                equipDiff = CompareAndUpdateEquipByteData((byte*)Unsafe.AsPointer(ref chara->DrawData.EquipmentModelIds[0]));
            }

            if (equipDiff && !_isOwnedObject)
            {
                Logger.LogTrace("[{this}] Changed", this);
                return;
            }

            bool customizeDiff = false;

            if (isHuman && PtrGuard.IsReadable(DrawObjectAddress, (nuint)sizeof(Human)))
            {
                var human = (Human*)drawObj;

                var gender = human->Customize.Sex;
                var raceId = human->Customize.Race;
                var tribeId = human->Customize.Tribe;

                if (_isOwnedObject && ObjectKind == ObjectKind.Player
                    && (gender != Gender || raceId != RaceId || tribeId != TribeId))
                {
                    Mediator.Publish(new CensusUpdateMessage(gender, raceId, tribeId));
                    Gender = gender;
                    RaceId = raceId;
                    TribeId = tribeId;
                }

                customizeDiff = CompareAndUpdateCustomizeData(human->Customize.Data);
            }
            else
            {
                customizeDiff = CompareAndUpdateCustomizeData(chara->DrawData.CustomizeData.Data);
            }

            if ((addrDiff || drawObjDiff || equipDiff || customizeDiff || nameChange) && _isOwnedObject)
            {
                Logger.LogDebug("[{this}] Changed, Sending CreateCacheObjectMessage", this);
                Mediator.Publish(new CreateCacheForObjectMessage(this));
            }
        }
        else if (addrDiff || drawObjDiff)
        {
            CurrentDrawCondition = DrawCondition.DrawObjectZero;
            Logger.LogTrace("[{this}] Changed", this);
            if (_isOwnedObject && ObjectKind != ObjectKind.Player)
                Mediator.Publish(new ClearCacheForObjectMessage(this));
        }
    }


    private unsafe bool CompareAndUpdateCustomizeData(Span<byte> customizeData)
    {
        bool hasChanges = false;

        for (int i = 0; i < customizeData.Length; i++)
        {
            var data = customizeData[i];
            if (CustomizeData[i] != data)
            {
                CustomizeData[i] = data;
                hasChanges = true;
            }
        }

        return hasChanges;
    }

    private unsafe bool CompareAndUpdateEquipByteData(byte* equipSlotData)
    {
        bool hasChanges = false;
        for (int i = 0; i < EquipSlotData.Length; i++)
        {
            var data = equipSlotData[i];
            if (EquipSlotData[i] != data)
            {
                EquipSlotData[i] = data;
                hasChanges = true;
            }
        }

        return hasChanges;
    }

    private unsafe bool CompareAndUpdateMainHand(Weapon* weapon)
    {
        var p = (nint)weapon;
        if (!PtrGuard.LooksLikePtr(p) || !PtrGuard.IsReadable(p, (nuint)sizeof(Weapon)))
            return false;

        bool hasChanges = false;
        hasChanges |= weapon->ModelSetId != MainHandData[0];
        MainHandData[0] = weapon->ModelSetId;
        hasChanges |= weapon->Variant != MainHandData[1];
        MainHandData[1] = weapon->Variant;
        hasChanges |= weapon->SecondaryId != MainHandData[2];
        MainHandData[2] = weapon->SecondaryId;
        return hasChanges;
    }

    private unsafe bool CompareAndUpdateOffHand(Weapon* weapon)
    {
        var p = (nint)weapon;
        if (!PtrGuard.LooksLikePtr(p) || !PtrGuard.IsReadable(p, (nuint)sizeof(Weapon)))
            return false;

        bool hasChanges = false;
        hasChanges |= weapon->ModelSetId != OffHandData[0];
        OffHandData[0] = weapon->ModelSetId;
        hasChanges |= weapon->Variant != OffHandData[1];
        OffHandData[1] = weapon->Variant;
        hasChanges |= weapon->SecondaryId != OffHandData[2];
        OffHandData[2] = weapon->SecondaryId;
        return hasChanges;
    }

    private void FrameworkUpdate()
    {
        try
        {
            var zoningDelayActive = !(_delayedZoningTask?.IsCompleted ?? true);
            _performanceCollector.LogPerformance(this, $"CheckAndUpdateObject>{(_isOwnedObject ? "Self" : "Other")}+{ObjectKind}/{(string.IsNullOrEmpty(Name) ? "Unk" : Name)}", () => CheckAndUpdateObject(allowPublish: !zoningDelayActive));
        }
        catch (Exception ex)
        {
            Logger.LogWarning(ex, "Error during FrameworkUpdate of {this}", this);
        }
    }

    private bool IsBeingDrawn()
    {
        EnsureLatestObjectState();

        if (_dalamudUtil.IsAnythingDrawing)
        {
            Logger.LogTrace("[{this}] IsBeingDrawn, Global draw block", this);
            return true;
        }

        Logger.LogTrace("[{this}] IsBeingDrawn, Condition: {cond}", this, CurrentDrawCondition);
        return CurrentDrawCondition != DrawCondition.None;
    }

    private void EnsureLatestObjectState()
    {
        if (_haltProcessing || !_frameworkUpdateSubscribed)
        {
            CheckAndUpdateObject();
        }
    }

    private void EnableFrameworkUpdates()
    {
        lock (_frameworkUpdateGate)
        {
            if (_frameworkUpdateSubscribed)
            {
                return;
            }

            Mediator.Subscribe<FrameworkUpdateMessage>(this, _ => FrameworkUpdate());
            _frameworkUpdateSubscribed = true;
        }
    }

    private unsafe DrawCondition IsBeingDrawnUnsafe()
    {
        if (Address == IntPtr.Zero) return DrawCondition.ObjectZero;
        if (DrawObjectAddress == IntPtr.Zero) return DrawCondition.DrawObjectZero;
        var visibilityFlags = ((FFXIVClientStructs.FFXIV.Client.Game.Object.GameObject*)Address)->RenderFlags;
        if (visibilityFlags != VisibilityFlags.None) return DrawCondition.RenderFlags;

        if (ObjectKind == ObjectKind.Player)
        {
            var modelInSlotLoaded = (((CharacterBase*)DrawObjectAddress)->HasModelInSlotLoaded != 0);
            if (modelInSlotLoaded) return DrawCondition.ModelInSlotLoaded;
            var modelFilesInSlotLoaded = (((CharacterBase*)DrawObjectAddress)->HasModelFilesInSlotLoaded != 0);
            if (modelFilesInSlotLoaded) return DrawCondition.ModelFilesInSlotLoaded;
        }

        return DrawCondition.None;
    }

    private void ZoneSwitchEnd()
    {
        if (!_isOwnedObject) return;

        try
        {
            _zoningCts?.CancelAfter(2500);
        }
        catch (ObjectDisposedException)
        {
            // ignore
        }
        catch (Exception ex)
        {
            Logger.LogWarning(ex, "Zoning CTS cancel issue");
        }
    }

    private void ZoneSwitchStart()
    {
        if (!_isOwnedObject) return;

        _zoningCts = new();
        Logger.LogDebug("[{obj}] Starting Delay After Zoning", this);
        _delayedZoningTask = Task.Run(async () =>
        {
            try
            {
                await Task.Delay(TimeSpan.FromSeconds(120), _zoningCts.Token).ConfigureAwait(false);
            }
            catch
            {
                // ignore cancelled
            }
            finally
            {
                Logger.LogDebug("[{this}] Delay after zoning complete", this);
                _zoningCts.Dispose();
            }
        }, _zoningCts.Token);
    }
}