using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using Dalamud.Game;
using Dalamud.Game.ClientState.Objects;
using Dalamud.Game.ClientState.Objects.Types;
using Dalamud.Plugin.Services;
using FFXIVClientStructs.FFXIV.Client.System.Framework;
using FFXIVClientStructs.FFXIV.Client.System.Memory;
using FFXIVClientStructs.FFXIV.Client.System.String;
using Lumina.Excel.Sheets;
using Microsoft.Extensions.Logging;
using Questionable.Model.Questing;

namespace Questionable.Functions;

internal sealed class ChatFunctions
{
	private delegate void ProcessChatBoxDelegate(nint uiModule, nint message, nint unused, byte a4);

	private static class Signatures
	{
		internal const string SendChat = "48 89 5C 24 ?? 48 89 74 24 ?? 57 48 83 EC 20 48 8B F2 48 8B F9 45 84 C9";
	}

	[StructLayout(LayoutKind.Explicit)]
	private readonly struct ChatPayload : IDisposable
	{
		[FieldOffset(0)]
		private readonly nint textPtr;

		[FieldOffset(16)]
		private readonly ulong textLen;

		[FieldOffset(8)]
		private readonly ulong unk1;

		[FieldOffset(24)]
		private readonly ulong unk2;

		internal ChatPayload(byte[] stringBytes)
		{
			textPtr = Marshal.AllocHGlobal(stringBytes.Length + 30);
			Marshal.Copy(stringBytes, 0, textPtr, stringBytes.Length);
			Marshal.WriteByte(textPtr + stringBytes.Length, 0);
			textLen = (ulong)(stringBytes.Length + 1);
			unk1 = 64uL;
			unk2 = 0uL;
		}

		public void Dispose()
		{
			Marshal.FreeHGlobal(textPtr);
		}
	}

	private readonly ReadOnlyDictionary<EEmote, string> _emoteCommands;

	private readonly GameFunctions _gameFunctions;

	private readonly ITargetManager _targetManager;

	private readonly ILogger<ChatFunctions> _logger;

	private readonly ProcessChatBoxDelegate _processChatBox;

	public ChatFunctions(ISigScanner sigScanner, IDataManager dataManager, GameFunctions gameFunctions, ITargetManager targetManager, ILogger<ChatFunctions> logger)
	{
		_gameFunctions = gameFunctions;
		_targetManager = targetManager;
		_logger = logger;
		_processChatBox = Marshal.GetDelegateForFunctionPointer<ProcessChatBoxDelegate>(sigScanner.ScanText("48 89 5C 24 ?? 48 89 74 24 ?? 57 48 83 EC 20 48 8B F2 48 8B F9 45 84 C9"));
		_emoteCommands = (from x in dataManager.GetExcelSheet<Emote>()
			where x.RowId != 0
			where x.TextCommand.IsValid
			select (RowId: x.RowId, Command: x.TextCommand.Value.Command.ToString()) into x
			where !string.IsNullOrEmpty(x.Command) && x.Command.StartsWith('/')
			select x).ToDictionary<(uint, string), EEmote, string>(((uint RowId, string Command) x) => (EEmote)x.RowId, ((uint RowId, string Command) x) => x.Command).AsReadOnly();
	}

	private unsafe void SendMessageUnsafe(byte[] message)
	{
		nint uIModule = (nint)Framework.Instance()->GetUIModule();
		using ChatPayload structure = new ChatPayload(message);
		nint num = Marshal.AllocHGlobal(400);
		Marshal.StructureToPtr(structure, num, fDeleteOld: false);
		_processChatBox(uIModule, num, IntPtr.Zero, 0);
		Marshal.FreeHGlobal(num);
	}

	private void SendMessage(string message)
	{
		_logger.LogDebug("Attempting to send chat message '{Message}'", message);
		byte[] bytes = Encoding.UTF8.GetBytes(message);
		if (bytes.Length == 0)
		{
			throw new ArgumentException("message is empty", "message");
		}
		if (bytes.Length > 500)
		{
			throw new ArgumentException("message is longer than 500 bytes", "message");
		}
		if (message.Length != SanitiseText(message).Length)
		{
			throw new ArgumentException("message contained invalid characters", "message");
		}
		SendMessageUnsafe(bytes);
	}

	private unsafe string SanitiseText(string text)
	{
		Utf8String* intPtr = Utf8String.FromString(text);
		intPtr->SanitizeString(AllowedEntities.UppercaseLetters | AllowedEntities.LowercaseLetters | AllowedEntities.Numbers | AllowedEntities.SpecialCharacters | AllowedEntities.CharacterList | AllowedEntities.OtherCharacters | AllowedEntities.Payloads | AllowedEntities.Unknown9, null);
		string result = intPtr->ToString();
		intPtr->Dtor();
		IMemorySpace.Free(intPtr);
		return result;
	}

	public void ExecuteCommand(string command)
	{
		if (command.StartsWith('/'))
		{
			SendMessage(command);
		}
	}

	public void UseEmote(uint dataId, EEmote emote)
	{
		IGameObject gameObject = _gameFunctions.FindObjectByDataId(dataId);
		if (gameObject != null)
		{
			_targetManager.Target = gameObject;
			ExecuteCommand(_emoteCommands[emote] + " motion");
		}
	}

	public void UseEmote(EEmote emote)
	{
		ExecuteCommand(_emoteCommands[emote] + " motion");
	}
}