//
// This file is part of the Tremble package by Tiny Goose.
// Copyright (c) 2024-2026 TinyGoose Ltd., All Rights Reserved.
//

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;

namespace TinyGoose.Tremble
{
	public class FgdWriter
	{
		// -----------------------------------------------------------------------------------------------------------------------------
		//		State
		// -----------------------------------------------------------------------------------------------------------------------------
		private FgdClass m_WorldSpawn;
		private readonly List<FgdClass> m_OtherClasses = new();
		private readonly List<FgdClass> m_BaseClasses = new();
		private readonly string m_VersionString;
		private readonly float m_ImportScale;

		public FgdWriter(string versionString, TrembleSyncSettings settings)
		{
			m_VersionString = versionString;
			m_ImportScale = settings.ImportScale;
			
			// Add base entities
			AddMapBaseEntity();
			AddMapPointBaseEntity();
			AddMapPrefabBaseEntity();
		}

		public FgdClass WorldspawnClass
		{
			get => m_WorldSpawn;
			set => m_WorldSpawn = value;
		}

		public IReadOnlyList<FgdClass> BaseClasses => m_BaseClasses;
		public IReadOnlyList<FgdClass> Classes => m_OtherClasses;

		public void AddClass(FgdClass entityClass)
		{
			if (entityClass.Name.Length > 31)
			{
				Debug.LogError($"Class '{entityClass.Name}' is too long - it cannot be longer than 31 characters." +
				               " Add a custom [PrefabEntity], [BrushEntity], or [PointEntity] attribute to this MonoBehaviour and set a shorter name!");
			}

			if (entityClass.Type == FgdClassType.Base)
			{
				int insertionIdx = m_BaseClasses.BinarySearch(entityClass, Comparer<FgdClass>.Create((c1, c2) => String.Compare(c1.Name, c2.Name, StringComparison.Ordinal)));
				if (insertionIdx < 0)
				{
					m_BaseClasses.Add(entityClass);
				}
				else
				{
					m_BaseClasses.Insert(insertionIdx, entityClass);
				}
			}
			else
			{
				int insertionIdx = m_OtherClasses.BinarySearch(entityClass, Comparer<FgdClass>.Create((c1, c2) => String.Compare(c1.Name, c2.Name, StringComparison.Ordinal)));
				if (insertionIdx < 0)
				{
					m_OtherClasses.Add(entityClass);
				}
				else
				{
					m_OtherClasses.Insert(insertionIdx, entityClass);
				}
			}
		}
		
		public void WriteFgd(StreamWriter stream, bool humanReadable = true)
		{
			if (humanReadable)
			{
				stream.WriteLine("// TrenchBroom game definition file (.fgd)");
				stream.WriteLine($"// Generated by Tremble for Unity v{m_VersionString}");
				stream.WriteLine($"// For: {Application.productName}. (c) {DateTime.UtcNow.Year} {Application.companyName}");
				stream.WriteLine();
				stream.WriteLine();

				stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				stream.WriteLine("//");
				stream.WriteLine("//                                        Base Classes");
				stream.WriteLine("//");
				stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
			}

			// Base entities
			foreach (FgdClass entity in m_BaseClasses)
			{
				if (humanReadable)
				{
					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
					stream.WriteLine($"// Tremble Base Class '{entity.Name}'");
					stream.WriteLine($"//       {entity.Description}");
					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				}

				entity.WriteFgd(stream, m_ImportScale);

				if (humanReadable)
				{
					stream.WriteLine();
					stream.WriteLine();
				}
			}

			if (m_WorldSpawn != null)
			{
				if (humanReadable)
				{
					stream.WriteLine();
					stream.WriteLine();
					stream.WriteLine();
					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
					stream.WriteLine("//");
					stream.WriteLine("//                             worldspawn - World Root Properties");
					stream.WriteLine("//");
					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				}

				m_WorldSpawn.WriteFgd(stream, m_ImportScale);

				if (humanReadable)
				{
					stream.WriteLine();
					stream.WriteLine();
				}
			}

			if (humanReadable)
			{
				stream.WriteLine();
				stream.WriteLine();
				stream.WriteLine();
				stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				stream.WriteLine("//");
				stream.WriteLine("//                                        Game Entities");
				stream.WriteLine("//");
				stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				stream.WriteLine();
			}

			foreach (FgdClass entity in m_OtherClasses)
			{
				if (humanReadable)
				{
					string type = entity.Type switch
					{
						FgdClassType.Base => nameof(ITrembleBaseClass),
						FgdClassType.Point => "Point Entity",
						FgdClassType.Brush => "Brush Entity",
						_ => throw new ArgumentOutOfRangeException()
					};

					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
					stream.WriteLine($"// {type}");
					stream.WriteLine($"//       {entity.Description}");
					stream.WriteLine("// ----------------------------------------------------------------------------------------------------");
				}
				
				entity.WriteFgd(stream, m_ImportScale);
			}
		}

		// -----------------------------------------------------------------------------------------------------------------------------
		//		Helpers
		// -----------------------------------------------------------------------------------------------------------------------------
		private void AddMapBaseEntity()
		{
			FgdClass mapBase = new(FgdClassType.Base, FgdConsts.CLASS_MAP_BASE, "The base class for all map entities");
			mapBase.Description = "Base class for common map properties";

			mapBase.AddField(new FgdTargetSourceField
			{
				Name = TrembleSyncSettings.Get().IdentityPropertyName,
				Description = "The ID/Name of this entity",
				DefaultValue = ""
			});

			mapBase.AddField(new FgdAnglesField
			{
				Name = FgdConsts.PROPERTY_ANGLES,
				Description = "Rotation Angles",
				DefaultValue = Vector3.zero
			});

			mapBase.AddField(new FgdVectorField
			{
				Name = FgdConsts.PROPERTY_ORIGIN,
				Description = "Spawn position of this entity",
				DefaultValue = Vector3.zero,
				ConvertToQ3 = true,
				ImportScale = m_ImportScale
			});

			AddClass(mapBase);
		}
		private void AddMapPointBaseEntity()
		{
			FgdClass mapBase = new(FgdClassType.Base, FgdConsts.CLASS_MAP_POINT_BASE, "The base class for all Point entities");
			mapBase.Description = "Base class for common Point properties";

			mapBase.AddField(new FgdTargetDestinationField
			{
				Name = FgdConsts.PROPERTY_PARENT,
				Description = "Parent Transform",
				DefaultValue = null
			});

			AddClass(mapBase);
		}

		private void AddMapPrefabBaseEntity()
		{
			FgdClass mapBase = new(FgdClassType.Base, FgdConsts.CLASS_MAP_PREFAB_BASE, "The base class for all Prefab entities");
			mapBase.Description = "Base class for common Prefab properties";

			mapBase.AddBaseClass(FgdConsts.CLASS_MAP_POINT_BASE);

			mapBase.AddField(new FgdVectorField
			{
				Name = FgdConsts.PROPERTY_SCALE,
				Description = "Prefab Scale",
				DefaultValue = Vector3.one
			});

			AddClass(mapBase);
		}
	}
}