using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using UnityEngine;

namespace Syntriax.Modules.Movement.Config
{
    public class MovementFactory : MonoBehaviour
    {
        private const string Name = "Movement Factory";
        private const int InitialCapacity = 64;

        private static MovementFactory _instance = null;
        public static MovementFactory Instance
        {
            get
            {
                if (_instance == null)
                    _instance = new GameObject(Name).AddComponent<MovementFactory>();

                return _instance;
            }
        }

        private Dictionary<string, Type> _types = null;
        public Dictionary<string, Type> Types
        {
            get
            {
                if (_types == null)
                    Initialize();

                return _types;
            }
        }

        private Func<Type, bool> predicate = type => !type.IsAbstract && type.IsSubclassOf(typeof(MonoBehaviour));

        private void Start()
        {
            if (_instance == this)
                return;

            Destroy(this);
        }

        public void Initialize()
        {
            if (_types == null)
                _types = new Dictionary<string, Type>(InitialCapacity);

            Reset();

            foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies())
                AddAssemblyToFactory(assembly);
        }

        public void Reset() => _types?.Clear();

        public void AddAssemblyToFactory(Assembly assembly)
        {
            foreach (Type type in assembly.GetTypes().Where(predicate))
                Types.Add(GetTypeName(type), type);
        }

        public Component AddToGameObject(GameObject gameObject, string name)
        {
            if (!Types.ContainsKey(name))
                throw new ArgumentException($"The key \"{name}\" does not exists in the current {Name}");

            return gameObject.AddComponent(Types[name]);
        }

        public static string GetTypeName(Type type)
        {
            if (string.IsNullOrEmpty(type.Namespace))
                return type.Name;

            return $"{type.Namespace}.{type.Name}";
        }
    }
}