using System;
using System.Collections.Generic;
using System.Reflection;

using Syntriax.Engine.Core.Factory;

namespace Syntriax.Engine.Core.Serialization;

public class SerializedClass
{
    private const BindingFlags PRIVATE_BINDING_FLAGS = BindingFlags.Instance | BindingFlags.NonPublic;
    private const BindingFlags PUBLIC_BINDING_FLAGS = BindingFlags.Instance | BindingFlags.Public;

    public string Type { get; set; } = string.Empty;
    public Dictionary<string, object?> Public { get; set; } = [];
    public Dictionary<string, object?> Private { get; set; } = [];

    public SerializedClass() { }
    public SerializedClass(object @class)
    {
        UpdateClass(@class);
    }

    private void UpdateClass(object @class)
    {
        Type type = @class.GetType();
        Type = type.FullName ?? type.Name;

        bool shouldSerializeAll = type.HasAttribute<SerializeAllAttribute>();

        Public.Clear();
        Private.Clear();

        foreach (PropertyInfo privatePropertyInfo in Utils.GetPropertyInfosIncludingBaseClasses(type, PRIVATE_BINDING_FLAGS))
        {
            if (privatePropertyInfo.HasAttribute<IgnoreSerializationAttribute>())
                continue;

            if (privatePropertyInfo.SetMethod is null)
                continue;

            if (!shouldSerializeAll && !privatePropertyInfo.HasAttribute<SerializeAttribute>())
                continue;

            object? value = privatePropertyInfo.GetValue(@class);
            if (value is IEntity entity)
                Private.Add(privatePropertyInfo.Name, entity.Id);
            else
                Private.Add(privatePropertyInfo.Name, value);
        }

        foreach (PropertyInfo publicPropertyInfo in Utils.GetPropertyInfosIncludingBaseClasses(type, PUBLIC_BINDING_FLAGS))
        {
            if (publicPropertyInfo.HasAttribute<IgnoreSerializationAttribute>())
                continue;

            if (publicPropertyInfo.SetMethod is null)
                continue;

            if (!shouldSerializeAll && !publicPropertyInfo.HasAttribute<SerializeAttribute>())
                continue;

            object? value = publicPropertyInfo.GetValue(@class);
            if (value is IEntity entity)
                Public.Add(publicPropertyInfo.Name, entity.Id);
            else
                Public.Add(publicPropertyInfo.Name, value);
        }

        foreach (FieldInfo privateFieldInfo in Utils.GetFieldInfosIncludingBaseClasses(type, PRIVATE_BINDING_FLAGS))
        {
            if (privateFieldInfo.HasAttribute<System.Runtime.CompilerServices.CompilerGeneratedAttribute>())
                continue;

            if (!shouldSerializeAll && !privateFieldInfo.HasAttribute<SerializeAttribute>())
                continue;

            object? value = privateFieldInfo.GetValue(@class);
            if (value is IEntity entity)
                Private.Add(privateFieldInfo.Name, entity.Id);
            else
                Private.Add(privateFieldInfo.Name, value);
        }

        foreach (FieldInfo publicFieldInfo in Utils.GetFieldInfosIncludingBaseClasses(type, PUBLIC_BINDING_FLAGS))
        {
            if (publicFieldInfo.HasAttribute<System.Runtime.CompilerServices.CompilerGeneratedAttribute>())
                continue;

            if (!shouldSerializeAll && !publicFieldInfo.HasAttribute<SerializeAttribute>())
                continue;

            object? value = publicFieldInfo.GetValue(@class);
            if (value is IEntity entity)
                Public.Add(publicFieldInfo.Name, entity.Id);
            else
                Public.Add(publicFieldInfo.Name, value);
        }
    }

    public object CreateInstance()
    {
        Type type = TypeFactory.GetType(Type);
        object instance = TypeFactory.Get(type);

        foreach ((string key, object? value) in Private)
            AssignVariable(key, type, instance, value, PRIVATE_BINDING_FLAGS);

        foreach ((string key, object? value) in Public)
            AssignVariable(key, type, instance, value, PUBLIC_BINDING_FLAGS);

        return instance;
    }

    public object CreateInstance(EntityRegistry? entityRegistry)
    {
        if (entityRegistry is null)
            return CreateInstance();

        Type type = TypeFactory.GetType(Type);
        object instance = TypeFactory.Get(type);

        foreach ((string key, object? value) in Private)
            AssignVariable(key, type, instance, value, PRIVATE_BINDING_FLAGS, entityRegistry);

        foreach ((string key, object? value) in Public)
            AssignVariable(key, type, instance, value, PUBLIC_BINDING_FLAGS, entityRegistry);

        return instance;
    }

    private static void AssignVariable(string key, Type type, object instance, object? value, BindingFlags bindingFlags, EntityRegistry entityRegistry)
    {
        if (type.GetField(key, bindingFlags) is FieldInfo fieldInfo)
        {
            if (typeof(IEntity).IsAssignableFrom(fieldInfo.FieldType))
                entityRegistry.QueueAssign(value?.ToString() ?? "", (entity) => fieldInfo.SetValue(instance, entity));
            else
                fieldInfo.SetValue(instance, value);
        }
        else if (type.GetProperty(key, bindingFlags) is PropertyInfo propertyInfo)
        {
            if (typeof(IEntity).IsAssignableFrom(propertyInfo.PropertyType))
                entityRegistry.QueueAssign(value?.ToString() ?? "", (entity) => propertyInfo.SetValue(instance, entity));
            else
                propertyInfo.SetValue(instance, value);
        }
    }

    private static void AssignVariable(string key, Type type, object instance, object? value, BindingFlags bindingFlags)
    {
        if (type.GetField(key, bindingFlags) is FieldInfo fieldInfo)
            fieldInfo.SetValue(instance, value);
        else if (type.GetProperty(key, bindingFlags) is PropertyInfo propertyInfo)
            propertyInfo.SetValue(instance, value);
    }
}