using System;
using System.Collections.Generic;
using System.Linq;

using Engine.Serialization.DTOs;

using YamlDotNet.Core;
using YamlDotNet.Core.Events;
using YamlDotNet.Serialization;

namespace Engine.Serialization;

internal class GameObjectYamlConverter : IYamlTypeConverter
{
    public bool Accepts(Type type) => type == typeof(GameObjectDTO);

    public object ReadYaml(IParser parser, Type type)
    {
        if (parser.Current is not MappingStart)
            throw new InvalidOperationException("Expected MappingStart");

        parser.MoveNext();
        var gameObject = new GameObjectDTO();
        while (parser.Current != null && parser.Current is not MappingEnd)
        {
            var propertyName = ((Scalar)parser.Current).Value;
            parser.MoveNext();
            switch (propertyName)
            {
                case nameof(GameObjectDTO.Id):
                    gameObject.Id = ((Scalar)parser.Current).Value;
                    break;
                case nameof(GameObjectDTO.Name):
                    gameObject.Name = ((Scalar)parser.Current).Value;
                    break;
                case nameof(GameObjectDTO.Transform):
                    gameObject.Transform = (TransformDTO)(new TransformYamlConverter().ReadYaml(parser, typeof(TransformDTO)) ?? new Exception());
                    break;
                // case nameof(GameObjectDTO.Behaviours):
                //     gameObject.Rotation = (List<BehaviourDTO>)(new BehaviourYamlConverter().ReadYaml(parser, typeof(BehaviourDTO)) ?? new Exception());
                //     break;
                case nameof(GameObjectDTO.StateEnable):
                    gameObject.StateEnable = (StateEnableDTO)(new StateEnableYamlConverter().ReadYaml(parser, typeof(StateEnableDTO)) ?? new Exception());
                    break;
            }
            parser.MoveNext();
        }
        return gameObject;
    }

    public void WriteYaml(IEmitter emitter, object? value, Type type)
    {
        var gameObject = (GameObjectDTO)(value ?? throw new Exception());

        TransformYamlConverter transformYamlConverter = new();
        StateEnableYamlConverter stateEnableYamlConverter = new();
        BehaviourControllerYamlConverter behaviourControllerYamlConverter = new();

        emitter.Emit(new MappingStart());
        emitter.Emit(new Scalar(nameof(GameObjectDTO.Id)));
        emitter.Emit(new Scalar(gameObject.Id.ToString()));
        emitter.Emit(new Scalar(nameof(GameObjectDTO.ClassType)));
        emitter.Emit(new Scalar(gameObject.ClassType));
        emitter.Emit(new Scalar(nameof(GameObjectDTO.Name)));
        emitter.Emit(new Scalar(gameObject.Name.ToString()));
        emitter.Emit(new Scalar(nameof(GameObjectDTO.Transform)));
        transformYamlConverter.WriteYaml(emitter, gameObject.Transform, typeof(TransformDTO));
        emitter.Emit(new Scalar(nameof(GameObjectDTO.StateEnable)));
        stateEnableYamlConverter.WriteYaml(emitter, gameObject.StateEnable, typeof(StateEnableDTO));
        emitter.Emit(new Scalar(nameof(GameObjectDTO.BehaviourController)));
        behaviourControllerYamlConverter.WriteYaml(emitter, gameObject.BehaviourController, typeof(BehaviourControllerDTO));
        emitter.Emit(new MappingEnd());
    }
}