using System;

using Engine.Serialization.DTOs;

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

namespace Engine.Serialization;

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

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

        parser.MoveNext();
        var behaviour = new BehaviourDTO();
        while (parser.Current != null && parser.Current is not MappingEnd)
        {
            var propertyName = ((Scalar)parser.Current).Value;
            parser.MoveNext();
            switch (propertyName)
            {
                case nameof(BehaviourDTO.ClassType):
                    behaviour.ClassType = ((Scalar)parser.Current).Value;
                    break;
                case nameof(BehaviourDTO.Priority):
                    behaviour.Priority = int.Parse(((Scalar)parser.Current).Value);
                    break;
                case nameof(BehaviourDTO.StateEnable):
                    behaviour.StateEnable = (StateEnableDTO)(new StateEnableYamlConverter().ReadYaml(parser, typeof(StateEnableDTO)) ?? new Exception());
                    break;
            }
            parser.MoveNext();
        }
        return behaviour;
    }

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

        StateEnableYamlConverter stateEnableYamlConverter = new();

        emitter.Emit(new MappingStart());

        emitter.Emit(new Scalar(nameof(BehaviourDTO.ClassType)));
        emitter.Emit(new Scalar(behaviour.ClassType.ToString()));

        emitter.Emit(new Scalar(nameof(BehaviourDTO.Priority)));
        emitter.Emit(new Scalar(behaviour.Priority.ToString()));

        emitter.Emit(new Scalar(nameof(BehaviourDTO.StateEnable)));
        stateEnableYamlConverter.WriteYaml(emitter, behaviour.StateEnable, typeof(StateEnableDTO));

        emitter.Emit(new MappingEnd());
    }
}