TimePasses/Model/IWhen.cs

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

namespace TimePasses.Model;

public interface IWhen {
    ReplacementText Text { get; }
    bool Slowly { get; }

    bool IsValid(Plugin plugin);
}

public class WhenNodeDeserialiser : INodeDeserializer {
    public bool Deserialize(IParser reader, Type expectedType, Func<IParser, Type, object?> nestedObjectDeserializer, out object? value) {
        if (expectedType != typeof(IWhen)) {
            value = null;
            return false;
        }

        reader.Consume<MappingStart>();
        var name = reader.Consume<Scalar>();
        if (!name.IsKey) {
            throw new YamlException("invalid when: missing key");
        }

        value = name.Value switch {
            "quest" => nestedObjectDeserializer(reader, typeof(WhenQuest)),
            "level" => nestedObjectDeserializer(reader, typeof(WhenLevel)),
            _ => throw new YamlException($"invalid when: unknown type \"{name.Value}\""),
        };

        reader.Consume<MappingEnd>();

        return true;
    }
}