using MessagePack;

namespace OECS;

/// <summary>
/// Serializable snapshot of the entire world state.
/// </summary>
[MessagePackObject]
public class WorldSnapshot
{
    [Key(0)] public EntitySnapshot[] Entities { get; set; } = [];
}

/// <summary>
/// A single entity and all its components, serialized as name/data pairs.
/// Entity ID and Version are stored separately to avoid issues with
/// MessagePack deserialization of the opaque Entity struct.
/// </summary>
[MessagePackObject]
public class EntitySnapshot
{
    [Key(0)] public uint Id { get; set; }
    [Key(1)] public uint Version { get; set; }
    [Key(2)] public ComponentEntry[] Components { get; set; } = [];

    [IgnoreMember]
    public Entity Entity => new(Id, Version);
}

/// <summary>
/// A single component, identified by its fully-qualified type name and
/// serialized as a MessagePack byte blob.
/// </summary>
[MessagePackObject]
public class ComponentEntry
{
    [Key(0)] public string TypeName { get; set; } = "";
    [Key(1)] public byte[] Data { get; set; } = [];
}