using System.Buffers.Binary;

namespace ICRebuild.Core;

public enum DashFilterMode { AllLocal, BlockListed, AllowListed }

public static class DashPolicy
{
    // Audited native consumer reads word [data], then flags at [data+2] and [data+3].
    public static ushort Timeline(ReadOnlySpan<byte> data) => data.Length>=4 ? BinaryPrimitives.ReadUInt16LittleEndian(data) : (ushort)0;
    public static bool Block(bool ready,nint owner,nint local,ushort timeline,DashFilterMode mode,IReadOnlySet<uint> list)
    {
        if(!ready || owner==0 || owner!=local || timeline==0) return false;
        return mode switch
        {
            DashFilterMode.AllLocal=>true,
            DashFilterMode.BlockListed=>list.Contains(timeline),
            DashFilterMode.AllowListed=>list.Count>0 && !list.Contains(timeline),
            _=>false
        };
    }
}

public sealed record DashObservation(ushort Timeline,byte Flags2,byte Flags3,byte MoveType,bool Blocked);

public sealed record MovementSkill(uint ActionId,string Name,uint Timeline,bool PlayerAction,bool AffectsPosition,bool PvP);
public static class MovementSkillCatalog
{
    public static MovementSkill[] Select(IEnumerable<MovementSkill> skills) => skills
        .Where(s=>s.PlayerAction && s.AffectsPosition).DistinctBy(s=>s.ActionId).OrderBy(s=>s.ActionId).ToArray();
    public static bool Mappable(MovementSkill skill) => skill.Timeline is >0 and <=ushort.MaxValue;
}