using System;
using static System.Buffers.Binary.BinaryPrimitives;

namespace PKHeX.Core;

public sealed class ItemInfo6 : SaveBlock<SAV6>
{
    public ItemInfo6(SAV6 sav, int offset) : base(sav) => Offset = offset;

    private const int BoundItemCount = 4;
    private const int RecentItemCount = 12;

    public int[] SelectItems
    {
        // UP,RIGHT,DOWN,LEFT
        get
        {
            var span = Data.AsSpan(Offset + 10);
            int[] list = new int[BoundItemCount];
            for (int i = 0; i < list.Length; i++)
                list[i] = ReadUInt16LittleEndian(span[(2 * i)..]);
            return list;
        }
        set
        {
            if (value.Length != BoundItemCount)
                throw new ArgumentException(nameof(value));
            var span = Data.AsSpan(Offset + 10);
            for (int i = 0; i < value.Length; i++)
                WriteUInt16LittleEndian(span[(2 * i)..], (ushort)value[i]);
        }
    }

    public int[] RecentItems
    {
        // Items recently interacted with (Give, Use)
        get
        {
            var span = Data.AsSpan(Offset + 20);
            int[] list = new int[RecentItemCount];
            for (int i = 0; i < list.Length; i++)
                list[i] = ReadUInt16LittleEndian(span[(2 * i)..]);
            return list;
        }
        set
        {
            if (value.Length != RecentItemCount)
                throw new ArgumentException(nameof(value));
            var span = Data.AsSpan(Offset + 20);
            for (int i = 0; i < value.Length; i++)
                WriteUInt16LittleEndian(span[(2 * i)..], (ushort)value[i]);
        }
    }
}