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

namespace PKHeX.Core
{
    public sealed class HallFame3Entry
    {
        private readonly byte[] Parent;
        private readonly bool Japanese;
        private readonly int Offset;

        private const int Count = 6;
        public const int SIZE = Count * HallFame3PKM.SIZE;

        public HallFame3Entry(byte[] data, int offset, bool japanese)
        {
            Parent = data;
            Japanese = japanese;
            Offset = offset;
        }

        private int GetMemberOffset(int index) => Offset + (index * HallFame3PKM.SIZE);
        private HallFame3PKM GetMember(int index) => new(Parent, GetMemberOffset(index), Japanese);

        public HallFame3PKM[] Team
        {
            get
            {
                var team = new HallFame3PKM[6];
                for (int i = 0; i < Count; i++)
                    team[i] = GetMember(i);
                return team;
            }
        }

        private const int MaxEntries = 50;
        private const int MaxLength = MaxEntries * SIZE;

        public static HallFame3Entry[] GetEntries(SAV3 sav)
        {
            byte[] data = sav.GetHallOfFameData();
            Debug.Assert(data.Length > MaxLength);
            bool Japanese = sav.Japanese;

            var entries = new HallFame3Entry[MaxEntries];
            for (int i = 0; i < entries.Length; i++)
                entries[i] = new HallFame3Entry(data, SIZE, Japanese);
            return entries;
        }

        public static void SetEntries(SAV3 sav, HallFame3Entry[] entries)
        {
            byte[] data = entries[0].Team[0].Data;
            sav.SetHallOfFameData(data);
        }
    }

    public sealed class HallFame3PKM
    {
        public const int SIZE = 20;

        public HallFame3PKM(byte[] data, int offset, bool jp)
        {
            Data = data;
            Offset = offset;
            Japanese = jp;
        }

        public readonly byte[] Data;
        private readonly int Offset;
        private readonly bool Japanese;

        public int TID { get => ReadUInt16LittleEndian(Data.AsSpan(0 + Offset)); set => WriteUInt16LittleEndian(Data.AsSpan(0 + Offset), (ushort)value); }
        public int SID { get => ReadUInt16LittleEndian(Data.AsSpan(2 + Offset)); set => WriteUInt16LittleEndian(Data.AsSpan(2 + Offset), (ushort)value); }
        public uint PID { get => ReadUInt32LittleEndian(Data.AsSpan(4 + Offset)); set => WriteUInt32LittleEndian(Data.AsSpan(4 + Offset), value); }
        private int SpecLevel { get => ReadUInt16LittleEndian(Data.AsSpan(8 + Offset)); set => WriteUInt16LittleEndian(Data.AsSpan(8 + Offset), (ushort)value); }

        private Span<byte> Nickname_Trash => Data.AsSpan(10 + Offset, 10);
        public string Nickname { get => StringConverter3.GetString(Nickname_Trash, Japanese); set => StringConverter3.SetString(Nickname_Trash, value.AsSpan(), 10, Japanese, StringConverterOption.ClearZero); }

        public int Species { get => SpecLevel & 0x1FF; set => SpecLevel = (SpecLevel & 0xFE00) | value; }
        public int Level { get => SpecLevel >> 9; set => SpecLevel = (SpecLevel & 0x1FF) | (value << 9); }
    }
}
