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

namespace PKHeX.Core;

/// <summary> Generation 8 <see cref="PKM"/> format. </summary>
public sealed class PK8 : G8PKM
{
    public override ReadOnlySpan<ushort> ExtraBytes =>
    [
        // Alignment bytes
        0x17, 0x1A, 0x1B, 0x23, 0x33, 0x3E, 0x3F,
        0x4C, 0x4D, 0x4E, 0x4F,
        0x52, 0x53, 0x54, 0x55, 0x56, 0x57,

        0x91, 0x92, 0x93,
        0x9C, 0x9D, 0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,

        0xC5,
        0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, // Pokejob
        0xE0, 0xE1, // Old Console Region / Region
        0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7,
        0x115, 0x11F, // Alignment

        0x13D, 0x13E, 0x13F,
        0x140, 0x141, 0x142, 0x143, 0x144, 0x145, 0x146, 0x147,
    ];

    public override PersonalInfo8SWSH PersonalInfo => PersonalTable.SWSH.GetFormEntry(Species, Form);
    public override IPermitRecord Permit => PersonalInfo;
    public override bool IsNative => SWSH;
    public override EntityContext Context => EntityContext.Gen8;

    public PK8() => AffixedRibbon = -1; // 00 would make it show Kalos Champion :)
    public PK8(byte[] data) : base(data) { }
    public override PK8 Clone() => new((byte[])Data.Clone());

    public void Trade(ITrainerInfo tr, int Day = 1, int Month = 1, int Year = 2015)
    {
        if (IsEgg)
        {
            // Eggs do not have any modifications done if they are traded
            // Apply link trade data, only if it left the OT (ignore if dumped & imported, or cloned, etc.)
            if ((tr.TID16 != TID16) || (tr.SID16 != SID16) || (tr.Gender != OT_Gender) || (tr.OT != OT_Name))
                SetLinkTradeEgg(Day, Month, Year, Locations.LinkTrade6);
            return;
        }

        // Process to the HT if the OT of the Pokémon does not match the SAV's OT info.
        if (!TradeOT(tr))
            TradeHT(tr);
    }

    public int DynamaxType { get => ReadUInt16LittleEndian(Data.AsSpan(0x156)); set => WriteUInt16LittleEndian(Data.AsSpan(0x156), (ushort)value); }

    public void FixMemories()
    {
        if (IsEgg) // No memories if is egg.
        {
            HT_Friendship = HT_TextVar = HT_Memory = HT_Intensity = HT_Feeling = HT_Language = 0;
            /* OT_Friendship */ OT_TextVar = OT_Memory = OT_Intensity = OT_Feeling = 0;

            // Clear Handler
            HT_Trash.Clear();
            return;
        }

        if (IsUntraded)
            HT_Friendship = HT_TextVar = HT_Memory = HT_Intensity = HT_Feeling = HT_Language = 0;

        int gen = Generation;
        if (gen < 6)
            OT_TextVar = OT_Memory = OT_Intensity = OT_Feeling = 0;
        if (gen != 8) // must be transferred via HOME, and must have memories
            this.SetTradeMemoryHT8(); // not faking HOME tracker.
    }

    private bool TradeOT(ITrainerInfo tr)
    {
        // Check to see if the OT matches the SAV's OT info.
        if (!(tr.ID32 == ID32 && tr.Gender == OT_Gender && tr.OT == OT_Name))
            return false;

        CurrentHandler = 0;
        return true;
    }

    private void TradeHT(ITrainerInfo tr)
    {
        if (HT_Name != tr.OT)
        {
            HT_Friendship = 50;
            HT_Name = tr.OT;
        }
        CurrentHandler = 1;
        HT_Gender = tr.Gender;
        HT_Language = (byte)tr.Language;
        this.SetTradeMemoryHT8();
    }

    // Maximums
    public override ushort MaxMoveID => Legal.MaxMoveID_8;
    public override ushort MaxSpeciesID => Legal.MaxSpeciesID_8;
    public override int MaxAbilityID => Legal.MaxAbilityID_8;
    public override int MaxItemID => Legal.MaxItemID_8;
    public override int MaxBallID => Legal.MaxBallID_8;
    public override int MaxGameID => Legal.MaxGameID_8;
    public bool IsSideTransfer => LocationsHOME.IsLocationSWSH(Met_Location);
    public override bool SV => Met_Location is LocationsHOME.SWSL or LocationsHOME.SHVL;
    public override bool BDSP => Met_Location is LocationsHOME.SWBD or LocationsHOME.SHSP;
    public override bool LA => Met_Location is LocationsHOME.SWLA;
    public override bool HasOriginalMetLocation => base.HasOriginalMetLocation && !(BDSP || LA);
}