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

namespace PKHeX.Core;

/// <summary>
/// <see cref="SaveFile"/> format for <see cref="GameVersion.Pt"/>
/// </summary>
public sealed class SAV4Pt : SAV4Sinnoh
{
    public SAV4Pt() : base(GeneralSize, StorageSize)
    {
        Initialize();
        Dex = new Zukan4(this, PokeDex);
    }

    public SAV4Pt(byte[] data) : base(data, GeneralSize, StorageSize, GeneralSize)
    {
        Initialize();
        Dex = new Zukan4(this, PokeDex);
    }

    public override Zukan4 Dex { get; }
    protected override SAV4 CloneInternal4() => State.Exportable ? new SAV4Pt((byte[])Data.Clone()) : new SAV4Pt();
    public override PersonalTable4 Personal => PersonalTable.Pt;
    public override ReadOnlySpan<ushort> HeldItems => Legal.HeldItems_Pt;
    public override int MaxItemID => Legal.MaxItemID_4_Pt;

    private const int GeneralSize = 0xCF2C;
    private const int StorageSize = 0x121E4; // Start 0xCF2C, +4 starts box data

    private void Initialize()
    {
        Version = GameVersion.Pt;
        GetSAVOffsets();
    }

    protected override int EventWork => 0xDAC;
    protected override int EventFlag => 0xFEC;

    private void GetSAVOffsets()
    {
        AdventureInfo = 0;
        Trainer1 = 0x68;
        Party = 0xA0;
        PokeDex = 0x1328;
        Geonet = 0xA4C4;
        WondercardFlags = 0xB4C0;
        WondercardData = 0xB5C0;

        DaycareOffset = 0x1654;
        OFS_HONEY = 0x7F38;

        OFS_UG_Stats = 0x3CB4;
        OFS_UG_Items = 0x4538;

        PoketchStart = 0x1160;

        OFS_PoffinCase = 0x52E8;
        Seal = 0x6494;

        Box = 4;
    }

    #region Storage
    private static int AdjustWallpaper(int value, int shift)
    {
        // Pt's  Special Wallpapers 1-8 are shifted by +0x8
        // HG/SS Special Wallpapers 1-8 (Primo Phrases) are shifted by +0x10
        if (value >= 0x10) // special
            return value + shift;
        return value;
    }

    public override int GetBoxWallpaper(int box)
    {
        if ((uint)box > 18)
            return 0;
        int value = Storage[GetBoxWallpaperOffset(box)];
        return AdjustWallpaper(value, -0x08);
    }

    public override void SetBoxWallpaper(int box, int value)
    {
        if ((uint)box >= 18)
            return;
        value = AdjustWallpaper(value, 0x08);
        Storage[GetBoxWallpaperOffset(box)] = (byte)value;
    }
    #endregion

    public override IReadOnlyList<InventoryPouch> Inventory
    {
        get
        {
            var info = ItemStorage4Pt.Instance;
            InventoryPouch[] pouch =
            {
                new InventoryPouch4(InventoryType.Items, info, 999, 0x630),
                new InventoryPouch4(InventoryType.KeyItems, info, 1, 0x8C4),
                new InventoryPouch4(InventoryType.TMHMs, info, 99, 0x98C),
                new InventoryPouch4(InventoryType.MailItems, info, 999, 0xB1C),
                new InventoryPouch4(InventoryType.Medicine, info, 999, 0xB4C),
                new InventoryPouch4(InventoryType.Berries, info, 999, 0xBEC),
                new InventoryPouch4(InventoryType.Balls, info, 999, 0xCEC),
                new InventoryPouch4(InventoryType.BattleItems, info, 999, 0xD28),
            };
            return pouch.LoadAll(General);
        }
        set => value.SaveAll(General);
    }

    public override int M { get => ReadUInt16LittleEndian(General[0x1280..]); set => WriteUInt16LittleEndian(General[0x1280..], (ushort)value); }
    public override int X { get => ReadUInt16LittleEndian(General[0x1288..]); set => WriteUInt16LittleEndian(General[0x1288..], (ushort)(X2 = value)); }
    public override int Y { get => ReadUInt16LittleEndian(General[0x128C..]); set => WriteUInt16LittleEndian(General[0x128C..], (ushort)(Y2 = value)); }

    public override Span<byte> Rival_Trash
    {
        get => RivalSpan;
        set { if (value.Length == MaxStringLengthOT * 2) value.CopyTo(RivalSpan); }
    }

    private Span<byte> RivalSpan => General.Slice(0x27E8, MaxStringLengthOT * 2);

    public override int X2 { get => ReadUInt16LittleEndian(General[0x287E..]); set => WriteUInt16LittleEndian(General[0x287E..], (ushort)value); }
    public override int Y2 { get => ReadUInt16LittleEndian(General[0x2882..]); set => WriteUInt16LittleEndian(General[0x2882..], (ushort)value); }
    public override int Z  { get => ReadUInt16LittleEndian(General[0x2886..]); set => WriteUInt16LittleEndian(General[0x2886..], (ushort)value); }

    public override uint SafariSeed { get => ReadUInt32LittleEndian(General[0x5660..]); set => WriteUInt32LittleEndian(General[0x5660..], value); }
    public override uint SwarmSeed { get => ReadUInt32LittleEndian(General[0x5664..]); set => WriteUInt32LittleEndian(General[0x5664..], value); }
    public override uint SwarmMaxCountModulo => 22;

    protected override ReadOnlySpan<ushort> TreeSpecies => new ushort[]
    {
        000, 000, 000, 000, 000, 000,
        415, 265, 412, 420, 190, 190,
        412, 420, 415, 190, 190, 214,
        446, 446, 446, 446, 446, 446,
    };

    public Roamer4 RoamerMesprit   => GetRoamer(0);
    public Roamer4 RoamerCresselia => GetRoamer(1);
    public Roamer4 RoamerUnused    => GetRoamer(2); // Darkrai
    public Roamer4 RoamerArticuno  => GetRoamer(3);
    public Roamer4 RoamerZapdos    => GetRoamer(4);
    public Roamer4 RoamerMoltres   => GetRoamer(5);

    private Roamer4 GetRoamer(int index)
    {
        const int size = Roamer4.SIZE;
        var ofs = 0x7FF4 + (index * size);
        var mem = GeneralBuffer.Slice(ofs, size);
        return new Roamer4(mem);
    }
}