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

namespace PKHeX.Core;

/// <summary>
/// <see cref="SaveFile"/> format for <see cref="GameVersion.DP"/>
/// </summary>
public sealed class SAV4DP : SAV4Sinnoh
{
    public SAV4DP() : base(GeneralSize, StorageSize)
    {
        Initialize();
        Dex = new Zukan4(this, PokeDex);
    }

    public SAV4DP(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 SAV4DP((byte[])Data.Clone()) : new SAV4DP();
    public override PersonalTable4 Personal => PersonalTable.DP;
    public override IReadOnlyList<ushort> HeldItems => Legal.HeldItems_DP;
    public override int MaxItemID => Legal.MaxItemID_4_DP;

    private const int GeneralSize = 0xC100;
    private const int StorageSize = 0x121E0; // Start 0xC100, +4 starts box data
    protected override int StorageStart => GeneralSize;

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

    protected override int EventWork => 0xD9C;
    protected override int EventFlag => 0xFDC;

    private void GetSAVOffsets()
    {
        AdventureInfo = 0;
        Trainer1 = 0x64;
        Party = 0x98;
        PokeDex = 0x12DC;
        Geonet = 0x96D9;
        WondercardFlags = 0xA6D0;
        WondercardData = 0xA7fC;

        DaycareOffset = 0x141C;
        OFS_HONEY = 0x72E4;

        OFS_UG_Stats = 0x3A2C;
        OFS_UG_Items = 0x42B0;

        PoketchStart = 0x114C;
        Seal = 0x6178;

        OFS_PoffinCase = 0x5050;

        Box = 4;
    }

    #region Storage
    public override int GetBoxWallpaper(int box)
    {
        if ((uint)box >= 18)
            return 0;
        return Storage[GetBoxWallpaperOffset(box)];
    }

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

    public override IReadOnlyList<InventoryPouch> Inventory
    {
        get
        {
            InventoryPouch[] pouch =
            {
                new InventoryPouch4(InventoryType.Items, Legal.Pouch_Items_DP, 999, 0x624),
                new InventoryPouch4(InventoryType.KeyItems, Legal.Pouch_Key_DP, 1, 0x8B8),
                new InventoryPouch4(InventoryType.TMHMs, Legal.Pouch_TMHM_DP, 99, 0x980),
                new InventoryPouch4(InventoryType.MailItems, Legal.Pouch_Mail_DP, 999, 0xB10),
                new InventoryPouch4(InventoryType.Medicine, Legal.Pouch_Medicine_DP, 999, 0xB40),
                new InventoryPouch4(InventoryType.Berries, Legal.Pouch_Berries_DP, 999, 0xBE0),
                new InventoryPouch4(InventoryType.Balls, Legal.Pouch_Ball_DP, 999, 0xCE0),
                new InventoryPouch4(InventoryType.BattleItems, Legal.Pouch_Battle_DP, 999, 0xD1C),
            };
            return pouch.LoadAll(General);
        }
        set => value.SaveAll(General);
    }

    // reverse crc32 polynomial, nice!
    private const uint MysteryGiftDPSlotActive = 0xEDB88320;

    public bool[] GetMysteryGiftDPSlotActiveFlags()
    {
        var span = General.AsSpan(WondercardFlags + 0x100); // skip over flags
        bool[] active = new bool[GiftCountMax]; // 8 PGT, 3 PCD
        for (int i = 0; i < active.Length; i++)
            active[i] = ReadUInt32LittleEndian(span[(4*i)..]) == MysteryGiftDPSlotActive;

        return active;
    }

    public void SetMysteryGiftDPSlotActiveFlags(ReadOnlySpan<bool> value)
    {
        if (value.Length != GiftCountMax)
            return;

        var span = General.AsSpan(WondercardFlags + 0x100); // skip over flags
        for (int i = 0; i < value.Length; i++)
            WriteUInt32LittleEndian(span[(4 * i)..], value[i] ? MysteryGiftDPSlotActive : 0);
    }

    public override MysteryGiftAlbum GiftAlbum
    {
        get => base.GiftAlbum;
        set
        {
            base.GiftAlbum = value;
            SetActiveGiftFlags(value.Gifts);
        }
    }

    private void SetActiveGiftFlags(IReadOnlyList<MysteryGift> gifts)
    {
        var arr = new bool[gifts.Count];
        for (int i = 0; i < arr.Length; i++)
            arr[i] = !gifts[i].Empty;
        SetMysteryGiftDPSlotActiveFlags(arr);
    }

    public override int M { get => ReadUInt16LittleEndian(General.AsSpan(0x1238)); set => WriteUInt16LittleEndian(General.AsSpan(0x1238), (ushort)value); }
    public override int X { get => ReadUInt16LittleEndian(General.AsSpan(0x1240)); set => WriteUInt16LittleEndian(General.AsSpan(0x1240), (ushort)(X2 = value)); }
    public override int Y { get => ReadUInt16LittleEndian(General.AsSpan(0x1244)); set => WriteUInt16LittleEndian(General.AsSpan(0x1244), (ushort)(Y2 = value)); }

    public override Span<byte> Rival_Trash
    {
        get => General.AsSpan(0x25A8, MaxStringLengthOT * 2);
        set { if (value.Length == MaxStringLengthOT * 2) value.CopyTo(General.AsSpan(0x25A8)); }
    }

    public override int X2 { get => ReadUInt16LittleEndian(General.AsSpan(0x25FA)); set => WriteUInt16LittleEndian(General.AsSpan(0x25FA), (ushort)value); }
    public override int Y2 { get => ReadUInt16LittleEndian(General.AsSpan(0x25FE)); set => WriteUInt16LittleEndian(General.AsSpan(0x25FE), (ushort)value); }
    public override int Z { get => ReadUInt16LittleEndian(General.AsSpan(0x2602)); set => WriteUInt16LittleEndian(General.AsSpan(0x2602), (ushort)value); }

    public override uint SafariSeed { get => ReadUInt32LittleEndian(General.AsSpan(0x53C4)); set => WriteUInt32LittleEndian(General.AsSpan(0x53C4), value); }
    public override uint SwarmSeed { get => ReadUInt32LittleEndian(General.AsSpan(0x53C8)); set => WriteUInt32LittleEndian(General.AsSpan(0x53C8), value); }
    public override uint SwarmMaxCountModulo => 28;

    public Roamer4 RoamerMesprit   => new(General, 0x73A0);
    public Roamer4 RoamerCresselia => new(General, 0x73B4);
    public Roamer4 RoamerUnused    => new(General, 0x73C8); // Darkrai
}