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

namespace PKHeX.Core;

/// <summary>
/// Generation 5 <see cref="SaveFile"/> object.
/// </summary>
public abstract class SAV5 : SaveFile, ISaveBlock5BW, IEventFlag37
{
    protected override PK5 GetPKM(byte[] data) => new(data);
    protected override byte[] DecryptPKM(byte[] data) => PokeCrypto.DecryptArray45(data);

    protected internal override string ShortSummary => $"{OT} ({(GameVersion)Game}) - {PlayTimeString}";
    public override string Extension => ".sav";

    public override ReadOnlySpan<ushort> HeldItems => Legal.HeldItems_BW;
    protected override int SIZE_STORED => PokeCrypto.SIZE_5STORED;
    protected override int SIZE_PARTY => PokeCrypto.SIZE_5PARTY;
    public override PK5 BlankPKM => new();
    public override Type PKMType => typeof(PK5);

    public override int BoxCount => 24;
    public override int MaxEV => 255;
    public override int Generation => 5;
    public override EntityContext Context => EntityContext.Gen5;
    public override int MaxStringLengthOT => 7;
    public override int MaxStringLengthNickname => 10;
    protected override int GiftCountMax => 12;
    public abstract int EventFlagCount { get; }
    public abstract int EventWorkCount { get; }
    protected abstract int EventFlagOffset { get; }
    protected abstract int EventWorkOffset { get; }

    public override ushort MaxMoveID => Legal.MaxMoveID_5;
    public override ushort MaxSpeciesID => Legal.MaxSpeciesID_5;
    public override int MaxAbilityID => Legal.MaxAbilityID_5;
    public override int MaxBallID => Legal.MaxBallID_5;
    public override int MaxGameID => Legal.MaxGameID_5; // B2

    protected SAV5(int size) : base(size)
    {
        Initialize();
        ClearBoxes();
    }

    protected SAV5(byte[] data) : base(data)
    {
        Initialize();
    }

    public override GameVersion Version
    {
        get => (GameVersion)Game;
        protected set => Game = (int)value;
    }

    private void Initialize()
    {
        Box = 0x400;
        Party = 0x18E00;
        AdventureInfo = 0x1D900;
    }

    // Blocks & Offsets
    protected override void SetChecksums() => AllBlocks.SetChecksums(Data);
    public override bool ChecksumsValid => AllBlocks.GetChecksumsValid(Data);
    public override string ChecksumInfo => AllBlocks.GetChecksumInfo(Data);

    protected int CGearInfoOffset;
    protected int CGearDataOffset;
    protected int EntreeForestOffset;
    private int AdventureInfo;
    public abstract int GTS { get; }
    public int PGL => AllBlocks[35].Offset + 8; // Dream World Upload

    // Daycare
    public override int DaycareSeedSize => Daycare5.DaycareSeedSize;
    public override bool? IsDaycareOccupied(int loc, int slot) => Daycare.IsOccupied(slot);
    public override int GetDaycareSlotOffset(int loc, int slot) => Daycare.GetPKMOffset(slot);
    public override uint? GetDaycareEXP(int loc, int slot) => Daycare.GetEXP(slot);
    public override void SetDaycareEXP(int loc, int slot, uint EXP) => Daycare.SetEXP(slot, EXP);
    public override void SetDaycareOccupied(int loc, int slot, bool occupied) => Daycare.SetOccupied(slot, occupied);
    public override void SetDaycareRNGSeed(int loc, string seed) => Daycare.SetSeed(seed);

    // Storage
    public override int PartyCount
    {
        get => Data[Party + 4];
        protected set => Data[Party + 4] = (byte)value;
    }

    public override int GetBoxOffset(int box) => Box + (SIZE_STORED * box * 30) + (box * 0x10);
    public override int GetPartyOffset(int slot) => Party + 8 + (SIZE_PARTY * slot);

    protected override int GetBoxWallpaperOffset(int box) => BoxLayout.GetBoxWallpaperOffset(box);
    public override int GetBoxWallpaper(int box) => BoxLayout.GetBoxWallpaper(box);
    public override void SetBoxWallpaper(int box, int value) => BoxLayout.SetBoxWallpaper(box, value);
    public override string GetBoxName(int box) => BoxLayout[box];
    public override void SetBoxName(int box, ReadOnlySpan<char> value) => BoxLayout.SetBoxName(box, value);
    public override int CurrentBox { get => BoxLayout.CurrentBox; set => BoxLayout.CurrentBox = value; }

    protected int BattleBoxOffset;

    public bool BattleBoxLocked
    {
        get => Data[BattleBoxOffset + 0x358] != 0; // wifi/live
        set => Data[BattleBoxOffset + 0x358] = value ? (byte)1 : (byte)0;
    }

    protected override void SetPKM(PKM pk, bool isParty = false)
    {
        var pk5 = (PK5)pk;
        // Apply to this Save File
        DateTime Date = DateTime.Now;
        if (pk5.Trade(OT, ID32, Gender, Date.Day, Date.Month, Date.Year))
            pk.RefreshChecksum();
    }

    // Player Data
    public override string OT { get => PlayerData.OT; set => PlayerData.OT = value; }
    public override uint ID32 { get => PlayerData.ID32; set => PlayerData.ID32 = value; }
    public override ushort TID16 { get => PlayerData.TID16; set => PlayerData.TID16 = value; }
    public override ushort SID16 { get => PlayerData.SID16; set => PlayerData.SID16 = value; }
    public int Country { get => PlayerData.Country; set => PlayerData.Country = value; }
    public int Region { get => PlayerData.Region; set => PlayerData.Region = value; }
    public override int Language { get => PlayerData.Language; set => PlayerData.Language = value; }
    public override int Game { get => PlayerData.Game; set => PlayerData.Game = value; }
    public override int Gender { get => PlayerData.Gender; set => PlayerData.Gender = value; }
    public override int PlayedHours { get => PlayerData.PlayedHours; set => PlayerData.PlayedHours = value; }
    public override int PlayedMinutes { get => PlayerData.PlayedMinutes; set => PlayerData.PlayedMinutes = value; }
    public override int PlayedSeconds { get => PlayerData.PlayedSeconds; set => PlayerData.PlayedSeconds = value; }
    public override uint Money { get => Misc.Money; set => Misc.Money = value; }
    public override uint SecondsToStart { get => ReadUInt32LittleEndian(Data.AsSpan(AdventureInfo + 0x34)); set => WriteUInt32LittleEndian(Data.AsSpan(AdventureInfo + 0x34), value); }
    public override uint SecondsToFame  { get => ReadUInt32LittleEndian(Data.AsSpan(AdventureInfo + 0x3C)); set => WriteUInt32LittleEndian(Data.AsSpan(AdventureInfo + 0x3C), value); }
    public override MysteryGiftAlbum GiftAlbum { get => Mystery.GiftAlbum; set => Mystery.GiftAlbum = (EncryptedMysteryGiftAlbum)value; }
    public override IReadOnlyList<InventoryPouch> Inventory { get => Items.Inventory; set => Items.Inventory = value; }

    protected override void SetDex(PKM pk) => Zukan.SetDex(pk);
    public override bool GetCaught(ushort species) => Zukan.GetCaught(species);
    public override bool GetSeen(ushort species) => Zukan.GetSeen(species);

    public sealed override string GetString(ReadOnlySpan<byte> data) => StringConverter5.GetString(data);

    public sealed override int SetString(Span<byte> destBuffer, ReadOnlySpan<char> value, int maxLength, StringConverterOption option)
    {
        return StringConverter5.SetString(destBuffer, value, maxLength, option);
    }

    public bool GetEventFlag(int flagNumber)
    {
        if ((uint)flagNumber >= EventFlagCount)
            throw new ArgumentOutOfRangeException(nameof(flagNumber), $"Event Flag to get ({flagNumber}) is greater than max ({EventFlagCount}).");
        return GetFlag(EventFlagOffset + (flagNumber >> 3), flagNumber & 7);
    }

    public void SetEventFlag(int flagNumber, bool value)
    {
        if ((uint)flagNumber >= EventFlagCount)
            throw new ArgumentOutOfRangeException(nameof(flagNumber), $"Event Flag to set ({flagNumber}) is greater than max ({EventFlagCount}).");
        SetFlag(EventFlagOffset + (flagNumber >> 3), flagNumber & 7, value);
    }

    public ushort GetWork(int index) => ReadUInt16LittleEndian(Data.AsSpan(EventWorkOffset + (index * 2)));
    public void SetWork(int index, ushort value) => WriteUInt16LittleEndian(Data.AsSpan(EventWorkOffset)[(index * 2)..], value);

    // DLC
    private int CGearSkinInfoOffset => CGearInfoOffset + (this is SAV5B2W2 ? 0x10 : 0) + 0x24;

    private bool CGearSkinPresent
    {
        get => Data[CGearSkinInfoOffset + 2] == 1;
        set => Data[CGearSkinInfoOffset + 2] = Data[PlayerData.Offset + (this is SAV5B2W2 ? 0x6C : 0x54)] = value ? (byte)1 : (byte)0;
    }

    private static ReadOnlySpan<byte> DLCFooter => new byte[] { 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x14, 0x27, 0x00, 0x00, 0x27, 0x35, 0x05, 0x31, 0x00, 0x00 };

    public byte[] CGearSkinData
    {
        get
        {
            if (CGearSkinPresent)
                return Data.AsSpan(CGearDataOffset, CGearBackground.SIZE_CGB).ToArray();
            return new byte[CGearBackground.SIZE_CGB];
        }
        set
        {
            SetData(value, CGearDataOffset);

            ushort chk = Checksums.CRC16_CCITT(value);
            var footer = Data.AsSpan(CGearDataOffset + value.Length);

            WriteUInt16LittleEndian(footer, 1); // block updated once
            WriteUInt16LittleEndian(footer[2..], chk); // checksum
            WriteUInt16LittleEndian(footer[0x100..], chk);  // second checksum

            DLCFooter.CopyTo(footer[0x102..]);

            ushort skinchkval = Checksums.CRC16_CCITT(footer[0x100..0x104]);
            WriteUInt16LittleEndian(footer[0x112..], skinchkval);

            // Indicate in the save file that data is present
            WriteUInt16LittleEndian(Data.AsSpan(0x19438), 0xC21E);

            WriteUInt16LittleEndian(Data.AsSpan(CGearSkinInfoOffset), chk);
            CGearSkinPresent = true;

            State.Edited = true;
        }
    }

    public EntreeForest EntreeData
    {
        get => new(Data.AsSpan(EntreeForestOffset, EntreeForest.SIZE).ToArray());
        set => SetData(value.Write(), EntreeForestOffset);
    }

    public abstract IReadOnlyList<BlockInfo> AllBlocks { get; }
    public abstract MyItem Items { get; }
    public abstract Zukan5 Zukan { get; }
    public abstract Misc5 Misc { get; }
    public abstract MysteryBlock5 Mystery { get; }
    public abstract Daycare5 Daycare { get; }
    public abstract BoxLayout5 BoxLayout { get; }
    public abstract PlayerData5 PlayerData { get; }
    public abstract BattleSubway5 BattleSubway { get; }
    public abstract Entralink5 Entralink { get; }
    public abstract Musical5 Musical { get; }
    public abstract Encount5 Encount { get; }

    public static int GetMailOffset(int index) => (index * Mail5.SIZE) + 0x1DD00;
    public byte[] GetMailData(int offset) => Data.AsSpan(offset, Mail5.SIZE).ToArray();
    public int GetBattleBoxSlot(int slot) => BattleBoxOffset + (slot * SIZE_STORED);

    public MailDetail GetMail(int mailIndex)
    {
        int ofs = GetMailOffset(mailIndex);
        var data = GetMailData(ofs);
        return new Mail5(data, ofs);
    }
}