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

namespace PKHeX.Core;

/// <summary>
/// Generation 7 <see cref="SaveFile"/> object.
/// </summary>
public abstract class SAV7 : SAV_BEEF, ITrainerStatRecord, ISaveBlock7Main, IRegionOrigin, IGameSync, IEventFlag37
{
    // Save Data Attributes
    protected internal override string ShortSummary => $"{OT} ({Version}) - {Played.LastSavedTime}";
    public override string Extension => string.Empty;

    public override IReadOnlyList<string> PKMExtensions => Array.FindAll(PKM.Extensions, f =>
    {
        int gen = f[^1] - 0x30;
        return gen <= 7 && f[1] != 'b'; // ignore PB7
    });

    protected SAV7(byte[] data, [ConstantExpected] int biOffset) : base(data, biOffset)
    {
    }

    protected SAV7([ConstantExpected] int size, [ConstantExpected] int biOffset) : base(size, biOffset)
    {
    }

    protected void ReloadBattleTeams()
    {
        var demo = this is SAV7SM && !Data.AsSpan(BoxLayout.Offset, 0x4C4).ContainsAnyExcept<byte>(0); // up to Battle Box values
        if (demo || !State.Exportable)
        {
            BoxLayout.ClearBattleTeams();
        }
        else // Valid slot locking info present
        {
            BoxLayout.LoadBattleTeams();
        }
    }

    #region Blocks
    public abstract MyItem Items { get; }
    public abstract MysteryBlock7 MysteryGift { get; }
    public abstract PokeFinder7 PokeFinder { get; }
    public abstract JoinFesta7 Festa { get; }
    public abstract Daycare7 Daycare { get; }
    public abstract RecordBlock6 Records { get; }
    public abstract PlayTime6 Played { get; }
    public abstract MyStatus7 MyStatus { get; }
    public abstract FieldMoveModelSave7 Overworld { get; }
    public abstract Situation7 Situation { get; }
    public abstract ConfigSave7 Config { get; }
    public abstract GameTime7 GameTime { get; }
    public abstract Misc7 Misc { get; }
    public abstract Zukan7 Zukan { get; }
    public abstract BoxLayout7 BoxLayout { get; }
    public abstract BattleTree7 BattleTree { get; }
    public abstract ResortSave7 ResortSave { get; }
    public abstract FieldMenu7 FieldMenu { get; }
    public abstract FashionBlock7 Fashion { get; }
    public abstract HallOfFame7 Fame { get; }
    #endregion

    // Configuration
    protected override int SIZE_STORED => PokeCrypto.SIZE_6STORED;
    protected override int SIZE_PARTY => PokeCrypto.SIZE_6PARTY;
    public override PK7 BlankPKM => new();
    public override Type PKMType => typeof(PK7);

    public override int BoxCount => 32;
    public override int MaxEV => EffortValues.Max252;
    public override int Generation => 7;
    public override EntityContext Context => EntityContext.Gen7;
    protected override int GiftCountMax => 48;
    protected override int GiftFlagMax => 0x100 * 8;
    public abstract int EventFlagCount { get; }
    public int EventWorkCount => 1000;
    private int EventWork => AllBlocks[05].Offset;
    private int EventFlag => EventWork + (EventWorkCount * 2); // After Event Const (u16)*n
    public override int MaxStringLengthOT => 12;
    public override int MaxStringLengthNickname => 12;

    public override int MaxBallID => Legal.MaxBallID_7; // 26
    public override int MaxGameID => Legal.MaxGameID_7;
    protected override PK7 GetPKM(byte[] data) => new(data);
    protected override byte[] DecryptPKM(byte[] data) => PokeCrypto.DecryptArray6(data);

    // Feature Overrides

    // Blocks & Offsets
    private const int MemeCryptoBlock = 36;

    protected void ClearMemeCrypto()
    {
        // The MemeCrypto block is always zero -- they could have hidden a secret inside it, but they didn't.
        Data.AsSpan(AllBlocks[MemeCryptoBlock].Offset + 0x100, MemeCrypto.SaveFileSignatureLength).Clear();
    }

    protected override byte[] GetFinalData()
    {
        BoxLayout.SaveBattleTeams();
        SetChecksums();

        // Applying the MemeCrypto signature will invalidate the checksum for that block.
        // This logic is not set up to revert that block after returning, so just return a copy of our data.
        var result = (byte[])Data.Clone();
        MemeCrypto.SignInPlace(result);
        return result;
    }

    public override GameVersion Version => Game switch
    {
        (int)GameVersion.SN => GameVersion.SN,
        (int)GameVersion.MN => GameVersion.MN,
        (int)GameVersion.US => GameVersion.US,
        (int)GameVersion.UM => GameVersion.UM,
        _ => GameVersion.Invalid,
    };

    public sealed override string GetString(ReadOnlySpan<byte> data) => StringConverter7.GetString(data);

    public sealed override int SetString(Span<byte> destBuffer, ReadOnlySpan<char> value, int maxLength, StringConverterOption option)
    {
        return StringConverter7.SetString(destBuffer, value, maxLength, Language, option);
    }

    // Player Information
    public override uint ID32 { get => MyStatus.ID32; set => MyStatus.ID32 = value; }
    public override ushort TID16 { get => MyStatus.TID16; set => MyStatus.TID16 = value; }
    public override ushort SID16 { get => MyStatus.SID16; set => MyStatus.SID16 = value; }
    public override int Game { get => MyStatus.Game; set => MyStatus.Game = value; }
    public override int Gender { get => MyStatus.Gender; set => MyStatus.Gender = value; }
    public int GameSyncIDSize => MyStatus7.GameSyncIDSize; // 64 bits
    public string GameSyncID { get => MyStatus.GameSyncID; set => MyStatus.GameSyncID = value; }
    public byte Region { get => MyStatus.Region; set => MyStatus.Region = value; }
    public byte Country { get => MyStatus.Country; set => MyStatus.Country = value; }
    public byte ConsoleRegion { get => MyStatus.ConsoleRegion; set => MyStatus.ConsoleRegion = value; }
    public override int Language { get => MyStatus.Language; set => MyStatus.Language = value; }
    public override string OT { get => MyStatus.OT; set => MyStatus.OT = value; }
    public int MultiplayerSpriteID { get => MyStatus.MultiplayerSpriteID; set => MyStatus.MultiplayerSpriteID = value; }
    public override uint Money { get => Misc.Money; set => Misc.Money = value; }

    public override int PlayedHours { get => Played.PlayedHours; set => Played.PlayedHours = value; }
    public override int PlayedMinutes { get => Played.PlayedMinutes; set => Played.PlayedMinutes = value; }
    public override int PlayedSeconds { get => Played.PlayedSeconds; set => Played.PlayedSeconds = value; }
    public override uint SecondsToStart { get => GameTime.SecondsToStart; set => GameTime.SecondsToStart = value; }
    public override uint SecondsToFame { get => GameTime.SecondsToFame; set => GameTime.SecondsToFame = value; }

    // Stat Records
    public int RecordCount => 200;
    public int GetRecord(int recordID) => Records.GetRecord(recordID);
    public void SetRecord(int recordID, int value) => Records.SetRecord(recordID, value);
    public int GetRecordMax(int recordID) => Records.GetRecordMax(recordID);
    public int GetRecordOffset(int recordID) => Records.GetRecordOffset(recordID);

    // Inventory
    public override IReadOnlyList<InventoryPouch> Inventory { get => Items.Inventory; set => Items.Inventory = value; }

    // Storage
    public override int GetPartyOffset(int slot) => Party + (SIZE_PARTY * slot);
    public override int GetBoxOffset(int box) => Box + (SIZE_STORED * box * 30);
    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; }
    public override int BoxesUnlocked { get => BoxLayout.BoxesUnlocked; set => BoxLayout.BoxesUnlocked = value; }
    public override byte[] BoxFlags { get => BoxLayout.BoxFlags; set => BoxLayout.BoxFlags = value; }

    protected override void SetPKM(PKM pk, bool isParty = false)
    {
        PK7 pk7 = (PK7)pk;
        // Apply to this Save File
        int CT = pk7.CurrentHandler;
        var now = EncounterDate.GetDate3DS();
        pk7.Trade(this, now.Day, now.Month, now.Year);
        if (CT != pk7.CurrentHandler) // Logic updated Friendship
        {
            // Copy over the Friendship Value only under certain circumstances
            if (pk7.HasMove(216)) // Return
                pk7.CurrentFriendship = pk7.OppositeFriendship;
            else if (pk7.HasMove(218)) // Frustration
                pk.CurrentFriendship = pk7.OppositeFriendship;
        }

        pk7.FormArgumentElapsed = pk7.FormArgumentMaximum = 0;
        pk7.FormArgumentRemain = (byte)GetFormArgument(pk);

        pk.RefreshChecksum();
        AddCountAcquired(pk);
    }

    private void AddCountAcquired(PKM pk)
    {
        Records.AddRecord(pk.WasEgg ? 008 : 006); // egg, capture
        if (pk.CurrentHandler == 1)
            Records.AddRecord(011); // trade
        if (!pk.WasEgg)
        {
            Records.AddRecord(004); // wild encounters
            Records.AddRecord(042); // balls used
        }
    }

    private static uint GetFormArgument(PKM pk)
    {
        if (pk.Form == 0)
            return 0;
        // Gen7 allows forms to be stored in the box with the current duration & form
        // Just cap out the form duration anyway
        return pk.Species switch
        {
            (int)Species.Furfrou => 5u, // Furfrou
            (int)Species.Hoopa => 3u, // Hoopa
            _ => 0u,
        };
    }

    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 override int PartyCount
    {
        get => Data[Party + (6 * SIZE_PARTY)];
        protected set => Data[Party + (6 * SIZE_PARTY)] = (byte)value;
    }

    public override StorageSlotSource GetSlotFlags(int index)
    {
        int team = Array.IndexOf(TeamSlots, index);
        if (team < 0)
            return StorageSlotSource.None;

        team /= 6;
        var result = (StorageSlotSource)((int)StorageSlotSource.BattleTeam1 << team);
        if (BoxLayout.GetIsTeamLocked(team))
            result |= StorageSlotSource.Locked;
        return result;
    }

    private int FusedCount => this is SAV7USUM ? 3 : 1;

    public int GetFusedSlotOffset(int slot)
    {
        if ((uint)slot >= FusedCount)
            return -1;
        return AllBlocks[08].Offset + (PokeCrypto.SIZE_6PARTY * slot); // 0x104*slot
    }

    public override int DaycareSeedSize => Daycare7.DaycareSeedSize; // 128 bits
    public override int GetDaycareSlotOffset(int loc, int slot) => Daycare.GetDaycareSlotOffset(slot);
    public override bool? IsDaycareOccupied(int loc, int slot) => Daycare.GetIsOccupied(slot);
    public override string GetDaycareRNGSeed(int loc) => Daycare.RNGSeed;
    public override bool? IsDaycareHasEgg(int loc) => Daycare.HasEgg;
    public override void SetDaycareOccupied(int loc, int slot, bool occupied) => Daycare.SetOccupied(slot, occupied);
    public override void SetDaycareRNGSeed(int loc, string seed) => Daycare.RNGSeed = seed;
    public override void SetDaycareHasEgg(int loc, bool hasEgg) => Daycare.HasEgg = hasEgg;

    protected override bool[] MysteryGiftReceivedFlags { get => MysteryGift.MysteryGiftReceivedFlags; set => MysteryGift.MysteryGiftReceivedFlags = value; }
    protected override DataMysteryGift[] MysteryGiftCards { get => MysteryGift.MysteryGiftCards; set => MysteryGift.MysteryGiftCards = value; }
    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(EventFlag + (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(EventFlag + (flagNumber >> 3), flagNumber & 7, value);
    }

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