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

namespace PKHeX.Core;

/// <summary>
/// <see cref="PersonalInfo"/> class with values from the <see cref="GameVersion.ZA"/> games.
/// </summary>
public sealed class PersonalInfo9ZA(Memory<byte> Raw) : PersonalInfo, IPersonalAbility12H, IPersonalInfoTM, IPermitPlus
{
    public const int SIZE = 0x50;

    private Span<byte> Data => Raw.Span;
    public override byte[] Write() => Raw.ToArray();

    public override int HP { get => Data[0x00]; set => Data[0x00] = (byte)value; }
    public override int ATK { get => Data[0x01]; set => Data[0x01] = (byte)value; }
    public override int DEF { get => Data[0x02]; set => Data[0x02] = (byte)value; }
    public override int SPE { get => Data[0x03]; set => Data[0x03] = (byte)value; }
    public override int SPA { get => Data[0x04]; set => Data[0x04] = (byte)value; }
    public override int SPD { get => Data[0x05]; set => Data[0x05] = (byte)value; }
    public override byte Type1 { get => Data[0x06]; set => Data[0x06] = value; }
    public override byte Type2 { get => Data[0x07]; set => Data[0x07] = value; }
    public override byte CatchRate { get => Data[0x08]; set => Data[0x08] = value; }
    public override int EvoStage { get => Data[0x09]; set => Data[0x09] = (byte)value; }
    private int EVYield { get => ReadUInt16LittleEndian(Data[0x0A..]); set => WriteUInt16LittleEndian(Data[0x0A..], (ushort)value); }
    public override int EV_HP { get => (EVYield >> 0) & 0x3; set => EVYield = (EVYield & ~(0x3 << 0)) | ((value & 0x3) << 0); }
    public override int EV_ATK { get => (EVYield >> 2) & 0x3; set => EVYield = (EVYield & ~(0x3 << 2)) | ((value & 0x3) << 2); }
    public override int EV_DEF { get => (EVYield >> 4) & 0x3; set => EVYield = (EVYield & ~(0x3 << 4)) | ((value & 0x3) << 4); }
    public override int EV_SPE { get => (EVYield >> 6) & 0x3; set => EVYield = (EVYield & ~(0x3 << 6)) | ((value & 0x3) << 6); }
    public override int EV_SPA { get => (EVYield >> 8) & 0x3; set => EVYield = (EVYield & ~(0x3 << 8)) | ((value & 0x3) << 8); }
    public override int EV_SPD { get => (EVYield >> 10) & 0x3; set => EVYield = (EVYield & ~(0x3 << 10)) | ((value & 0x3) << 10); }
    public override byte Gender { get => Data[0x0C]; set => Data[0x0C] = value; }
    public override byte HatchCycles { get => Data[0x0D]; set => Data[0x0D] = value; }
    public override byte BaseFriendship { get => Data[0x0E]; set => Data[0x0E] = value; }
    public override byte EXPGrowth { get => Data[0x0F]; set => Data[0x0F] = value; }
    public override int EggGroup1 { get => Data[0x10]; set => Data[0x10] = (byte)value; }
    public override int EggGroup2 { get => Data[0x11]; set => Data[0x11] = (byte)value; }
    public int Ability1 { get => ReadUInt16LittleEndian(Data[0x12..]); set => WriteUInt16LittleEndian(Data[0x12..], (ushort)value); }
    public int Ability2 { get => ReadUInt16LittleEndian(Data[0x14..]); set => WriteUInt16LittleEndian(Data[0x14..], (ushort)value); }
    public int AbilityH { get => ReadUInt16LittleEndian(Data[0x16..]); set => WriteUInt16LittleEndian(Data[0x16..], (ushort)value); }
    public override int FormStatsIndex { get => ReadUInt16LittleEndian(Data[0x18..]); set => WriteUInt16LittleEndian(Data[0x18..], (ushort)value); }
    public override byte FormCount { get => Data[0x1A]; set => Data[0x1A] = value; }
    public override int Color { get => Data[0x1B]; set => Data[0x1B] = (byte)value; }
    public bool IsPresentInGame { get => Data[0x1C] != 0; set => Data[0x1C] = value ? (byte)1 : (byte)0; }
    // 0x1D unused
    public ushort DexIndex { get => ReadUInt16LittleEndian(Data[0x1E..]); set => WriteUInt16LittleEndian(Data[0x1E..], value); }
    public override int Height { get => ReadUInt16LittleEndian(Data[0x20..]); set => WriteUInt16LittleEndian(Data[0x20..], (ushort)value); }
    public override int Weight { get => ReadUInt16LittleEndian(Data[0x22..]); set => WriteUInt16LittleEndian(Data[0x22..], (ushort)value); }
    public ushort HatchSpecies { get => ReadUInt16LittleEndian(Data[0x24..]); set => WriteUInt16LittleEndian(Data[0x24..], value); } // ZA: no eggs, but we'll retain it
    public byte LocalFormIndex { get => (byte)ReadUInt16LittleEndian(Data[0x26..]); set => WriteUInt16LittleEndian(Data[0x26..], value); } // local region base form
    public ushort RegionalFlags { get => ReadUInt16LittleEndian(Data[0x28..]); set => WriteUInt16LittleEndian(Data[0x28..], value); }
    public bool IsRegionalForm { get => (RegionalFlags & 1) == 1; set => RegionalFlags = (ushort)((RegionalFlags & 0xFFFE) | (value ? 1 : 0)); }
    public ushort RegionalFormIndex { get => (byte)ReadUInt16LittleEndian(Data[0x2A..]); set => WriteUInt16LittleEndian(Data[0x2A..], value); }

    public override int EscapeRate { get => 0; set { } }

    /// <summary>
    /// Gets the Form that any offspring will hatch with, assuming it is holding an Everstone.
    /// </summary>
    public byte HatchFormIndexEverstone => IsRegionalForm ? (byte)RegionalFormIndex : LocalFormIndex;

    /// <summary>
    /// Checks if the entry shows up in any of the built-in Pokédex.
    /// </summary>
    public bool IsInDex => DexIndex != 0;

    public override int AbilityCount => 3;
    public override int GetIndexOfAbility(int abilityID) => abilityID == Ability1 ? 0 : abilityID == Ability2 ? 1 : abilityID == AbilityH ? 2 : -1;
    public override int GetAbilityAtIndex(int abilityIndex) => abilityIndex switch
    {
        0 => Ability1,
        1 => Ability2,
        2 => AbilityH,
        _ => throw new ArgumentOutOfRangeException(nameof(abilityIndex), abilityIndex, null),
    };

    private const int TM = 0x2C;
    private const int CountTM = 230;
    private const int ByteCountTM = (CountTM + 7) / 8;

    public bool GetIsLearnTM(int index)
    {
        if ((uint)index >= CountTM)
            return false;
        return (Data[TM + (index >> 3)] & (1 << (index & 7))) != 0;
    }

    public void SetIsLearnTM(int index, bool value)
    {
        if ((uint)index >= CountTM)
            return;
        if (value)
            Data[TM + (index >> 3)] |= (byte)(1 << (index & 7));
        else
            Data[TM + (index >> 3)] &= (byte)~(1 << (index & 7));
    }

    public void SetAllLearnTM(Span<bool> result)
    {
        var moves = MachineMoves;
        var span = Data.Slice(TM, ByteCountTM);
        for (int index = CountTM - 1; index >= 0; index--)
        {
            if ((span[index >> 3] & (1 << (index & 7))) != 0)
                result[moves[index]] = true;
        }
    }

    public bool IsRecordPermitted(int index) => false; // Game never sets these flags, as TMs are infinite use.

    private const int COUNT_RECORD_BASE = 200; // Up to 200 TM flags, but not all are used.
    private const int COUNT_RECORD_DLC = 104; // 13 additional bytes allocated for DLC1/2 TM Flags
    public ReadOnlySpan<ushort> RecordPermitIndexes => MachineMoves;
    public int RecordCountTotal => COUNT_RECORD_BASE + COUNT_RECORD_DLC;
    public int RecordCountUsed => CountTM;

    /// <summary>
    /// Technical Machine moves corresponding to their index within TM bitflag permissions.
    /// </summary>
    public static ReadOnlySpan<ushort> MachineMoves =>
    [
        029, 337, 473, 249, 046, 347, 092, 086, 812, 280,
        339, 157, 058, 424, 423, 113, 182, 612, 408, 583,
        422, 332, 009, 008, 242, 412, 129, 091, 007, 014,
        115, 104, 034, 400, 203, 317, 446, 126, 435, 331,
        352, 202, 019, 063, 282, 341, 097, 120, 196, 315,
        219, 414, 188, 434, 416, 038, 261, 442, 428, 248,
        421, 053, 094, 076, 444, 521, 085, 257, 089, 250,
        304, 083, 057, 247, 406, 710, 398, 523, 542, 334,
        404, 369, 417, 430, 164, 528, 231, 191, 390, 399,
        174, 605, 200, 018, 269, 056, 377, 127, 118, 441,
        527, 411, 526, 394, 059, 087, 370,
    ];

    public override int BaseEXP { get => ReadUInt16LittleEndian(Data[0x4C..]); set => WriteUInt16LittleEndian(Data[0x4C..], (ushort)value); }
    public ushort AlphaMove { get => ReadUInt16LittleEndian(Data[0x4E..]); set => WriteUInt16LittleEndian(Data[0x4E..], value); }

    public int PlusCountTotal => (33 + 12) * 8; // 360
    public int PlusCountUsed => 247;

    // Set by Seed of Mastery or Alpha Move granted
    public static ReadOnlySpan<ushort> PlusMoves =>
    [
        007, 008, 009, 014, 016, 017, 018, 019, 022, 029,
        033, 034, 036, 038, 039, 040, 042, 043, 044, 045,
        046, 048, 052, 053, 054, 055, 056, 057, 058, 059,
        060, 061, 063, 064, 071, 073, 074, 075, 076, 077,
        078, 079, 081, 083, 084, 085, 086, 087, 088, 089,
        091, 092, 093, 094, 095,      098, 100, 103, 104,
        105, 106, 108, 109, 113, 114, 115, 116, 118, 120,
        122, 126, 127, 129, 133, 137, 141, 150, 151, 153,
        157, 162, 163, 164, 172, 174, 182, 183, 188, 191,
        192, 195, 196, 197, 200, 202, 203, 204, 205, 209,
        211, 219, 223, 224, 225, 231, 232, 234, 235, 236,
        239, 242, 245, 247, 248, 249, 250, 257, 261, 268,
        269, 273, 280, 282, 297, 304, 313, 315, 317, 319,
        328, 331, 332, 334, 337, 339, 340, 341, 344, 345,
        347, 348, 350, 352, 369, 370, 377, 390, 392, 394,
        396, 398, 399, 400, 403, 404, 405, 406, 407, 408,
        411, 412, 413, 414, 416, 417, 418, 420, 421, 422,
        423, 424, 425, 427, 428, 430, 434, 435, 436, 437,
        438, 441, 442, 444, 446, 452, 453, 457, 473, 482,
        484, 521, 523, 526, 527, 528, 529, 532, 535, 538,
        540, 542, 555, 556, 560, 564, 566, 567, 570, 571,
        573, 574, 575, 576, 577, 583, 584, 585, 586, 588,
        591, 592, 593, 594, 595, 596, 598, 601, 605, 609,
        611, 612, 613, 614, 615, 616, 617, 621, 670, 679,
        687, 693, 710, 748, 784, 812, 920,
        097, // lol
    ];

    public ReadOnlySpan<ushort> PlusMoveIndexes => PlusMoves;
}
