using System;
using System.Collections.Generic;
using System.Linq;
using pkNX.Structures;

namespace pkNX.Randomization;

public class MoveRandomizer : Randomizer
{
    private readonly IReadOnlyList<IMove> MoveData;
    private readonly IPersonalTable SpeciesStat;
    private readonly GameInfo Config;

    private GenericRandomizer<int> RandMove;
    internal MovesetRandSettings Settings = new();

    public MoveRandomizer(GameInfo config, IReadOnlyList<IMove> moves, IPersonalTable t)
    {
        Config = config;
        var maxMoveId = config.MaxMoveID;
        MoveData = moves;
        SpeciesStat = t;
        RandMove = new GenericRandomizer<int>(Enumerable.Range(1, maxMoveId - 1).ToArray());
    }

    public override void Execute() => throw new Exception("Shouldn't be called.");

    public static ReadOnlySpan<int> FixedDamageMoves => [49, 82];

    public void Initialize(MovesetRandSettings settings, int[] bannedMoves)
    {
        Settings = settings;

        var banned = new List<int>();
        banned.AddRange(Legal.Taboo_Moves.Concat(Legal.Z_Moves).Concat(Legal.Max_Moves));
        if (Settings.BanFixedDamageMoves)
            banned.AddRange(FixedDamageMoves);
        banned.AddRange(bannedMoves);

        Settings.BannedMoves = banned.ToArray();

        var all = Enumerable.Range(1, Config.MaxMoveID - 1);
        var moves = all.Except(banned);
        RandMove = new GenericRandomizer<int>(moves.ToArray());
    }

    public int[] GetRandomLearnset(int index, int movecount) => GetRandomLearnset(SpeciesStat[index], movecount);

    public int[] GetRandomLearnset(IPersonalType Types, int movecount)
    {
        var oldSTABCount = Settings.STABCount;
        Settings.STABCount = (int)(Settings.STABPercent * movecount / 100);
        int[] moves = GetRandomMoveset(Types, movecount);
        Settings.STABCount = oldSTABCount;
        return moves;
    }

    public int[] GetRandomMoveset(int index, int movecount = 4) => GetRandomMoveset(SpeciesStat[index], movecount);

    public int[] GetRandomMoveset(IPersonalType Types, int movecount = 4)
    {
        int loopctr = 0;
        const int maxLoop = 666;

        int[] moves;
        do { moves = GetRandomMoves(Types, movecount); }
        while (!IsMovesetMeetingRequirements(moves, Types, movecount) && loopctr++ <= maxLoop);

        return moves;
    }

    private int[] GetRandomMoves(IPersonalType Types, int movecount = 4)
    {
        int[] moves = new int[movecount];
        int i = 0;
        if (Settings.STAB)
        {
            for (; i < Settings.STABCount; i++)
                moves[i] = GetRandomSTABMove(Types);
        }

        for (; i < moves.Length; i++) // remainder of moves
            moves[i] = RandMove.Next();
        return moves;
    }

    private int GetRandomSTABMove(IPersonalType types)
    {
        int move;
        int ctr = 0;
        do { move = RandMove.Next(); }
        while (!types.IsType((Types)MoveData[move].Type) && ctr++ < RandMove.Count);
        return move;
    }

    private bool IsMovesetMeetingRequirements(int[] moves, IPersonalType types, int count)
    {
        if (Settings.DMG && Settings.DMGCount > moves.Count(move => MoveData[move].Category != 0))
            return false;

        if (Settings.STAB)
        {
            var stabCt = moves.Count(move => types.IsType((Types)MoveData[move].Type));
            if (stabCt < Settings.STABCount)
                return false;
        }

        if (moves.Any(Settings.BannedMoves.Contains))
            return false;

        return moves.Distinct().Count() == count;
    }

    public void ReorderMovesPower(IList<int> moves) => ReorderMovesPower(moves, MoveData);

    private static void ReorderMovesPower(IList<int> moves, IReadOnlyList<IMove> movedata)
    {
        var data = moves.Select((Move, Index) => new { Index, Move, Data = movedata[Move] });
        var powered = data.Where(z => z.Data.Power > 1).ToList();
        var indexes = powered.ConvertAll(z => z.Index);
        var order = powered.OrderBy(z => z.Data.Power * Math.Max(1, (z.Data.HitMin + z.Data.HitMax) / 2m)).ToList();

        for (var i = 0; i < order.Count; i++)
            moves[indexes[i]] = order[i].Move;
    }

    private static readonly int[] firstMoves =
    [
        1,   // Pound
        40,  // Poison Sting
        52,  // Ember
        55,  // Water Gun
        64,  // Peck
        71,  // Absorb
        84,  // Thunder Shock
        98,  // Quick Attack
        122, // Lick
        141, // Leech Life
    ];

    private static readonly GenericRandomizer<int> first = new(firstMoves);

    public static int GetRandomFirstMoveAny()
    {
        first.Reset();
        return first.Next();
    }

    public int GetRandomFirstMove(int index) => GetRandomFirstMove(SpeciesStat[index]);

    public int GetRandomFirstMove(IPersonalType types)
    {
        first.Reset();
        int ctr = 0;
        int move;
        do
        {
            move = first.Next();
            if (++ctr == firstMoves.Length)
                return move;
        } while (!types.IsType((Types)MoveData[move].Type));
        return move;
    }

    public bool SanitizeMovesetForBannedMoves(int[] moves, int index)
    {
        bool updated = false;
        for (int m = 0; m < moves.Length; m++)
        {
            if (!Settings.BannedMoves.Contains(moves[m]))
                continue;
            updated = true;
            moves[m] = GetRandomFirstMove(index);
        }

        return updated;
    }
}