using System;
using System.Diagnostics;
using System.Linq;

namespace pkNX.Structures;

public class MegaEvolutionSet
{
    private readonly byte[] Data;
    private const int OFS_FORM = 0;
    private const int OFS_METHOD = 2;
    private const int OFS_ARGUMENT = 4;
    public const int SIZE = 8;

    public MegaEvolutionSet(byte[] data, int index)
    {
        Debug.Assert(data.Length % SIZE == 0);
        Data = new byte[SIZE];
        Array.Copy(data, index*SIZE, Data, 0, SIZE);
    }

    public static MegaEvolutionSet[] ReadArray(byte[] data)
    {
        var count = data.Length / SIZE;
        var result = new MegaEvolutionSet[count];
        for (int i = 0; i < count; i++)
            result[i] = new MegaEvolutionSet(data, i);
        return result;
    }

    public static byte[] WriteArray(MegaEvolutionSet[] data)
    {
        return data.SelectMany(z => z.Write()).ToArray();
    }

    public int ToForm
    {
        get => BitConverter.ToUInt16(Data, OFS_FORM);
        set => BitConverter.GetBytes((ushort) value).CopyTo(Data, OFS_FORM);
    }

    public int Method
    {
        get => BitConverter.ToUInt16(Data, OFS_METHOD);
        set => BitConverter.GetBytes((ushort)value).CopyTo(Data, OFS_METHOD);
    }

    public int Argument
    {
        get => BitConverter.ToUInt16(Data, OFS_ARGUMENT);
        set => BitConverter.GetBytes((ushort)value).CopyTo(Data, OFS_ARGUMENT);
    }

    public void Clear()
    {
        for (int i = 0; i < Data.Length; i++)
            Data[i] = 0;
    }

    public byte[] Write() => (byte[])Data.Clone();

    public void Write(byte[] data, int index) => Data.CopyTo(data, index * SIZE);

    public void RemoveRestrictions()
    {
        if (Method != (int) MegaEvolutionMethod.None)
            Method = (int) MegaEvolutionMethod.NoRequirement;
    }
}